(a)
State whether the statement “thinner the wall, the higher is the area ratio of a sampling tube” is true or false.
(a)
Answer to Problem 12.1P
The given statement is
Explanation of Solution
Show the expression for the area ratio.
Here,
As per the formula, the area has the direct proportional relationship with the value of
The formula denotes if the wall thickness of the sampling tube is high, the area ratio will be higher and vice versa.
Hence, the given statement is
(b)
State whether the statement “samples recovered from the split-spoon samplers are highly disturbed” is true or false.
(b)
Answer to Problem 12.1P
The given statement is
Explanation of Solution
Split-spoon samplers are used to obtain representative samples suitable for the field examination of soil texture and fabric. The samples obtained by this process are highly disturbed.
Hence, the given statement is
(c)
State whether the statement “
(c)
Answer to Problem 12.1P
The given statement is
Explanation of Solution
Express the relationship between standard penetration numbers
In
Thus, the value of
Hence, the given statement is
(d)
State whether the statement “
(d)
Answer to Problem 12.1P
The given statement is
Explanation of Solution
Express the relationship between the effective overburden pressure
Here,
The value of
The value of
The value of
Hence, the given statement is
(e)
State whether the statement “vane shear test can be carried out in sands” is true or false.
(e)
Answer to Problem 12.1P
The given statement is
Explanation of Solution
The un-drained shear strength of soft clay is estimated directly by the Vane shear test. Reliable results only in medium stiff clays and soft clays are obtained from the field vane shear test.
Vane shear test is valid for only cohesive soil and it is not suitable for clays which contain sand or silt laminations in it.
Hence, the given statement is
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Chapter 12 Solutions
Fundamentals of Geotechnical Engineering (MindTap Course List)
- A sand deposit has been identified beneath a site located adjacent to a river. The sand deposit is 15 feet thick and the top of the layer is 12 feet below the ground surface and overlain by a very stiff clay and is undertain by bedrock. The water level has been measured to be at a depth of 10 feet. The standard penetration resistance of the layer has been determined to be 12 blows per foot and a standard sampler was used; a drill rig with a safety hammer with an efficiency of 60% was used. The length of the drill rod is 10 meters and the borehole diameter is 5 inches (127 mm). The design earthquake has been designated as a moment magnitude 6-3/4 event on a nearby fault and the maximum ground acceleration is expected to be 0.40 g. The wet unit weight of the clay soils is 150 pounds per cubic foot and the wet unit weight of the sand soils is 180 pounds per cubic foot. The sands have 35% fines content according to a grain size analysis. Determine the cyclic stress ratio, CSR. Express your…arrow_forwardA sand deposit has been identified beneath a site located adjacent to a river. The sand deposit is 15 feet thick and the top of the layer is 12 feet below the ground surface and overlain by a very stiff clay and is undertain by bedrock. The water level has been measured to be at a depth of 10 feet. The standard penetration resistance of the layer has been determined to be 12 blows per foot and a standard sampler was used: a drill rig with a safety hammer with an efficiency of 60% was used. The length of the drill rod is 10 meters and the borehole diameter is 5 inches (127 mm). The design earthquake has been designated as a moment magnitude 6-3/4 event on a nearby fault and the maximum ground acceleration is expected to be 0.40 g The wet unit weight of the clay soils is 150 pounds per cubic foot and the wet unit weight of the sand soils is 180 pounds per cubic foot. The sands have 35% fines content according to a grain size analysis. Compute the factor of safety against liquefaction of…arrow_forwardA sand deposit has been identified beneath a site located adjacent to a river. The sand deposit is 15 feet thick and the top of the layer is 12 feet below the ground surface and overlain by a very stiff clay and is underlain by bedrock. The water level has been measured to be at a depth of 10 feet. The standard penetration resistance of the layer has been determined to be 12 blows per foot and a standard sampler was used; a drill rig with a safety hammer with an efficiency of 60% was used. The length of the drill rod is 10 meters and the borehole diameter is 5 inches (127 mm). The design earthquake has been designated as a moment magnitude 6-3/4 event on a nearby fault and the maximum ground acceleration is expected to be 0.40 g. The wet unit weight of the clay soils is 150 pounds per cubic foot and the wet unit weight of the sand soils is 180 pounds per cubic foot. The sands have 35% fines content according to a grain size analysis. Determine the magnitude scaling factor, MSF. Express…arrow_forward
- In a site consisting entirely of clays, an electric friction conepenetrometer measures the cone resistance qc at a depth of8.0 m as 0.75 MN/m2. The water table is at 3.0 m below theground level. The unit weights of the clay above and belowthe water table are 16.5 kN/m3 and 19.0 kN/m3, respectively.Estimate the undrained shear strength, preconsolidationpressure, and overconsolidation ratio at this depth.arrow_forwardIn a falling head permeameter, tge sample used is 18cm long havibg a cross sectional area of 22cm^2. The sample of soil is mqde of three layers. The thickness of the first layer from the top is 8cm and has a value of k1=4x10^-4 cm/sec, the second layer of thickness 8cm has k2=5.5x10^-4 cm/sec and the bottom later of thickness 4 cm has k3=7x10^-4 cm/sec. Assume that the flow is taking place perpendicular to the layers. The cross sectional area of the stand pipe is 3cm^2. A.Calculate the equivalent coefficient permeability in cm/sec of the soils ib tye direction of the flow Choices: 4.44 x10^-4 cm/s 4.97x10^-4 cm/s 3.24x10^-4 cm/s 3 53x10^-4 cm/s B.Calculate the flow rate in cm^3/hr when the head drops from 25cm to 12cm Choices: 18.20,24.58,28.42,20.65 C.Calculate the time recquired for a drop of head from 25 cm to 12 cm Choices: 58.22,62.91,97.05,60.44arrow_forwardA standard penetration test was carried out in a normallyconsolidated sand at 25 ft depth where the N60 was determinedto be 28. The unit weight of the sand is 110 lb/ft3, andthe grain-size distribution suggests that D50 5 1.2 mm andCu 5 3.2. The age of the soil since deposition is approximately5000 years. Determine the relative density using thedifferent correlations discussed in Section 3.15arrow_forward
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