scholarly journals A non-stationary earthquake probability assessment with the Mohr–Coulomb failure criterion

2015 ◽  
Vol 15 (10) ◽  
pp. 2401-2412 ◽  
Author(s):  
J. P. Wang ◽  
Y. Xu
Keyword(s):  
Failure Criterion ◽  
Model Development ◽  
Model Parameters ◽  
New Model ◽  
Earthquake Probability ◽  
Coulomb Failure ◽  
Characteristic Earthquakes ◽  
Stress States ◽  
Coulomb Failure Criterion ◽  
Central Taiwan

Abstract. From theory to experience, earthquake probability associated with an active fault should be gradually increasing with time since the last event. In this paper, a new non-stationary earthquake assessment motivated/derived from the Mohr–Coulomb failure criterion is introduced. Different from other non-stationary earthquake analyses, the new model can more clearly define and calculate the stress states between two characteristic earthquakes. In addition to the model development and the algorithms, this paper also presents an example calculation to help explain and validate the new model. On the condition of best-estimate model parameters, the example calculation shows a 7.6 % probability for the Meishan fault in central Taiwan to induce a major earthquake in years 2015–2025, and if the earthquake does not occur by 2025, the earthquake probability will increase to 8 % in 2025–2035, which validates the new model that can calculate non-stationary earthquake probability as it should vary with time.

Axisymmetric Punching Capacity Analysis for Concrete Slabs

2012 ◽  
Vol 446-449 ◽  
pp. 463-470
Author(s):  
Xiao Rong Hu ◽  
Xiao Mei Fan
Keyword(s):  
Principal Stress ◽  
Failure Criterion ◽  
Three Dimensional ◽  
Intermediate Principal Stress ◽  
Concrete Slabs ◽  
Stress Effects ◽  
Coulomb Failure ◽  
Failure Properties ◽  
Stress States ◽  
Coulomb Failure Criterion

The axisymmetric punching analysis for concrete slabs is researched with the triple-shear unified failure criterion, which can explain the failure properties rationally for concrete under the three dimensional stress states, especially the failure properties of the intermediate principal stress effects. Moreover, a new intermediate principal stress parameter is proposed to interpret the different stress states in failure zones for different concrete. It is shown that the coefficients of b and m, which interprets the effects and the magnitudes of the intermediate principal stress have significant impacts on the axisymmetric punching capacity of concrete slabs. For a given thickness of the concrete slabs, the bearing capacity increases with the b and reaches its maximum value approximately when m=1. Using the Mohr-Coulomb failure criterion to analyze the problem of axisymmetric punching of concrete slabs often underestimate the actual ultimate punching capacity significantly.

scholarly journals The Mohr–Coulomb criterion for intact rock strength and friction – a re-evaluation and consideration of failure under polyaxial stresses

Solid Earth ◽  
2016 ◽  
Vol 7 (2) ◽  
pp. 493-508 ◽  
Author(s):  
Abigail Hackston ◽  
Ernest Rutter
Keyword(s):  
Friction Coefficient ◽  
Failure Criterion ◽  
Fault Plane ◽  
Stress Conditions ◽  
Intact Rock ◽  
Rock Types ◽  
State Dependent ◽  
Failure Envelopes ◽  
Coulomb Failure ◽  
Coulomb Failure Criterion

Abstract. Darley Dale and Pennant sandstones were tested under conditions of both axisymmetric shortening and extension normal to bedding. These are the two extremes of loading under polyaxial stress conditions. Failure under generalized stress conditions can be predicted from the Mohr–Coulomb failure criterion under axisymmetric shortening conditions, provided the best form of polyaxial failure criterion is known. The sandstone data are best reconciled using the Mogi (1967) empirical criterion. Fault plane orientations produced vary greatly with respect to the maximum compressive stress direction in the two loading configurations. The normals to the Mohr–Coulomb failure envelopes do not predict the orientations of the fault planes eventually produced. Frictional sliding on variously inclined saw cuts and failure surfaces produced in intact rock samples was also investigated. Friction coefficient is not affected by fault plane orientation in a given loading configuration, but friction coefficients in extension were systematically lower than in compression for both rock types. Friction data for these and other porous sandstones accord well with the Byerlee (1978) generalization about rock friction being largely independent of rock type. For engineering and geodynamic modelling purposes, the stress-state-dependent friction coefficient should be used for sandstones, but it is not known to what extent this might apply to other rock types.

Establishment of a Dynamic Mohr–Coulomb Failure Criterion for Rocks

2012 ◽  
Vol 13 (1) ◽  
Author(s):  
Sheng Huang ◽  
Kaiwen Xia ◽  
Feng Dai
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Shear Strength ◽  
Failure Criterion ◽  
Dynamic Range ◽  
Split Hopkinson Pressure Bar ◽  
Rock Properties ◽  
Hopkinson Pressure Bar ◽  
Coulomb Failure ◽  
Coulomb Failure Criterion

AbstractStatic Mohr–Coulomb Failure Criterion for rocks has been used extensively in various rock engineering applications. In this model, the compressive strength, tensile strength, and shear strength are related. To investigate the applicability of the Mohr–Coulomb model to dynamic failures, we studied the correlation of the three dynamic rock properties: compressive strength, tensile strength and punch shear strength. The strengths are quantified using a split Hopkinson pressure bar (SHPB) system. The methods for acquiring these strengths were briefly discussed. A fine-grained sandstone, Longyou sandstone (LS) was studied using these methods. The results showed that the compressive strength calculated from the punch shear strength of LS matched well with the experimental UCS results, thus the punch shear strength could be effectively used to predict the UCS of rocks. The tensile strength calculated from the punch shear strength of LS also has exhibited a good trend with the experimental results of Brazilian tensile strength. We concluded that the famous Mohr–Coulomb criterion can be extended to the dynamic range. However, caution has to be taken in determining the loading rates for different strength results.

scholarly journals Three-Dimensional Numerical Analysis of the Tunnel for Polyaxial State of Stress

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Wenge Qiu ◽  
Chao Kong ◽  
Kai Liu
Keyword(s):  
Numerical Simulation ◽  
Mechanical Behavior ◽  
Principal Stress ◽  
Failure Criterion ◽  
Rock Strength ◽  
Strength Criterion ◽  
Intermediate Principal Stress ◽  
State Of Stress ◽  
Coulomb Failure ◽  
Coulomb Failure Criterion

The aim of this study is to have a comprehensive understanding of the mechanical behavior of rock masses around excavation under different value of intermediate principal stress. Numerical simulation was performed to investigate the influence of intermediate principal stress using a new polyaxial strength criterion which takes polyaxial state of stress into account. In order to equivalently substitute polyaxial failure criterion with Mohr-Coulomb failure criterion, a mathematical relationship was established between these two failure criteria. The influence of intermediate principal stress had been analyzed when Mohr-Coulomb strength criterion and polyaxial strength criterion were applied in the numerical simulation, respectively. Results indicate that intermediate principal stress has great influence on the mechanical behavior of rock masses; rock strength enhanced by intermediate principal stress is significant based on polyaxial strength criterion; the results of numerical simulation under Mohr-Coulomb failure criterion show that it does not exert a significant influence on rock strength. Results also indicate that when intermediate principal stress is relatively small, polyaxial strength criterion is not applicable.

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