Analysis For Anti-slide Piles In Deeply Excavated Expansive Soil Slope Of South To North Water Diversion Project

According to the situation of the landslide appearing in the canal slope of the south to the north water diversion project, the mechanism of landslide for expansive soil slopes in deep excavation section were analyzed by numerical simulation. The main content of this paper was to obtain the landside mechanism of deep excavation expensive soil and the anti-slide mechanism of anti-slide piles by analysis for soil displacement,strain and stress of pile and arching affection in between of soil and pile under the impact of cyclic wetting and drying effects on canal slope landslide and effect of anti slide. The detail contents of the paper were outlined.Firstly,by the test in lab, the basic mechanics parameters of pile and expansive soil such as the soil water characteristic curve, direct shear strength parameters, swelling force and resilient modulus and Poisson rate were obtained for the finite element numerical simulation of the expansive soil slopes models and the anti-slide models in deep excavation section.Secondly, the finite element models were established for two-standard slope in Nanyang section. Based on the theory analysis of rainfall seepage with the natural climate condition in Nanyang, by the simulation of canal slope under dry-wet cycle analysis, the affected zones of dry-wet cycle in different periods are computed.Thirdly, based on the shear strength theory of unsaturated soil and strength reduction method, the mechanism of deep landslide for the two-standard expansive soil slope under the affection of the dry-wet cycle was analyzed by the aspects of stress, strain and displacement. The mechanism showed that the deep landslide mainly occurred along the weak structural plane of the two-standard expansive soil slope in the influence of the dry-wet cycle.Finally, the anti-slide mechanism of anti-slide piles in the two-standard expansive soil slope was illustrated by the analysis of dry-wet cycle and pile-soil slope stability. Some measures were put forward to improve the stability of the ant-slide expansive soil slope according to the anti-slide mechanism.