High Level Feasibility Study for the Remediation of Cadshaw Embankment and Retaining Wall

HIGH LEVEL FEASIBILITY STUDY FOR THE REMEDIATION OF CADSHAW EMBANKMENT AND RETAINING WALL

PREPARED BY: Wilde Consultants Ltd DATE: October 2019 WILDE REF: 762-014-R01/P2 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

HIGH LEVEL FEASIBILITY STUDY FOR THE REMEDIATION OF CADSHAW EMBANKMENT & RETAINING WALL Wall Name: Cadshaw

Road Name: A666 Blackburn Road

Location: E 370420, N 418273 (Grid Ref.) (SD704182)

BwDBC Ref: 930.01

Structure Type: Embankment & Retaining Wall

REPORT CONTROL SHEET

Prepared Version Date Status Checked Approved By

October D Freeman D Freeman P1 First Issue O Hawkes 2019 CEng MICE CEng MICE

October Second D Freeman D Freeman P2 O Hawkes 2019 Issue CEng MICE CEng MICE

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CONTENTS

REPORT CONTROL SHEET i

CONTENTS ii

LOCATION PLAN iii

1.0 EXECUTIVE SUMMARY 1

2.0 INTRODUCTION 4

3.0 DESCRIPTION OF EXISTING STRUCTURE 5

4.0 PREVIOUS SITE INVESTIGATION 7

5.0 AVAILABLE INFORMATION 9

6.0 EXISTING UNDERGROUND SERVICES 10

7.0 LAND OWNERSHIP 11

8.0 INDICATIVE DESIGN OPTIONS AND COST ESTIMATES 12

9.0 RECOMMENDATIONS 28

10.0 HEALTH AND SAFETY 30

11.0 TRAFFIC MANAGEMENT 31

12.0 FURTHER WORK REQUIRED 32

13.0 ENVIRONMENTAL IMPACT CONTROL MEASURES AND CUSTOMER CARE ISSUES 33

APPENDIX A – EXISTING ARRANGEMENT A

APPENDIX B – OPTIONS SKETCHES B

APPENDIX C – STATUTORY UNDERTAKERS INFORMATION C

APPENDIX D – LAND OWNERSHIP DETAILS D

APPENDIX E – SKETCH BY BwDBC INDICATING EXTENT OF PEAT E

APPENDIX F – C3 ESTIMATES F

APPENDIX G. PHOTOGRAPHS TAKEN ON SITE G

ii CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

LOCATION PLAN

iii

CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

1.0 EXECUTIVE SUMMARY

1.1 Wilde Consultants Ltd have been engaged by Blackburn with Darwen Borough Council (BwDBC) to prepare a high-level feasibility report to consider options for the replacement or refurbishment of the highway and retaining wall adjacent to Cadshaw Bridge on the A666 south of Darwen.

1.2 The A666 runs approximately South to North and is the primary route connecting the towns of Bolton and Darwen. Cadshaw Bridge, which carries the A666 over Cadshaw Brook is located approximately 2.5km south of Darwen town centre and 10km North of Bolton town centre.

1.3 Directly to the North of the bridge, approach structures support the highway. The comprise a masonry retaining wall to the East side and an embankment to the West side.

1.4 The highway, retaining wall and embankment to the north of Cadshaw bridge have been found to be in POOR condition, with settlement and break-up of the carriageway surfacing alongside bulging and local collapse of the retaining wall. The cause of this degradation is the presence of a thick “localised layer of alluvial peat and soft alluvium with peat inclusions beneath the highway” (Capita, 2019), this is discussed in detail in the Ground Investigation Report produced by Capita, August 2019.

Monthly safety inspections undertaken by BwCBC have highlighted the deteriorating condition of the retaining wall over a relatively short period of time.

1.5 A site walkover was conducted by Wilde Consultants on the 3rd October 2019 and found the retaining wall and carriageway surfacing to be in POOR condition with numerous significant defects.

1.6 The aims of this feasibility report are: • to consider high level options for the refurbishment or replacement of the highway and embankment retaining wall • to provide high level cost estimates • to highlight further works required to deliver the preferred option.

1.7 The following options have been considered;

Option 1 – Dig out all of the potentially compressible materials including alluvial peat, alluvium and glacial till, and back fill with engineering fill material.

Option 2 – Inject a ground stabilising resin to improve the bearing capacity of the embankment and install a sheet pile wall in front of the existing masonry retaining wall.

Option 3 – Inject a ground stabilising resin to improve the bearing capacity of the embankment and install ground anchors/soil nails to support the existing wall.

Option 4 – Inject a ground stabilising resin to improve the bearing capacity of the embankment and construct a gravity retaining wall in front of the existing masonry wall.

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Option 5 – Inject a ground stabilising resin to improve the bearing capacity of the embankment and regrade the east embankment with imported material to make the existing retaining wall redundant.

Option 6 – Install a piled slab to support the carriageway above the weak strata

Option 7 – A do minimum approach where no remedial works are specified and the wall/highway are allowed to degrade in time.

1.8 Option 3 – Inject a ground stabilising resin to improve the bearing capacity of the embankment and install a reinforced concrete facing wall soil nailed into the stabilised embankment, to support the existing retaining wall is recommended due to the following; • Can be constructed mostly under single lane closure traffic management. • Minimal land take required when casting an RC facing against the existing wall. • Service diversions not required. • Minimal temporary works or establishment of plant required to facilitate soil nailing.

A summary of the various options presented in this report can be found in the following table.

Option Brief Description Estimated Service Approximate Cost Diversions Land Take Dig out all unsuitable material Yes 1 £1,300,000.00 None and back fill with (+£600,000.00) imported fill. Stabilise the embankment using 2 resin injection & £815,000.00 None <100m2 install sheet pile wall. Stabilise the embankment using resin injection & 3 install £925,000.00 None Minimal Gabion/RC facing wall soil nailed into embankment. Stabilise the embankment using 4 resin injection & £920,000.00 None ~200m2 install gravity retaining structure. Stabilise the embankment using resin injection and 5 regrade the east £855,000.00 None ~600m2 embankment burying the existing wall.

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Install pile supported slab to Yes 6 £570,000.00 None support the (+£600,000.00) carriageway. 7 Do nothing. NA NA NA

1.9 It is estimated that it will take 36 weeks to complete the proposed works.

1.10 The estimated construction cost of Option 3 is £925,000.00

1.11 A full list of recommended Further Work is included in Section 12 of this report.

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2.0 INTRODUCTION 2.1 Wilde Consultants Ltd have been engaged by Blackburn with Darwen Borough Council to prepare a high-level feasibility report to consider options for the refurbishment of the A666 adjacent to Cadshaw Bridge and the adjacent embankment retaining wall.

2.2 The existing embankment and retaining wall have had no significant remedial works undertaken to date, and is estimated to be ~170 years old.

The wall and highway are in a POOR condition, see photos taken on site by Wilde Consultants in appendix G of this report.

BwDBC have provided the results of site investigations consisting of a desk top study and SSL exploratory holes were undertaken in 2019. The results of these are discussed in the Ground Investigation Report.

These results are discussed and summarised in section 3.10 and 4.0.

2.3 The aims of this feasibility report are: • to consider high level options for the refurbishment of the A666 and embankment retaining wall. • to provide high level cost estimates. • to highlight further works required to deliver the preferred option.

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3.0 DESCRIPTION OF EXISTING STRUCTURE

3.1 Cadshaw Bridge is a single span masonry arch spanning South to North. The bridge carries the A666 Blackburn Road over Cadshaw Brook approximately 2.5km south of Darwen town centre. Immediately north of the bridge the highway is raised above local ground level to the level of the bridge deck by an embankment, the east side of this embankment is supported by a masonry retaining wall.

