scholarly journals COMPARING THE HOEK-BROWN AND MOHR-COULOMB FAILURE CRITERIA IN FEM ANALYSIS

2021 ◽  
Vol 30 ◽  
pp. 69-75
Author(s):  
Tereza Poklopová ◽  
Veronika Pavelcová ◽  
Michal Šejnoha
Keyword(s):  
Fem Analysis ◽  
Failure Criteria ◽  
Correct Choice ◽  
Failure Model ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Finite Element Software ◽  
Coulomb Failure ◽  
Coulomb Model ◽  
The Stability

This paper revisits the issue of a potential substitutions of the Hoek-Brown failure model by the standard Mohr-Coulomb model in the stability analysis of rock masses. The derivation of equivalent shear strength parameters of the Mohr-Coulomb proposed by Hoek et al. [1] is addressed with emphases on the suitable range of stresses for which the equivalence of the two failure criteria applies. To that end, a simple numerical analysis of the oedometric test is carried out. It is seen that a correct choice of the upper limit of the minimum compressive principal stress is crucial for the Mohr-Coulomb model to provide predictions comparable to the Hoek-Brown model. This issue is addressed next in the light of the solution of slope stability problem. All the presented results were derived with the help of the GEO5 FEM finite element software [2].

Slope Stability Analysis in Anisotropic Winnipeg Clays

1974 ◽  
Vol 11 (1) ◽  
pp. 59-71 ◽  
Author(s):  
W. S. Freeman ◽  
Hugh B. Sutherland
Keyword(s):  
Shear Strength ◽  
Cross Sections ◽  
Strength Properties ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Residual Shear Strength ◽  
Lower Shear ◽  
The Stability ◽  
Mechanism Of Failure ◽  
Cut Slopes

Two major aspects of an investigation dealing with the stability of natural and cut slopes in the Winnipeg area are described. The first concerns an experimental investigation of the anisotropic shear strength characteristics of the layered Lake Agassiz clays and the second is a study of the mechanism of failure for slopes in these layered clays.Four main types of clay were investigated and it was found that the effective shear strength parameters were greater for failure across the layers than for failure along the layers. Residual shear strength parameters were also determined.Stability analyses were carried out for representative slope cross sections using circular and noncircular failure surfaces, taking into account the anisotropic shear strength effects measured in the laboratory tests.Factors of safety were found for the conventional method of analysis assuming circular arc failure surfaces and isotropic shear strength properties. These factors of safety were found to be up to 0.5 greater than those obtained from noncircular failure surfaces which partially passed along the layers and so mobilized the lower shear strength properties of these layers.

scholarly journals Modified Limiting Equilibrium Method for Stability Analysis of Stratified Rock Slopes

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Rui Yong ◽  
Chang-Dong Li ◽  
Jun Ye ◽  
Man Huang ◽  
Shigui Du
Keyword(s):  
Three Gorges Reservoir ◽  
Rock Slope ◽  
Bedding Plane ◽  
Three Gorges ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Bedding Planes ◽  
Equilibrium Method ◽  
The Stability ◽  
Stratified Rock

The stratified rock of Jurassic strata is widely distributed in Three Gorges Reservoir Region. The limit equilibrium method is generally utilized in the stability analysis of rock slope with single failure plane. However, the stratified rock slope cannot be accurately estimated by this method because of different bedding planes and their variable shear strength parameters. Based on the idealized model of rock slope with bedding planes, a modified limiting equilibrium method is presented to determine the potential sliding surface and the factor of safety for the stratified rock slope. In this method, the S-curve model is established to define the spatial variations of the shear strength parameterscand  φof bedding plane and the tensile strength of rock mass. This method was applied in the stability evaluation of typical stratified rock slope in Three Gorges Reservoir Region, China. The result shows that the factor of safety of the case study is 0.973, the critical sliding surface for the potential slip surface appears at bedding plane C, and the tension-controlled failure occurs at 10.5 m to the slope face.

