NATURAL SOIL DEPOSITS Soils are produced by weathering of rock. Weathering is the physical or chemical breakdown of rock. Physical Processes: - Unloading - Frost Action - Organism Growth - Crystal Growth - Abrasion Chemical Processes: - Oxidation - Hydration - Hydrolysis - Carbonation - Solution after FM 5-410 Military Soils Engineering Slide 1 of 17
ROCK-SOIL RELATIONSHIPS Igneous Rocks Granite > silty sands Basalts > clayey soils Sedimentary rocks Shales > clays and silts Sandstones > sandy soil Limestone > coarse or fine grained soils Metamorphic rocks Gneiss > silty sands Slate > clayey soils Marble > fine grained soils Quartzite > coarse grained soils from Dr. Larry Muszynski Slide 2 of 17
SOIL FORMATION METHODS Two Main Groups: Residual Soils Rock material weathered in place via mechanical and chemical processes (chemical usually dominant factor). As a result of this process, and because the rock material may have an assorted mineral structure, the upper layers of soils are usually fine-grained and relatively impervious to water. Example: Piedmont (Eastern US). Transported Soils Soils transported from place of origin via three main processes: 1. Water 2. Glacial 3. Air Most soils are transported soils. Example: Cape Cod. after FM 5-410 Military Soils Engineering Slide 3 of 17
RESIDUAL SOILS TYPICAL WEATHERING PROFILES (a) Mudstone, Shale, and Slate (b) Gneiss and Schist (c) Granite to Gabbro; from Sowers, G.F. 1988. Foundation problems in residual soils. Proceedings, Engineering Problems of Regional Soils: 154-171. Beijing, China and Sowers, G.F. (1994). "Residual soil settlement related to the weathering profile." Vertical and Horizontal Deformations of Foundations and Embankments, ASCE GSP 40, 1689-1702. Slide 4 of 17
RESIDUAL SOILS TYPICAL WEATHERING PROFILES ZONE Colluvium of other transported soils; pebble marker common here I Residual Soil IA A horizon IB B horizon IC C horizon (Saprolite) (a) Metamorphic Rocks (b) Intrusive Igneous Rocks ZONE Colluvium etc. IA IB IC II Weathered Rock IIA Transition from Saprolite to Weathered Rock IIB Partly Weathered Rock IIA IIB III Unweathered Rock III Figure 3-2. from NHI-06-088 (after Deere and Patton, 1971). Slide 5 of 17
RESIDUAL SOILS PIEDMONT PROVINCE Covers ~1/3 of SC and NC. Eastern Border of Province called Fall Line Georgia Red Clay Residual Soil Figure from Finke, K.A., Mayne, P.W. & Klopp, R.A. (2001). Piezocone penetration testing in Atlantic Piedmont residuum. Journal of Geotechnical & Geoenvironmental Engineering 127 (1). Slide 6 of 17
TRANSPORTED SOIL DEFINITIONS Glacial Soils: formed by transportation and deposition of glaciers. Alluvial Soils: transported by running water and deposited along streams. Lacustrine Soils: formed by deposition in quiet lakes. Marine Soils: formed by deposition in seas/oceans. Aeolian Soils: transported and deposited by the wind. Colluvial Soils: formed by movement of soil from its original place by gravity (e.g. landslides). from Das, B.M. (1998). Principles of Geotechnical Engineering, 4th edition, PWS Publishing Company. Slide 7 of 17
14.330 Soil Mechanics - Geology TRANSPORTED SOILS Meander and Erosion along Rivers Meander Development & Cutoff from FM 5-410 Military Soils Engineering Slide 8 of 17
14.330 Soil Mechanics - Geology TRANSPORTED SOILS Oxbow Lake Deposits from FM 5-410 Military Soils Engineering Slide 9 of 17
TRANSPORTED SOILS 14.330 Soil Mechanics - Geology Oxbow Lake Example Northampton, MA Map courtesy of Google.com Slide 10 of 17
14.330 Soil Mechanics - Geology TRANSPORTED SOILS Major Floodplain Features from FM 5-410 Military Soils Engineering Slide 11 of 17
14.330 Soil Mechanics - Geology NEW ENGLAND GEOLOGY Slide 12 of 17
NEW ENGLAND GEOLOGY Slide 13 of 17
NEW ENGLAND GEOLOGY Slide 14 of 17
NEW ENGLAND GEOLOGY Slide 15 of 17
14.330 Soil Mechanics - Geology NEW ENGLAND GEOLOGY Surficial Geologic Map of the Ashby-Lowell-SterlingBillerica 11-Quadrangle Area (Stone and Stone, 2007) Slide 16 of 17
14.330 Soil Mechanics - Geology Slide 17 of 17