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# Soil Mechanics (181-200)

Updated: Apr 27, 2020

181. Degree of freedom of a block type machine foundation is

182. Given that damping ratio = 0.10 and damping coefficient = 225 kN sec/m.

Then the critical damping coefficient in kN sec/m will be 2250

183. The natural frequency of a vibrating foundation system

i) increases as the square root of the

ii) decreases with the square root of the\ mass of the body

184.In case of free over damped vibration 185. As per converse Labarre formula, group efficiency offrictionpiles is given by: 186. The correct increasing order of the surface areas of the given soils is

sand, silt, clay, colloids

₁₀ ₂₀ ₃₀ ₄₀ 𝒸 ᵤ

187. For a given soil sample,

C𝒸 = coefficient of gradation

C = coefficient of uniformity

D₁₀ = effective size

D₃₀ = diameter through which 30 per cent

of the total soil mass is passing

If C𝒸 = 1.0 and c, = 4.0, then the value of

D₃₀/D₁₀ would be

188.

Stoke- Velocity of settling particle Darcy- Flow of water through a soil mass Poiseuille- Flow through capaillary Atterberg-Consistency limits

189. In a standard Proctor compaction, the water content (w) and maximum dry

density (γdmax) are related a

γdmax corresponds to a unique value of w

190. Using Mohr's diagram, the relation between major principal stress oi, and

minor principal stress σ₁ and σ₃shear parameters c and Φ is given by

(1 +sinΦ)/(l-sinΦ)

191. A and B are Skempton's pore pressure parameters and Δσ₁ and Δσ₃ are

incremental principal stresses. Skempton's pore pressure equation is given by

Δu = B[Δσ₃ + A(Δσ₁ - Δσ₃)]

192. The total settlement of a compressible soil stratum 2 m deep and having a coefficient of volume compressibility of 0.02 cm²/ kg under a pressure increment of 2 kg/cm will be 8 cm

193. Given that for a single degree of freedom system,

k = stiffness coefficient

m = mass of machine and foundation,

critical damping is best defined by the

expression 2√km

194.The relationship between water content (w%) and number of blows (N) in soils, as obtained from Casagrande's liquid limit device, is given by

w = 20 - log₁₀ N

The liquid limit of the soil is 18.6%

195. The results (curves A,B,C and D) of four compaction tests on different soils are

shown in Fig. 8.3 1. Silty sand, modified test

2. Silty sand, standard test

3. Fat clay, modified test

4. Fat clay, standard test

196. The results of a consolidated drained triaxial shear test on a normally

consolidated clay are shown in Fig.8.4 The angle of internal friction is 197.Which one of the following statements provides the best argument that direct

shear tests are not suited for determining shear parameters of a clay soil ?

Pore pressures developed cannot be measured.

198. 199.Two specimens of clay A and B are tested in a consolidation apparatus.

If(mv)A = 3.6x l04m²/kNand

(mv)B= l.8x l0⁻⁴ m²/ k N ,

(Cv)A = 3.8x l0⁻⁴ cm²/s,

(CV)B= l.9x l0⁻⁴ cm²/s,

4

200.Terzaghi's equation of ultimate bearing capacity for a strip footing may be used for square footing resting on pure clay soil with the correction factor

1.3