MT. EDGECUMBE HIGH SCHOOL AQUATIC FACILITY GEOTECHNICAL INVESTIGATION SITKA, ALASKA
Owner: Alaska Department of Education & Early Prepared for: Development ECI/HYER Architects, Inc. 101 West Benson, Suite 306 Mt. Edgecumbe High School Anchorage, Alaska 99503 1330 Seward Avenue Sitka, Alaska 99835 Prepared by: R&M Engineering, Inc. Contracting Agency: 6205 Glacier Highway State of Alaska DOT&PF Juneau, Alaska 99801 Statewide Public Facilities
R&M Project No. 121173 February 19, 2013 Mt. Edgecumbe High School Aquatic Facility Geotechnical Investigation
TABLE OF CONTENTS
1. INTRODUCTION ...... 1 1.1 Background ...... 1 1.2 Project Information ...... 1 1.3 Purpose and Scope of Work ...... 1 1.4 Previous Subsurface Investigations ...... 2 1.5 Project Location and Site Conditions...... 2 2. GEOLOGY ...... 3 2.1 Seismicity ...... 3 2.2 Local Climate ...... 3 2.3 Tidal Data ...... 4 3. GEOTECHNICAL INVESTIGATION ...... 4 3.1 Fieldwork ...... 4 3.2 Drilling of boreholes and Sampling ...... 5 3.3 Soil Density ...... 5 3.4 rock Geological Description ...... 5 3.5 Soil and Core Samples ...... 6 4. LABORATORY TESTING ...... 7 5. RESULTS AND FINDINGS ...... 7 5.1 Fuel / Oil Contaminated Soil ...... 7 5.2 General Subsoil Conditions ...... 7 6. CONCLUSIONS AND RECOMMENDATIONS ...... 9 6.1 Seismic Evaluation and Site Class ...... 9 6.2 Geotechnical Design Parameters ...... 10 6.3 Permissible foundation Bearing Pressure ...... 11 6.3.1 Passive and Active Resistance for Shallow Foundations .... 11 6.3.2 Slab-On-Grade ...... 12 6.3.3 Foundation Walls and Retaining Walls ...... 12 6.4 Pool Building Foundation ...... 13 6.5 Parking Areas Site Preparation (TH-7 & TH-8) ...... 15 7. CONSTRUCTION CONSIDERATIONS ...... 15 7.1 Drainage and Dewatering ...... 15 7.2 Temporary Excavation Supports ...... 16 7.3 Frost Protection ...... 16 7.4 Underground Utilities ...... 16 8. LIMITATIONS ...... 17 9. REFERENCES ...... 18
APPENDIX APPENDIX 1 Selected Photographs APPENDIX 2 Drill Test Hole Location Map APPENDIX 3 Test Hole Logs APPENDIX 4 Soil Profiles APPENDIX 5 Laboratory Test Results
Mt. Edgecumbe High School Aquatic Facility Geotechnical Investigation
1. INTRODUCTION
1.1. Background
The Alaska Department of Transportation and Public Facilities (AKDOT&PF) has entered into a contract with ECI/Hyer Architecture and Interiors, Inc. to develop construction documents for a new aquatic facility at Mt. Edgecumbe High School (MEHS) on Japonski Island, in Sitka, Alaska. Following site selection analysis, ECI/Hyer commissioned R&M Engineering, Inc. (R&M) to perform the geotechnical investigation for the foundation design and construction of a new aquatic facility on Lot 15D, U.S. Survey 1496, otherwise known as the former power plant site.
Per the agreed scope of work, R&M mobilized its geotechnical drilling team on November 12, 2012 to the selected site of a new aquatic facility at Mt. Edgecumbe High School in Sitka, Alaska. The geotechnical investigation program was limited to the drilling of 8 boreholes distributed over the proposed location of the aquatic facility building and parking areas as agreed and approved by ECI/Hyer.
This geotechnical report presents the interpretation of the geotechnical investigation work. The basis for the interpretation of this report is the field data, available previous geotechnical data near the project site, published soil and rock properties from geotechnical engineering reference books, and laboratory test data. The Appendices consists of the Selected Photographs, Drill Test Hole Location Map, Test Hole Logs, Soil Profiles, and Laboratory Test Results on selected representative samples.
1.2. Project Information
The proposed Mt. Edgecumbe High School (MEHS)aquatic facility entails construction of a two- level steel framed aquatic recreational center building with two swimming pools, diving area, locker rooms, office spaces, public spaces, and associated parking areas. The main swimming pool will be 50 meters in length with diving platforms at the deep end. The aquatic facility building is to be approximately 260’ x 130’ in size. The project also includes construction of access roads and site utilities.
1.3. Purpose and Scope of Work
The purpose of the geotechnical investigation is to achieve site specific and necessary information of the ground conditions and to provide necessary geotechnical recommendations to aid the engineer / designer in the detailed design of the proposed MEHS aquatic facility structures.
The authorized scope of this geotechnical investigation consists of drilling eight (8) boreholes to drilling depths of 20’, 30’, 35’ and 50’, SPT sampling, core drilling into bedrock, conducting laboratory tests on selected representative samples, and submission of this final geotechnical report.
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1.4. Previous Subsurface Investigations
Review of available historic geotechnical investigation on Japonski Island was conducted by R&M and submitted to ECI/Hyer on September 13, 2012. The reports from most recent to oldest are: Phase I ESA Reports, August 2012; MEHS Building 1330 Academic Expansion, R&M Engineering, Inc., November 2004; Sitka-Japonski Island Streets and Utilities, DOWL-HKM, May 2003; Sitka Airport Access Improvements, AKDOT&PF, February 2002; Soil Gas Survey, Sitka Airport Access Road, Woodward-Clyde Consults, May 1988; and MEHS Phase III, R&M Engineering, Inc., March 28, 1986. The past geotechnical information is cited as reference 8.
1.5. Project Location and Site Conditions
The project site is adjacent Mt. Edgecumbe High School campus on Japonski Island, west of Sitka, Alaska. The project site is the site of a former above-ground bulk fuel storage tank and power plant for the US Naval base during World War II. The power plant building, located north of the project site, still existed during the geotechnical investigation, but is no longer in service. The existing power plant building is planned to be demolished to allow for the construction of the new aquatic facility. The above ground bulk-fuel tank has previously been removed from the site.
The ground surface elevation at the proposed aquatic facility is generally at 24’-26’ above Mean Lower Low Water and is slightly elevated from Airport Road and UAS Access Road. The finished elevation of the proposed parking area at Airport Road is approximately 18’-20’. Outcrops of bedrock and elevated natural soil deposits are exposed at the site. The exposed rock outcropping on the south side of the site has been identified as a “historical” rock outcropping and is to be preserved. The top of the elevated natural deposits are at approximately elevation 35’-36’. Currently, MEHS maintenance staff uses the former bulk fuel tank area as Project Site an equipment and materials storage area.
Sitka Channel (east) and the Sealing Airport Cove Harbor (south) are the main body Road of water nearest the site. Mean sea level is recorded as 9.8’. The recorded highest tide level is 14.9’ (4.53 m). UAS Access Road
Figure 1.5-1: Proposed Project Site Project Site
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2. GEOLOGY The project site is located on Japonski Island in Sitka, Alaska. Sitka is located on Baranof Island on the outer west coast of Southeast Alaska. Japonski Island (1-mile long and ½ mile wide), is composed largely of bedrock overlain by glacial drift, volcanic cinders and ash, and muskeg. At present, man-made fill is overlying the natural deposits at the project site.
Japonski Island and Sitka’s bedrock consists of a sedimentary unit with subgroups of greywacke and some argillites of Lower Cretaceous to Upper Jurassic age. Glacial drift can range from sandy gravel with varying degrees of silt to pure glacial till containing more than 50% silt content. Mount Edgecumbe, a volcano located across Sitka Sound about 15 miles to the west, is estimated to have last erupted 10,000 years ago and deposited a sequence of thick ash layers during the waning phase of glaciation.
