(a)
State whether the statement “addition of lime to clays increases the plasticity” is true or false.
(a)
Answer to Problem 11.1P
The given statement is
Explanation of Solution
Flocculation‑agglomeration is a chemical reaction that occurs when the lime is added to clayey soils and this reaction makes a texture change in the clay soil. In this process, the clay particle clumps together and forms larger particles due to the presence of lime resulting in plasticity reduction.
Therefore, the given statement is
(b)
State whether the statement “fly ash is pozzalanic” is true or false.
(b)
Answer to Problem 11.1P
The given statement is
Explanation of Solution
Fly ash is a by-product of pulverized coal and is extracted from flue gases through Electrostatic precipitator in dry form. Fly ash is a fine material and possesses good pozzalanic property.
Therefore, the given statement is
(c)
State whether the statement “vibrofoltation is more effective on clays than sands” is true or false.
(c)
Answer to Problem 11.1P
The given statement is
Explanation of Solution
Vibrofoltation is a construction technique used for the densification of thick layers of loose soils.
Refer Figure 11.3, “Effective range of grain-size distribution of soil for vibration” to identify the grain size in which vibrofloation is effective.
Vibrofoltation is effective for gravel, with 0% to 100% fines and with a grain size of 10 mm to 100 mm.
For coarse and fine sand, with a grain size of 0.1 mm to 10 mm and with 0% to 100% fines, vibrofoltation is effective.
For silts and clay, vibrofoltation is effective for clays with 0% to 40% fines and with a grain size of 0.1 mm to 0.001 mm.
Thus, vibrofoltation is more effective on sands than clays.
Therefore, the given statement is
(d)
State whether the statement “pre-compression is mostly applied on normally consolidated clays” is true or false.
(d)
Answer to Problem 11.1P
The given statement is
Explanation of Solution
Normally consolidation clays (NCC) are highly compressible. Thus, large constructions over the layer of NCC soils result in large consolidation settlement.
Pre-compression is applied on NCC to prevent the post consolidation settlement.
Ordinary soils generally are not highly compressive and thus less post consolidation settlement.
Thus, pre-compression are mostly applied on NCC.
Therefore, the given statement is
(e)
State whether the statement “duration of pre-compression is shorter, when the surcharge is larger in pre-compression” is true or false.
(e)
Answer to Problem 11.1P
The given statement is
Explanation of Solution
Show the pre-compression on normally consolidated clay due to structural load
Figure 1 shows the settlement-time relationship under the surcharge load of
The settlement,
The settlement of the clay layer rises with increase in time in both the cases (settlement due to structural load and surcharge load). Thus, the surcharge increases with the increase in the settlement with respect to time.
Therefore, the given statement is
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Chapter 11 Solutions
Fundamentals of Geotechnical Engineering (MindTap Course List)
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- Effective stress on soil O(A) Increases voids ratio and decreases permeability O(B) Increases both voids ratio and permeability OC) Decreases both voids ratio and permeability O(D) Decreases voids ratio and increases permeabilityarrow_forwardanswer 10 onl 1. When consolidation of a saturated soil sample occurs, the degree of saturation A.Increases B.Decreases C.Remains constant D.May increase or decrease 2. The process opposite to consolidation is called swelling, which involves an increase in the volume of the voids due to the water content A.Decreasing B.Increasing C.Equalize D. None of the above 3. OC: is refer to A. An over consolidation ratio as the ratio of the preconsolidation pressure to the present vertical effective stress. (B. A normally consolidated clay is defined as a clay that has a present (in situ) vertical effective stress oo' equal to its preconsolidation pressure oc C. An overconsolidated clay is defined as a clay that has a present vertical effective stress of less than its preconsolidation pressure D. None of the above Сс 4. Coefficient of consolidation of a soil is affected by A.Compressibility B.Permeability C.Both compressibility and permeability D.None of the above 5. The shear strength of a soil…arrow_forwardhand written solution in white page neat clean all units and formula concept mentionedarrow_forward
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