Soil Index Properties PDF

CHAPTER 1 ORIGIN OF SOIL AND SOIL WATER RELATIONSHIP pacity of soil. 6. Soil is derived...

CHAPTER 1 ORIGIN OF SOIL AND SOIL WATER RELATIONSHIP pacity of soil. 6. Soil is derived from Latin word : 1. Soil transported by wind is called (a) Sonum (b) Soila (a) Aeolian soil (b) Alluvial soil (c) Solia (d) None of these (c) Marine soil (d) Lacustrine soil Ans. (d) The word 'soil' is derived from the Latin word Ans. (a) "Solium" according to Webster's Soil Deposited by dictionary,which means the upper layer of the Alluvial Soil River/running water earth that may be dug or plowed, specifically, Marine Soil Sea water the loose surface material of the earth in which Lacustrine Soil Still water like as lakes plants grow. Aeolian Soil Wind like as Sand-dunes, Loess 7. Removed of soil from rivulets by concentrated Glacial Soil Ice ( Till/drift ) overland flow is known as : 2. Planting trees would reduce pollution by sedi- (a) Sheet erosion (b) Channel erosion ments and will also prevent (c) Rill erosion (d) Gully erosion (a) Soil Settlement (b) Consolidation Ans. (d) Gully erosion is the removal of soil from rivulets (c) Soil Erosion (d) Population by concentrated overland flow.It is the removal Ans. (c) of soil along drainage lines by surface water Soil erosion is the detachment transport deposition of runoff. soil particles on land surface. It is also known as loss of 8. Humidity refers to the____. soil. (a) Volume of the air Various methods for preventing & reducing soil ero- (b) Water vapour in the air sion are- (c) Pressure of the moisture (a) Plantation of deforestation (d) Mass of the air (b) Plantation of trees & plants Ans. (b) Moisture in the air is known as humidity. Humid- (c) Plantation of excessive grazing ity is the measure of the amount of water vapour 3. Which scientist is associated with theory in Soil in a general area. Mechanics? Humidity can be classified into 2 types - (a) Karl Terzaghi (b) Fellenius (i) Absolute humidity - It is expressed in %. (c) Kray (d) Henkel (ii) Relative humidity - It is expressed in kg/m3. Ans. (a) 9. If liquid limit is increased, then compression in-  Father of Soil Mechanics Dr. Karl Terzaghi coined dex will be the term ‘‘Soil Mechanics’’ in 1925. (a) Increase and decrease 4. Which of the following is a/an incorrect process (b) Constant of physical disintegration in-regards to the for- (c) Decrease mation of soils? (d) Increase (a) Wedging action of Ice Ans. (d) cc = 0.007 (wL –10) Remoulded soil (by Skempton). (b) Spreading of roots of plants So, If the liquid limit is increased. Then, the compression (c) Solution index of soil will increase. (d) Abrasion 10.The grooving tool used for liquid limit determina- Ans. (c) Soils are formed by either physical disintegration tion is or chemical disintegration of rocks. (a) Casagrande tool Disintegration processes are- (b) ASTM tool Physical disintegration - (c) Both above Temperature changes, wedging action of Ice, spreading of (d) None of the above roots of plant, abrasion Ans. (c) The grooving tool for liquid limit determination Chemical disintegration - is used for both casagrade tool and ASTM tool. Hydration, carbonation, oxidation, hydrolysis For sandy soils- only ASTM tool is used. 5. Presence of organic matter in soil makes it 11. Toughness Index of a soil is the ratio of : (a) Swell at low moisture content (a) Shrinkage index to liquidity Index (b) Spongy in nature (b) Plasticity Index to flow Index (c) Shrink with increasing moisture content (c) Liquidity Index to shrinkage index (d) None of these (d) Liquidity Index to consistency Index Ans. (b) Most of soil contains 2-10% organic Ans. (b) Toughness Index: It gives us an idea of strength matter.Presence of organic matter in soil makes it spongy of soil at plastic limit. in nature. In addition to providing nutrients & habital to IP S organisms living in the soil, organic matter also binds soil It   log P particles into aggregates & improves the water holding ca- If Sl  MISCELLANEOUS TOPICS 303 SP = Shear strength at plastic limit (a) It's particles are cohesive Sl= Shear strength at liquid limit (b) It's permeability is uncertain 12. If soil is dried beyond the shrinkage limit, it will (c) It's low bearing capacity show (d) It undergoes volumetric change with moisture (a) Large volume change Ans. (d) Black cotton soil: Residual deposits form basalt (b) No volume change or trap rocks, contain clay mineral. Very poor (c) Low volume change bearing capacity (50-100 kN/m2). (d) Moderate volume change  If depth of layer of B.C.S. is shallow, Then remove its Ans. (b) Shrinkage limit layer for making structure. It is minimum water content at which soil is completely  If depth of layer of BCS is Deep, then we use under- saturated or the maximum water content at which further reamed piles In foundation for making structure. reduction in water content does not cause any descrease in  Generally we use raft foundation in black cotton soil. the volume of soil sample.  