Beach deposits are common in low lying areas, where shore environments prevailed. Several raised shore lines exist in Sitka, remnants of beach locations formed during uplift (isostatic rebound) of the land.
2.1. Seismicity
Southeast Alaska is dissected by a number of active faults. Baranof Island, which hosts the City and Borough of Sitka is truncated by two major faults. To the east is the Chatham Strait fault and to the west, the Queen Charlotte/Fairweather fault. The Queen Charlotte/Fairweather fault traces the western edge of Southeast Alaska and is considered responsible for many large earthquakes with Richter magnitudes of 8 and larger. Many less pronounced faults cut the island, one in the immediate vicinity of Sitka.
According to the U.S.G.S. Historic Earthquakes Data, a strong earthquake with Magnitude 7.6 was felt in Sitka on July 30, 1972. A few chimneys fell and some minor landslides were reported. The Fairweather fault ruptured over a length of 75 kilometers. At least 19 aftershocks were felt in Sitka through August 29, 1972, and a tsunami of 8 centimeters was recorded.
2.2. Local Climate
The Sitka climate is typical for northern marine coastal locations. It has relatively mild rainy winters and cool summers with somewhat less rainfall. The record maximum temperature is 85o F and the record minimum is -5oF. The table below presents a summary of the average annual and monthly temperatures, precipitation and snowfall for Sitka. Data provided by the National Weather Service, Juneau, Forecast Office.
Figure 2.2-1: Local Climate Ave Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Temp 43 32 34 36 39 45 52 54 55 52 45 37 34 Ave 50 37 39 43 48 55 57 61 63 61 52 45 39 High Ave 37 27 28 30 34 39 45 48 48 45 39 34 28 Low Ave 95 9 7 7 6 5 4 5 7 11 15 11 10 precip Ave 62 16 12 11 3 T ------T 6 14 Snow Reference: Geotechnical Investigation Report, Sitka Airport Access, February 2002.
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2.3. Tidal Data
Tidal data provided by the U.S. National Oceanic and Atmospheric Administration (NOAA) for Sitka, Baranof Island, Sitka Sound based on a 19-year record from January 1983 to December 2001 is as follows:
Figure 2.3-1: Extreme Events Tidal Data Highest Observed Water Level (11/02/1948) 4.534 m (14.87 ft.)
Mean High High Water (MHHW) 3.029 m (9.94 ft.)
Mean High Water (MHW) 2.791 m (9.15 ft.)
Mean Tide Level (MTL) 1.618 m (5.31 ft.)
Mean Sea Level (MSL) 1.610 m (5.28 ft.)
Mean Low Water (MLLW) 0.0 m (0.0 ft.)
Lowest Observed Water Level (12/14/2008) -1.250 m (-4.1 ft.)
3. GEOTECHNICAL INVESTIGATION 3.1. Fieldwork R&M’s CME-55 truck mounted hydraulically-powered drill rig was mobilized to the project site via Alaska State Ferry on November 11, 2012. The R&M field drilling crew mobilized to the site on November 12, 2012 via Alaska Airlines. The borehole drilling work was conducted from November 12 to 20, 2012. The locations of the boreholes as approved by ECI/Hyer were marked and laid out by R&M’s geotechnical engineer, Edmon Cruz, prior to drilling. Mr. Cruz also conducted a site reconnaissance, monitored the drilling operations and logged the drill test holes. The location of the boreholes is reflected in the Drill Test Hole Location Map shown in the Appendix 2. The duration of work and the final depth of boreholes are tabulated as follows:
Figure 3.1-1: Geotechnical Boreholes
Borehole Date Date Borehole Ground Bedrock ID Drilled Completed Depth Elevation Elevation (feet) (feet) (feet) TH-1 Nov-19-12 Nov-19-12 31.0 24.3 14.3 TH-2 Nov-16-12 Nov-16-12 35.0 24.8 10.7 TH-3 Nov-12-12 Nov-13-12 50.0 26.2 21.2 TH-4 Nov-15-12 Nov-16-12 35.0 25.7 8.2 TH-5 Nov-19-12 Nov-20-12 30.0 25.1 18.1 TH-6 Nov-13-12 Nov-15-12 50.0 25.2 21.2 TH-7 Nov-18-12 Nov-18-12 20.0 18.9 7.9 TH-8 Nov-18-12 Nov-18-12 20.0 17.7 5.7
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The weather during drilling was overcast with light rain, with temperatures in the 40oF range. Interrupted rain was experienced for the duration of the drilling work. Logging of test holes was conducted by R&M’s geotechnical engineer. Boreholes were field surveyed upon completion of drilling to establish ground surface elevation and horizontal position.
3.2. Drilling of Boreholes and Sampling
The boreholes were advanced using a combination of hollow-stem auger with pilot head and Standard Penetration Test (SPT) for soil and diamond core drilling for bedrock. Drilling was accomplished by first advancing a 5-ft long 8” diameter hollow stem auger with pilot head into the ground to start the borehole. The full length of each segment of hollow stem auger is 5 feet. If soil sampling was conducted, the auger pilot head was withdrawn and the SPT sampler was inserted.
Standard Penetration Test (SPT) was conducted at 5-foot intervals to obtain information on the consistency or relative density of the soil. The SPTs were conducted per the American Society for Testing Materials (ASTM) as set forth under D1586-08a, and were performed using the standard 2-inch (50 mm) outside-diameter split-spoon sampler coupled to the end of drill rods. The sampler was driven by a 140-lb automatic trip hammer with an impact height of 30-inches. The number of blows for the first 6-inch and the two successive 6-inch penetrations were recorded. The sum of the last two 6-inch penetrations represents the N-value. These results are incorporated in the attached borehole logs.
A rotary drilling procedure using a wireline NQ3 double-tube core barrel obtaining 2.5” (6.3cm) rock core sample was used to advance through rock formations. Coring was generally conducted at full runs of 5 feet (150 cm). Shorter runs were also conducted to minimize core losses. Retrieved core samples were measured for its drive run, recovery, Rock Quality Designation (RQD), and arranged sequentially in core boxes.
3.3. Soil Density
Since the soil at the site is generally non-cohesive (cohesionless), the relative density description based on Standard Penetration Test (SPT) blow counts (AASHTO T-206, ASTM D1586) were determined from the table below.
Figure 3.3-1: Soil Relative Density
Number of Blows per Foot Consistency 0-4 Very loose 5-10 Loose 11-30 Medium dense 31-50 Dense >51 Very dense
3.4. Rock Geological Description
All samples retrieved from the boreholes were described in accordance with the procedure set forth under ASTM D2488 (Description and Identification of Soil, Visual-Manual Procedure). Classification of weathered rock has been carried out in accordance with the approaches in DOT&PF Alaska Field Rock Classification and Structural Mapping Guide (reference 5). From this, the degree of weathering is classified as:
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Figure 3.4-1: Degree of Rock Weathering
• Grade I: Fresh; • Grade II: Slightly weathered; • Grade III: Moderately weathered; • Grade IV: Highly weathered; • Grade V: Completely weathered; and • Grade VI: Residual soil.
The rock quality was measured based on percent of core recovery and Rock Quality Designation (RQD). The RQD (ASTM D6032) measures the total length of intact core segments over 4 inches (10 cm) long as a percentage of the core run length. RQD and core recovery percentage taken together provide a subjective, but numerical evaluation of the rock quality. The rock quality was expressed based on the RQD value in the table below:
Figure 3.4-2: Rock Quality Designation
RQD Value Description of Rock Quality 0% - 25% Very poor 26% - 50% Poor 51% - 75% Fair 76% - 90% Good 91% - 100% Excellent
The classification of the rock strength in accordance with DOT&PF Alaska Field Rock Classification and Structural Mapping Guide (reference 5), in terms of the Unconfined Compressive Strength (UCS) may be estimated in the table below.
