Abstract: Ultimate bearing capacity has always been a difficult and hot issue in mining and rock and soil fields, which seriously affects the safety and stability of slope and adjacent slope structures. Based on the upper bound theorem of limit analysis, the failure mechanism of heterogeneous layered slope with rigid multi-sliders was established in three modes. The upper bound solution of slope ultimate bearing capacity was deduced, and the optimal value was obtained by sequential quadratic programming algorithm (SQP). The north slope of Sancha mine was taken as the engineering background to verify effectiveness of the proposed method by comparing with the numerical method, and then the influence analysis of two parameters of different slope angles and the distances between dump and slope shoulder was carried out. The results were concluded as follows. (1) The results of the proposed method are in good agreement with those of numerical method, indicating that the proposed upper limit solution of slope ultimate bearing capacity is reasonable and effective. (2) The ultimate bearing capacity of slope has a linear negative correlation with slope angle and a linear positive correlation with the distance between the dump and the slope shoulder. Compared with the distance between the dump and the slope shoulder, the slope angle is more sensitive to the bearing capacity of slope. (3) The change of slope angle has a great influence on the slope failure mode, but the change of the distance between the dump and the slope shoulder has no obvious influence on the slope failure mode. (4) Both slope angle and the distance between the dump and the slope shoulder have an impact on the initial position and the overflow position of the slip surface. The initial position of the slip surface is greatly affected by the distance between the dump and the slope shoulder, but less affected by the slope angle. The overflow position of slip surface is greatly affected by slope angle but less affected by the distance between dump and slope shoulder. Relevant research results are expected to provide theoretical support for slope and adjacent slope foundation design.

Key words: slope engineering, ultimate bearing capacity, upper limit analysis, heterogeneous slope, rigid multi-sliders, slope stability