scholarly journals Strength Characteristics and Slope Stability of Expansive Soil from Pingdingshan, China

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Ju-yun Zhai ◽  
Xiang-yong Cai
Keyword(s):  
Shear Strength ◽  
Slope Stability ◽  
Expansive Soil ◽  
Friction Angle ◽  
Natural Soil ◽  
Soil Slope ◽  
The Finite Element Method ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
The Stability

By analyzing the characteristics of expansive soil from Pingdingshan, China, the shear strength parameters at different water contents, dry densities, and dry-wet cycles of expansive soil are obtained. It is found that, at higher soil-water content, the internal friction angle is 0° and the shallow layer of expansive soil slope will collapse and destroy; this has nothing to do with the height of the slope and the size of the slope. The parameters of soil influenced by atmosphere are the ones which have gone through dry-wet cycles, and the parameters of soil without atmospheric influence are the same as those of natural soil. In the analysis of slope stability, the shear strength parameters of soil can be determined by using the finite element method, and the stability coefficient of the expansive soil slope can be calculated.

Application of the Complex Variable Differential Method in the Back Analysis of Geotechnical Engineering

2010 ◽  
Vol 168-170 ◽  
pp. 2439-2444
Author(s):  
Ming Wei Liu ◽  
Ying Ren Zheng
Keyword(s):  
Shear Strength ◽  
Complex Variable ◽  
Back Analysis ◽  
Optimization Method ◽  
Differential Method ◽  
Analysis Method ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Measuring Point ◽  
The Stability

On the stability analysis of complex slope, the determination of rock-soil masses shear strength parameters is very important. It’s very necessary to use the back analysis method to verify experiment result of rock-soil masses parameters for the important slope engineering. Because the sensitivity of shear strength parameters to displacement parameters is very poor, so that we couldn’t get the satisfactory shear strength parameters result by traditional back analysis method. Aiming at the problems of traditional back analysis method, this paper puts forward a totally new method of back analysis, which is applicable to the shear strength parameters of rock-soil masses through the integration of complex variable differentiation method, optimization method and elastic-plasticity finite-element method. The method mathematically back calculates shear strength parameters of rock-soil masses on the basis of displacement of measuring point. The sample calculation result indicates that the method possesses high accuracy and searching efficiency, and is a method of back analysis of displacement deserving popularizing.

scholarly journals Lessons learnt from design and construction of dams in Brazil

2000 ◽  
Vol 22 ◽  
Author(s):  
Paulo Teixeira da Cruz
Keyword(s):  
Power Generation ◽  
Construction Materials ◽  
Field Tests ◽  
Residual Soils ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Peculiar Behaviour ◽  
History Of ◽  
The Stability ◽  
Design And Construction

This paper deals with design and construction of dams built in Brazil. A brief introduction on the history of these dams is followed by the main types of dams, that due to the environment, site topography, climate, foundation conditions and borrow materials, have been considered the most adequate and economical both for irrigation purposes or power generation. A second item deals with peculiar behaviour of the residual soils used as construction materials regarding flow aspects and construction pore pressures. The use of saprolitic soils is also discussed as well as of rock materials that disintegrate under drying and wetting cycles. The shear strength parameters of these materials obtained in laboratory and field tests are presented. The compressibility and the stability of the dams, and the measured flows through the foundations are reported.

scholarly journals Experimental Investigation on Shear Strength Parameters of Lime Stabilized Loess

2019 ◽  
Vol 11 (19) ◽  
pp. 5397 ◽  
Author(s):  
Liang Jia ◽  
Jian Guo ◽  
Yanbin Jiang ◽  
Yong Fu ◽  
Zhidong Zhou ◽  
...  
Keyword(s):  
Shear Strength ◽  
Yellow River ◽  
Friction Angle ◽  
Experimental Results ◽  
Triaxial Tests ◽  
Curing Time ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Lime Content ◽  
Coulomb Failure