Figure 3.4-3: Rock Strength
Rock Strength Classification Unconfined Compressive Strength (p.s.i.) Extremely Weak Rock 35 - 70 Very Weak Rock 150 - 725 Weak Rock 725 – 3,500 Medium Weak Rock 3,500 – 7,000 Strong Rock 7,000 – 15,000 Very Strong Rock 15,000 – 36,000 Extremely Strong Rock >36,000
Following the previously described rock geological descriptions, standard soil and rock descriptions are illustrated by the following two examples reflected in the soil boring logs:
• Soil: "Loose, dark Sand and Gravel with little silt, moist"; and • Rock: "Strong to very strong, gray massive, slightly weathered Greywacke, with widely spaced, smooth to rough, and planar fracture joints.
3.5. Soil and Core Samples
The soil samples obtained from the SPT split-spoon samplers were visually classified, labeled, and then carefully sealed in water-tight plastic bags while core samples were placed and
Page 6 of 18 Mt. Edgecumbe High School Aquatic Facility Geotechnical Investigation arranged sequentially in 2’ long x 5’ wide plastic core boxes. The soil and rock samples were transported to and stored at R&M laboratory in Juneau, Alaska.
4. LABORATORY TESTING
All testing procedures conformed to the American Society for Testing and Materials (ASTM). The Unified Soil Classification System (USCS) was used in the classification of borehole samples. Below is a tabulation of the tests conducted on selected samples:
Figure 4.1: Laboratory Testing Standards ASTM DESIGNATION TITLE/ DESCRIPTION D2488-00 Description and Classification of Soils by Visual-Manual Procedure D2487-00 Classification of Soils for Engineering Purposes. D2216-00 Water (moisture) Content of Soil, Rock, and Soil-Aggregate Mixtures. D422-63 Particle size Analysis of Soils (Mechanical Sieve only).
5. RESULTS AND FINDINGS
5.1. Fuel / Oil Contaminated Soil
Suspected fuel/oil contaminated soil was recovered at TH-3 (2.5’ depth), TH-4 (4’-16’ depth) and at TH-2 (2.5’-7.5’ depth). The soil samples were suspected of fuel/oil contamination due to the smell of diesel odor. The soil in TH-4 was assumed to be the most contaminated as it exhibited a bright gray color and had a very strong diesel odor. The rest of the soil samples collected had no distinguishable petroleum odor. Further review of the environmental site conditions is recommended by the project team environmental engineer.
5.2. General Subsoil Conditions
Based on the results of the eight (8) drilled holes, the subsoil at the site may be categorized into four (4) distinct soil layers, namely; Fill (gravel and sand and cobbles/boulders), Muskeg, Glacial Till/Ash, and Bedrock. In general, it appears the original site development for the power plant fuel storage tank was cleared and grubbed of vegetation, organic layer removed and the bedrock drilled and blasted. The site was then capped with a combination of imported fill or rock blasted on site. The approximate depths and thickness of the different layers are shown on the following page.
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Figure 5.2-1: Thickness of Soil/Rock Layers Approximate Depth (Thickness of Soil Layers), feet Soil Type TH-1 TH-2 TH-3 TH-4 TH-5 TH-6 TH-7 TH-8 Gravel & Sand Fill 0-5 0-9 0-2.5 0-16.5 0-7 0-1.5 0-5 0-3 (5) (9) (2.5) (16.5) (7) (1.5) (5) (3) Cobbles / Boulders 5-10 9-14 2.5-5 - - 1.5-4 - - Fill (5) (5) (2.5) (2.5) Muskeg/Original ------5-9 3-10 ground (4) (7) Glacial Till - - - 16.5- - - 9-11 10-12 17.5 (2) (2) (1) Bedrock 10-31 14-35 10-31 17.5-50 7-30 4-50 11-20 12-20 (20) (21) (20) (32.5) (23) (46) (9) (8) " - " means not encountered or barely noticed " " means at least
Referring to the table above, the different soil layers may be further described as follows:
Gravel and Sand Fill: This is the upper most soil layer at the site, consisting mainly of processed NFS gravel and sand with thickness varying from 1.5’-16.5’. SPT N-values ranged from 10 to 21, indicating loose to medium relative density. Laboratory test results on selected sample from TH-2, 7.5'-9.0' (see attached sieve analysis report) showed that the fines (material passing #200 sieve) is 4%, indicating a non-frost susceptible soil. Moisture content is 9%, indicating dry to moist in-situ condition. Classification falls under GP in the Unified Soil Classification System.
Cobbles/Boulders Fill: This coarse fill layer appears to be a shot rock borrow and/or loose rocks after blasting of the native bedrock underlying the project site. Thickness varies from 2.5’ to 5’. Core samples retrieved from TH-2 (10’-14’) and TH-6 (1.5’-4’) revealed broken Greywacke rocks, with sizes varying from 6” to 2’. SPT blow counts indicated hitting “refusal”, but may not be the actual density of the layer as material larger than the size of the SPT sampler give high N-values.
Organic Soil/Original Ground: This layer was observed at TH-7 and TH-8 beneath the gravel and sand fill. Thickness varies from 4’ to 7’ between TH-7 and TH-8, respectively. It is described as loose, brownish gray organic gravelly Sand, trace of silt. SPT N-values ranged from 10 to 21, indicating loose to medium dense relative density. Laboratory test results on selected sample from TH-8, 4'-5.5' (see attached sieve analysis report) showed that the fines (material passing #200 sieve) is about 6%. Classification falls under SP-SM in the Unified Soil Classification System. The moisture content is 40.5%, which is quite high for SP-SM materials. The high moisture content could be attributed to the significant amount of organics present in the soil sample.
Glacial Till: This is a consolidated natural deposit encountered in TH-4, TH-7 and TH-8 overlying the bedrock layer. Thickness is 2‘ in TH-7 and TH-8, and only about 1’ in TH-4. SPT N-values conducted on this layer at TH-4 at 16.5’ depth and TH-7 at 9’ depth yielded practically refusal N-value (N>60), indicating a very dense soil deposit.
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Bedrock: The surface of the bedrock is undulating at the project site. It was encountered as shallow as 4’ (TH-6) below ground surface to the deepest depth of 17.5’ (TH-4). Based on the ground surface elevations of the boreholes at the proposed aquatic facility location (TH-1 through TH-6), bedrock elevations vary from 21.2’ to 8.2’ mllw. This rock strata extends to the termination depth of all boreholes, and is believed to extend to significant depths.
The encountered bedrock is generally described as strong to very strong, gray, massive, fresh to slightly weathered Greywacke, with closely to widely spaced fracture joints. Dip was estimated ranging from 10 degrees to 80 degrees. Rock Quality Designation’s (RQD) ranged from 0 to 100%, with arithmetical mean of 54%. Plot of measured RQD’s are shown below for easy reference.
PLOT OF ROCK QUALITY VS. DEPTH
110
100
90
80
70 TH-1 TH-2 TH-3 60 MEAN RQD=54% TH-4 TH-5 50 TH-6 TH-7 40 TH-8
30 ROCK QUALITY DESIGNATION (RQD), % (RQD), DESIGNATION QUALITY ROCK
20
10
0 0 102030405060 DEPTH, FEET
6. CONCLUSIONS AND RECOMMENDATIONS
6.1. Seismic Evaluation and Site Class
The IBC uses a recurrence level of 2% chance of exceedance in 50 years (a 2,500 year recurrence interval) as a basis for design. Based on USGS AK 2007 update, the mapped 0.2sec spectral response acceleration, Ss, and the 1sec spectral response acceleration, S1, is equivalent to 78% and 47%, respectively. The spectral response was derived based on Latitude = 57o02’59” N Longitude = 135o20’56”W.
Peak ground acceleration (PGA) of 0.326g was estimated based on the U.S. Geological Survey maps “Probabilistic Seismic Hazard Maps of Alaska” 2007 update.