Black cotton soil have high shrinkage & swelling char- 13. Soils are basically : acteristics, it’s shearing strength is extremely low. It is (a) Organic and inorganic materials due to Montmorillonite mineral. (b) Organic materials 21. Which of these does NOT affect the suction ca- (c) Inorganic materials pacity of soil? (d) Mineral materials (a) Temperature (b) Dissolved salts Ans. (a) Soils are complete mixture of organic & inorganic (c) Angle of contact (d) Pressure of water materials. Ans. (d) 14. Lacustrine soils are those which are: Prassure of water does not affect the suction capacity (a) Wind (b) Rivers of soil. (c) Lakes (d) Sea When a dry soil is submerge under water meniscus is Ans. (c) Soils which are deposited by flowing water or sur- destroyed resulting in a reduction of soil suction to face runoff while entering a lake are called zero value. lacustrine deposits. 22. As per IS : 1893 : 2002, soft soil is categorized as 15. For which of the following soil, plasticity index (a) Type - I (b) Type - II is maximum? (c) Type - III (d) None of these (a) Clay (b) Cobble Ans. (c) (c) Gravel (d) Silt As per IS : 1893 : 2002, soft soil categorized as type - Ans. (a) A soil with a high clay content usually has high LL III. & PL.Silts have plasticity only occasionally, their PL being IS : 1893 : 2002 - Criteria for earthquake resistant de- equal to or slightly greater than 0. Sand, gravel & peat have sign of structures. no plasticity (PL= 0). 23. What is known as the setting and distribution of 16. Cohesionless soil is : particles in the soil mass? (a) Silt (b) Sand (a) Fakes (b) Frame (c) Clay (d) None of the above (c) Fabric (d) Fuller Ans. (b)Cohesionless soils are sand or gravel, whose Ans. (c) Fabric is known as the settling & distribution of strength depends on friction between particles. particles in the soil mass. 17. The soil transported by flowing water is called- Fabric denotes the geometrical arrangement of the con- (a) Aeolian soil (b) Marine soil stituent mineral particles, including void spaces, that (c) Alluvial soil (d) Sandy soil can be observed visually or directly using optical & Ans. (c) Alluvial soil is the type of soil which is strongly electron microscope techniques. transported by running water. These generally 24. Sand is NOT ideal, if it : get deposited at the river banks. (a) Contains silicon dioxide 18. Most fertile soil is : (b) Is chemically inert (a) Alluvial (b) Black soil (c) Is free from organic salts (c) Laterite soil (d) Red soil (d) Is soft Ans. (a) Alluvial soil is most fertile soil. Mostly these soils Ans. (d) Sand used for the preparation of mortar should contains adequate proportion of potash, phos- posses following properties - phoric acid and lime which are ideal for the It should be free from presence of salts. growth of wheat, sugarcane and other cereal and It should be chemically inert. pulse crop. It should be well graded. 19. A sticky, plastic, dark coloured clay is defined as It should be free from organic matter. (a) Marl (b) Gumbo 25. The trace moisture absorbed by a dry soil from (c) Peat (d) Muck the atmosphere is called Ans. (b) (a) Moisture content Gumbo: It is a black coloured soil, which is sticky & highly (b) Water content plastic in nature.It has some small amounts of sand or (c) Hygroscopic moisture organic material, but it is typically defined by the over- (d) None of these whelming presence of very fine particles of clay. Ans. (c) Hygroscopic water - It can not be removed easily Marl: It is a combination of clay, loam and calcareous sands. from the soil particles.It is absorbed by the particles of dry Peat: Fibrous aggregate with decomposed fragments of soil from the atmosphere & is held as a very thin film on vegetable matter. the surface of the soil particles due to adhesion or attrac- 20. Black cotton soil is unsuitable for foundations due tion between surface of a particles & water molecules. to 26. Coefficient of softening for clay is :  304 (Civil Ki Goli Publication 9255624029) (a) One (b) Zero 3. Climatic changes cause vertical swelling (c) Two and shrinkage of loess (d) Can not be determined 4. Permeability of loess in horizontal Ans. (b) Coefficient of softening of a material is the ratio direction is less than that in the vertical of compressive strength of a saturated material to it's compressive strength in dry state. direction For clay, it's value is zero. Which of the statement given above are For glass, it's value is one. correct 27. The water content of a highly organic soil is de- (a) 1 and 4 (b) 2 and 4 termined in oven at a temperature of: (c) 2 and 3 (d) 1 and 3 (a) 35°c (b) 100°c Ans.