Numerical Analysis Method for Hydraulic Fracturing

Criterion for hydraulic fracturing in rock foundations of embankment dams

Abstract

The aim of this study is to evaluate quantitatively the influence of characteristics of rock, depth of ponding and filling rate on hydraulic fracturing of rock foundation and is to propose the criterion for hydraulic fracturing in rock foundations of embankment dams. The hydro-mechanical coupled finite deformation analysis using Cam-clay model was applied as the evaluation method. In this paper, three kinds of laboratory hydraulic fracturing test for rock and clayey soil materials were simulated to approve the validity of this method before proposal of the criterion. As the result, by using the tensile strength of material and the yield surface of Cam-clay model as failure criterion, it can be seen that failure initiation from borehole surface or notch/slit edge and the injection pressure at hydraulic fracturing could be evaluated. The method to determine the Cam-clay parameters for rock, particularly compression and swelling index and yield stress, were considered.