Based on International Building Code, 2006 Edition (reference 1), in our opinion, the prevailing subsoil condition at the site may be classified under the “A” category.
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6.2. Geotechnical Design Parameters
Figure 6.2-1: Unit Weights and Strength Parameters Soil/Rock type Effective Unit Shear Strength, Angle of Effective Weights, su Friction, φ cohesion, c' dry/'sat [PSF] [°] [PSF] [PCF] Compacted 115/65 n.a. 36 0 Granular Fill Organic Soil/ 95/35 0 22 0 Original Ground 1000 Bedrock 140/135 - 45
Figure 6.2-2: Hydraulic Parameters Soil/Rock type Constrained Modulus, M Permeability, k Kips/ft2 m/s (ft/sec)
Compacted 600 -6 -4 -6 -4 1 ×10 to 1×10 (3.28 ×10 to 3.28 ×10 ) Granular Fill -9 -6 -9 -6 Bedrock 9,000 1 ×10 to 2.5×10 (3.28 ×10 to 8.2 ×10 )
The above permeability values are purely an estimate based on standard values. Actual permeability coefficient may be determined by conducting packer tests in the boreholes. The actual permeability of the rocks based on theoretical studies is strongly dependent on fracture aperture.
Figure 6.2-3: Rock Properties Uniaxial Compressive Strength (UCS) = 500 kips/ft2 Reference [5], pp-10-22 Rock Quality Designation (RQD) = 54% RQD results Modulus of Elasticity, Es = 300 ksi Derived below Poisson’s Ratio, = 0.23 Reference [2], pp-10-27 Friction Angle = 45 degrees Reference [2], pp-278 Moist Unit Weight = 140 PCF Reference [2], pp-278
Based on the AASHTO LRFD Bridge Design Specifications, 4th Addition, 2007 (reference 6), pp. 10-26, the average value of modulus of deformation, Ei for the greywacke (comparable to sandstone rock) can be assumed as 2000 ksi. The modulus of elasticity, Es of in-situ rock can be determined as:
Es = Ke x Ei = 0.15 x 2000 = 300 ksi; the reduction factor, Ke was estimated based on RQD in reference [6].
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For Poisson's ratio = 0.23, the Young's Modulus, E, and the Shear Modulus, G, are related to the constrained modulus, M, as:
1 12 E = 0.86 x M 1
12 G G = 0.70 x M 1
6.3. Permissible Foundation Bearing Pressure
It is concluded that the presence of the in-situ bedrock at shallow depths (TH-3 and TH-6) at the proposed aquatic facility site is favorable for supporting the construction of the foundation of the aquatic facility. It is therefore recommended that the deep pool foundation be founded directly on the underlying competent bedrock (Greywacke rock) where elevations allow. Footings on bedrock may be of ordinary concrete spread footing design.
Considering the influence of joints, shear zones, solution features and discontinuities, in proportioning the footing pads under dead load plus code-specified live loads, a conservative allowable or safe net bearing pressure up to 12.0 kips/ft2 may be assumed. (Net pressure means gross pressure less the minimum overburden pressure around the edge of the subject foundation). This allowable bearing pressure may be increased by one-third (1/3) when load combinations involving wind or earthquake effects are considered, where allowed by the building code. Elastic settlement may be assumed to be practically nil.
During excavation for the deep pool foundation, it is recommended the bedrock surface be exposed to ensure the pool foundation footing is bearing on the competent bedrock and not boulders or loose rocks. The bedrock surface should be clean and level. If a level rock surface is difficult to achieve, a D-1 leveling course can be placed.
6.3.1. Passive and Active Resistance for Shallow Foundations
The resistance to sliding and eccentricity limits (overturning) for foundations on bedrock may be determined using the soil parameters presented below.
Angle of Internal Friction 45 degrees
Coefficient of friction s=0.30 Cohesion 0 Moist Unit Weight 140 PCF
It is suggested that passive resistance at the footing level should be conservatively ignored, unless provided with a base key.
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6.3.2. Slab-On-Grade
For the analysis of integrated concrete foundation or mat (slab-on-grade) on bedrock, designed to resist hydrostatic uplift, a subgrade modulus of not more than 500 kips/ft3 may be assumed. Portions of the pool shell may bear on bedrock surfaces or on engineered fill.
6.3.3. Foundation Walls and Retaining Walls
Pool walls and other walls that retain earth will need to be designed for the lateral earth pressures imposed upon them. Cast-in-place concrete walls are relatively rigid and should be designed for two conditions: 1) saturated earth at rest and 2) active earth pressure with pressures due to seismic accelerations. Pool walls and retaining walls beneath the building footprint will likely be backfilled with compacted shot-rock material or selected borrow (sand/gravel). These will be drained with foundation drainage system.
Both earth pressure coefficients at rest Ko (to be applied for stiff structures at rest-foundation walls) and active earth pressure coefficients Ka (to be applied for retaining walls) are derived from the frictional angles of the actual applied backfill materials, assumed roughness and inclination of surface of backfill. For stiff constructions at rest the degree of compaction applied will affect the earth pressure on the structure.
The walls shall be designed to resist the maximum anticipated water pressure. For a horizontal, static ground water table, the total hydrostatic water pressure shall be determined using the following relationship. 2 wHw Pw 2 Where wis unit weight of water and Hw is the full height of water to be considered.
If the ground water levels differ on opposite sides of the wall, the effects of seepage forces on wall stability shall be considered. Hydrostatic pressures and seepage shall be controlled by providing free-draining granular backfill and weep holes through the wall. Weep holes shall be placed through the wall at the lowest elevation that will permit gravity drainage. Portions of walls below the level of weep pipes shall be designed for full hydrostatic pressure unless a deeper drainage pipe is provided behind and at the base of the wall.
We recommend a well-drained soil for backfill and positive foundation wall and footing drainage. We recommend water proofing the foundation with a membrane, water stops in the concrete construction joints and other appropriate measures to maintain a waterproof barrier.
Walls are likely to be founded on bedrock based on our preliminary understanding of the site development. In designing the walls, the pressure coefficients (K-at-rest, K-active, K-passive) may be estimated based on the following soil parameters.
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Soil Layers Granular Compacted Bedrock NFS Fill Effective Angle of Internal Friction, ’ 36o degrees 45o degrees Effective Cohesion, c 0 1000 PSF
Soil Unit Weight, s 115 PCF 140 PCF
Added Lateral Force Due to Seismic
The NAVFAC DM 7.02 (reference 9) suggests that the earth pressure coefficient for dynamic increase in lateral force can be approximated as ¾ x 0.326 (horizontal acceleration). The dynamic lateral force is assumed to act at 0.6H above the wall base.
In the analysis of the wall bearing on the bedrock the following safety factor, FS, is recommended:
Failure Mode Recommended Safety Factor, FS Deep slip 1.25 to 1.5 Overturning 1.5 to 2.0 Sliding 1.5 to 2.0 Foundation Failure 2.0 to 2.5
6.4. Pool Building Foundation
The field investigation for this project indicates that bedrock excavation will be required for some aspects of the construction of the MEHS aquatic facility foundation structure. In soft, weathered rock, the rock may be “rippable” with excavator equipped with ripper bucket or hydraulic rock breaker. In stronger, harder and non-weathered bedrock formations, drilling and blasting operations will be necessary. Although no pool finish deck elevations have been established, it is likely the finish pool deck elevation will be a few feet higher than the adjacent paved roadways and blasting of the deep pool section will be necessary. The rock core samples obtained in this investigation showed different orientation of fracture joints, which indicates excessive overbreak or ground displacement is possible if blasting is not controlled. A controlled blast is performed by:
Drilling holes into bedrock to design depth, diameter and spacing as prepared by a certified blast consultant; Placement of a charge, carefully designed for optimal breakage, into the drilled hole; and Timed detonation of the charges in an optimal sequence to fragment the rock while minimizing vibration and noise.