3.2 The masonry retaining wall to the north east of Cadshaw bridge is approximately 63m long. The retaining wall and carriageway surfacing are in POOR condition, with multiple significant defects observed indicating differential settlement of the embankment. For the purpose of this report, the site refers to a length of highway approximately 63m long to the north of Cadshaw bridge, encompassing the retaining wall the east to and the embankment slope to the west.

3.3 The retained height of the wall varies along its length, from available topographical information of the site, the maximum retaining height is approximately 1700mm. The wall in in a POOR condition with significant bulging along its length and loose masonry.

3.4 There exists a footway on the east side of the carriageway adjacent to the retaining wall, the footway surfacing is in POOR condition and is subsiding in areas.

3.5 The retaining wall is topped with an 800mm high masonry parapet, this parapet is in POOR condition and exhibiting rotation away from the carriageway and significant bulging.

3.6 The length of the retaining wall and embankment considered in this report is approximately 63m.

3.7 Highway drainage gullies are present on both sides of the carriageway along the full length of the site, the location of the outfall from these inlets is not known.

3.8 At its south end the retaining wall returns into and abuts the north east wing wall of Cadshaw bridge, no positive connection between the two structures was observed during a site walkover by Wilde Consultants.

3.9 A recent topographical survey of the site undertaken by Paragon Surveys and provided by BwDBC indicates that the west embankment, at which no retaining structure is present, slopes away from the carriageway with an approximately 1:2 batter, this slope appears stable and is vegetated all over. However, a local area of subsidence of the carriageway surfacing, on the west side was noted on site.

3.10 The results of ground investigations undertaken by Sub Surface North West Limited, specified by Capita and provided by BwDBC were made available at the time of writing.

A layer of peat up to ~4.0m thick was detected directly below the carriageway this is though to be partly responsible for the ongoing settlement of material at carriageway level.

The bore hole logs from 4 No. boreholes carried out on the site show that at between approximately 257m AOD and 260.5m AOD, around ~9.0m below the existing surface level of the carriageway, dense ground with a relatively high SPT N value is encountered on site.

5 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

However, strata between this level and existing ground level typically have low SPT N values, ranging from 2 – 10.

These results show that the highway sits directly atop weak and compressible strata with a low bearing capacity.

Furthermore, these results show the retaining wall retains loose to very loose strata with a low theoretical angle of repose resulting in high lateral forces on the wall.

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4.0 PREVIOUS SITE INVESTIGATION

4.1 No previous remedial works are known to have been undertaken to the retaining wall.

4.2 Geotechnical site investigations were carried out on behalf of BwDBC in early 2019 by Sub Surface North West Limited consisting of: • 4 No. dynamic sampling boreholes • 4 No. rotary follow-on boreholes • 5 No. trail pits • In situ testing • Geotechnical laboratory testing • Contamination analysis • Installation of standpipes followed by groundwater and ground gas monitoring

A factual report detailing the results of the above investigations, including borehole data logs, was provided at the time of writing.

4.3 An interpretative ground investigation report produced by Capita dated August 2019 discusses the findings of the above site investigations. The following table is taken directly from this report and summarises the various strata detected on site.

Material Type Strata Level (Top) Level (Base) (m bgl) (m bgl)

Asphalt / Bituminous Made Ground – 0.00 0.30 – 0.45 Macadam Highway

Grey Gravelly silt SAND Made Ground – 0.30-0.45 1.60-4.50 with clay pockets and low Embankment to medium sandstone cobble content or soft grey brown silty sandy gravelly CLAY with medium cobble content of mixed lithologies. Very soft brown and dark Made Ground - 0.00 0.30-0.50 silty sandy gravelly CLAY Topsoil with low cobble content and occasional pockets of peat. Light orangish brown Natural Topsoil 0.00 0.50 clayey silty gravelly SAND

Very soft to firm brown Alluvium 0.60 – 5.10 1.10 – 8.10 and grey silty sandy gravelly CLAY with low cobble content and occasional pockets of peat.

7 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

Very soft to soft spongy Alluvial Peat 0.50 – 2.80 0.80 – 6.95 dark brown pseudo- fibrous PEAT with intact plant remains and localised clay bands Initially soft, becoming Glacial Till 0.80 – 8.10 2.00 – 11.80 firm to stiff, brown and grey slightly sandy gravelly CLAY with medium cobble content or loose becoming dense silty sandy GRAVEL with low cobble content Weak thinly bedded grey Rossendale 2.00 – 11.80 >18.00 MUDSTONE/SILTSTONE Formation with strong thinly bedded light grey SANDSTONE and rare weak thinly laminated black COAL

4.4 A topographical survey of the site was produced by Paragon Surveys in June 2019 on behalf of BwDBC.

4.5 Services in the East Footway and West Embankment have previously been positively identified by means of trial holes. Services present are as follows:

East Footway • ENWL COMS VODAFONE DUCT • VIRGIN MEDIA • BT OPEN REACH • ASSUMED HIGHWAYS DRAINAGE

West Embankment • 6.6KV ELECTRIC CABLE • BT OPENREACH • ASSUMED HIGHWAS DRAINAGE

The location and depth of these services is shown in drawing CS096582-CAP-VUT- ZZ-SU-Z-0004 dated 02/10/19 included in Appendix C of this report.

4.6 A C3, cost of service diversions, estimate was obtained by Blackburn and Darwen Council in accordance with SA 10/05.

The total cost of a temporary diversion of all services onto adjacent land was estimated by the statutory undertakers to be £613,752.14.

The is considered to be a significant cost and will likely prove to be prohibitive to any options presented in this report which involve the temporary or permanent diversion of services.

8 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

5.0 AVAILABLE INFORMATION Previous Assessments 5.1 No previous assessments of the retaining wall were available at the time of writing.

Previous Inspections

5.2 A previous inspection report of Cadshaw Bridge dated 2018 was provided by Blackburn and Darwen Borough Council (BwDBC), “moderate to minor bulging” was noted to the North East wingwall, adjacent to the existing retaining structure considered in this report.

It is recommended that this be monitored for further deterioration during the works.

Note that remedial works to the bridge structure are outside the scope of this report.

5.3 The following Information was made available by BwDBC

• Land ownership information

• Statutory undertaker service plans

• A C3 estimate for the diversion of all services in Cadshaw Embankment

• Topographical Survey – By Paragon Surveys

• An Ordnance Survey tile of the site and surrounding area

• Sketch showing possible extent of the peat layer, included in appendix E. It is recommended that additional site investigations be carried out to more accurately determine the extent of the peat layer.

• Ground Investigation Factual Report (Ian Farmer Associates, June 2019, Doc Ref. 6718)

• Ground Investigation Report (Capita, August 2019, Doc Ref. CS-096582- CAP-VGT-ZZ-RP-GE-0002, Rev P01)

• Traffic Count Data for the A666 at Cadshaw Embankment recorded by BwDBC in October 2019.

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6.0 EXISTING UNDERGROUND SERVICES

6.1 Statutory undertaker’s plans for the main utilities (Gas, Electricity, Water, Telephone and Sewers) have been checked to establish if their apparatus may be affected by this scheme. See Appendix C.

6.2 Statutory undertaker’s plans show an ENWL comms Vodafone low voltage cable in the east footway.

6.3 Statutory undertaker’s plans show a BT services cable in the east footway.

6.4 Statutory undertaker’s plans show a 6.6kV electricity cable in the west embankment.

6.5 Statutory undertaker’s plans show no gas services in the vicinity of Cadshaw Bridge and the North Embankment.

6.6 Statutory undertaker’s plans show Virgin Media services in the east footway.

6.7 A C3 Estimate for the temporary diversion of existing services onto adjacent land was obtained, the total C3 estimate for the diversion of all existing services vicinity of the proposed works is £613,752.14.

This C3 Estimate is included in Appendix F of this report.

