tec 224 soils final exam questions with correct detailed answers.

What is the generally accepted differentiation between rock and soil? - correct answer Soil can be removed without blasting Limestone and granite are following types of rock: - correct answer Sedimentary and igneous respectively. Which statement is false? - correct answer The minerals present in soil formed due to chemical weathering of rock are same as parent rock. Which of the following is aeolian deposit (wind deposit)? - correct answer Loess Working with soils (or designing structures in soil) is challenging, why? - correct answer Properties of soil are highly variable and Properties of soil change with time and water content. The two primary weathering processes that cause soil particles to be formed are: - correct answer . Mechanical and Chemical Rock changed to soil through decomposition, but soil can never change back to rock through natural forces. - correct answer False The two major groups of soils from geological standpoint include - correct answer Residual and Transported Fine-grained igneous rocks were formed where magma was trapped below the earth's surface and was cooled slowly. - correct answer False Windblown soils are NOT stable because - correct answer They have uniform particle sizes What are the forces that cause physical weathering of rocks? - correct answer Temperature change, Frost action, Rainfall and Running water Relative to material specifications, why study soils? - correct answer It is important to understand soil for bidding process and Important for the design of structure and its foundation. What are the three primary types of rock? - correct answer Igneous, sedimentary and metamorphic Why would a wind-laid deposit be a potential problem during construction? - correct answer Uniform particle size which produces low strength when wet. With respect to contract specifications, what is the difference between classified and unclassified rock? (Hint: please refer to internet) - correct answer Classified is tested and known rock. Unclassified is bidding without full knowledge of rock. Which of the following rocks is coarse-grained? - correct answer Granite Which type of soil is formed due to weathering of basalt? - correct answer Clays Which soil horizon contains weathered rock?Note: Please see remaining video entitled "Weathering and Soils" for answering this question. - correct answer Horizon C Approximately how many years did it take to develop one meter of fertile soil in the Midwest?Note: Please see remaining video entitled "Weathering and Soils" for answering this question. - correct answer 15,000 years Select the correct match of name of the agent and corresponding deposit formed by that agent. - correct answer Wind - aeolian deposits; Running water - alluvial deposits; Gravity - landslides Because both clay and silt soils pass No. 200 sieve, clay and silt have the same particle sizes. - correct answer False A soil's plastic limit is 21% and its liquid limit is 42%. The soil's plasticity index = liquid limit - plastic limit = ? - correct answer 21% A soil sample weighed 120 grams when it was wet, and the same soil sample weighed 100 grams after it was dried in an oven. The soil's water content when it was wet =? - correct answer 20% % passing sieve size 19 mm is: - correct answer 100% % passing sieve size 9.5 mm is: - correct answer 92.1% % passing sieve size 4.75 mm is: - correct answer 76.7% % passing sieve size 2.00 mm is: - correct answer 46.3% % passing sieve size 0.425 mm is: - correct answer 13.7% % passing sieve size 0.150 mm is: - correct answer 2.5% % passing sieve size 0.075 mm is: - correct answer 0.4% What is the sieve number that separate coarse from fine grained soils? - correct answer #200 Which of the following terms are coarse-grain soil fractions? - correct answer . Sand, gravel Which of the following terms are the fine-grained soil fractions? - correct answer Silt, clay What is the shape of a clay particle? - correct answer Flat plate like Why silts are different from clays? - correct answer Both are fine but silt is cohesionless and Clay is less than 0.005 mm in size, silt is 0.005 mm to 0.1 mm Why is soil structure important to the contractor? - correct answer Contractor can bid accurately and To determine required excavation, soil improvement (if any) What is water (or moisture) content of soil? - correct answer Ratio of mass of water to dry mass of soil expressed as percentage. Which of the following soil classification method is widely used and recommended by ASTM standard? - correct answer Unified Soil Classification method A soil was tested by conducting sieve analysis. Following results were determined: Cu = 20 and Cc = 2.5 What information regarding gradation you get from above data? - correct answer Soil is well graded Moisture content at which soil begins to flow is called as: - correct answer Liquid Limit Hydrometer test is conducted for characterizing soil finer than - correct answer #200 sieve Which soil is good for construction? - correct answer Well graded A sensitive (or quick) clay is having - correct answer Liquidity Index is greater than 1 A soil was tested for Plastic Limit. The two Plastic Limit determinations had water contents of 23.1% and 23.6%. What is the Plastic Limit of soil (average)? - correct answer 23.4% A soil has liquid limit = 30% and plastic limit = 20%. What is the plasticity index (PI) of soil? - correct answer 10% At shrinkage limit, degree of saturation (%) of soil is: - correct answer 100% The two major soil classification systems, AASHTO and USCS, classify soils using the information on soil's: - correct answer gradation and plasticity The Unified Soil Classification System is based on - correct answer Grain size distribution and plasticity Granular soil materials are generally better as compared to fine-grained soil as subgrade materials (Note: subgrade is foundation soil of a pavement or road). - correct answer True Which of the following soils is organic soil? - correct answer Peat A soil is classified as SW with the USCS method. The symbol SW means that the soil is: - correct answer well-graded sand A soil is classified as ML with the USCS method. The symbol ML means that the soil is: - correct answer silt with low plasticity Soil has properties (see attached sieve analysis):Liquid Limit = 40.0%; Plastic Limit = 20.0%;% retained on No. 4 sieve (or % gravel) is - correct answer 22.0%