Rock blasting creates three effects of concern on this project: Flyrock, excessive ground motion and airblast. Mitigation measures to protect public health, safety and property include, but are not limited to submission of a blasting plan by a certified blast consultant, pre-blast survey of existing structures within 1,000 feet of the project site, ground and vibration monitoring during the blast, mandatory advance public notification plan and use of blasting mats to prevent flyrock.
Page 13 of 18 Mt. Edgecumbe High School Aquatic Facility Geotechnical Investigation
During bedrock excavation, a temporary vertical slope of 0.25:1 (H:V) may be assumed. A flatter slope of 0.5:1 (H:V) is recommended for permanent rock slopes. Any overblasting should be backfilled with compacted shot rock fill or D-1. If access roads or structures are adjacent to above grade rock cut slopes, a 10’ wide rockfall protection zone should be implemented in the project design.
Pool Building Site Preparation
It is recommended that all frost susceptible soils be removed to reduce frost penetration and possible pool foundation settlement from freeze/thaw cycles when not in a bedrock cut condition. The following site preparation methods are recommended for this site:
1. Install erosion and sediment control devices prior to beginning construction. 2. Clear and grub trees and vegetation designated for removal within the project site. 3. Install dewatering devices as necessary to maintain a dry work zone. 4A. Over-excavate the area beneath the pool building foundation (10’ outside each side of building foundation) to a depth of 4’ minimum below bottom of proposed footing. Excavate for the contour of the pool bottom a minimum of 4’ below the foundation mat. See 5, 6 and 7 below for further site preparation recommendations. 4B. In bedrock condition, excavate and remove soils above bedrock strata. Excavate bedrock by machine methods, or drilling and blasting per the approved blasting plan to 6”-12” below the bottom of pool foundation. Place 6”-12” depth of base course grading D-1 compacted to 95% of the maximum dry density unit weight. 5. Static proof roll the bottom of the excavation using a 10-ton self-propelled compactor. Should areas be observed to “pump” or “settle” further, excavate and replace with shot rock borrow. 6. Place 12” minus well graded shot rock borrow, 3’ minimum depth and compact with a vibratory grid roller (minimum centrifugal force shall be 50,000 lb.) with minimum of 8 passes prior to placement of subsequent lifts. One pass is considered down and back. Initial lift thickness shall be a maximum of 24” in depth; all other lifts 12”. Shot rock gradation should include enough fines such that the surface will seal and not be subject to voids from loss of fine material. As an option, geotextile separation fabric could be placed above the shot rock to prevent loss of fines and potential formation of voids and settlement beneath the pool structural shell. 7. Select borrow material above the shot rock borrow shall be placed in maximum 12” lifts compacted to 95% of the maximum dry density unit weight as determined by modified proctor (ASTM D1557). This material shall be placed up to the bottom of the base coarse below the pool building floor slab or pool mat.
Non-frost susceptible (N.F.S.) select borrow material shall consist of sand, gravel, fractured rock or combination thereof containing no muck, frozen materials, roots or other deleterious materials. The material shall have a plasticity index not greater than 6 as determined by AASHTO T90 and shall contain no more than 6% passing the #200 sieve based on material that passes a 3-inch screen.
The engineered embankment will have an allowable soil bearing pressure of 2,500 psf if constructed in accordance with the guidelines stated in 4A above. The majority of overall
Page 14 of 18 Mt. Edgecumbe High School Aquatic Facility Geotechnical Investigation building site settlement should occur during embankment construction. After construction, settlement is estimated at less than 1½” with differential settlement of less than 1”.
6.5. Parking Areas Site Preparation (TH-7 & TH-8)
The following typical section of improvement is recommended to prepare the existing soils for asphalt paved parking areas:
1. Clear and grub the site as required, removing the surficial organics in undisturbed natural areas. Install erosion control devices as necessary. 2. Excavate the parking lot area down to 60” below design finish grade. 3. Proof roll the bottom of the excavation using a 10-ton or larger self propelled compactor. Should areas be observed to “pump” or “settle”, excavate and replace with N.F.S. or clean granular subbase and compact to 95% of its modified proctor test density (ASTM D1557 or AASHTO T180). 4. Place a geotextile fabric prior to placing the shot rock borrow. The purpose of the geotextile fabric is to contain the fill from punching through the underlying loose ground and to distribute the load of the fill minimizing local shear failure. 5. Place and compact a 52” depth of non-frost susceptible (N.F.S.) well-graded 6” minus shot rock material in 12” lifts to achieve desired fill height to bottom of base course. Shot rock should be compacted with a vibratory grid roller (minimum centrifugal force shall be 50,000- lb) with minimum of 8 passes prior to placement of subsequent lifts. 6. Place a minimum of 6” of crushed aggregate base course, conforming to CBS base course grading D-1 specifications. Compact to 95% of the maximum laboratory dry density per ASTM D 1557, Method D specifications. Water content during compaction should be within + 2% of the optimum moisture content determined from laboratory modified proctor test (ASTM D1557 or AASHTO T180). 7. Place a single 2” lift of hot asphalt pavement Type II, Class B mix requirements.
7. CONSTRUCTION CONSIDERATIONS
7.1. Drainage and Dewatering
After drilling it was not possible to determine a true water level in the boreholes as core drilling into the bedrock was accomplished using water mixed with bentonite drilling mud. The drilling mud sealed the voids in the soil and fractures in the bedrock, thus water was trapped and the boreholes remain full of the drilling solution after drilling operations. Groundwater during the field investigation was only observed at TH-3 at 4.0’ depth above the bedrock surface. The observed groundwater appeared to be perched groundwater as similar ground water was not noted at the rest of the boreholes.
It may be expected that large surface run-offs during wet periods of the year are expected to produce ponding on the rock surface that could affect project construction. For this condition, dewatering at the base of the excavation will likely be required to maintain a dry rock surface during construction of the foundation.
Engineering measures must be initiated to prevent water inflow into the pool foundation excavation and all other areas during construction. The excavation bottom must be kept dry as possible. Excessive rain or snow might have a similar effect during construction.
Page 15 of 18 Mt. Edgecumbe High School Aquatic Facility Geotechnical Investigation
Post construction surface and groundwater problems should not occur as long as:
1. All below-grade portions of the pool building are properly water and moisture-proofed by waterproofing the below grade foundation walls and placement of a plastic vapor barrier below the floor slabs. 2. Surface water is effectively isolated from entering all soils below foundation footings and floor slabs. 3. Surface grading is accomplished in a manner that will positively divert surface water runoff away from the structure. 4. Concentrated runoff is controlled by installing perimeter foundation and roof drain systems to route surface and subsurface drainage away from the building.
7.2. Temporary Excavation Supports
Excavation shoring may not be necessary due to the shallow location of bedrock. The relatively wide area will also allow construction of stable temporary excavation slopes on overburden soil. The temporary excavation side slopes may be constructed based on the table below.
Soil / Fill Material Height of Cut (ft) Slope Gradient H:V Loose to Medium dense Less than 5 ft 1:1 overburden soil > 5 to 10 ft 1.5:1 Bedrock Up to 10 ft 0.25:1
7.3. Frost Protection
Footings founded on bedrock should not be affected by seasonal frost heave. Therefore embedment depth for frost protection is not required. In conditions where the foundation is bearing on an engineered fill, a minimum fill of 32” is recommended over the top of the footing for frost protection.
7.4. Underground Utilities
Water and sewer utilities will be connected to the CBS public systems located with UAS Access Road. 8” pvc sanitary sewer stub out is located on the west side of the UAS Access Road adjacent the site for connecting to. No onsite disposal of wastewater or private water well use is anticipated. 8” DIP water main stub out is located on the west side of UAS Access Road. No unusual difficulties are foreseen provided standard design and construction techniques are employed, such as, proper bedding of buried pipes, compacting trench backfill to 95% of modified proctor and sufficient pipe embedment to prevent freezing (5’ to top of waterline). Sanitary sewer and water lines should be constructed in accordance with applicable codes and standards of the CBS Public Works Department. The pool drain will be located at the low point of the pool shell and may require pumping to get to drain to the 8” pvc gravity sewer line.
