We have shown that linear Mogi criterion does a good job in representing rock failureunder polyaxial stress states. When σ2 = σ3 the linear version of Mogi's triaxial failurecriterion reduces exact ...
Abstract A non-linear Unified Strength criterion for rock material is presented. It is the development of the Unified Strength Theory (in: M. Jono, T. Inoue (Eds.), Mechanical Behaviour of Materials-VI (ICM-6), Pergamon, Oxford, 1991, pp. 841–846) and the modification of the Hoek–Brown strength criterion (Underground Excavations in Rock, The Institution of Mining and Metallurgy, London, 1980). The effect of intermediate principal stress on rock strength is considered in the non-linear Unified St...
In this study we examine seven different failure criteria by comparing them to published polyaxial test data (σ1>σ2>σ3) for five different rock types at a variety of stress states. We employed a grid search algorithm to find the best set of parameters that describe failure for each criterion and the associated misfits. Overall, we found that the polyaxial criteria Modified Wiebols and Cook and Modified Lade achieved a good fit to most of the test data. This is especially true for rocks with a hi...
#1M.K. Kim(UCLA: University of California, Los Angeles)H-Index: 1
#2Poul V. Lade(UCLA: University of California, Los Angeles)H-Index: 57
Abstract A general, three-dimensional failure criterion for rock is proposed. This criterion is formulated in terms of the first and third stress invariants of the stress tensor, and it involves only three independent material parameters. Although these parameters interact with one another, each parameter corresponds to one of the three failure characteristics of rock behaviour. These material parameters may be determined from simple tests such as uniaxial compression and triaxial compression te...
This book deals with the geotechnical aspects of the design of underground openings for mining and civil engineering purposes. It contains a number of worked examples to assist the reader in applying the techniques described to his or her own problems. The data are presented under the following chapter headings: (1) planning considerations; (2) classification of rock masses; (3) geological data collection; (4) graphical presentation of geological data; (5) stresses around underground excavations...
A NEW TRIAXIAL COMPRESSION TECHNIQUE HAS MADE POSSIBLE THE STUDY ON GENERAL LAWS OF FRACTURE AND FLOW OF ROCKS UNDER GENERAL TRIAXIAL STRESS STATES, IN WHICH ALL THREE PRINCIPAL STRESSES ARE DIFFERENT. IN THIS PAPER, THE EFFECTS OF THE STRESS STATES ON FRACTURE AND YIELDING OF ROCKS ARE EXPERIMENTALLY STUDIED BY THIS METHOD. THE EXPERIMENTAL PROCEDURE IS DESCRIBED, AND THE EQUATIONS FOR STRESS STATES PRODUCING FRACTURE AND YIELDING ARE GIVEN AS MONOTONIC INCREASING FUNCTIONS OF THE THREE PRINCIP...
Abstract Pillar recovery requires stable backfill upon side exposure in open stoping mining methods. Until now, the solutions used to estimate the required strength of side-exposed backfill are mainly based on a wedge model where the effect of rock-wall closure was neglected. In this paper, the influence of mine depth and adjacent extraction on the stability of side-exposed backfill is analyzed through numerical modeling with FLAC 3D. The failure mechanism and cohesion at failure (cf) of backfil...
#2Somi Jung(Pukyong National University)H-Index: 4
Last. Won-Bae Na(Pukyong National University)H-Index: 14
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Abstract Several studies have identified stability issues related to artificial reefs (ARs) installed on the seabed. However, initial AR settlement during free-fall installation has not been well examined. We performed a laboratory-scale experiment, regression analysis, and numerical simulation to evaluate the initial settlements of two cube-type AR models during free-fall installation into soft soil. Settlement tended to increase by impact velocity and AR mass but to decrease as soil density in...
The constant mi is a fundamental parameter required in the Hoek–Brown (H–B) failure criterion for estimating rock strength. Triaxial tests for the calculation of this constant are time-consuming and expensive. In this paper, a new perspective is presented for the physical meaning of the parameter mi of the H–B model in consideration of the contact friction coefficient. A correlation between the contact friction coefficient and mi is established using published data. A practical approach is propo...
#2Haluk Akgün(METU: Middle East Technical University)H-Index: 14
Last. Jaak J.K. Daemen(UNR: University of Nevada, Reno)H-Index: 16
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This paper formulates an empirical strength criterion for the heterogeneous Antalya tufa rock mass assuming that the heterogeneity effect is represented by the unit weight and the porosity of the tufa rock, which is highly variable from a geomechanical point of view. Unconstrained non-linear regression analyses have been used to identify the strength criterion and material constants in terms of fitting an equation and determining its regression parameters. Prior to this approach, the fitting of ...
#1Jun Peng(CUMT: China University of Mining and Technology)H-Index: 18
#2Ming Cai(Northeastern University (China))H-Index: 39
Abstract Residual strength of rock is required in stability evaluation of underground excavations such as tunnels and caverns. Accurate determination of residual strength of rock can facilitate cost-effective design of these underground structures. This study investigates the methods for determining residual strength of intact rocks. Firstly, previous methods for determining residual strength of intact rocks are examined from a literature review, and a new method, which uses the concept of cohes...
#1Hongwei Zhang(CUMT: China University of Mining and Technology)H-Index: 5
#2Zhijun Wan(CUMT: China University of Mining and Technology)H-Index: 14
Last. Cheng Jingyi(CUMT: China University of Mining and Technology)H-Index: 2
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The mechanical behavior of geomaterials under plane-strain biaxial stress state (PSBSS, a special case of biaxial stress state) is often considered in geotechnical structures such as highwall and longwall coal pillars. In this study, a modified statistical damage constitutive model based on Weibull distribution was established to explain the mechanical behavior of rocks under the PSBSS. The modified Wiebols-Cook criterion, Drucker-Prager criterion, and extremum method were adopted in this model ...
#2Ming Cai(CAS: Chinese Academy of Sciences)H-Index: 39
Last. Xia-Ting Feng(NU: Northeastern University)H-Index: 46
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The influence of the end effect on rock strength in true triaxial compression testing was studied using a numerical approach. The influence of the intermediate principal stress (σ2) on rock strength was isolated by using the two-dimensional Mohr–Coulomb failure criterion that depends only on the major principal stress (σ1) and minor principal stress (σ3). Thus, any enhancement to the rock strength with the increase of σ2 can be attributed to the end effect. It was shown that the end effect can r...
#4Xibing Li(CSU: Central South University)H-Index: 44
AbstractStatistical damage constitutive models (SDCMs) have been widely employed to describe the mechanical response of strain-softening rock, especially in brittle failure under moderate confining pressure. The residual strength, referring to the strength of strain-softening rock in the postpeak region, has not been accurately considered in present works. In this study, an extended definition of damage was proposed based on the fact that the intact material gradually evolves into another damage...