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7.0 LAND OWNERSHIP

7.1 The ownership of land adjacent to Cadshaw Bridge is as indicated on the plan included in Appendix D.

7.2 The land to the West of the highway is registered to UNITED UTILITIES WATER LIMITED care of The Legal Manager Grasmere House Lingley Mere Business Park Lingley Green Avenue Great Sankey Warrington WA5 3LP

7.3 The land to the East of the highway is registered to UNITED UTILITIES WATER LIMITED care of The Legal Manager Grasmere House Lingley Mere Business Park Lingley Green Avenue Great Sankey Warrington WA5 3LP

7.6 Most of the options considered within this feasibility report will require temporary and permanent land take.

Note that challenge fund awards cannot be used to procure privately owned land, upon selection of a preferred option, BwDBC should engage with the relevant land owners at the earliest possibility to discuss arrangements for any temporary or permanent land take required of the scheme.

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8.0 INDICATIVE DESIGN OPTIONS AND COST ESTIMATES

8.1 The following options have been considered;

Option 1 – Dig out all of the potentially compressible materials including alluvial peat, alluvium and glacial till, and back fill with engineered fill material.

Option 2 – Inject a ground stabilising resin to improve the bearing capacity of the embankment and install a sheet pile wall Infront of the existing masonry retaining wall.

Option 3 – Inject a ground stabilising resin to improve the bearing capacity of the embankment and install a reinforced concrete facing/gabion basket wall ground anchored into the stabilised embankment, to support the existing retaining wall.

Option 4 – Inject a ground stabilising resin to improve the bearing capacity of the embankment and construct a gabion basket retaining wall in front of the existing masonry wall.

Option 5 – Inject a ground stabilising resin to improve the bearing capacity of the embankment, regrade the west embankment using imported material to make the existing retaining wall redundant.

Option 6 - Install a piled slab to support the carriageway above the weak strata.

Option 7 – A do minimum approach where no remedial works are specified and the wall/highway are allowed to degrade in time.

8.2 The cost estimates exclude the following:

• Legal fees • Permanent/temporary land take costs • Inflation • Site Investigation costs • Geotechnical testing • Ecological Surveys • Further topographical Surveying • VAT • Consultants design fees • Further Boreholes and Ground Investigations

8.3 The main challenges to be overcome during the construction phase are as follows:

• Presence of services beneath the east footway and west embankment and the high cost of diverting these.

• Steep slope on the east embankment would require significant temporary works to provide plant access to the base of the wall.

• Mature trees and vegetation close to the base of the existing wall will require clearing for most options.

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• Low SPT N values of strata which form the embankment will make founding gravity retaining structures and temporary works difficult.

• A lengthy full road closure would not be practicable given the prominence of this route into Darwen. Furthermore, partial collapse of a retaining wall on the most direct diversion route means that putting additional traffic on this route is an unfavourable option (Refer to Grange Brook Feasibility study for further details).

• The solution will need to address the presence of a peat layer below the carriageway to prevent future subsidence.

• The suspected presence of Himalayan Balsam on the east embankment, the contractor must be familiar with and adhere to, the requirements of the wildlife and countryside act 1981. The presence of invasive species is to be confirmed by an ecology report.

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8.3 OPTION 1: Dig out all of the materials unsuitable for use as fill including alluvial peat, alluvium and glacial till with low SPT N values, and back fill with engineered fill material.

• Option 1 would comprise the excavation of all unsuitable material unable to support the above highway, and back filling with a specified engineering fill such as 6F2 material. The depth of excavation required to remove all peat would be in excess of 9.0m below the level of the carriageway.

• The existing retaining wall would be taken down and rebuilt. A new retaining structure could be constructed of gabion baskets or other structural forms.

• Removal and replacement of the poor-quality compressible material would allow the carriageway surface to be re-laid in its existing location without being susceptible to future settlement.

• This option would require a full closure of the highway for the duration of the works.

• A high-level estimate of the quantity of material to be removed is in the order of 5000m3 which equates to somewhere in the region of 550 lorry loads of site won material to be taken away and 550 lorry loads of engineering fill to be imported to site.

• In order to more accurately determine the volume of material that would need to be excavated, further boreholes would be required to determine an accurate extent and thickness of the peat layer.

• No land take would be required by this option as a new gravity retaining structure could be constructed on the line of the existing wall once the embankment material had been excavated.

• No vegetation removal would be required for this option.

The suggested construction sequence would be as follows; 1. Set up road closure and associated diversion routes. 2. Remove existing carriageway surfacing, locate and temporarily divert any services onto adjacent United Utilities owned land. 3. Excavate all unsuitable material from the embankment and from below the embankment, remove all site won material from the site. 4. Deconstruct existing retaining wall once retained material is excavated, rebuild or replace wall with new gravity retaining structure along the original alignment of the wall. 5. Backfill excavation with imported engineering fill, compressing layers of fill in accordance with MCHW specifications. 6. Relay carriageway.

Estimated Construction Cost £1,275,000.00 Anticipated construction period 45 weeks

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Advantages • No permanent land take required. • Minimal vegetation removal required.

Disadvantages • Long closure of the highway required. • Significant volumes of material to be removed from and imported to site resulting in large numbers of HGV movements associated with the works. • High cost of moving the site won and imported material to and from site. • Temporary diversion of services is required during the excavation.

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8.4 OPTION 2: Inject a ground stabilising resin to improve the bearing capacity of the embankment and install a sheet pile wall Infront of the existing masonry retaining wall.

See Appendix B, options sketches 762-014-005

Option 2 would comprise the following: • Installation of a sheet pile wall in front of the existing masonry retaining wall.

• Improving the bearing capacity of the peat and alluvial deposits by injecting an expanding resin-based material directly into the strata from existing carriageway level, this can be installed around the services without temporary diversion.

• The gap between the new sheet pile wall and existing masonry wall would be backfilled and the existing parapet taken down and either rebuilt or replaced with a suitable vehicle restraint system (VRS).

• No service diversions or lengthy full closure of the highway would be required during the works.

• The benefit of sheet piling is that minimal temporary works on the embankment would be required to install the sheet piles, a pile press could be mobilised at the north end of the wall and work its way south, without the need to install a piling platform along the full length of the wall, Figure 8.1 shows a piling press installing sheet piles along a highway embankment with the highway above, pile lengths could be in excess of 15m if required.

• Up to 11 mature trees shown on the topographical survey would need to be removed from the embankment.

• <100m2 of permanent land take required.

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Figure 8.1, Sheet piling into an embankment adjacent to a highway above using a pile press. The suggested construction sequence would be as follows; 1. Set up traffic management: i. Single lane closure to allow installation of resin-based material into west embankment and west side of the carriageway. ii. Single lane closure to allow installation of resin-based material into east embankment, east footway and east side of the carriageway. iii. Night time full closures to allow stabilisation through the central width of the carriageway. iv. Single lane closure to facilitate installation of sheet pile wall and VRS. 2. Install resin-based material into embankment through carriageway surfacing, material to be installed to the west and east of the carriageway, see sketch 762- 014-005 for suggested extent. 3. Site testing to ensure successful installation of resin. 4. Construct temporary works, piling platform, to facilitate installation of sheet pile wall. 5. Install sheet piles in front of the existing masonry retaining wall using a Pile Press working from North to South. 6. Backfill between sheet pile wall and existing masonry wall. 7. Remove temporary works. 8. Take down masonry parapet. 9. Replace carriageway and footway surfacing. 10. Install suitable vehicle restraint system. 11. Reopen highway.

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Estimated Construction Cost £815,000.00 Anticipated construction period 36 weeks

Advantages • New sheet pile structure provided with 120-year design life. • Majority of works can be completed under single lane closure with traffic management. • Low volumes of back fill and imported materials required to be brought to site, likely the lowest number of HGV movements required for the scheme of all the options considered. • No service diversions required. • Minimal temporary works required as a piling platform would only be required to install the first few sheet piles.

