Evolution of Unsaturated Shear Strength and Microstructure of a Compacted Silty Clay on Wetting Paths

2021 ◽  
Vol 21 (12) ◽  
Author(s):  
Qian-Feng Gao ◽  
Ling Zeng ◽  
Zhen-Ning Shi ◽  
Rui Zhang
Keyword(s):  
Shear Strength ◽  
Silty Clay

scholarly journals Study on Water Characteristic Curve and Shear Characteristics of Typical Unsaturated Silty Clay in Shaoxing

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Ruiqian Wu ◽  
Youzhi Tang ◽  
Shaohe Li ◽  
Wei Wang ◽  
Ping Jiang ◽  
...  
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Unsaturated Soil ◽  
Direct Shear Test ◽  
Shear Test ◽  
Characteristic Curve ◽  
Friction Angle ◽  
Matric Suction ◽  
Silty Clay ◽  
Direct Shear

In order to probe into one simplified method to predict the shear strength of Shaoxing unsaturated silty clay, the test method combining unsaturated soil consolidation instrument and conventional direct shear instrument is used to study the shear strength, and the method is compared and verified with the results of equal suction direct shear test. The research results show that the soil water characteristic curve fitted by the measured data points and VG model has obvious stage characteristics in the range of 0~38 kPa, 38~910 kPa, and 910~10000 kPa. The shear strength of unsaturated soil measured by consolidation meter combined with conventional direct shear test is in good agreement with that measured by equal suction direct shear test in the range of 0~500 kPa. The results show that the shear strength, total cohesion, and effective internal friction angle of soil increase slightly with the increase of matric suction in the range of 0~38 kPa. When the matric suction increases from 38 kPa to 500 kPa, the shear strength and total cohesion force of the soil have similar stage characteristics with the SWCC, which first increases and then tends to be stable, while the effective internal friction angle changes slightly. Finally, taking the air-entry value as the demarcation point, an improved model of unsaturated shear strength is proposed by analyzing the error value. Compared with the measured value, the absolute value of relative error is basically kept in the range of 5%~10%, which is close to the measured value.

The 1994 landslide at Sainte-Monique, Quebec: geotechnical investigation and application of progressive failure analysis

2015 ◽  
Vol 52 (4) ◽  
pp. 490-504 ◽  
Author(s):  
A. Locat ◽  
S. Leroueil ◽  
A. Fortin ◽  
D. Demers ◽  
H.P. Jostad
Keyword(s):  
Shear Strength ◽  
Failure Analysis ◽  
Progressive Failure ◽  
High Sensitivity ◽  
Failure Surface ◽  
Soil Mass ◽  
Silty Clay ◽  
High Plasticity ◽  
Geotechnical Investigation ◽  
Progressive Failure Analysis

In 1994, a landslide occurred in the municipality of Sainte-Monique, Quebec. The debris of the landslide had graben and host shapes, typical of spreads in sensitive clays. The geotechnical investigation shows that the soil involved is a firm to stiff, sensitive, nearly normally consolidated grey silty clay of high plasticity. This soil exhibits a high sensitivity and a high brittleness during shear and is therefore susceptible to progressive failure. Traditional stability analysis cannot explain this landslide. This gives the opportunity to examine the applicability of progressive failure analysis to this spread. Using the finite elements method, it is demonstrated that the initiation and observed extent of the failure surface are explained by a soil having high brittleness during shear and a large-deformation shear strength close to the remoulded shear strength of the soil. The dislocation of the soil mass can also be explained by the active failure occurring in the soil mass above the failure surface during or shortly after failure propagation. It is therefore numerically demonstrated that progressive failure explains the initiation and the extent of the failure surface of this spread.

Experimental Study of Shear Strength of Unsaturated Silty Clay of Yellow River Levee

2012 ◽  
Vol 446-449 ◽  
pp. 1979-1983
Author(s):  
Cui Ran Liu ◽  
Li Wang ◽  
Jin Jun Guo
Keyword(s):  
Shear Strength ◽  
Unsaturated Soil ◽  
Yellow River ◽  
Effective Means ◽  
Silty Clay ◽  
Long Duration ◽  
Matrix Suction ◽  
Strength Formula ◽  
Relationship Of ◽  
The Relationship

Tri-axial test is one of effective means to measure the strength of unsaturated soil. But because of complexity and exquisite requirement with and long duration of test, unsaturated tri-axial test wasn’t used extensively in civil engineering before. The tests of shear strength of unsaturated soil are performed with the improved tri-axial apparatus for unsaturated soil. According to test data, the relationship of strength between water content and matrix suction are studied. In addition, the new shear strength formula suitable for yellow river is derived. The formula is the theory basis for analysis of unsaturated slope stability.

scholarly journals Influence of lime stabilization on shear strength parameters of silty clay soil

2018 ◽  
pp. 143-156
Author(s):  
Marko Spasic ◽  
Nikola Zivanovic ◽  
Grozdana Gajic
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Clay Soil ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Silty Clay ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Lime Stabilization ◽  
Silty Clay Soil

Lime soil stabilization is a well-known and often used method. One of the methods of landslide stability improvement is changing soil with materials that have better physical and mechanical characteristics. In most of the methods for determining slope stability, the main input data are internal friction angle and cohesion. The main objective of this paper was to find out if the sampled silty clay soil was suitable for lime stabilization, and to get the values of shear strength parameters from soil samples with and without added lime. The results showed that by increasing lime content, internal friction angle rises, while cohesion values decrease, as well as deformations, all the way to 15% of lime by mass. The changes in internal friction angle, cohesion and deformations were most noticeable between 0 and 5% of added lime. Samples that endured the largest pressures were those containing 10% of lime.

