Influence of matric suction on shear strength behavior of remolded unsaturated basalt residual soil

2015 ◽  
pp. 309-313
Author(s):  
J Chen ◽  
X Lei ◽  
F Cheng ◽  
Q Meng
Keyword(s):  
Shear Strength ◽  
Matric Suction ◽  
Residual Soil ◽  
Strength Behavior

Shear strength behavior of compacted unsaturated residual soil

2013 ◽  
Vol 7 (1) ◽  
pp. 1-9 ◽  
Author(s):  
F A M Marinho ◽  
O M Oliveira ◽  
H Adem ◽  
S Vanapalli
Keyword(s):  
Shear Strength ◽  
Residual Soil ◽  
Strength Behavior

Rate of strength increase of unsaturated lateritic soil

2008 ◽  
Vol 45 (9) ◽  
pp. 1335-1343 ◽  
Author(s):  
Meen-Wah Gui ◽  
Chun-Ming Yu
Keyword(s):  
Shear Strength ◽  
Failure Criterion ◽  
Matric Suction ◽  
Slope Instability ◽  
Lateritic Soil ◽  
Strength Increase ◽  
Residual Soil ◽  
Strength Tests ◽  
Soil Shear Strength ◽  
Intact Soil

Lateritic soil is a kind of residual soil that is widely distributed in Asia. The water table of the soil is normally very deep so the upper part of the soil is often unsaturated. The largest lateritic soil area in Taiwan is the Linkou terrace. Because the soil here is loosely cohered and consolidated, the problem of slope instability and landslides has always been a major concern. To evaluate the triggering mechanism of landslides, it is necessary to obtain the failure criterion that represents both the saturated and unsaturated conditions of the soil before any analysis is carried out. The parameter required to define such a failure criterion is the rate of shear strength increase, tan φb, which can be obtained via a series of laboratory strength tests in a modified triaxial system under various matric suction levels. Both the intact and remolded lateritic soils taken from Linkou terrace have been tested for this purpose. The results confirm that matric suction in the lateritic soil contributes significantly to the soil shear strength and that intact soil has a higher strength than remolded soil.

EXPERIMENTAL STUDY ON NONLINEAR SHEAR STRENGTH BEHAVIOR OF A TROPICAL GRANITIC RESIDUAL SOIL (GRADE VI) AT VARIOUS INITIAL MOISTURE CONTENTS

2017 ◽  
Vol 79 (2) ◽  
Author(s):  
Pooya Saffari ◽  
Mohd Jamaludin Md Noor ◽  
Shervin Motamedi ◽  
Roslan Hashim ◽  
Zubaidah Ismail ◽  
...  
Keyword(s):  
Shear Strength ◽  
Slope Failure ◽  
Soil Mechanics ◽  
Characteristic Curve ◽  
Triaxial Tests ◽  
Residual Soil ◽  
Strength Behavior ◽  
Non Linear ◽  
Linear Shear ◽  
Linear Envelope

The conventional theories of soil mechanics use linear envelope to derive shear strength; this however, leads to an overestimation of the factor of safety in the examination of slopes. Therefore, the incorporation of methods that acknowledge the existence of non-linear characteristics of shear strength is necessary in the analysis of slopes specifically. This is due to the substantial influence of non-linear shear strength behavior on the slope failure mechanism when they are at low stress levels. In this paper, the nonlinearity of shear strength for grade VI granitic residual soil is studied. “Non-Axis Translation Consolidated Drained Triaxial” tests were performed at various ranges of net stress and suction. Thereafter, to characterize shear strength behavior, shear strength parameters were derived. The soil-water characteristic curve was plotted after conducting “Pressure Plate Extractor” test at a series of suction. The result substantiated the non-linearity of shear strength for granitic residual soil based on net stress and suction.  

Influence of matric suction on shear strength behavior of a residual clayey soil

2007 ◽  
Vol 53 (4) ◽  
pp. 891-901 ◽  
Author(s):  
C. Kayadelen ◽  
M. A. Tekinsoy ◽  
T. Taşkıran
Keyword(s):  
Shear Strength ◽  
Clayey Soil ◽  
Matric Suction ◽  
Strength Behavior

Shear-strength characteristics of a residual soil

1995 ◽  
Vol 32 (1) ◽  
pp. 60-77 ◽  
Author(s):  
H. Rahardjo ◽  
T.T. Lim ◽  
M.F. Chang ◽  
D.G. Fredlund
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Matric Suction ◽  
Residual Soil ◽  
Test Results ◽  
Angle Of Internal Friction ◽  
Slip Surfaces