(b): Loess is a uniformly graded silt deposit made (c) 70°c (d) 60°c by wind. These deposits have low density & High Ans. (d) In oven drying method, the temperature to be main- compressibility. tained in the oven is 105°- 110° C for 24 hours. 31. Consider the following statement If the temperature is more than 105° C to 110° C, there 1. Each year black cotton soil appereciably will be a breaking of the crystalline structure of soil par- ticle & loss of chemically bound structural water. shrinks during dry season and swells If the temperature is lower than 105° C to 110° C, there during rainy season.This alternate cycle will be incomplete evaporation. of shrinking and swelling causes server For highly organic soils, a low temperature of about 60° stresses in structure supported directly C is preferable. by such soil If Gypsum is present, then temperature should not be more 2. Black cotton soil contains predominantly than 80° C but for a long time. a clay mineral called kaolinite, which is responsible for causing appreciable shrinking and swelling 28. The term 'Loess' indicate those soil which are 3. Shrinking and swelling of black cotton 1. Uniformly graded soils are observed only upto a certain 2. Poorly graded depth below the ground level. Below that 3. Made up of 50% or more size particles level, There is neither shrinking nor 4. Made up of more than 50% of silt swelling particles Which of the these statement is/are correct Which of the above statement are correct (a) 1, 2 and 3 (b) 3 only (a) 1 and 3 (b) 1 and 4 (c) 2 and 3 only (d) 1 and 3 only (c) 2 and 3 (d) 2 and 4 Ans.(d): Black cotton soil: Residual deposits form Ans.(b): Loess is a uniformly graded silt (more than basalt or trap rocks, contain clay mineral 50% of total particles) deposit made by wind. These  If depth of layer of B.C.S. is shallow, Then re- deposits have low density & High compressibility. move its layer for making structure 29. Consider the following effects as indicative  If depth of layer of BCS is Deep, then we use of complete saturation of a soil sample: uncler-reamed piles for In foundation for making 1. Pore water pressure is positive. structure 2. Volume of water to volume of voids is  Generally we use raft foundation in BCS. equal to 1.  Black cotton soil have high shrinkage & swelling 3. Relative density is equal to 1. characteristics, its shearing strength is extremely Which of the above statements are correct ? low. It is due to Montmorillonite mineral. (a) 1 and 2 only (b) 1 and 3 only 32. Consider the following statement (c) 2 and 3 only (d) 1, 2 and 3 1. Partially saturated soil sample is an Ans.(a):Relative density is the indicator or measure example of three-phase system of packing of soil particles that is how closely packed 2. Submerged density of a soil sample is are soil particles is measured by relative density. equal to the saturated density divided by There is no relation of degree of saturation and rela- (1 + water content) expressed as a tive density. Therefore, statement is incorrect. fraction When there is saturation in soil, then pore water pres- 3. Void ratio of a soil sample is defined as sure is positive. So statement 1 is correct. the ratio of volume of voids to volume Vw of soil grains Degree of saturation S  V. Which of the statement given above are v correct At full saturation, Vw = VV (a) 1 and 2 only (b) 1 and 3 only and so statement 2 is also correct. (c) 2 and 3 only (d) 1, 2 and 3 30. Consider the following statement Ans.(b): Phase diagram 1. Loess is of volcanic origin Diagrammatic Representation of the different phases 2. Loess soil are uniformly graded silt size in a soil mass. particle  MISCELLANEOUS TOPICS 305 3 Phase tent state. Consistency Index: It is also called relative (Partially Saturated) consistency. Wa 0 WL  W Ic = W  W Va Air L P Vv Liquidity Index Vw Water W  WP Ww V W IL= W  W (Note: Ic + IL = 1) L P Vs Solid Ws Consistency Ic IL Very stiff >1