Abstract
In order to investigate the influence of faults on the spatial distribution of the initial rock stress, a simple model of faulted ground has been presented and the numerical solutions have been compared to the trends of the observed stress by means of the stress relieving method in the world. The observed stress data have been firstly presented and analyzed to make clear the trends of them. The significant difference between the observed vertical stress and the overburden pressure has been examined as shown in Fig. 3, and the non-linear characteristics of the horizontal maximum and minimum stresses as a function of the depth have been discussed by seting out their limitting envelope curves as shown in Figs. 4 and 5.
The numerical analysis has been performed by the Displacement Discontinuity Method. Practically, a twodimentional semi-infinite elastic ground model with two sets of parallel faults intersecting the surface has been presented as shown in Fig. 6, considering fractal geometry of faults, and the stress changes caused by the frictionless sliding on the fault surface have been analyzed under the various primary stress conditions. Numerical solutions show that the trends of the observation can be fairly well explained with the present model, and it has been concretely shown that the variation of the initial rock stress with location is closely depending upon the sliding mode of adjacent faults and the primary stress condition.