Disadvantages • High cost of sheet piling. • Some permanent land take required.

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8.5 OPTION 3: Inject a ground stabilising resin to improve the bearing capacity of the embankment and install a facing wall, soil nailed into the stabilised embankment, to support the existing retaining wall.

See Appendix B, options sketch 762-014-006 & 762-014-007

Option 3 would comprise the following;

• Improving the bearing capacity of the peat and alluvial deposits by injecting an expanding resin-based material directly into the strata from existing carriageway level.

• Install ducts through the existing wall allow ground anchors to be installed through it.

• Either cast a reinforced concrete facing against the existing masonry retaining wall or place gabion baskets in front of it, to support the existing wall. Figure 8.2 shows ground anchors being pushed through gabion baskets to provide additional over turning resistance. Sketches of both gabion baskets and reinforced concrete facings have been provided, however a reinforced concrete facing is considered the preferred option.

• Soil nail into the stabilised embankment through the existing masonry retaining wall to anchor the new reinforced concrete/gabion basket facing.

• Up to 11 mature trees shown on the topographical survey would need to be removed from the east embankment.

• <100m2 of permanent land take would be required.

Figure 8.2, Ground anchors being installed through a gabion basket retaining wall to provide additional over turning resistance.

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The suggested construction sequence would be as follows; 1. Set up traffic management: i. Single lane closure to allow installation of resin-based material into west embankment and west side of the carriageway. ii. Single lane closure to allow installation of resin-based material into east embankment, east footway and east side of the carriageway. iii. Night time full closures to allow stabilisation through the central width of the carriageway. iv. Single lane closure to facilitate installation of sheet pile wall and VRS.

2. Inject resin stabiliser into peat layer from existing carriageway level. 3. Construct temporary plant access route on the east embankment at the foot of the existing retaining wall, include some vegetation removal. 4. Install ducts through existing retaining wall. 5. Place gabion baskets/cast concrete facing directly in front of retaining wall. 6. Install ground anchors through existing retaining wall into improved ground to anchor new wall facing. 7. Deconstruct temporary works access route. 8. Take down and rebuild/replace parapet. 9. Relay carriageway and footway surfacing.

Estimated Construction Cost £925,000.00 Anticipated construction period 36 weeks

Advantages • No service diversions required. • Majority of works can be completed under single lane closure with traffic management. • Concrete can be cast directly against the existing face of the wall.

Disadvantages • Significant temporary works and vegetation removal required along the full length of the foot of the retaining wall to facilitate soil nailing & installation of gabion baskets. • High cost associated with soil nailing and setting up of temporary works. • Some durability concerns regarding gabion baskets adjacent to watercourses. • Large volume of materials required to be brought to site to fill and found gabions if selected.

20 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

8.6 OPTION 4: Inject a ground stabilising resin to improve the bearing capacity of the embankment and construct a gravity retaining structure in front of the existing masonry wall.

See Appendix B, options sketch 762-014-008

Option 4 would comprise the following;

• Improving the bearing capacity of the peat and alluvial deposits by injecting an expanding resin-based material directly into the strata from existing carriageway level. Figure 8.3 shows resin injection ground stabilisation works underway under single lane closure conditions.

• Improve the bearing capacity of the east embankment where the new gravity retaining structure is to be founded, current ground conditions are likely not appropriate to support a new gravity retaining structure.

• Removal of vegetation from embankment and construction of haul road to facilitate installation of a new wall in front of existing.

• Construction of a gravity retaining structure on the east embankment in front of the existing retaining wall.

• Backfilling between the existing masonry retaining wall and new gravity retaining structure.

• Up to 11 mature trees shown on the topographical survey would need to be removed from the east embankment.

• ~>200m2 of permanent land take would be required.

Figure 8.3, Resin injection ground stabilisation works to improve the ground bearing capacity of strata below a highway, note that the works are taking place under single lane closure conditions.

21 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

2. Inject resin stabiliser into peat layer from existing carriageway level. 3. Conduct vegetation removal and construct temporary access route on west embankment. 4. Excavate the new retaining structures foundation footprint in embankment and install foundations. 5. Construct new gravity retaining structure on new foundations. 6. Take down existing parapet and back fill between new and existing retaining walls. 7. Install new vehicle restraint system. 8. Resurface carriageway.

Estimated Construction Cost £915,000.00 Anticipated construction period 36 weeks

Advantages • Low cost associated with design and installation of gravity retaining structure.

Disadvantages • Significant permanent land take required to install new wall in front of existing. • New retaining structure would be designed for a significant retained height due to being founded on a sloping embankment. • Significant excavation, vegetation removal and temporary works would be required on the east embankment to facilitate installation of a new gravity retaining structure.

22 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

8.7 OPTION 5: Inject a ground stabilising resin to improve the bearing capacity of the embankment, regrade the East embankment using imported material to make the existing retaining wall redundant.

See Appendix B, options sketch 762-014-009

Option 5 would comprise the following;

• Injecting resin ground stabiliser into the embankment below the carriageway and on the east and west embankments.

• Use imported material to create a 1:2 slope on the east embankment from highway level to the small watercourse running approximately parallel with the highway.

• Install, for example, rock rolls in the watercourse at the bottom of the new slope to prevent erosion.

• At least 11 mature trees would need to be removed from the east embankment, perhaps more.

• Over 600m2 of permanent land take would be required to enable the regrading of the east embankment.

The suggested construction sequence would be as follows;

1. Set up traffic management: i. Single lane closure to allow installation of resin-based material into west embankment and west side of the carriageway. ii. Single lane closure to allow installation of resin-based material into east embankment, east footway and east side of the carriageway. iii. Night time full closures to allow stabilisation through the central width of the carriageway. iv. Single lane closure to facilitate installation of sheet pile wall and VRS. 2. Inject resin stabiliser into peat layer from existing carriageway level and west embankment. 3. Conduct vegetation removal and construct temporary access route for plant on east embankment. 4. Inject resin stabiliser into the east embankment. 5. Place imported material on to the east embankment to create new 1:2 slope up to highway level, include watercourse training works at the bottom of this slope to prevent erosion. 6. Install new vehicle restraint system or take down and rebuild existing wall parapet. 7. Resurface carriageway.

Estimated Construction Cost £850,000.00 Anticipated construction period 36 weeks

23 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

Advantages • Majority of works can be carried out under single lane closure conditions. • Low maintenance costs associated with new embankment compared to a new retaining wall.

Disadvantages • Significant volumes of imported material required to regrade the west embankment. • Significant volume of vegetation removal required on the west embankment to enable regrading of the slope. • Large area of land take required, land take is expensive and time consuming to arrange and is likely to impact the potential start date of the works.

24 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

8.8 OPTION 6: Install a piled slab to support the carriageway above the weak strata.

See Appendix B, options sketch 762-014-010

Option 6 would comprise the following;

• Installation of a piling platform on the existing embankment, this would require a full closure of the carriageway and on-site testing to ensure the piling platform provides a suitable bearing resistance for piling rigs to operate.

• Installation of CFA piles through the weak strata terminating in the Rossendale formation below, Figure 8.4 shows CFA piles being installed through an existing carriageway surfacing, note that due to the ground conditions at Cadshaw, significant temporary works and on-site testing of the temporary works will be required.

• Cast a pile supported reinforced concrete slab to carry the carriageway.

• With the piled slab in place to take traffic loading, carry out remedial works to the existing retaining wall to prevent further deterioration of the structure, remedial works could include taking down and rebuilding the existing structure, or installing a new retaining structure such as a sheet pile wall or gravity retaining structure described in options 2 and 4 respectively.

• No permanent land take or significant vegetation removal from the east embankment would be required to installed a slab under the carriageway.

