Soil Mechanics - Exam 1 Questions And 100% Correct Verified Answers.

Soil Mechanics - correct answer Application of static, mechanics of materials, and fluid mechanics to describe the behavior of soils Soil - correct answer Weathering rocks and minerals What are the differences between sand and clay? (size, shape, strength comes from __?) - correct answer Sand: larger/coarse grained, rounder, strength from frictional forces between particles Clay: small/fine grained, flat, strength from water interaction Effective stress - correct answer stress felt by soil skeleton Consolidation - correct answer water forced out of pore spaces settlement - correct answer volume is changing differential settlement - correct answer one side settles, not the other Geosynthetics - correct answer man made plastic sheets (hydraulic barriers) Retaining Structures - correct answer Hold soil at steeper slope than the soil can stand How old is the Earth? - correct answer 4.6 billion years Lithosphere - correct answer rocky upper mantle and crust, moves as solid plate Asthenosphere - correct answer low mantle, hot, weak, ductile Rock - correct answer naturally formed aggregate(collection) of minerals Igneous Rock - correct answer solidified from molten rock Diff between magma and lava? - correct answer magma is underground (intrusive), lava is above (extrusive) Mineral - correct answer naturally formed, solid, forged inorganically, specified chemical composition Which are minerals? ice, water, coal - correct answer ice=mineral water=not mineral coal=not mineral Regolith - correct answer loose layer of debris from weathering What are the three main rock groups? - correct answer igneous, sedimentary, metamorphic What rocks make up the crust, what rocks make up the surface? - correct answer crust = 95% igneous and metamorphic surface = 75% sedimentary Cycle for rocks - correct answer rocks formed -- uplift -- weathering Residual soil - correct answer rate of soil formation is faster than transportation/erosion Eolian soil - correct answer transported by wind saltation - correct answer large sand picked up and moved a short distance loess - correct answer wind blown salt (homogeneous size) Fluvial Soil - correct answer deposited by streams and fresh water esker - correct answer uniform What are the 4 phases of field investigation - correct answer 1. collect info 2. familiarize with site 3. detailed site investigation 4. write report Boring and Drilling - correct answer destructive method of sub surface exploration visual ID of soil type with sample collection Continuous flight boring - correct answer destructive method of sub surface exploration -solid stem (have to keep removing it from hole, time consuming) -hollow stem (auger acts as casing to equalize pressure) -hand auger (cheap, limited depth) -water borings (pressurized water down drill shaft) What are three methods of retrieving a soil sample - correct answer shelby tube split spoon block Sizes for coarse and fine grain? - correct answer coarse .075mm fine .075mm size for coarse and fine gravel - correct answer coarse = 19-75mm fine=4.75-19mm Non-clay physical characteristics - correct answer particle size, particle distribution, particle shape, surface texture Is surface force more important for coarse grain or fine grain material? - correct answer fine what is a typical specific gravity? - correct answer 2.6-2.8 1m^3=?L - correct answer 1000L Unit Weight= - correct answer Unit Weight=W/V Dry Unit Weight= - correct answer Dry Unit Weight=W(solids)/V(total) Water Unit Weight= - correct answer Water Unit Weight=9.81=W(water)/V(water) Saturated Unit Weight= - correct answer W(solids)+W(water)/V(total) where V(water)=V(voids) Gravemetric Water Content= - correct answer Water Content=W(water)/W(solids) Volumetric Water Content= - correct answer Volumetric Water Content=V(water)/V(total) Typical Gs - correct answer 2.7 Void Ratio= - correct answer Void Ratio=V(void)/V(solid) Porosity= - correct answer Porosity=Vv/Vt=e/(1+e) Saturation= - correct answer Saturation=Vw/Vv Stokes Law - correct answer D=sqrt(18mz/(Gs-1)*unitweightwater*t)) D-particle size diameter Gs=specific gravity of soilds m=viscosity fluid z=depth from hydrometer ***stokes law doesn't apply to clay Plasticity Index - correct answer PI=LL-PL liquid limit - correct answer water content for liquid behavior plastic limit - correct answer water content for plastic behavior liquidity index= - correct answer LI(or IL)=(w-PL)/(LL-PL) LI0 - correct answer semi-solid (strong) 0LI1 - correct answer Plastic LI1 - correct answer Liquid (low strength) What are the three types of clay structures - correct answer kaoline-strong bonding Illite-stable, K bond Sretile/Montmorillonite-weak bond Relationship between surface area and interaction - correct answer more surface area more interaction