scholarly journals Influence of calcareous nodules content on scaling effect in shear strength of cohesive soil containing calcareous nodules

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Chuan-yang Liang ◽  
Yue-dong Wu ◽  
Jian Liu ◽  
Lei Zhang ◽  
Lai-he Lin ◽  
...  
Keyword(s):  
Shear Strength ◽  
Cohesive Soil ◽  
Calculation Model ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Scaling Effect ◽  
Large Size ◽  
The Difference ◽  
Calcareous Nodule

AbstractThe difference in the shear strength and other characteristics of the cohesive soil containing calcareous nodules (CSCN) between samples with large size and corresponding scaling size, which is called scaling effect, is significantly affected by its calcareous nodule content (CNC) of the gradation composition. However, current researches rarely reveal the influence of the CNC on the scaling effect in shear strength of samples. In this study, how and why the CNC affects the scaling effect in shear strength were explored. Then a method to reduce the scaling effect based on the reason for influence was proposed. Results show that the correlation between the scaling effect in shear strength and the CNC presents a step curve. This is attributed to that it is easier to form a skeleton effect in samples with scaling size for the same CNC. Considering the skeleton effect, a calculation model for the shear strength parameters of CSCN samples with large size is proposed to reduce the scaling effect. This paper demonstrates that the proposed calculation model provides an access to obtain calculated shear strength parameters of CSCN samples with large size by using measured results of samples with corresponding scaling size.

Behaviour of the stiff and sensitive Saint-Jean-Vianney clay in intact, destructured, and remoulded conditions

2002 ◽  
Vol 39 (5) ◽  
pp. 1075-1087 ◽  
Author(s):  
Faten Saihi ◽  
Serge Leroueil ◽  
Pierre La Rochelle ◽  
Ivan French
Keyword(s):  
Shear Strength ◽  
Large Deformation ◽  
Limit State ◽  
Triaxial Tests ◽  
Compression Tests ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Soft Clays ◽  
The Difference ◽  
State Curve

The role of the degree of microstructure on the behaviour of clayey soils has been the focus of many studies. However, none so far have quantified the evolution of the shear strength parameters for a given soil for degrees of microstructure going from an intact condition to complete remoulding. In the present study, a series of compression triaxial tests have been performed on specimens of the naturally highly structured Saint-Jean-Vianney clay under the following conditions: intact, destructured by straining outside the limit state curve, and reconstituted and reconsolidated after complete remoulding. The results show that the limit state curve is influenced by the level of destructuration reached before testing, and moreover, that the shear strength parameters at large deformation are influenced by the level of destructuration at the beginning of the test. The compression tests infer that the soil seems to retain the memory of its initial microstructure, at least for consolidation volumetric strains up to 14%. The observed behaviour has implications for the understanding and modelling of natural clays; it also explains to some extent the difference in strength parameters used in stability analyses of embankments on soft clays and natural slopes in clay.Key words: clay, microstructure, destructuration, shear strength, large deformation shear strength, triaxial test.

Reliability Method to Estimate Shear Strength Parameters

2011 ◽  
Vol 52-54 ◽  
pp. 1752-1756
Author(s):  
Li Hong Chen ◽  
Yu Fei Zhao
Keyword(s):  
Shear Strength ◽  
Linear Regression ◽  
Moment Method ◽  
Limit State ◽  
Safety Evaluation ◽  
Regression Method ◽  
Linear Regression Method ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Reliability Method

The design and safety evaluation of a geotechnical project is influenced by the shear strength parameters of geo-material. Moment method and linear regression method are the mainly used methods to estimate the shear strength parameters. But moment method is always over estimate the variation of strength parameters due to the smaller sample size, meanwhile the conventional linear regression method cannot obtain the standard deviation. Base on the reliability theory, a new method employing Solver add-in of spreadsheet was developed to calculate the shear strength parameters. The method was simplified by the principle that the shortest distance form origin point to the limit state surface in the normalization space was the reliability index. Four hundred and four samples of direct shear tests of rock mass from many large hydraulic projects in China were analyzed by four statistic methods including the new proposed one. Comparing results of different methods indicated that the new reliability statistic method had good performance than the traditional ways.

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