Figure 8.4, Installation of CFA piles with plant operating on an existing highway. 25 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

The suggested construction sequence would be as follows; • Put road closure and associated diversion routes in place. • Install a temporary piling platform on the existing carriageway. • Test piling platform to ensure it complies with the requirements of piling plant. • Install CFA piles through the weak strata, terminating in the Rossendale formation below the carriageway. • Cast a piled slab over the piles to support the new carriageway. • Relay carriageway surfacing over the new piled slab. • Re open carriageway. • Remedial works to the retaining wall

Estimated Construction Cost £575,000.00 Anticipated construction period 45 weeks

Advantages • No permanent land take required. • Minimal working on the embankments.

Disadvantages • Full closure of the carriageway required in order to carry out piling and cast a new slab. • The cost of diverting services is considered prohibitive, therefore the area in which piling operations are permitted by service owners is likely to constrain the design of a piled slab. • Low SPT N values for ground immediately below the carriageway mean that a piling platform would be of significant depth and likely require geo-grid reinforcement in order to provide suitable bearing resistance for piling operations. • High cost of importing material to construct a large piling platform.

26 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

8.9 OPTION 7: A do minimum approach where no remedial works are specified and the wall/highway are allowed to degrade in time.

See appendix B Options Sketch 762-014-011

Option 7 would comprise the following; • Continual monitoring of the site for further deterioration of the wing wall and carriageway surfacing.

• Continued degradation of the carriageway surfacing.

• Eventual full closure of the highway when wall fails or risk of failure becomes unacceptable.

• Without any remediation differential settlement in the peat and soft alluvial layers below the carriageway will continue to degrade the carriageway surfacing and be detrimental to the condition of the retaining wall.

• No land take of vegetation removal required.

The suggested construction sequence would be as follows; 1. Regular inspections of the site to record further deterioration of the carriageway surfacing and retaining wall. 2. Closure of the carriageway after risk assessment.

Advantages • Lowest Cost Option

Disadvantages • Not considered a solution, failure of the retaining wall and further deterioration of the carriageway surfacing is inevitable.

27 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

9.0 RECOMMENDATIONS

9.1 Option 1 - Dig out all of the potentially compressible materials including alluvial peat, alluvium and glacial till, and back fill with engineering fill material is rejected due to the following; • Full road closures required for a significant length of time. • High cost of removing site won and importing fill material. • Significant environmental impact due to required number of HGV movements. • High costs of diverting services based on C3 estimate provided.

9.2 Option 2 - Inject a ground stabilising resin to improve the bearing capacity of the embankment and install a sheet pile wall Infront of the existing masonry retaining wall is rejected due to the following; • Significant cost associated with establishment of piling plant.

However, this option should be considered the “2nd Preferred” option.

9.3 Option 3 – Inject a ground stabilising resin to improve the bearing capacity of the embankment and install a gabion basket/reinforced concrete facing wall soil nailed into the stabilised embankment, to support the existing retaining wall is recommended due to the following; • Can be constructed mostly under single lane closure traffic management. • Minimal land take required when casting an RC facing against the existing wall. • Service diversions not required. • Minimal temporary works or establishment of plant required to facilitate soil nailing.

9.4 Option 4 - Inject a ground stabilising resin to improve the bearing capacity of the embankment and construct a gravity retaining structure in front of the existing masonry wall is rejected due to the following; • Significant permanent land take required to construct new retaining structure. • Significant vegetation removal and temporary works required on the embankment. • Large volume of materials required to be brought to site.

9.5 Option 5 - Inject a ground stabilising resin to improve the bearing capacity of the embankment, regrade the East embankment using imported material to make the existing retaining wall redundant is rejected due to the following; • Significant vegetation removal required on the east embankment to install regraded embankment. • High volume of imported material required to be placed on the east embankment. • Significant land take means lengthy negotiations with landowners which could impact on the scheme delivery.

9.6 Option 6 - Install a piled slab to support the carriageway above the weak strata is rejected due to the following; 28 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

• A full closure of the carriageway is required to conduct piling operations. • Large volume of materials which must be delivered to site for construction of piling platform, piles and slab. • High probability of service diversions required to facilitate piling. • Excessive works associated with creating a piling platform.

9.7 Option 7 – A do minimum approach where no remedial works are specified and the wall & highway are allowed to degrade over time is rejected due to the following; • Not a solution to the degradation of the highway and wall. • Safety concerns for the continued use of a failing structure. • Cost of a remedial scheme in the future will likely be higher if the wall & highway are allowed to degrade further.

29 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

10.0 HEALTH AND SAFETY

10.1 Any works will need to be carried out in accordance with all current Health and Safety legislation, including: -

The Construction (Design and Management) Regulations 2015

It is envisaged the construction work for all options will be more than 500-person days of construction and/or will last more than 30 days with at least 20 workers simultaneously at any point. There will therefore be a requirement to notify the HSE of the project.

The main site-specific hazards that have been identified at this stage are: -

(i) Working adjacent to highway. (ii) Working at height. (iii) Working on a restricted site. (iv) Working adjacent to a watercourse (v) Working adjacent to services

30 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

11.0 TRAFFIC MANAGEMENT 11.1 The A666 Blackburn Road is a major North-South route between Bolton and Darwen/Blackburn a clear width between kerbs of 6.4m.

11.2 All of the options discussed in this report will require some full or partial closures of the highway.

Options 1 & 6 would require lengthy closures of both the northbound and southbound carriageway.

At this stage it is envisaged that options 2, 3, 4 & 5 could be completed with mostly partial, single lane closures. Temporary full lane closures may be required to inject resin through the central portion of the carriageway install temporary works and for plant movements.

Option 7, the do-nothing approach, would result in the eventual full closure of the carriageway until such a time that remedial works are undertaken.

11.3 Significant traffic management will therefore be required as part of any scheme, the creation of diversion routes should be considered by BwDBC to minimise the impact on highway users.

Advance warning signs, informing the general public of the scheme should also be installed well in advance of the commencement of any works.

11.4 Traffic count data for the A666 at Cadshaw embankment was provided by Blackburn with Darwen Borough Council.

In summary the following vehicle movements were recorded over a non-continuous 12-hour period: • 196 HGVs • 786 Light Trucks • 104 Large Busses • 7 Small Busses • 5221 Car/Vans • 48 Motorbikes • 12 Push Bikes

31 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

12.0 FURTHER WORK REQUIRED

12.1 This high-level feasibility study has investigated high level design options, the indicative programme and indicative costs to remedy the deteriorating A666 Blackburn Road carriageway and retaining wall adjacent to Cadshaw Bridge.

The below further works are required to enable the detailed design of Option 2 to be complete:

• Liaison with Blackburn with Darwen Council Traffic Department to discuss traffic management proposals and obtain approval. • Ecology survey of proposed site. • Customer Care Plan – Consultation with affected stakeholders • Liaison with Landowners regarding permanent and temporary land take requirements. • Further geotechnical site investigation to determine the extent of the peat strata. • Full detailed design calculations and drawings. • Undertake trial digs to determine the line of the foundation for the existing masonry retaining wall on the east embankment to determine if this steps-out in front of the face of the wall. • Undertake trial digs to accurately determine the line of the services in advance of the works.

32 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

13.0 ENVIRONMENTAL IMPACT CONTROL MEASURES AND CUSTOMER CARE ISSUES

13.1 Environmental control measures should be put in place in accordance with current legislation. It will be necessary for these measures to be checked in advance of the works by means of approving the method statements and developing systems of work with the Contractor(s). It is recommended that an Ecology survey is carried out prior to the works commencing on site.

13.2 Consultations with stakeholders well in advance of the works should commence as early in the design process as possible. A Customer Care Plan should be developed from feasibility stages onwards. This plan should identify all aspect of customer consultation and co-ordination measures.

