Physical and particle flow modeling of jointed rock block behavior under uniaxial loading

Abstract Laboratory experiments and numerical simulations, using Particle Flow Code (PFC3D ), were performed to study the behavior of jointed blocks of model material under uniaxial loading. The effect of joint geometry parameters on the uniaxial compressive strength of jointed blocks was investigated and this paper presents the results of the experiments and numerical simulations. The fracture tensor component in a given direction is used to quantify the combined directional effect of joint geometry parameters including joint density, orientation and size distributions, and the number of joint sets. The variation of the uniaxial compressive strength of the jointed blocks of the model material with the fracture tensor component was investigated. Both the laboratory experiments and the numerical simulations showed that the uniaxial block strength decreases in a nonlinear manner with increasing values of the fracture tensor component. It was observed that joint geometry configuration controls the mode of failure of the jointed blocks and three modes of failure were identified, namely (a) tensile splitting through the intact material, (b) failure by sliding along the joint plane and/or by displacement normal to the joint plane and, (c) mixed mode failure involving both the failure mechanisms in (a) and (b). It has also been shown that with careful parameter calibration procedures, PFC3D could be used to model the strength behavior of jointed blocks of rock.

[1]  Evert Hoek,et al.  Practical estimates of rock mass strength , 1997 .

[2]  P. A. Cundall,et al.  FORMULATION OF A THREE-DIMENSIONAL DISTINCT ELEMENT MODEL - PART I. A SCHEME TO DETECT AND REPRESENT CONTACTS IN A SYSTEM COMPOSED OF MANY POLYHEDRAL BLOCKS , 1988 .

[3]  Edwin T. Brown,et al.  Strength of Models of Rock with Intermittent Joints , 1970 .

[4]  Richard E. Goodman,et al.  CLOSURE ON A MODEL FOR THE MECHANICS OF JOINTED ROCK , 1968 .

[5]  Herbert H. Einstein,et al.  MODEL STUDIES ON MECHANICS OF JOINTED ROCK , 1973 .

[6]  Otis R. Walton,et al.  Explicit particle-dynamics model for granular materials , 1982 .

[7]  P. Cundall,et al.  A discrete numerical model for granular assemblies , 1979 .

[8]  Masanobu Oda,et al.  FABRIC TENSOR FOR DISCONTINUOUS GEOLOGICAL MATERIALS , 1982 .

[9]  F. Heuźe,et al.  Scale effects in the determination of rock mass strength and deformability , 1980 .

[10]  P. Cundall,et al.  FORMULATION OF A THREE-DIMENSIONAL DISTINCT ELEMENT MODEL - PART II. MECHANICAL CALCULATIONS FOR MOTION AND INTERACTION OF A SYSTEM COMPOSED OF MANY POLYHEDRAL BLOCKS , 1988 .

[11]  P. Kulatilake.  Estimating Elastic Constants and Strength of Discontinuous Rock , 1985 .

[12]  Z. T. Bieniawski,et al.  The significance of in situ tests on large rock specimens , 1975 .

[13]  Z. T. Bieniawski,et al.  The effect of specimen size on compressive strength of coal , 1968 .

[14]  EFFECTS OF FINITE-SIZE JOINTS ON THE DEFORMABILITY OF JOINTED ROCK AT THE TWO-DIMENSIONAL LEVEL , 1994 .

[15]  F. E. Heuze,et al.  Analysis of Explosions in Hard Rocks: The Power of Discrete Element Modeling , 1993 .

[16]  Ove Stephansson,et al.  Effect of finite size joints on the deformability of jointed rock in three dimensions , 1993 .

[17]  H. R. Pratt,et al.  The effect of speciment size on the mechanical properties of unjointed diorite , 1972 .

[18]  E. T. Brown,et al.  EMPIRICAL STRENGTH CRITERION FOR ROCK MASSES , 1980 .

[19]  A. E. Skinner.  A Note on the Influence of Interparticle Friction on the Shearing Strength of a Random Assembly of Spherical Particles , 1969 .