Study On Stability Of High Embankment On Slope Soft-soil Foundation

A large number of high filled embankments or embankments on slope ground, sometimes embankments on soft-soil ground, will be inevitably encountered in highway construction in mountainous areas. Every type of the embankment mentioned above is liable to lose its stability. If an embankment is constructed in situation in which the previous three conditions are all satisfied, the probability of its failure will be evidently increased. Therefore, it is very important to study the failure patterns and stability of this embankment timely and accurately in order to adopt corresponding support measures.In this paper, depending on the project of high filled embankment on slope and soft-soil foundation in the Chen-Ning highway from K183+440 to K183+680, the destruction pattern was analyzed on the basis of collecting previous researches, investigating and monitoring in the field. Combining theoretical analysis with numerical simulation, the stability of this embankment was also studied. Main achievements are concluded as follows:(1)After reviewing recent limit equilibrium methods, the classical earth pressure theory was utilized for setting the reasonable thrust line position of soil slice. The over determined linear equations including F_v as variable were established by the condition of static equilibrium and torque equilibrium, where F_v is the safety factor of the slice interface. According to maximum principle and the reasonable conditions: F_v≥F_s, a method of slope stability analysis which is based on the least squares theory was proposed in this paper.(2)After reviewing recent limit analysis law, a circular sliding failure mode of slope employing radial slice method was built to slove the key problem that the coordination velocity field is difficult to establish. Based on the limit analysis theory of plasticity, the upper limit method of radial slice analysis of homogeneous slope was derived according to the definition of strength safety coefficient in this paper. (3)According to monitoring data and the designed section type, the failure pattern of this high filled embankment on slope and soft-soil foundation was analyzed. And then, the safety factors of each typical section were analyzed by employing the traditional analysis methods and the modified methods proposed in this paper.(4)According to the terrain conditions and geological structure features of this high filled embankment on slope and soft-soil foundation, a three-dimensional geological model was set up by the geological object computer aided design software (GOCAD). FLAC^3D program was used to analyze the deformation and stability of this embankment under its self-weight when layer by layer filled.