Abstract: Critical slip surface search is one of key problems in slope stability analysis. Present search methods include mathematic programming methods and brainpower search methods, which are based on the assumption of arc or arc-polyline slide style, and developed on basis of soil slope. It is not fit for rock slope. Critical slip field theory is based on residual thrust method and optimization theory. Useing new structure surface processing method, it can calculate the biggest residual thrust field, which is almost consistent with actual condition and easily search slip surface of respectively possible exits. Therefore, it can find the whole slope critical slip surface. First of all, using example of homogeneous material slope validates credibility of calculation result to be consistent with the result of shear strength reduction technique and the Spencer's precedure of limit equilibrium. Then, an example of open strip mine side slope is given to validate the practicability of this method.

Key words: critical slip field, structural surface, rock slope, critical slip surface