A Study On The Deformation And Stability Of Typical Debris & Embankment Slope With Complicated Environment In Southwestern China

Southwestern China is located on the eastern margin of Qinghai-tibet Plateau, with complex techonic setting, plenty of active faults, and various topograpgy types. Debris & embankment slope is common in this area. Combining with plenty of typical Debris & embankment slope, a systematic study on the slope deformation and stability under complicated environment has been carried out, obeying the following procedure: study of the complication of geological environment - analysis of control factors - construction of failure model - assessment and prediction of the deformation and stability. And some creative conclusions are put out as the following.(1) Beginning with the study of complex geological condition in south-western China, systematic summarizes and analysis were made on the classification, characteristics, controlling factors of stability, basic failure models of the Debris & embankment slope basing on research of typical slopes; and systematic studies were carried out on the stability and deformation of these slopes in complex environment such as complicated foundation, reservoir impounding, earthquake, cables archor etc., based on the study of characteristics, control factors of stability and main failure mode of debris & embankment slope, and with several methods such as geological process analyzing, 3-D numerical simulation. And then a system was established to, assessing and predicting the deformation and stability of the debris & embankment slopes.(2) Taking Libo airport high embankment slope as an example, deformation and stability of embankment slope were studied systematically with several methods. The results show: the deformation of high embankment slope composed of gravel or gravel soil is relative to its foundation fluctuation, stiffness and height; And its deformation is mostly vertical, accompanying with some deformation outward of slope, the nearer to the slope top, the more proportion of vertical deformation; The vector angle is the function of inclination of the slope surface and foundation, increasing with inclination accretion; The deformation vector distributes convergent on the plane, specially to the embankment slope with restrict exit, distributing along gulch.(3) Based on the study on dynamical mechanism, the deformation and failure regularity of embankment slope encountering earthquake are realed. The results show: with the dynamic actions of earthquake, high embankment slope will loose initially towards the free surface, with the ground uplifting; in mid and final range of the earthquake, the loose soil will fall and be compacted; And more, with the development of the earthquake, the scale of deformation expands from toe to top. Its vector distribution is relative to the shape of front exit.(4) The conception of spatial effect of the deformation and stability of debris slope distributing along gulch is offered in this paper. The study shows: there distributes a "supporting arch" holding up the accumulation displacement downward in the lower part of the debris. The supporting arch contributes to the slope stability. If the soil distributing supporting arch is caved, the restriction will recess, and then shear outlet of slide surface is raised.