Geotechnical Engineering - Final Exam Prep Questions And Correct Answers Verified.

Soil Mechanics - correct answer Study of physical properties of soil and it's behavior under applied forces. It also deals with flow of water through soil and it's a combination of solid mechanics and fluid mechanics. Igneous Rocks - correct answer Formed from magma cooling Sedimentary Rocks - correct answer formed by the deposition of material at the Earth's surface and within bodies of water. ( Soil layers being compressed by pressure "lithification") Metamorphic Rocks - correct answer formed from pressure and head, this process is also known as metamorphism. Organic Soils - correct answer formed from decayed plant and animal life Inorganic Soils - correct answer chemical and mechanical weathering of rocks Weathering - correct answer process of breaking down rocks by mechanical and chemical process. Mechanical Weathering - correct answer rocks are broken down without any change in the chemical nature of the rocks. (temperature change) Chemical Weathering - correct answer rocks are broken down by chemical reactions. (carbonation, oxidation, hydration) Sieve Analysis - correct answer consists of shaking soil sample through set of sieves that have progressively smaller opening. What is the opening in (mm) for sieve number 4? - correct answer 4.75 mm What is the opening in (mm) for sieve number 200? - correct answer 0.075 mm At what particle diameter size is Hydrometer Analysis used for? - correct answer used for particle size less than 0.075 mm in diameter (or opening) Stroke's Law - correct answer Rate of settlement of solid spheres dispersed in a liquid. Effective Size (D10) - correct answer diameter from curve corresponding to 10% finer The unit weight of water is equal to ( English units) - correct answer 62.4 lb/ft^3 The unit weight of water is equal to (SI Units) - correct answer 9.81 kN/m^3 Volume is a function of - correct answer Temperature and Pressure What does it mean when soil sample is saturated? - correct answer The void spaces are completely filled with water. Shrinkage Limit - correct answer Moisture content at which the transition from solid to semisolid state takes place. Plastic Limit - correct answer Moisture content at point of transition form semisolid to plastic state Liquid Limit - correct answer Moisture content at point of transition form plastic to liquid state Atterberg Limits - correct answer Water content (moisture content) at certain limiting or critical stages in soil behavior. At low moisture, how does the soil behave? - correct answer Soil behaves like solid. At high moisture, how does the soil behave? - correct answer Soil behaves likes liquid. At what height is the brass cup dropped from during the Liquid Limit Test? - correct answer 10 mm During the liquid limit test, what is the number of blows required to close a 12.5 mm distance along bottom of the groove? - correct answer 25 Blows What distance of closure is required along the bottom of the groove during a liquid limit test? - correct answer 12.5 mm What are the dimensions of the top and bottom faces of the grooving tools during the liquid limit test? - correct answer -11mm (vertical) - 8mm (horizontal) -2mm (vertical) What are the two methods used in determining the liquid limit? - correct answer One-point method and Fall Cone method. The plastic limit is the higher limit of the plastic stage of soil (T/F) - correct answer F- lower limit of the plastic stage When volume of soil mass ceases to change, this is known as the - correct answer shrinkage limit Liquidity Index - correct answer is an indicator of soil behavior and level of disturbance, and if clay is "sensitive". Compaction - correct answer Disinfection of soils by removing air through application of mechanical energy and moisture conditioning. Optimum moisture content - correct answer Moisture content at which the maximum dry unit is attained Number of layers in Compaction Energy Equation - correct answer 3 Number of Blows in Compaction Energy Equation - correct answer 25 Weight of Hammer in Compaction Energy Equation (English,SI) - correct answer 5.5 lb , 2.5 kg (convert to kN) Height of Drop in Compaction Energy Equation (English, SI) - correct answer 0.305 m , 1 ft Volume of mold in Compaction Energy Equation (SI, English) - correct answer 944 x 10^-6 , 1/30 Why do you need to provide suction in specific gravity test? - correct answer To remove the air from the voids For moisture content test the specimen has to be kept in an oven at what temperature and for how long? - correct answer 110 degrees Celsius and 24 hours In a standard proctor test, ZAV will only vary with - correct answer water content in the same soil sample Can the compaction curve be to the right of the ZAV curve? - correct answer No, the compaction curve cannot be to the right of the ZAV curve Why do we seal the soil sample with a watertight plastic bag in a moisture content test? - correct answer To prevent the moisture from evaporation In modified proctor test, as compaction energy increases , dry unit weight - correct answer increases In modified proctor test, as compaction energy increase, optimum moisture content - correct answer decreases What are the factors that affect compaction? - correct answer 1. Soil Type 2. Compaction Energy What type of structures does clay have? - correct answer Flocculated structure At low moisture content, clay is usually - correct answer highly flocculated Dry soil mixing - correct answer is a ground improvement technique that improves the characteristics of soft, high moisture content clays, peats, and other weak soils, using dry cementitious binder. Water can only flow through - correct answer voids The values of k (hydraulic conductivity) are influenced by - correct answer 1. Pore/Particle size distribution (shape)