A 25 ft thick layer of stiff, saturated clay is underlain by a layer of sand. The sand layer underlying the clay was observed to be under artesian pressure. If an open excavation is to be made in the clay, how deep can the excavation proceed before the stability of the clay is lost? (15.1 ft) 25t Gs= 20 16 t

A 25 ft thick layer of stiff, saturated clay is underlain by a layer of sand. The sand layer underlying the clay was observed to be under artesian pressure. If an open excavation is to be made in the clay, how deep can the excavation proceed before the stability of the clay is lost? (15.1 ft) 25t Gs= 20 16 t

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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An exploratory drill hole was made in a stiff saturated clay having a moisture content of 29% and G, = 2.68 (Figure 9.27). The sand layer underlying the clay was observed to be under artesian pressure. Water in the drill hole rose to a height of 6 m above the top of the sand layer. a. If an open excavation is to be made in the clay, determine the safe depth of excavation before the bottom heaves. b. How much is the pressure at the interface of the clay and sand? c. If a factor of safety of 2.0 is to be ensured, how deep should be the excavation from the ground surface?
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geotechnical engineering question
9.7 An exploratory drill hole was made in a stiff saturated clay having a moisture content of 29% and G, = 2.68 (Figure 9.27). The sand layer underlying the clay was observed to be under artesian pressure. Water in the drill hole rose to a height of 6 m above the top of the sand layer. If an open excavation is to be made in the clay, determine the safe depth of excavation before the bottom heaves. Exploratory drill hole 10 m 45 m Saturated clay Sand Figure 9.27
The answer should be 9.56"
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A 3-m layer (double drainage) of saturated clay under a surcharge loading underwent 90% primary consolidation in 75 days. Find the coefficient of consolidation of clay for the pressure range..
By referring to the question B-1, the capillary height, hc for the clayey sand is: O 0.07 m O 5.59 m O 3.07 m O 2.30 m
Please solve this problem and explain each step clearly, Please explain the theory and show your work clearly, I really want to understand. Thank you
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 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 cyclic resistance ratio, CRR. Use this…
Time left 1:24:08 An excavation is to be performed in a stratum of clay, 9 m thick, underlain by a bed of sand. In a trial bore hole, the ground-water is observed to rise up to an elevation 3 m below ground surface.Find the depth of which the excavation can be safely carried out without the bottom becoming unstable under uplift pressure of ground-water. The specific gravity of clay particles is 2.70 andthe void ratio is 0.70. If the excavation is to be safely carried to a depth of 7 m, how much should the water table be lowered in the vicinity of the trench ? O a. 6 m O b. 9 m C. O c. 10 m O d. 8 m SHOT ON POCO F3