scholarly journals Experimental investigations of using deep mixing method to stabilise problematic clays in Ontario

2021 ◽  
Author(s):  
Shuihan Li
Keyword(s):  
Shear Strength ◽  
Strength Properties ◽  
Undrained Shear Strength ◽  
Experimental Investigations ◽  
Silty Clay ◽  
Slag Cement ◽  
Mixing Method ◽  
Sensitive Marine Clay ◽  
Strength Improvement ◽  
Undrained Shear

Champlain Sea clay is a sensitive marine clay which can lose more than 90% of its strength when disturbed. Organic silty clay, commonly found in Ontario, has a high compressibility and a low shear strength. In this experimental study, different binders were applied to Champlain Sea clay and organic silty clay to improve its strength properties. The results indicate that cement and slag/cement can significantly improve the strength of these problematic clays. A cement dosage ranging from 150 kg/m3 to 250 kg/m3 can consistently improve the undrained shear strength of Champlain Sea clay and organic silty clay with the maximum strength improvement ratio of 10 and 18 respectively. A slag/cement dosage of 290 kg/m3 with a mass ratio of 3:1 can improve the undrained shear strength of Champlain Sea clay for more than 50 times. Lime was found to be effective in treating organic silty clay as well.

scholarly journals Effect of Roughness on Shear Characteristics of the Interface between Silty Clay and Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yonghong Wang ◽  
Xueying Liu ◽  
Mingyi Zhang ◽  
Xiaoyu Bai
Keyword(s):  
Shear Strength ◽  
Shear Stiffness ◽  
Test System ◽  
Engineering Practice ◽  
Silty Clay ◽  
Interface Pressure ◽  
Interface Shear ◽  
Piezoresistive Sensor ◽  
Shear Characteristics ◽  
Concrete Interface

In order to study the effect of roughness on the mechanical parameters of silty clay-concrete interface, and to explore the applicability of silicon piezoresistive sensor to test the interface pressure, a large-scale direct shear test system was used to carry out experimental research on the shear characteristics of silty clay-concrete interface under different roughness conditions. Based on silicon piezoresistive sensor, the shear characteristics of silty clay-concrete interface are analyzed. The results show that the silicon piezoresistive sensor has excellent performance in measuring the interface pressure and can accurately obtain the shear characteristics of the silty clay-concrete interface. The roughness has a significant influence on the shear strength, shear stiffness, and other mechanical properties of the prefabricated pile-soil interface. With the increase of roughness, interface shear strength, interface friction angle, shear stiffness coefficient, and interface residual shear stress all show an increasing trend, with the maximum increase of 37.0%. The interface adhesion decreased first and then increased with the increase of roughness, with an increase of 23.7%. The test results can provide reference for the engineering practice of jacked pile.

scholarly journals Prediction of unsaturated shear strength from microstructurally based effective stress

2019 ◽  
Vol 92 ◽  
pp. 07005
Author(s):  
Régis Mpawenayo ◽  
Pierre Gerard
Keyword(s):  
Shear Strength ◽  
Effective Stress ◽  
Unsaturated Soils ◽  
Mercury Intrusion Porosimetry ◽  
Clay Soil ◽  
Large Range ◽  
Triaxial Tests ◽  
Silty Clay ◽  
Wide Range ◽  
Silty Clay Soil

This work aims at investigating the adequacy of microstructurally based effective stress to predict the shear strength of unsaturated soils over a wide range of suction. For that purpose, shear strength data are acquired on a silty clay soil through two types of unsaturated triaxial tests: suction controlled triaxial tests and unconsolidated triaxial tests at constant water content. The microstructure of the soil is determined with Mercury Intrusion Porosimetry and is directly used in different expressions of microstructurally based effective stresses available in the literature. The large range of suction tested allows to determine the most consistent expression of the effective stress to reproduce the experimental observations.

The September 5, 1987, landslide on the La Grande River, James Bay, Quebec, Canada

1991 ◽  
Vol 28 (2) ◽  
pp. 263-275 ◽  
Author(s):  
Guy Lefebvre ◽  
Peter Rosenberg ◽  
Jean Paquette ◽  
J. G. Lavallée
Keyword(s):  
Shear Strength ◽  
Ground Surface ◽  
Bank Erosion ◽  
Undrained Shear Strength ◽  
Silty Clay ◽  
James Bay ◽  
River Bank ◽  
River Erosion ◽  
Sensitive Clay ◽  
Undrained Shear

The September 5, 1987, landslide at kilometre 82.5 on La Grande River affected a slope about 60 m high inclined at about 35°. The site had been identified as presenting high risks of a major landslide and had been under observation for several years. The conditions existing before the landslide are relatively well documented from a deep boring put down in 1975 at the slide location and from prior observations and photographs of the river bank erosion. The overburden deposit, sand at the ground surface changing to a silty clay at depth, was normally consolidated but affected by a strong underdrainage. Stability analyses confirm the strong underdrainage deduced from the 1975 piezometric reading. The slide retrogressed 290 m from the river on a surface inclined at 6°. The location of the retrogression surface appears related to the undrained shear strength profile. Key words: landslide, earthflow, sensitive clay, groundwater, river erosion, slope stability.

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