9.4 An exploratory drill hole was made in a stiff saturated clay (see Figure 9.9). The sand layer underlying the clay was observed to be under artesian pressure. Water in the drill hole rose to a height of 4 m above the top of the sand layer. If an open excavation is to be made in the clay, how deep can the excavation proceed before the bottom heaves? Ans: 3.97 m 6.1m E 4m £ Exploratory drill hole Saturated clay Sand Figure (9.9) G₁=2.72 Moisture content=w=35%

9.4 An exploratory drill hole was made in a stiff saturated clay (see Figure 9.9). The sand layer underlying the clay was observed to be under artesian pressure. Water in the drill hole rose to a height of 4 m above the top of the sand layer. If an open excavation is to be made in the clay, how deep can the excavation proceed before the bottom heaves? Ans: 3.97 m 6.1m E 4m £ Exploratory drill hole Saturated clay Sand Figure (9.9) G₁=2.72 Moisture content=w=35%

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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In a drained triaxial test on consolidated clay the stress and angle are as follows : Deviator stress is 20 lb/in2 and friction angle 210 . calculate the effective confining pressure at failure.?
A clay layer of 30 m thick with a unit weight of 20 kN/m3 overlies a sand layer. The groundwater table is at the ground surface initially. A 20 m deep excavation is made in the clay layer. Piezometric measurements show artesian pressure at the bottom of the clay layer, amounting to a water level of 8 m above the excavation base. Calculate the factor of safety against the bottom heave for the excavation.
9.4 An exploratory drill hole was made in a stiff saturated clay (see Figure 9.9). The sand layer underlying the clay was observed to be under artesian pressure. Water in the drill hole rose to a height of 4 m above the top of the sand layer. If an open excavation is to be made in the clay, how deep can the excavation proceed before the bottom heaves? Exploratory drill hole G₁=2.72 6.1 m Moisture content -35% m 4m £ Saturated clay Sand
12.14 Following are the results of consolidated-undrained triaxial tests on undisturbed soils retrieved from a 4-m thick saturated clay layer in the field (yat = 20.7 kN/m³). Chamber Deviator stress, (Ao), (kN/m?) Pore pressure at failure, (Au) (kN/m?) Test pressure, o; (kN/m?) no. 75 166 -11 2 150 295 -52 3 250 410 -80 a. Estimate graphically the Mohr-Coulomb shear strength parameters c' and o'. b. Estimate the shear strength in the middle of the clay layer.
A consolidated-undrained test on a normally consolidate clay yield the following results: Confining Pressure = 151 KPa; Deviator Stress = 187 KPa; Pore Pressure = 71 KPa. Calculate the consolidated undrained friction angle. Please answer this asap. For upvote. Thank you very much
Problem 4: An inclined permeameter tube is filled with layers of soil of different permeability as shown below. Find the total head, elevation head and pore water pressure at points (A-B-C-D) with respect to the given datum, Given: 1.5k1=2k2=3k3=k4 k4=2x10-3 cm/sec 35 сm 9 cm K4 K3 K1 K2 15 cm 11 cm 7 cm 4 cm Datum شاشة 4cm
Q2: Available field data indicate that the permeahility for the clay is varies with depth. For layer 1: ku = 3.2 x 10 cmis; k = 1.1 x 10 cmis. For layer 2: kg - 1.7 x 10 em's; ka - 3.4 x 10" cm/s. For layer 3: kg - 1.4 x 10 cmis; ka - 44 x 10* cm/s. Compute the equivalent permeability for flow parullel and perpendicular to the clay layers shuwn in Fig.2. Layr 1 L 2 Layer a Fig.2 180 m
A 25 m thick layer of clay with a saturated unit weight of 21 kN/m³ is underlain by a layer of sand, as shown in the Figure. The sand is under an artesian pressure. 1. Determine (by calculations) whether the bottom of the excavation will heave or not when no water inside the excavation (h=0). 2. The height of water in the excavation (h) for ó = 0 at the base of clay layer. 6 m 25 m 13 m 12 m W.T. Clay Sand
Estimate the total consolidation settlement (primary & secondary) after 2 years and 3 months after the completion of primary consolidation settlement of an over consolidated clay layer under the bridge pier as shown below. The pier's dimensions are (2 m x 3 m). Use Yw= 10 kN/m³ and note that the time for completion the primary consolidation is 3 years. | Qo= 960 kN G.W.L 1m Sand Ya=16.5 kN/m 2 m Ysat = 18 kN/m³ Silty Sand Ya=17.5 kN/m 3 m Ysat = 18.5 kN/m3 Clay Ya=20 kN/m , Ysat = 21 kN/m3 e, = 0.6 , Ae=0.04 , o= 78.3 kN/m2 4 m Cc= 0.4, Cs= 0.1, Ca= 0.02
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In a drained triaxial test on consolidated clay the stress and angle are as follows: Deviator stress is 20 lb/in2 and friction angle is 21°. Calculate the effective confining pressure at failure.? a) 21 lb/in2 b) 22.2 lb/in2 c) 25.4 lb/in 2 d) 17.9 lb/in2
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