DETERMINATION OF CRITICAL SLIP SURFACE OF HIGHSTEEP SLOPE BASED ON THEORY OF THE STRESS EFFECT COEFFICIENT

The critical slip surface is controlled by two aspects,one is the combination relation with rock mass discontinuity and slope,another aspect is the size and the lie of the load. The failure mechanism of highsteep slope intact rock is very complex,the search for critical slip surface is tedious. The shape and position of 3D critical slip surface of highsteep slope intact rock under load are analyzed based on the stress effect coefficient. The effects of influence factors on the shape and position of 3D critical slip surface are analyzed. Results show that the shape of critical slip surface of highsteep slope intact rock under load should be an irregular wedge body and mainly in front region of the foundation,and the side of wedge is related to the size of bridge foundation,slope and the distance of bridge foundation. The load strength has no effect on the shape of critical slip surface,and the distance of bridge foundation has an important effect on it. The range of critical slip line of highsteep slope intact rock under load increases with the size or distance of bridge foundation,and with the slope increased,the length of critical slip line decreases,the depth increases. The range of 3D critical slip surface on highsteep slope intact rock is determined as follow:  Pw=08444L-05098+05759S+693716,Ph=01148L+0171B+11725+00733S-5719．