13.3 Noise and vibrations, particularly during any night time works may affect local residents and should be considered.

13.4 Stakeholders identified at this stage are as follows:

• Land Owners • Blackburn with Darwen Council Planning Department • Blackburn with Darwen Council Conservation Officer • Blackburn with Darwen Council Traffic section • Utility Companies • Emergency Services • Media and Press • Local Councillors and District Assemblies • Local residents and businesses

33 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

APPENDIX A – EXISTING ARRANGEMENT

CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

APPENDIX B – OPTIONS SKETCHES

CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

APPENDIX C – STATUTORY UNDERTAKERS INFORMATION

C Cadshaw

2c .0225 Cu Farm 1P

R 3

1P 4

3x1c 185 SAC XLPE 6.6 TP

Cadshaw 270.1m Cottages

2 3 ETL

1 x 32

48fOPUG PT

2 x 150

2 x 150 Overview4 5

3x1c 185 SAC XLPE 6.6 TP

Def

Requested by: Ricky Wilson Company: Blackburn with Darwen Borough Council Date Requested: 10/10/2019 Job Reference: 16692507 Your Scheme/Reference: 2 Data Management Electricity North West Dig Sites: Linley House Dickinson Street Area Line Manchester, M1 4LF

Unless otherwise indicated the depth of Electricity North West Limited cables are in accordance with NJUG (450mm for Low Voltage & 600mm for 11kV cables) 33kV and 132kV Phone: 0800 195 4141 cables are laid at depths as marked. The depth and positions of Electricity North West Limited equipment was accurate as shown when the equipment was installed. However third Email: [email protected] parties may have altered the level & other reference data. Therefore Electricity North West Limited accept no responsibility for the position of Electricity North West Limited equipment being different from shown. No person, body or company, shall be relieved from liability for damage caused to Electricity North West Limited equipment by reason of being located differently to the indications on this drawing. Service cables are not necessarily shown but must be assumed to exist to all premises, streetlights and signs. There may Scales on A4 paper: be other Electricity North West Limited apparatus in the vicinity which is not indicated on the cable records. Other apparatus may also be present which is owned by a third party 1:1250 Area dig site other than Electricity North West Limited. 1:250 Line dig site Reproduced from or based upon Ordnance Survey's map with the permission of Her Majesty's Stationary Office. Crown Copyright Reserved. LICENCE No. 100017892. Unauthorised reproduction may lead to Prosecution or Civil Proceedings.

Reference should be made to HSE Guidance, HS(G)47 "Avoiding Danger from Underground Services" and GS6 "Avoidance of Danger from Overhead Power Lines".

Electricity North West Limited 304 Bridgewater Place, Birchwood Park, Warrington WA3 6XG. Registered in England and Wales. Registered No 02366949

Plans generated by DigSAFE Pro (tm) software provided by PelicanCorp 2c .0225 Cu 1P

3x1c 185 SAC XLPE 6.6 TP Requested by: Ricky Wilson Company: Blackburn with Darwen Borough Council 2 Date Requested: 10/10/2019 3 Job Reference: 16692507 Your Scheme/Reference: 2 Data Management Electricity North West Dig Sites: Linley House Dickinson Street Area Line Manchester, M1 4LF

Reference should be made to HSE Guidance, HS(G)47 "Avoiding Danger from Underground Services" and GS6 "Avoidance of Danger from Overhead Power Lines".

Electricity North West Limited 304 Bridgewater Place, Birchwood Park, Warrington WA3 6XG. Registered in England and Wales. Registered No 02366949

Plans generated by DigSAFE Pro (tm) software provided by PelicanCorp 1

3x1c 185 SAC XLPE 6.6 TP

2 3

1 x 32

48fOPUG PT

2 x 150

Requested by: Ricky Wilson Company: Blackburn with Darwen Borough Council 4 Date Requested: 10/10/2019 5 Job Reference: 16692507 Your Scheme/Reference: 2 Data Management Electricity North West Dig Sites: Linley House Dickinson Street Area Line Manchester, M1 4LF

Reference should be made to HSE Guidance, HS(G)47 "Avoiding Danger from Underground Services" and GS6 "Avoidance of Danger from Overhead Power Lines".

Electricity North West Limited 304 Bridgewater Place, Birchwood Park, Warrington WA3 6XG. Registered in England and Wales. Registered No 02366949

Plans generated by DigSAFE Pro (tm) software provided by PelicanCorp 1

3x1c 185 SAC XLPE 6.6 TP

Cadshaw 270.1m Cottages

2 3

Requested by: Ricky Wilson Company: Blackburn with Darwen Borough Council 5 Date Requested: 10/10/2019 Job Reference: 16692507 Your Scheme/Reference: 2 Data Management Electricity North West Dig Sites: Linley House Dickinson Street Area Line Manchester, M1 4LF

Reference should be made to HSE Guidance, HS(G)47 "Avoiding Danger from Underground Services" and GS6 "Avoidance of Danger from Overhead Power Lines".

Electricity North West Limited 304 Bridgewater Place, Birchwood Park, Warrington WA3 6XG. Registered in England and Wales. Registered No 02366949

Plans generated by DigSAFE Pro (tm) software provided by PelicanCorp 2

4 5

Requested by: Ricky Wilson Company: Blackburn with Darwen Borough Council Date Requested: 10/10/2019 6 Job Reference: 16692507 Your Scheme/Reference: 2 Data Management Electricity North West Dig Sites: Linley House Dickinson Street Area Line Manchester, M1 4LF

Reference should be made to HSE Guidance, HS(G)47 "Avoiding Danger from Underground Services" and GS6 "Avoidance of Danger from Overhead Power Lines".

Electricity North West Limited 304 Bridgewater Place, Birchwood Park, Warrington WA3 6XG. Registered in England and Wales. Registered No 02366949

Plans generated by DigSAFE Pro (tm) software provided by PelicanCorp 2 3

2 x 150

4 5

Requested by: Ricky Wilson Company: Blackburn with Darwen Borough Council 6 Date Requested: 10/10/2019 Job Reference: 16692507 Your Scheme/Reference: 2 Data Management Electricity North West Dig Sites: Linley House Dickinson Street Area Line Manchester, M1 4LF

Reference should be made to HSE Guidance, HS(G)47 "Avoiding Danger from Underground Services" and GS6 "Avoidance of Danger from Overhead Power Lines".

Electricity North West Limited 304 Bridgewater Place, Birchwood Park, Warrington WA3 6XG. Registered in England and Wales. Registered No 02366949

Plans generated by DigSAFE Pro (tm) software provided by PelicanCorp 4 5

3x1c 185 SAC XLPE 6.6 TP

Reference should be made to HSE Guidance, HS(G)47 "Avoiding Danger from Underground Services" and GS6 "Avoidance of Danger from Overhead Power Lines".