Loess is a typical collapsible soil, which is widely distributed in the upper and middle areas around the Yellow River of China. The stabilization of loess with lime provides a significant improvement in the physical and the mechanical characteristics of the loess and is therefore widely used in the pavement base and subgrade. Therefore, a systematic investigation of Mohr-Coulomb failure envelope of lime stabilized loess needs to be conducted. In this pursuit, the present research envisages the investigation of the effects of the lime content, porosity and curing time on the strength parameters (friction angle (φ) and cohesion (c)), using a series of triaxial tests performed on lime stabilized loess specimens. The experimental results revealed that the friction angle (φ) was independent of the lime content, the porosity and the curing time of the specimen for a given lime stabilized loess, while the factors mentioned above had a significant effect on the cohesion (c) of the lime stabilized loess. For a relatively short curing time (7 days), the change in the lime content did not present an obvious effect on the cohesion (c) of the stabilized loess. However, when the curing time (28, 90 and 180 days) was longer, the increase of the lime content significantly enhanced the cohesion of the stabilized loess. When the lime content was constant, the cohesion (c) of the stabilized loess increased linearly with the decrease in the void ratio. A power function equation was proposed to assess the comprehensive influences of the factors like the lime content, porosity and curing time on cohesion (c). Finally, the Mohr-Coulomb failure envelopes were drawn based on the triaxial test for 47 specimens with various curing time and confining pressure, and the shear strength parameters obtained by the proposed equation were also compared with the experimental results.

Using Excel to Evaluate Shear Strength Parameters of Soil

2013 ◽  
Vol 709 ◽  
pp. 579-582
Author(s):  
Meng Hua Fan
Keyword(s):  
Shear Strength ◽  
Shear Test ◽  
Triaxial Tests ◽  
Mathematics Model ◽  
Direct Shear ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Direct Shear Tests ◽  
Allowable Deviation ◽  
Coulomb Failure

It is difficult to determine the Mohr-Coulomb failure envelope visually, and it is strongly influenced by abnormal test data evaluating the shear strength parameters of soil via trend line and unable to adjust the scope of permissible error. So it is recommended to evaluate shear strength parameters of soil using Solver of Excel for direct shear tests and triaxial tests and you can control the allowable deviation. The mathematics model of nonlinear programming was established to evaluate shear strength parameters of soil from the results of direct shear test and triaxial shear test. The related Excel worksheet was created and the optimum results of the objective function were obtained by setting the Solver parameters dialog box accurately. The method is simple, inexpensive and rapid.

scholarly journals A Copula-Based Method for Estimating Shear Strength Parameters of Rock Mass

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Da Huang ◽  
Chao Yang ◽  
Bin Zeng ◽  
Guoyang Fu
Keyword(s):  
Shear Strength ◽  
Rock Mass ◽  
Probabilistic Method ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Copula Functions ◽  
In Situ Tests ◽  
Underground Caverns ◽  
The Stability

The shear strength parameters (i.e., the internal friction coefficientfand cohesionc) are very important in rock engineering, especially for the stability analysis and reinforcement design of slopes and underground caverns. In this paper, a probabilistic method, Copula-based method, is proposed for estimating the shear strength parameters of rock mass. The optimal Copula functions between rock mass qualityQandf,Qandcfor the marbles are established based on the correlation analyses of the results of 12 sets of in situ tests in the exploration adits of Jinping I-Stage Hydropower Station. Although the Copula functions are derived from the in situ tests for the marbles, they can be extended to be applied to other types of rock mass with similar geological and mechanical properties. For another 9 sets of in situ tests as an extensional application, by comparison with the results from Hoek-Brown criterion, the estimated values offandcfrom the Copula-based method achieve better accuracy. Therefore, the proposed Copula-based method is an effective tool in estimating rock strength parameters.

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