ABSTRACT:

The anisotropy of rock mass was mainly due to the conditions of the joints. In order to study the anisotropism behavior of infilled joint rockmass a mathematical model of the filling material was implemented to the two-dimensional distinct element code-UDEC using FISH language. The numerical analysis on anisotropy of the rockmass having one set of infilled joints was conducted. The results showed that the value of the cohesion of the filling material had a large influence on the test results. And the compressive stress of the sample changed a Jot when the joints were infilled compared to nonfilled joints rockmass. With the increasing of the dip angle the compressive stress increased first and then decreased, and increase again at a certain dip angle.

1 INTRODUCTION

At present many people, Barla (1974), Kwasniewski (1993), believed that the cause of the anisotropy of rock mass could be divided into two categories: one was the anisotropy of the rock, the other was the conditions of the joints. And the anisotropy of rock mass was mainly due to the joints. Jeajer & Cook (1969) studied a single joint rock mass and found that the anisotropy of rock mass was controlled by the dip angle of the joint. His work provided a good beginning and many research results of the anisotropy of rock mass were based on it, like Priest (1993), Ramamurthy & Arora (1994), Qiao (2004), Mao & Yang (2005).

This paper tried to analyze the influence of the filling material on infilled rockmass. And a mathematical modeling of the filling material and Two-dimensional distinct element code-UDEC were introduced to study the anisotropism behavior of one set infilled joint rockmass.

2 MATHEMATICAL MODELING OF THE FILLING MATERIAL

When the filler is thicker than the asperity height the joint can fail through a continuous surface not intercepted by the asperity. The failure modes of filling joints can be divided into the 'interface controlled model' and the 'filling controlled model', which one is dominate is depended on the stress conditions of the two parts. If the filling joints failed on the filling material as shown in Figure 1, the shear stress of the filling were given by Shi et al. (2012) as shown in Equation 1.

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