Electricity North West Limited 304 Bridgewater Place, Birchwood Park, Warrington WA3 6XG. Registered in England and Wales. Registered No 02366949

Plans generated by DigSAFE Pro (tm) software provided by PelicanCorp

United Utilities Maps for Safe Dig

Centre : X : 370496 Y : 418381 Date : 10/10/2019 15:13:18 Scale Approx : 1999.99999999999

Extract from maps of United Utilities' Underground Assets

The position of the underground apparatus shown on this plan is approximate only and is given in accordance with the best information currently available. The actual positions may be different from those shown on the plan and private service pipes may be shown by a blue broken line. United Utilities Water will not accept liability for any damage caused by the actual position being different from those shown. Crown copyright and database rights 2019.The Ordnance survey 100022432. This plan is based on the Ordnance Survey Map with the sanction of the Controller of H.M. Stationary Office. Crown and United Utilities Water copyrights are reserved. Unauthorised reproduction will (c) Crown copyright and database rights 2019 Ordnance Survey 100019209 Date: 10/10/19 Scale: 1:1741 Map Centre: 370496,418381 Data updated: 02/09/19 Telecoms Plan A4

Important Information - please read The purpose of this plan is to identify Virgin Media apparatus. We have [email protected] tried to make it as accurate as possible but we cannot warrant its accuracy. In addition, we caution that within Virgin Media apparatus there may be instances where mains voltage power cables have been placed inside green, rather than black ducting. Further details can be found using the "Affected Postcodes.pdf", which can be downloaded from this website. Therefore, you must not rely solely on this plan if you are carrying out any excavation or other works in the vicinity of Virgin Media apparatus. The actual position of any underground service must be verified by cable detection equipment, etc. and established on site before any mechanical plant is used. Accordingly, unless it is due to the negligence of Virgin Media, its employees or agents, Virgin Media will not have any liability for any omissions or inaccuracies in the plan or for any loss or damage caused or arising from the use of and/or any reliance on this plan. This plan is produced by Virgin Media Limited (c) Crown copyright and database rights 2019 Ordnance Survey 100019209. CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

APPENDIX D – LAND OWNERSHIP DETAILS

THIS IS A PRINT OF THE VIEW OF THE REGISTER OBTAINED FROM HM LAND REGISTRY SHOWING THE ENTRIES SUBSISTING IN THE REGISTER ON 1 OCT 2019 AT 14:03:50. BUT PLEASE NOTE THAT THIS REGISTER VIEW IS NOT ADMISSIBLE IN A COURT IN THE SAME WAY AS AN OFFICIAL COPY WITHIN THE MEANING OF S.67 LAND REGISTRATION ACT 2002. UNLIKE AN OFFICIAL COPY, IT MAY NOT ENTITLE A PERSON TO BE INDEMNIFIED BY THE REGISTRAR IF HE OR SHE SUFFERS LOSS BY REASON OF A MISTAKE CONTAINED WITHIN IT. THE ENTRIES SHOWN DO NOT TAKE ACCOUNT OF ANY APPLICATIONS PENDING IN HM LAND REGISTRY. FOR SEARCH PURPOSES THE ABOVE DATE SHOULD BE USED AS THE SEARCH FROM DATE. THIS TITLE IS DEALT WITH BY HM LAND REGISTRY, FYLDE OFFICE. TITLE NUMBER: LAN75537 There is no application or official search pending against this title.

A: Property Register This register describes the land and estate comprised in the title. BLACKBURN WITH DARWEN 1 (12.09.2008) The Freehold land shown edged with red on the plan of the above title filed at the Registry and being land on the West side of Bolton Road, Darwen. 2 (12.09.2008) As to the part tinted pink the mines and minerals together with ancillary powers of working are excepted with provision for compensation in the event of damage caused thereby.

B: Proprietorship Register This register specifies the class of title and identifies the owner. It contains any entries that affect the right of disposal. Title absolute 1 (12.09.2008) PROPRIETOR: UNITED UTILITIES WATER LIMITED (Co. Regn. No. 2366678) care of The Legal Manager, Grasmere House, Lingley Mere Business Park, Lingley Green Avenue, Great Sankey, Warrington WA5 3LP.

C: Charges Register This register contains any charges and other matters that affect the land. 1 (12.09.2008) The land tinted blue on the title plan is subject to the rights reserved by a Conveyance thereof dated 3 March 1894 made between (1) Reverend William Arthur Duckworth and (2) Eliza Deakin. NOTE: Copy filed. 2 (12.09.2008) The land tinted pink is subject to the rights reserved by a Conveyance thereof and other land dated 8 February 1896 made between (1) The Reverend William Arthur Duckworth and (2) The Mayor Aldermen and Burgesses of the Borough of Bolton. NOTE:-Copy filed under LAN74958.

End of register

1 of 1 THIS IS A PRINT OF THE VIEW OF THE REGISTER OBTAINED FROM HM LAND REGISTRY SHOWING THE ENTRIES SUBSISTING IN THE REGISTER ON 1 OCT 2019 AT 14:03:10. BUT PLEASE NOTE THAT THIS REGISTER VIEW IS NOT ADMISSIBLE IN A COURT IN THE SAME WAY AS AN OFFICIAL COPY WITHIN THE MEANING OF S.67 LAND REGISTRATION ACT 2002. UNLIKE AN OFFICIAL COPY, IT MAY NOT ENTITLE A PERSON TO BE INDEMNIFIED BY THE REGISTRAR IF HE OR SHE SUFFERS LOSS BY REASON OF A MISTAKE CONTAINED WITHIN IT. THE ENTRIES SHOWN DO NOT TAKE ACCOUNT OF ANY APPLICATIONS PENDING IN HM LAND REGISTRY. FOR SEARCH PURPOSES THE ABOVE DATE SHOULD BE USED AS THE SEARCH FROM DATE. THIS TITLE IS DEALT WITH BY HM LAND REGISTRY, FYLDE OFFICE. TITLE NUMBER: LAN75709 There is no application or official search pending against this title.

A: Property Register This register describes the land and estate comprised in the title. BLACKBURN WITH DARWEN 1 (16.09.2008) The Freehold land shown edged with red on the plan of the above title filed at the Registry and being land on the east side of Bolton Road, Darwen. 2 (16.09.2008) As to the part tinted blue on the title plan the mines and minerals together with ancillary powers of working are excepted with provision for compensation in the event of damage caused thereby. 3 (16.09.2008) The land has the benefit of the rights reserved by but is subject to the rights granted by a Conveyance of the land in this title dated 17 February 1993 made between (1) North West Water Limited (vendor) and (2) Michael John Anderson and Lynne Christina Anderson (purchasers). NOTE:-Copy filed.

B: Proprietorship Register This register specifies the class of title and identifies the owner. It contains any entries that affect the right of disposal. Title absolute 1 (16.09.2008) PROPRIETOR: UNITED UTILITIES WATER LIMITED (Co. Regn. No. 2366678) care of The Legal Manager, Grasmere House, Lingley Mere Business Park, Lingley Green Avenue, Great Sankey, Warrington WA5 3LP.

C: Charges Register This register contains any charges and other matters that affect the land. 1 (16.09.2008) The land tinted pink on the title plan is subject to such restrictive covenants as may have been imposed thereon before 15 February 1989 and are still subsisting and capable of being enforced. 2 (16.09.2008) The land tinted blue on the title plan is subject to the rights reserved by a Conveyance thereof and other land dated 8 February 1896 made between (1) The Reverend William Arthur Duckworth and (2) The Mayor Aldermen and Burgesses of the Borough of Bolton. NOTE:-Copy filed under LAN74958. 3 (16.09.2008) The land is subject to the rights granted by a Conveyance of 3 Cadshaw Road dated 18 July 1978 made between 1) North West Water Authority (Vendor) and (2) Raymond John Meehan and Lesley Ann Meehan

1 of 2 Title number LAN75709 C: Charges Register continued (Purchasers). NOTE:-Copy filed. 4 (16.09.2008) The land is subject to the rights granted by a Conveyance of the land lying to the north of the land in this title dated 17 July 1981 made between (1) North West Water Authority (Vendor) and (2) Edmund Proctor Limited (Purchaser). NOTE:-Copy filed. 5 (16.09.2008) The land is subject to the rights granted by a Conveyance of 4 Cadshaw Cottages dated 20 February 1984 made between (1) North West Water Authority and (2) Joseph Samuel Heathcote and Marilyn Heathcote. NOTE:-Copy filed under LA497815.

