2017 Geotechnical Engineering Manual Geotechnical Engineering Section 1/19/2017 MnDOT Geotechnical Manual ii 2017 GEOTECHNICAL ENGINEERING MANUAL ..................................................................................................... I GEOTECHNICAL ENGINEERING SECTION ............................................................................................................... I 1 PURPOSE & OVERVIEW OF MANUAL ........................................................................................................ 8 1.1 PURPOSE ............................................................................................................................................................ 8 1.2 GEOTECHNICAL ENGINEERING ................................................................................................................................. 8 1.3 OVERVIEW OF THE GEOTECHNICAL SECTION .............................................................................................................. 8 1.4 MANUAL DESCRIPTION AND DEVELOPMENT .............................................................................................................. 9 2 GEOTECHNICAL PLANNING ....................................................................................................................... 12 2.1 PURPOSE, SCOPE, RESPONSIBILITY ......................................................................................................................... 12 2.2 PPMS AND PROGRAMMED PROJECTS .................................................................................................................... 13 2.3 GEOTECHNICAL REQUEST FORM ............................................................................................................................ 14 2.4 OFFICE REVIEW .................................................................................................................................................. 14 2.4.1 Geologic Maps ..................................................................................................................................... 14 2.4.2 Existing Borings .................................................................................................................................... 15 2.4.3 Hydraulics Reports ............................................................................................................................... 15 2.4.4 Site Visit ............................................................................................................................................... 15 2.4.5 Boring and In Situ Test Frequency ........................................................................................................ 15 2.4.6 Subsurface Investigation Plan .............................................................................................................. 19 3 FIELD INVESTIGATIONS ............................................................................................................................. 23 3.1 UTILITY CLEARANCE ............................................................................................................................................ 24 3.2 PROPERTY ACCESS .............................................................................................................................................. 24 3.3 ROADWAY SAFETY AND TRAFFIC CONTROL .............................................................................................................. 24 3.3.1 Location Surveys .................................................................................................................................. 24 3.3.2 Site Clean-Up ........................................................................................................................................ 24 3.4 SUBSURFACE INVESTIGATIONS ............................................................................................................................... 25 3.4.1 Diamond Core Drilling .......................................................................................................................... 25 3.4.2 Soil Sampling ........................................................................................................................................ 26 3.4.3 Continuous Soil Sampling ..................................................................................................................... 27 3.4.4 Boring Depths ...................................................................................................................................... 27 3.4.5 Field Logs ............................................................................................................................................. 28 3.4.6 Borehole Sealing .................................................................................................................................. 31 3.4.7 Special Well Construction Areas .......................................................................................................... 33 3.4.8 Transporting and Storing Samples ....................................................................................................... 33 3.5 IN SITU MEASUREMENTS ..................................................................................................................................... 33 3.5.1 In Situ Rock Measurements .................................................................................................................. 34 3.5.2 Standard Penetration Test (SPT) .......................................................................................................... 34 3.5.3 MnDOT Modified Standard Penetration Test (SPT) ............................................................................. 37 3.5.4 Cone Penetration Test (CPT) ................................................................................................................ 38 3.5.5 Flat Plate Dilatometer (DMT) (ASTM D6635-01) ............................................................................... 40 3.5.6 Pressuremeter Test (PMT) (ASTM D4719) .......................................................................................... 41 3.5.7 Test Pits ................................................................................................................................................ 42 3.5.8 Geophysical Methods ........................................................................................................................... 42 3.6 GROUNDWATER INVESTIGATIONS .......................................................................................................................... 45 3.6.1 Borings & Soundings ............................................................................................................................ 45 3.6.2 Piezometers.......................................................................................................................................... 46 3.6.3 In-Situ Testing ...................................................................................................................................... 46 4 LABORATORY TESTING ............................................................................................................................. 48 4.1 MINIMUM TESTING RATES ................................................................................................................................... 48 4.2 MOISTURE CONTENT TESTS .................................................................................................................................. 48 1/19/2017 MnDOT Geotechnical Manual iii 4.3 UNCONFINED COMPRESSION TESTS ....................................................................................................................... 48 4.4 ONE DIMENSIONAL CONSOLIDATION TESTS ............................................................................................................. 49 4.5 TRIAXIAL COMPRESSION TESTS .............................................................................................................................. 49 4.6 UNIT WEIGHT TESTS ........................................................................................................................................... 49 4.7 SPECIFIC GRAVITY ............................................................................................................................................... 50 4.8 ENGINEERING PROPERTIES ................................................................................................................................... 50 4.8.1 Atterberg Limit Tests ............................................................................................................................ 50 4.8.2 In-place Volume and Weight Relationships ......................................................................................... 51 4.8.3 Grain Size Analysis ............................................................................................................................... 53 4.8.4 Organic Content Tests .......................................................................................................................... 54 4.8.5 Unconfined Compression Tests for Rock .............................................................................................. 54 5 SOIL & ROCK CLASSIFICATION AND LOGGING ........................................................................................... 55 5.1 FIELD IDENTIFICATION ........................................................................................................................................