Page 16 of 18 Mt. Edgecumbe High School Aquatic Facility Geotechnical Investigation
8. LIMITATIONS
This report was prepared to aid the Client/Engineer in the design of this specific project. Its scope is limited to the project and location described herein and represents our understanding of the surface and subsurface conditions at the site, at the time of the investigation. This report was prepared in accordance with generally accepted professional principles and practices in the field of geotechnical engineering at the time this report was prepared. The exact nature and extent of subsurface variations across the site may not become evident until construction. If, during construction, fill, soil, rock, bedrock, surface water, or groundwater conditions appear to be different from those described herein, R&M’s geotechnical engineer should be advised immediately so re-evaluation of the recommendations herein can be made.
R&M is not responsible for safety programs, methods or procedures of operation, or the construction of the design recommendations provided in this report. Where recommendations are general, or not called out, the recommendations shall conform to standards of the industry. This geotechnical report is for use on this project only and is not intended for reuse without written approval from R&M. This geotechnical report is not to be used in a manner that would constitute a detriment directly, or indirectly, to R&M.
Thank you for the opportunity to be of service to ECI/Hyer, Inc. on this important public building project. Should you have questions concerning this report, please contact us at 780-6060.
Sincerely,
R&M ENGINEERING, INC.
2/19/2013
Mark J. Pusich, P.E. Edmon Cruz Civil Engineer Geotechnical Engineer
I:\2012\121173\Report\130219, MEHS Aquatic Center Draft Geotech Report.docx
Page 17 of 18 Mt. Edgecumbe High School Aquatic Facility Geotechnical Investigation
9. REFERENCES 1. International Building Code, 2006 Edition. 2. Foundation Analysis and Design, Joseph E. Bowles, 5th Edition. 3. American Society for Testing & Materials, Vol. 4.8 & 4.9. 4. DOT&PF Alaska Field Guide for Soil Classification. 5. DOT&PF Alaska Field Rock Classification and Structural Mapping Guide. 6. AASHTO LRFD Bridge Design Specifications, 4th Edition 2007. 7. Soil Mechanics in Engineering Practice, Third Edition, 1996, Terzaghi et. al. 8. Mt. Edgecumbe High School Aquatic Facility, Geotechnical Review of Available Information, R&M Engineering, Inc. Project No. 121368, September 13, 2012 9. Naval Facilities, Design Manual, Volume 7.02, Foundation and Earth Structures
Page 18 of 18
APPENDIX 1
SELECTED PHOTOGRAPHS
The proposed parking areas where boreholes TH-7 and TH-8 were drilled. The building in the background is the Mt. Edgecumbe High School Maintenance (MEHS) Building
The existing old power plant building. Boreholes TH-1, TH-2 and TH-5 were drilled around the building.
The MEHS maintenance temporary stockpile and storage area. Boreholes TH-3, TH-4 and TH-6 were drilled in this area.
Page 1 of 5
Borehole TH-1, located northeast side of the existing power plant building.
Borehole TH-2, located south side of the Photo showing R&M CME-55 set-up at existing power plant building. borehole TH-2.
Drilling operation at borehole TH-3 in progress.
Page 2 of 5
Photo showing daytime and night time drilling operations at borehole TH-4.
Borehole TH-5 located northwest of the Photo showing drilling operation at TH-5. existing power plant building.
R&M drill rig set up and drilling at borehole Drilling operation at night time at borehole TH-6. TH-6.
Page 3 of 5
Photo showing borehole TH-7. The stake was Drilling operation at borehole TH-7 (proposed offset 10’ towards the building corner. parking area).
Photo showing borehole TH-8 (proposed Drilling operation conducted at night at TH-8 parking area) after completing borehole TH-7.
Core samples from TH-1, showing fractured Greywacke rocks.
Page 4 of 5
Core samples from TH-2, 16’-26.5’ depth. Core samples from TH-3, 5’-14.5’ depth.
Contaminated soil sample recovered from TH-4 at 14’ to 16’ depth. The upper soil layer was also found contaminated.
Core samples from TH-4, 22’-32’ depth. Core samples from TH-6, 25’-35’ depth.
Page 5 of 5
APPENDIX 2
DRILL TEST HOLE LOCATION MAP SYMBOLS TEST HOLE DEPTH
TH-1 (50') A DRILL TEST HOLE
UAS ACCESS ROAD TH-1 (30') 25'
31'
EXISTING POWERHOUSE B 50' MT. EDGECUMBE 5' TH-2 (35') HIGH SCHOOL BUILDING TH-5 (30') 20' PROPOSED AQUATIC CENTER 23' TH-4 (35')
68'
CONEX 59'
TH-3 (50') 10'
5' A
CONEX CONEX
48.5'
45' CONEX EXISTING MAINTENANCE TH-7 (20') BUILDING 65' TH-6 (50') 20' B WORK FLOAT ACCESS PROPOSED PARKING AREA
TH-8 (20')
AIRPORT ROAD
MT. EDGECUMBE HIGH SCHOOL DRILL TEST HOLE LOCATION MAP AQUATIC FACILITY GEOTECHNICAL INVESTIGATION
SITKA , ALASKA 1 OF 1
APPENDIX 3
TEST HOLE LOGS EXPLANATION SAMPLER TYPE SYMBOLS UNFROZEN GROUND Ss 1.4" SPLIT SPOON WITH 140 LB. HAMMER Sz 1.4" SPLIT SPOON WITH 340 LB. HAMMER ORGANIC MATERIAL Sh 2.5" SPLIT SPOON WITH 340 LB. HAMMER Sp 2.5" SPLIT SPOON, PUSHED Little Visible Ice 0-10 Vx A AUGER SAMPLE A.B. ICE DESCRIPTION Cs CORE SAMPLE SAMPLE NUMBER Bs BULK SAMPLE 1 Ss, 72, 57.1%, 85.9pcf DRY DENSITY SOIL SYMBOLS WATER CONTENT ORGANIC SAND & BLOWS/FOOT GRAVEL 5 SAMPLER TYPE MATERIAL GRAVEL COBBLES & BEACH W.D. WATER TABLE CLAY APPROX. STRATA CHANGE BOULDERS SHELLS SILT BEDROCK BEDROCK W.D.-WHILE DRILLING/DIGGING FROZEN GROUND SAND GLACIAL TILL A.B.-AFTER BORING T.H.-1 T.H.-1 CONT. T.H.-2 T.H.-2 CONT. CME-55 SOIL DESCRIPTION CME-55 SOIL DESCRIPTION CME-55 SOIL DESCRIPTION CME-55 SOIL DESCRIPTION SAMPLED SAMPLED SAMPLED SAMPLED FROZEN FROZEN FROZEN FROZEN DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK GROUND EL.=24.33' 11-19-12 DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK 11-19-12 DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK GROUND EL.=24.77' 11-16-12 DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK 11-16-12
10.0'-31.0' Strong to very strong, gray, massive, 0'-2.5' Very loose, dark brown Silty Sand with slightly weathered Greywacke, with widely Organics and fine gravel. spaced, smooth to rough, and planer 0'-5.0' Loose, Dark Sand and Gravel, little Silt, fracture joints dipping 10° to 80°. 8 Cs, Recovery = 100% RQD = 100% moist. 5 Cs, Recovery = 100%, RQD = 50% 2.5'-7.5' Coarse Gravel with Silt (Contaminated with fuel). 1 Ss, N=10 9 Cs, Recovery = 100% RQD = 100% 5 30 6 Cs, Recovery = 100%, RQD = 79% 5 1 Ss, N=19 30 14.0'-35.0' Strong to very strong, gray, massive, slightly weathered Greywacke, with widely - End of Test Hole at 31.0' 5.0'-10.0' Coarse Gravel and Cobbles. spaced, stepped, smooth to rough, and planar fracture joints dipping 10° to 80°.