End of register

2 of 2 THIS IS A PRINT OF THE VIEW OF THE REGISTER OBTAINED FROM HM LAND REGISTRY SHOWING THE ENTRIES SUBSISTING IN THE REGISTER ON 1 OCT 2019 AT 14:01:42. BUT PLEASE NOTE THAT THIS REGISTER VIEW IS NOT ADMISSIBLE IN A COURT IN THE SAME WAY AS AN OFFICIAL COPY WITHIN THE MEANING OF S.67 LAND REGISTRATION ACT 2002. UNLIKE AN OFFICIAL COPY, IT MAY NOT ENTITLE A PERSON TO BE INDEMNIFIED BY THE REGISTRAR IF HE OR SHE SUFFERS LOSS BY REASON OF A MISTAKE CONTAINED WITHIN IT. THE ENTRIES SHOWN DO NOT TAKE ACCOUNT OF ANY APPLICATIONS PENDING IN HM LAND REGISTRY. FOR SEARCH PURPOSES THE ABOVE DATE SHOULD BE USED AS THE SEARCH FROM DATE. THIS TITLE IS DEALT WITH BY HM LAND REGISTRY, FYLDE OFFICE. TITLE NUMBER: LAN76035 There is no application or official search pending against this title.

A: Property Register This register describes the land and estate comprised in the title. BLACKBURN WITH DARWEN 1 (22.09.2008) The Freehold land shown edged with red on the plan of the above title filed at the Registry and being Land on the North West side of Blackburn Road, Darwen. 2 (22.09.2008) The mines and minerals together with ancillary powers of working are excepted with provision for compensation in the event of damage caused thereby.

B: Proprietorship Register This register specifies the class of title and identifies the owner. It contains any entries that affect the right of disposal. Title absolute 1 (22.09.2008) PROPRIETOR: UNITED UTILITIES WATER LIMITED (Co. Regn. No. 2366678) care of The Legal Manager, Grasmere House, Lingley Mere Business Park, Lingley Green Avenue, Great Sankey, Warrington WA5 3LP.

C: Charges Register This register contains any charges and other matters that affect the land. 1 (22.09.2008) The land is subject to the rights reserved by a Conveyance of the land in this title and other land dated 9 October 1895 made between (1) Peter Arthur Marsham Hoare and (2) Bolton Corporation. NOTE:-Copy filed under LAN75226. 2 (14.02.2017) The parts of the land affected thereby are subject to the rights granted by a Lease of Telecommunications Equipment dated 26 January 2017 referred to in the schedule of leases hereto. NOTE: Copy lease filed under LAN187440 . 3 (14.02.2017) The parts of the land affected thereby are subject to the leases set out in the schedule of leases hereto. The leases grant and reserve easements as therein mentioned.

Schedule of notices of leases 1 14.02.2017 Telecommunications 26.01.2017 LAN187440 Edged and Equipment From and

1 of 2 Title number LAN76035 Schedule of notices of leases continued numbered 1 in including blue 26.1.2017 NOTE: See entry in the Charges Register relating to the rights granted by this lease.

End of register

2 of 2 THIS IS A PRINT OF THE VIEW OF THE REGISTER OBTAINED FROM HM LAND REGISTRY SHOWING THE ENTRIES SUBSISTING IN THE REGISTER ON 1 OCT 2019 AT 14:02:33. BUT PLEASE NOTE THAT THIS REGISTER VIEW IS NOT ADMISSIBLE IN A COURT IN THE SAME WAY AS AN OFFICIAL COPY WITHIN THE MEANING OF S.67 LAND REGISTRATION ACT 2002. UNLIKE AN OFFICIAL COPY, IT MAY NOT ENTITLE A PERSON TO BE INDEMNIFIED BY THE REGISTRAR IF HE OR SHE SUFFERS LOSS BY REASON OF A MISTAKE CONTAINED WITHIN IT. THE ENTRIES SHOWN DO NOT TAKE ACCOUNT OF ANY APPLICATIONS PENDING IN HM LAND REGISTRY. FOR SEARCH PURPOSES THE ABOVE DATE SHOULD BE USED AS THE SEARCH FROM DATE. THIS TITLE IS DEALT WITH BY HM LAND REGISTRY, FYLDE OFFICE. TITLE NUMBER: LAN76466 There is no application or official search pending against this title.

A: Property Register This register describes the land and estate comprised in the title. BLACKBURN WITH DARWEN 1 (30.09.2008) The Freehold land shown edged with red on the plan of the above title filed at the Registry and being land on the east side of Blackburn Road, Darwen.

B: Proprietorship Register This register specifies the class of title and identifies the owner. It contains any entries that affect the right of disposal. Title absolute 1 (30.09.2008) PROPRIETOR: UNITED UTILITIES WATER LIMITED (Co. Regn. No. 2366678) care of The Legal Manager, Grasmere House, Lingley Mere Business Park, Lingley Green Avenue, Great Sankey, Warrington WA5 3LP.

End of register

1 of 1 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

APPENDIX E – SKETCH BY BwDBC INDICATING EXTENT OF PEAT

CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

APPENDIX F – C3 ESTIMATES

F CS/098709 A666 Bolton Road - C3 Estimate Status

Date sent Affected C3 Estimate Undertaker Date Received Ref: Contact C3 Estimate Description Lead in time Notes C4 out Yes/No Including VAT

Denise Tinning Trial hole survey confirmed the presence of a water valve in the east UU Water confirm there is no apparatus in the United Utilities 18/07/2019 31/07/2019 No 4100398113/DT £0.00 footway. Valve cover in kerb. area of the proposed works. Assume abandoned.

Gregory Moss Temporary diversion of cable from east footway onto UU land. Estimate Breakdown: Virgin Media 19/07/2019 25/07/2019 Yes VM/CIP/363315 87,680.76 £105,216.91 Permanent diversion back into east footway. 6 months Design £1,059.36 Budget Est £86,621.40 [email protected] Temporary diversion of fibreoptic cable from east footway onto UU Estimate Breakdown: Vodafone 26/07/2019 02/08/2019 Yes NRSWA/3.03/006251 91,693.00 £110,031.60 land. Permanent diversion back into east footway. 6 months Design £4,000 Budget Est £87,693.00 Trial hole survey confirmed the presence of a gas valve in the east Cadent confirm there is no apparatus in the area Cadent Gas 18/07/2019 23/07/2019 No NW_GW1B_3FWP_048649 £0.00 footway and pipe on north side. of the proposed works. Assume abandoned.

Matthew Lee Temporary diversion of 6.6kV cable from west verge onto UU owned ENW confirm cable cannot be supported. Electricity North West 31/05/2019 26/06/2019 Yes 5500151605/A 0843 311 3543 40,000.00 £48,000.00 land. Permanent diversion into west verge. TBC [email protected] Dave Wright Temporary diversion of cables from west carriageway and east Estimate Breakdown: BT Openreach 31/05/2019 11/06/2019 Yes BQRA31/819427 292,086.36 £350,503.63 footway onto UU land. Permanent diversions into west carriageway 6 months Design £3,807.00 and east footway. Budget Est £288,279.36

TOTAL £511,460.12 £613,752.14 CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

APPENDIX G. PHOTOGRAPHS TAKEN ON SITE

G CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

The following photographs were taken by Wilde Consultants during a site visit on the 3rd October 2019.

Photo 1, View of the footway and retaining wall parapet looking south.

Photo 2, View of the footway and retaining wall parapet looking north. G CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

Photo 3, Typical view of the drop side face of the retaining wall, looking north.

Photo 4, The retaining wall abuts the North East wingwall of Cadshaw Bridge at its south end. G CADSHAW EMBANKMENT & RETAINING WALL HIGH LEVEL FEASIBILITY STUDY BLACKBURN WITH DARWEN BOROUGH COUNCIL 762-014-R01/P2 OCTOBER 2019

Photo 5, Cracking of the carriageway surfacing due to embankment settlement on the west (northbound) side.

Photo 6, Vegetation closure to the existing wall on the east embankment (looking north) will need to be removed to facilitate major works in this area. G