Shallow landslides in natural residual soils slopes are common all over the world. The slip surfaces associated with these landslides are often situated above the groundwater table. Therefore, it is important to quantify the contribution of negative pore-water pressure to the shear strength of soil. The shear-strength characteristics of residual soil from the Jurong Formation in Singapore were assessed using multistage, consolidated drained triaxial tests. These tests involved shearing under either a constant net confining pressure and varying matric suctions or under a constant matric suction and varying net confining pressures. An extended form of the Mohr–Coulomb equation was used to interpret the test results. The test results show that for matric suctions up to 400 kPa, the angle of internal friction associated with the matric suction, [Formula: see text], is similar to the effective angle of internal friction, [Formula: see text], which averages 26° for the residual soil of the Jurong Formation. The residual soil can maintain a high degree of saturation for matric suctions as high as 400 kPa. Examples involving stability analyses of a residual soil slope with varying pore-water pressure profiles indicate that soil suction contributes significantly to the factor of safety, particularly for shallow slip surfaces. Key words : residual soil, unsaturated soil, matric suction, shear strength, multistage triaxial test, slope stability.

Shear strength characteristics of two saprolitic soils

1996 ◽  
Vol 33 (4) ◽  
pp. 595-609 ◽  
Author(s):  
Julian K-M Gan ◽  
D G Fredlund
Keyword(s):  
Shear Strength ◽  
Characteristic Curve ◽  
Matric Suction ◽  
Coarse Grained ◽  
Triaxial Tests ◽  
Direct Shear ◽  
Strength Behavior ◽  
Decomposed Granite ◽  
Insight Into ◽  
Completely Decomposed Granite

The saturated and unsaturated shear strength behavior of an undisturbed, completely decomposed fine ash tuff and an undisturbed, completely decomposed granite from Hong Kong were studied using direct shear and triaxial tests. The completely decomposed fine ash tuff is a fine- to medium-grained saprolite. The completely decomposed granite is a coarse-grained saprolite. Results show that matric suction increases the shear strength of both soils. The extent of the increase is the shear strength with matric suction is related to the soil-water characteristic curve for the soil and to the amount of dilation during shear. The effect of matric suction on the shear strength was more pronounced for the fine- to medium-grained completely decomposed fine ash tuff than for the coarse-grained completely decomposed granite. These studies on the saprolitic soils provide insight into the understanding of the shear strength of unsaturated, coarse-grained soils. Key words: saprolites, shear strength, matric suction, triaxial, direct shear, coarse-grained soils.

Shear strength behavior of Mont Terri Opalinus Claystone in fault zone

2015 ◽  
Vol 10 (1) ◽  
pp. 31-38
Author(s):  
Ildikó Buocz ◽  
Nikoletta Rozgonyi-Boissinot ◽  
Ákos Török
Keyword(s):  
Shear Strength ◽  
Fault Zone ◽  
Strength Behavior ◽  
Mont Terri

Shear strength and dilative characteristics of an unsaturated compacted completely decomposed granite soil

2010 ◽  
Vol 47 (10) ◽  
pp. 1112-1126 ◽  
Author(s):  
Md. Akhtar Hossain ◽  
Jian-Hua Yin
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Matric Suction ◽  
Water Retention Curve ◽  
Direct Shear ◽  
Normal Stresses ◽  
Soil Water Retention Curve ◽  
Strength Data ◽  
Decomposed Granite ◽  
Completely Decomposed Granite

Shear strength and dilative characteristics of a re-compacted completely decomposed granite (CDG) soil are studied by performing a series of single-stage consolidated drained direct shear tests under different matric suctions and net normal stresses. The axis-translation technique is applied to control the pore-water and pore-air pressures. A soil-water retention curve (SWRC) is obtained for the CDG soil from the equilibrium water content corresponding to each applied matric suction value for zero net normal stress using a modified direct shear apparatus. Shear strength increases with matric suction and net normal stress, and the failure envelope is observed to be linear. The apparent angle of internal friction and cohesion intercept increase with matric suction. A greater dilation angle is found at higher suctions with lower net normal stresses, while lower or zero dilation angles are observed under higher net normal stresses with lower suctions, also at a saturated condition. Experimental shear strength data are compared with the analytical shear strength results obtained from a previously modified model considering the SWRC, effective shear strength parameters, and analytical dilation angles. The experimental shear strength data are slightly higher than the analytical results under higher net normal stresses in a higher suction range.

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