7.5'-9.0' Gray dense, Sandy Gravel, trace of Silt.(GP) 10 Cs, Recovery = 80% RQD = 73% 2 Ss, N=41 21 2 Ss, N= 2" (refusal). 10 35 10 35 - Bedrock started at 10' depth 9.0'-14.0' Cobbles to Boulder size Greywacke rocks, - End of Test Hole at 35.0' 1 with Silt infill, 1 2' to over 2' size rocks. 3 Cs, Recovery = 59%, RQD = 67% 3 Cs, Recovery = 96% RQD = 29%
15 40 15 40 10.0'-31.0' Strong to very strong, gray, massive, 4 Cs, Recovery = 81% RQD = 69% slightly weathered Greywacke, with widely spaced, smooth to rough, and planar fracture joints dipping 10° to 80°. 5 Cs, Recovery = 100% RQD = 0% 14.0'-35.0' Strong to very strong, gray, massive, slightly weathered Greywacke, with widely 4 Cs, Recovery = 59%, RQD = 27% spaced, stepped, smooth to rough, and 20 45 20 planar fracture joints dipping 10° to 80°. 45 6 Cs, Recovery = 100% RQD = 90%
7 Cs, Recovery = 100% RQD = 67%
MT. EDGECUMBE HIGH SCHOOL TEST HOLE LOGS AQUATIC FACILITY GEOTECHNICAL INVESTIGATION
SITKA , ALASKA 1 OF 4 EXPLANATION SAMPLER TYPE SYMBOLS UNFROZEN GROUND Ss 1.4" SPLIT SPOON WITH 140 LB. HAMMER Sz 1.4" SPLIT SPOON WITH 340 LB. HAMMER ORGANIC MATERIAL Sh 2.5" SPLIT SPOON WITH 340 LB. HAMMER Sp 2.5" SPLIT SPOON, PUSHED Little Visible Ice 0-10 Vx A AUGER SAMPLE A.B. ICE DESCRIPTION Cs CORE SAMPLE SAMPLE NUMBER Bs BULK SAMPLE 1 Ss, 72, 57.1%, 85.9pcf DRY DENSITY SOIL SYMBOLS WATER CONTENT ORGANIC SAND & BLOWS/FOOT GRAVEL 5 SAMPLER TYPE MATERIAL GRAVEL COBBLES & BEACH W.D. WATER TABLE CLAY APPROX. STRATA CHANGE BOULDERS SHELLS SILT BEDROCK BEDROCK W.D.-WHILE DRILLING/DIGGING FROZEN GROUND SAND GLACIAL TILL A.B.-AFTER BORING T.H.-3 T.H.-3 CONT. T.H.-4 T.H.-4 CONT. CME-55 SOIL DESCRIPTION 11-12-12 CME-55 SOIL DESCRIPTION 11-12-12 CME-55 SOIL DESCRIPTION 11-15-12 CME-55 SOIL DESCRIPTION 11-15-12 SAMPLED SAMPLED SAMPLED SAMPLED FROZEN FROZEN FROZEN FROZEN DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK GROUND EL.=26.20' 11-13-12 DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK 11-13-12 DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK GROUND EL.=25.65' 11-16-12 DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK 11-16-12
5 Cs, Recovery = 100%, RQD = 50% 5 Cs, Recovery = 67%, RQD = 0% 0'-2.5' Gray Silty Gravel with Sand. (Contaminated with fuel)
2.5'-5.0' Cobbles and Boulders. 6 Cs, Recovery = 100%, RQD = 25% 6 Cs, Recovery = 67%, RQD = 60% H2O @ 4.0' 7 Cs, Recovery = 61%, RQD = 28% 5 30 5 30 0'-16.5' Loose Gray Gravel with Sand and Silt. (Contaminated with oil) 26.5'-35.0' Strong to very strong, gray, massive, fresh to slightly weathered Greywacke, 7 Cs, Recovery = 96%, RQD = 44% 1 Cs, Recovery =100%, RQD = 75% closely to widely spaced, smooth to rough, stepped, and planar joints dipping 0° to 80°. 8 Cs, Recovery = 67%, RQD = 39% 8 Cs, Recovery = 100%, RQD = 0% 10 35 9 Cs, Recovery = 100%, RQD = 50% 10 35 - End of Test Hole at 35.0'
2 Cs, Recovery = 100%, RQD = 73% 10 Cs, Recovery = 100%, RQD = 42%
5.0'-50.0' Strong to very strong, gray, massive, fresh 11 Cs, Recovery = 100%, RQD = 0% to slightly weathered Greywacke, with widely spaced, stepped but also smooth 15 planar fracture joints dipping 0° to 80°. 40 15 40 62 1 Ss, N = 4" (refusal) 16.5'-17.5' Gray, very dense, Glacial Till. 3 Cs, Recovery = 90%, RQD = 70% 12 Cs, Recovery = 100%, RQD = 67%
2 Cs, Recovery = 77%, RQD = 54%
20 45 20 45 3 Cs, Recovery = 75%, RQD = 21% 13 Cs, Recovery = 100%, RQD = 50% 17.5'-26.5' Medium weak to very strong, gray, massive, slightly weathered Greywacke, 4 Cs, Recovery = 92%, RQD = 60% with closely to widely spaced, smooth to rough, and planar fracture joints dipping 14 Cs, Recovery = 100%, RQD = 83% 0° to 80°. 4 Cs, Recovery = 86%, RQD = 29% - End of Test Hole at 50.0'
MT. EDGECUMBE HIGH SCHOOL TEST HOLE LOGS AQUATIC FACILITY GEOTECHNICAL INVESTIGATION
SITKA , ALASKA 2 OF 4 EXPLANATION SAMPLER TYPE SYMBOLS UNFROZEN GROUND Ss 1.4" SPLIT SPOON WITH 140 LB. HAMMER Sz 1.4" SPLIT SPOON WITH 340 LB. HAMMER ORGANIC MATERIAL Sh 2.5" SPLIT SPOON WITH 340 LB. HAMMER Sp 2.5" SPLIT SPOON, PUSHED Little Visible Ice 0-10 Vx A AUGER SAMPLE A.B. ICE DESCRIPTION Cs CORE SAMPLE SAMPLE NUMBER Bs BULK SAMPLE 1 Ss, 72, 57.1%, 85.9pcf DRY DENSITY SOIL SYMBOLS WATER CONTENT ORGANIC SAND & BLOWS/FOOT GRAVEL 5 SAMPLER TYPE MATERIAL GRAVEL COBBLES & BEACH W.D. WATER TABLE CLAY APPROX. STRATA CHANGE BOULDERS SHELLS SILT BEDROCK BEDROCK W.D.-WHILE DRILLING/DIGGING FROZEN GROUND SAND GLACIAL TILL A.B.-AFTER BORING T.H.-5 T.H.-5 CONT. T.H.-6 T.H.-6 CONT. CME-55 SOIL DESCRIPTION 11-19-12 CME-55 SOIL DESCRIPTION 11-19-12 CME-55 SOIL DESCRIPTION 11-13-12 CME-55 SOIL DESCRIPTION 11-13-12 SAMPLED SAMPLED SAMPLED SAMPLED FROZEN FROZEN FROZEN FROZEN DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK GROUND EL.=25.10' 11-20-12 DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK 11-20-12 DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK GROUND EL.=25.24' 11-15-12 DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK 11-15-12
0'-1.5' Gray Silty Sand with Gravel (Fill). 9 Cs, Recovery = 83%, RQD = 53% 1.5'-4.0' Cobbles and Boulders, observed little oil 9 Cs, Recovery = 100%, RQD = 91% sticking in the surface of broken rocks. 0'-7.0' Medium dense, brownish gray Gravel and 1 Cs, Recovery = 83%, RQD = 17% Sand with few Cobbles, trace of silt. 10 Cs, Recovery = 100%, RQD = 40%
