Abstract: In the design of landslide prevention, the determination of thrust is a precondition for reasonable design of control engineering. The progressive deformation failure modes of three types of landslides were analyzed, and the progressive evolution process of the different types of landslides were described based on the weakening of sliding zone parameters in this study. The different part of sliding zone were portrayed spatially for going through three states of the pre-peak stress state, critical stress state and residual stress state according to the corresponding mechanical strength in the three stages of the pre-peak stress stage, the softening stage and the residual stress stage. The distinguish criterion of sliding block of critical state was proposed based on the unbalanced thrust method. The calculation model and calculation formula of thrust of progressive failure of landslides were established, and the parameter value method of sliding zone was proposed. Moreover, the thrust variation in the process of progressive failure was analyzed from the points of view of different types of landslides. The results show that when the different types of landslides were progressively damaged to the fifth states, the thrust of retrogressive landslide, load-caused landslide and complex landslide was 4 100, 4 980 and 3 150 kN/m respectively, and the thrust of load-caused landslide is the largest, indicating that there is a significant difference in landslide thrust in different modes. This method can not only reflects the progressive failure process of different types of landslides, but also solves the problem of the thrust calculation of landslide with strain softening properties, and further can provide a reasonable thrust estimation for the design of landslide prevention.

Key words: landslide types, progressive failure, value method, thrust calculation