Consolidation Of Soils Practice Questions

Which one of the following saturated fine-grained soils can attain a negative Skempton's pore pressure coefficient $( \mathrm{A})$ ?

The contact presure distribution shown in the figure belongs to a

The total primary consolidation settlement $\left(S_{C}\right)$ of a building constructed on a $10 \mathrm{~m}$ thick saturated clay layer is estimated to be $50 \mathrm{~mm}$ . After 300 days of the construction of the building. primary consolidation settlement was reported as $10 \mathrm{~mm}$ . The additional time (in days) required to achieve $50 \%$ of $S_{c}$ will be ____ (rounded off to the nearest integer).

A soil sample was consolidated at a cell pressure of $20 \mathrm{kPa}$ and a back pressure of $10 \mathrm{kPa}$ for 24 hours during a consolidated undrained (CU) triaxial test. The cell pressure was increased to $30 \mathrm{kPa}$ on the next day and it resulted in the development of pore water pressure of $1 \mathrm{kPa}$ . The soil sample failed when the axial stress was gradually increased to $50 \mathrm{kPa}$ . The pore water pressure at failure was recorded as $21 \mathrm{kPa}$ . The value of skempton's pore pressure parameter $B$ for the soil sample is ______ (round off to 2 decimal places).

The specific gravity of a soil is 2.60 . The soil is at $50 \%$ degree of saturation with a water content of $15 \%$ . The void ratio of the soil is

In a triaxial unconsolidated undrained (UU) test on a saturated clay sample, the cell pressure was 100 kPa. If the deviatoric stress at failure was 150 kPa, then the undrained shear strength of the soil is _________ kPa. (in integer)

A raft foundation of 30 m x 25 m is proposed to be constructed at a depth of 8 m in a sand layer. A 25 m thick saturated clay layer exists 2 m below the base of the raft foundation. Below the clay layer, a dense sand layer exists at the site. A 25 mm thick undisturbed sample was collected from the mid-depth of the clay layer and tested in a laboratory oedometer under double drainage condition. It was found that the soil sample had undergone 50% consolidation settlement in 10 minutes. The time (in days) required for 25% consolidation settlement of the raft foundation will be ______. (round off to the nearest integer)

A saturated compressible clay layer of thickness h is sandwiched between two sand layers, as shown in the figure. Initially, the total vertical stress and pore water pressure at point P, which is located at the mid-depth of the clay layer, were 150 kPa and 25 kPa, respectively. Construction of a building caused an additional total vertical stress of 100 kPa at P. When the vertical effective stress at P is 175 kPa, the percentage of consolidation in the clay layer at P is _____________. (in integer)

A clay layer of thickness H has a preconsolidation pressure $p_{c}$ and an initial void ratio $e_{0}$ .The initial effective overburden stress at the mid-height of the layer is $p_{0}$ . At the same location, the increment in effective stress due to applied external load is $\Delta p$ . The compression and swelling indices of the clay are $C_{c}$ and $C_{s}$ , respectively. If $p_{0} \lt p_{c} \lt \left(p_{0}+\Delta p\right)$ , then the correct expression to estimate the consolidation settlement $\left(S_{c}\right)$ of the clay layer is

The void ratio of a clay soil sample M decreased from 0.575 to 0.510 when the applied pressure is increased from 120 kPa to 180 kPa. For the same increment in pressure, the void ratio of another clay soil sample N decreases from 0.600 to 0.550. If the ratio of hydraulic conductivity of sample M to sample N is 0.125, then the ratio of coefficient of consolidation of sample M to sample N (round off to three decimal places) is ______________

The soil profile at a road construction site is as shown in figure (not to scale). A large embankment is to be constructed at the site. The ground water table (GWT) is located at the surface of the clay layer, and the capillary rise in the sandy soil is negligible. The effective stress at the middle of the clay layer after the application of the embankment loading is $180 \mathrm{kN} / \mathrm{m}^{2}$ . Take unit weight of water, $\gamma_{w}=9.81 \mathrm{kN} / \mathrm{m}^{3}$ . The primary consolidation settlement (in m, round off to two decimal places) of the clay layer resulting from this loading will be ______

The soil profile at a construction site is shown in the figure (not to scale). Ground water table (GWT) is at 5 m below the ground level at present. An old well data shows that the ground water table was as low as 10 m below the ground level in the past. Take unit weight of water, $\gamma_{W}=9.81 \mathrm{kN} / \mathrm{m}^{3}$ . The overconsolidation ratio (OCR)(round off to two decimal places) at the mid-point of the clay layer is _______

A footing of size 2m x 2m transferring a pressure of 200 $kN/m^2$ , is placed at a depth of 1.5 m below the ground as shown in the figure (not drawn to the scale). The clay stratum is normally consolidated. The clay has specific gravity of 2.65 and compression index of 0.3. Considering 2:1 (vertical to horizontal) method of load distribution and $\gamma _w = 10 kN/m^3$ , the primary consolidation settlement (in mm, round off to two decimal places) of the clay stratum is _________.

A one-dimensional consolidation test is carried out on a standard 19 mm thick clay sample. The oedometer's deflection gauge indicates a reading of 2.1 mm, just before removal of the load, without allowing any swelling. The void ratio is 0.62 at this stage. The initial void ratio (round off to two decimal places) of the standard specimen is ________.

A 10 m thick clay layer is resting over a 3 m thick sand layer and is submerged. A fill of 2 m thick sand with unit weight of 20 $kN/m^3$ is placed above the clay layer to accelerate the rate of consolidation of the clay layer. Coefficient of consolidation of clay is $9 \times 10^{-2} m^2/year$ and coefficient of volume compressibility of clay is $2.2 \times 10^{-4} m^2/kN$ . Assume Taylor?s relation between time factor and average degree of consolidation. The settlement (in mm, round off to two decimal places) of the clay layer, 10 years after the construction of the fill, is _________.

Construction of a new building founded on a clayey soil was completed in January 2010. In January 2014, the average consolidation settlement of the foundation in clay was recorded as 10 mm. The ultimate consolidation settlement was estimated in design as 40 mm. Considering double drainage to occur at the clayey soil site, the expected consolidation settlement in January 2019 (in mm, round off to the nearestinteger) will be ________

The void ratio of a soil is 0.55 at an effective normal stress of 140 kPa. The compression index of the soil is 0.25. In order to reduce the void ratio to 0.4, an increase in the magnitude of effective normal stress (in kPa, up to one decimal place) should be ______

The compression curve (void ratio, e vs. effective stress, ${\sigma_{v}}'$ ) for a certain clayey soil is a straight line in a semi-logarithmic plot and it passes through the points $(e = 1.2; {\sigma_{v}}' = 50 kPa)$ and $(e = 0.6; {\sigma_{v}}' = 800 kPa).$ The compression index (up to two decimal places) of the soil is ______

Consider the following statements related to the pore pressure parameters, A and B: P. A always lies between 0 and 1.0 Q. A can be less than 0 or greater than 1.0 R. B always lies between 0 and 1.0 S. B can be less than 0 or greater than 1.0 For these statements, which one of the following options is correct?