DESIGN OF REINFORCEMENT FOR ROCK SLOPES

Abstract

The stability of rock slopes is one of the important factors used by the civil and mining engineers. Rock falls, rotational slides, translational slides and flows are some of the terms to describe the movement of rocks or soils in the slope engineering. With the increase in construction activities and change in the geological conditions with passage of time, in fragile ecosystem of the Himalaya, it becomes necessary to evaluate the stability of hill slopes. The basic modes of failure of rock mass are planer sliding, wedge sliding, circular failure and toppling failure. The problem frequently encountered in rock slopes is that involving sliding of a wedge on two intersecting discontinuities i.e wedge failure. The wedge failure is analysed by analytical method, stereographic projection method and engineering graphics method. But Hoek and Bray (1981) introduced a wedge solution for rapid computation. In the present work, Hoek and Bray's method (Rigorous analysis) has been used and design of reinforcement to enhance the factor of safety has been made. It accounts for tension cracks, dip of top terrace, earthquake, seepage, bolt force and foundation load. It has advantages over other methods. The remedial measures to increase the stability of the slope are also discussed. In the present study, a Computer program for stability analysis and design of reinforcement of rock slopes with tetrahedral wedge sliding by rigorous analysis with interactive graphics has been developed. In the program `FORTRAN' language along with `GRAPH X' library has been used to present the results of analysis and design, with interactive graphics display on P.C. monitor. As Personal Computers are readily available with the engineers and geologists at their offices, the present work provides an efficient means to analyse the rock slopes and gives insight into a slide problem. Graphics display shows the line of intersection of Joints, 3D-view of the rock wedge, end view and the rock reinforcement.