1 Ss, N=21 5 30 5 30 - End of Test Hole at 30.0'
10 Cs, Recovery = 100%, RQD = 93% 2 Cs, Recovery = 100%, RQD = 59% 2 Cs, Recovery = 100%, RQD = 38% 4.0'-50.0' Strong to very strong, massive, fresh to slightly weathered Greywacke, with widely 4.0'-50.0' Strong to very strong, massive, fresh to spaced, stepped but smooth to rough, and slightly weathered Greywacke, with widely 3 Cs, Recovery = 100%, RQD = 67% planar fracture joints dipping 0° to 80°. 10 35 10 spaced, stepped but smooth to rough, and 35 planar fracture joints dipping 0° to 80°. 11 Cs, Recovery = 100%, RQD = 100% 4 Cs, Recovery = 100%, RQD = 25% 3 Cs, Recovery = 100%, RQD = 40% 7.0'-30.0' Medium weak, gray, massive, moderately weathered Greywacke, with closely spaced, rough, and planar fracture joints dipping 12 Cs, Recovery = 100%, RQD = 83% 0° to 80°. Significant Feldspour/Calcite from 19' to 25' depth. 4 Cs, Recovery = 83%, RQD = 33% 15 40 15 40 5 Cs, Recovery = 100%, RQD = 67%
-Sample fell and grinded. 13 Cs, Recovery = 100%, RQD = 58%
6 Cs, Recovery = 57%, RQD = 0% 5 Cs, Recovery = 100%, RQD = 67%
6 Cs, Recovery = 100%, RQD = 57% 20 45 20 45 14 Cs, Recovery = 100%, RQD = 83% 7 Cs, Recovery = 100%, RQD = 33% 7 Cs, Recovery = 100%, RQD = 18%
15 Cs, Recovery = 100%, RQD = 67% 8 Cs, Recovery = 83%, RQD = 53% 8 Cs, Recovery = 83%, RQD = 50%
- End of Test Hole at 50.0'
MT. EDGECUMBE HIGH SCHOOL TEST HOLE LOGS AQUATIC FACILITY GEOTECHNICAL INVESTIGATION
SITKA , ALASKA 3 OF 4 EXPLANATION SAMPLER TYPE SYMBOLS UNFROZEN GROUND Ss 1.4" SPLIT SPOON WITH 140 LB. HAMMER Sz 1.4" SPLIT SPOON WITH 340 LB. HAMMER ORGANIC MATERIAL Sh 2.5" SPLIT SPOON WITH 340 LB. HAMMER Sp 2.5" SPLIT SPOON, PUSHED Little Visible Ice 0-10 Vx A AUGER SAMPLE A.B. ICE DESCRIPTION Cs CORE SAMPLE SAMPLE NUMBER Bs BULK SAMPLE 1 Ss, 72, 57.1%, 85.9pcf DRY DENSITY SOIL SYMBOLS WATER CONTENT ORGANIC SAND & BLOWS/FOOT GRAVEL 5 SAMPLER TYPE MATERIAL GRAVEL COBBLES & BEACH W.D. WATER TABLE CLAY APPROX. STRATA CHANGE BOULDERS SHELLS SILT BEDROCK BEDROCK W.D.-WHILE DRILLING/DIGGING FROZEN GROUND SAND GLACIAL TILL A.B.-AFTER BORING T.H.-7 T.H.-8 CME-55 SOIL DESCRIPTION CME-55 SOIL DESCRIPTION SAMPLED SAMPLED FROZEN FROZEN DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK GROUND EL.=18.89' 11-18-12 DEPTH(FT.) SOIL GRAPH LOCATION DRILL TRUCK GROUND EL.=17.70' 11-18-12
0'-3.0' Dark coarse Gravel with Sand, moist. 0'-5.0' Gray Gravel and Sand with few 6" Cobbles.
1 Ss, No penetration , refusal on boulders. -3.2' Observed some Organics, possibly original 1 Ss, N=6 ground surface.
5 5 2 Ss, N=3 3.0'-8.0' Loose, brownish gray Organic Gravelly 5.0'-9.0' Organics including sticks and Peat, loose Sand, moist, with trace of Silt. (SP-SM) drilling.
8.0'-10.0' Organics mixed with Cobbles.
9.0'-11.0' Gray, dense, Glacial Till. 3 Ss, N=29 10 2 Ss, N=72 10
10.0'-12.0' Gravel with Silt. (Till) - Hit bedrock at 11.0' 3 Cs, Recovery = 77%, RQD = 23%
4 Cs, Recovery = 100%, RQD = 68% 4 Cs, Recovery = 80%, RQD = 40% 11.0'-20.0' Moderately weak to strong, gray, massive, 12.0'-20.0' Strong to very strong, gray, massive, moderately to slightly weathered slightly to moderately weathered 15 Greywacke, with closely to widely spaced, 15 Greywacke, with closely to widely spaced, smooth to rough, planar fracture joints smooth to rough planar fracture joints dipping 0° to 80°. dipping 10° to 80°. 5 Cs, Recovery = 100%, RQD = 0% 5 Cs, Recovery = 100%, RQD = 56%
6 Cs, Recovery = 100%, RQD = 100% 6 Cs, Recovery = 25%, RQD = 0%
20 20 - End of Test Hole at 20.0' - End of Test Hole at 20.0'
MT. EDGECUMBE HIGH SCHOOL TEST HOLE LOGS AQUATIC FACILITY GEOTECHNICAL INVESTIGATION
SITKA , ALASKA 4 OF 4
APPENDIX 4
SOIL PROFILES MT. EDGECUMBE HIGH SCHOOL SOIL PROFILES AQUATIC FACILITY GEOTECHNICAL INVESTIGATION
SITKA , ALASKA 1 OF 1
APPENDIX 5
LABORATORY TEST RESULTS Sieve Analysis 6205 GLACIER HIGHWAY JUNEAU, ALASKA 99801 ASTM D422
Client ECI/Hyer Project # 121173 Project MEHS AQUATIC FACILITY Received Date 11/3/2012 Location SITKA, ALASKA Reported Date 12/5/2012
Material/Source IN-SITU SOIL / BOREHOLE Tested by/date EBC 12-3-12 Sampled by/date R.KENNY, R&M Engineering / 11-16&18-2012 Moisture 9.3% 40.5% #DIV/0! #DIV/0! SIEVE SIZE Percent passing Required Percent passing Required Percent passingRequired Percent passing Requ specs specs specs ired TH-2 TP-8 spec 0 0 7.5-9.0' 4.0'-5.5'
4 " 3 " ##### 2 " ##### ##### 1 1/2 " 100 ##### ##### 1 " 92 100 ##### ##### 3/4 " 79 86 ##### ##### 1/2 " 68 83 ##### ##### 3/8 " 57 76 ##### ##### No 4 44 57 ##### ##### No 8 33 46 ##### ##### No 10 30 43 ##### ##### No 1625 35 ##### ##### No 30 19 23 ##### ##### No 40 18 19 ##### #####
No 50 sandy Gray trace of silt crushed Gravel, (GP) 15 15 ##### ##### No 100 9 9 ##### ##### No 200 4.2 (SP-SM) organics of silt with trace Sand, gravelly Gray 5.9 ##### #####
Grain Size Distribution Curve 2-1/2" 2" 1-1/2" 1" 3/4" 1/2" 3/8" #4 #8 #10 #16 #30 #40 #50 #100 #200
100 TH-2 90 7.5-9.0'
80 TP-8 4.0'-5.5' 70
60 Series2
50
40
30
20 % passing individual sieves passing individual%
10
0 100 10 1 0.1 0.01 Particle Size in mm
Cobbles and Gravel Sand Silt and Clay I:\2012\121173\Gradation 12-4-12 SHEET 1 OF 1