2013 Geotechnical Engineering Manual Geotechnical Engineering Section Minnesota Department of Transportation 12/11/13 MnDOT Geotechnical Manual ii 2013 GEOTECHNICAL ENGINEERING MANUAL ..................................................................................................... I GEOTECHNICAL ENGINEERING SECTION ............................................................................................................... I MINNESOTA DEPARTMENT OF TRANSPORTATION ............................................................................................... 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 ....................................................................................................................... 11 2.1 PURPOSE, SCOPE, RESPONSIBILITY ......................................................................................................................... 11 2.2 PPMS AND PROGRAMMED PROJECTS .................................................................................................................... 12 2.3 GEOTECHNICAL REQUEST FORM ............................................................................................................................ 12 2.4 OFFICE REVIEW .................................................................................................................................................. 12 2.4.1 Geologic Maps ..................................................................................................................................... 13 2.4.2 Existing Borings .................................................................................................................................... 13 2.4.3 Hydraulics Reports ............................................................................................................................... 13 2.4.4 Site Visit ............................................................................................................................................... 13 2.4.5 Boring and In Situ Test Frequency ........................................................................................................ 14 2.4.6 Subsurface Investigation Plan .............................................................................................................. 17 3 FIELD INVESTIGATIONS ............................................................................................................................. 20 3.1 UTILITY CLEARANCE ............................................................................................................................................ 21 3.2 PROPERTY ACCESS .............................................................................................................................................. 21 3.3 ROADWAY SAFETY AND TRAFFIC CONTROL .............................................................................................................. 21 3.3.1 Location Surveys .................................................................................................................................. 21 3.3.2 Site Clean-Up ........................................................................................................................................ 21 3.4 SUBSURFACE INVESTIGATIONS ............................................................................................................................... 22 3.4.1 Diamond Core Drilling .......................................................................................................................... 22 3.4.2 Soil Sampling ........................................................................................................................................ 23 3.4.3 Continuous Soil Sampling ..................................................................................................................... 24 3.4.4 Boring Depths ...................................................................................................................................... 24 3.4.5 Field Logs ............................................................................................................................................. 25 3.4.6 Borehole Sealing .................................................................................................................................. 28 3.4.7 Special Well Construction Areas .......................................................................................................... 30 3.4.8 Transporting and Storing Samples ....................................................................................................... 30 3.5 IN SITU MEASUREMENTS ..................................................................................................................................... 30 3.5.1 In Situ Rock Measurements .................................................................................................................. 31 3.5.2 Standard Penetration Test (SPT) .......................................................................................................... 31 3.5.3 MnDOT Modified Standard Penetration Test (SPT) ............................................................................. 34 3.5.4 Cone Penetration Test (CPT) ................................................................................................................ 35 3.5.5 Flat Plate Dilatometer (DMT) (ASTM D6635-01) ............................................................................... 37 3.5.6 Pressuremeter Test (PMT) (ASTM D4719) .......................................................................................... 38 3.5.7 Test Pits ................................................................................................................................................ 39 3.5.8 Geophysical Methods ........................................................................................................................... 39 3.6 GROUNDWATER INVESTIGATIONS .......................................................................................................................... 42 3.6.1 Borings & Soundings ............................................................................................................................ 43 3.6.2 Piezometers.......................................................................................................................................... 43 3.6.3 In-Situ Testing ...................................................................................................................................... 43 4 LABORATORY TESTING ............................................................................................................................. 44 4.1 MINIMUM TESTING RATES ................................................................................................................................... 44 12/11/13 MnDOT Geotechnical Manual iii 4.2 MOISTURE CONTENT TESTS .................................................................................................................................. 44 4.3 UNCONFINED COMPRESSION TESTS ....................................................................................................................... 44 4.4 ONE DIMENSIONAL CONSOLIDATION TESTS ............................................................................................................. 45 4.5 TRIAXIAL COMPRESSION TESTS .............................................................................................................................. 45 4.6 UNIT WEIGHT TESTS ........................................................................................................................................... 45 4.7 SPECIFIC GRAVITY ............................................................................................................................................... 46 4.8 ENGINEERING PROPERTIES ................................................................................................................................... 46 4.8.1 Atterberg Limit Tests ............................................................................................................................ 46 4.8.2 In-place Volume and Weight Relationships ......................................................................................... 47 4.8.3 Grain Size Analysis ............................................................................................................................... 49 4.8.4 Organic Content Tests .......................................................................................................................... 50 4.8.5 Unconfined Compression Tests for Rock .............................................................................................