Mechanism And Numerical Analysis Of Anti-slide Piles For Expansive Soil Slope

Nowadays, commonly used design method of anti-slide pile is based on the theory of limit equilibrium and the theory of pile foundation. For expansive soil slope, expansion force is bound to have an impact on the mechanics mechanism of anti-slide piles, and affect the design and construction of the piles. Furthermore, the expansion force induced by expansive soil may be an important factor affecting the effectiveness and safety of the reinforcement of the slope. A typical project is studied in this paper. The basic mechanics parameters of expansive soil are obtained by lab test as well as some numerical simulation results by numerical software.1. The basic mechanics parameters of expansive soil are firstly obtained by referring to relevant literature and the basic mechanics parameter lab test. According to the design document and related drawings, the geometric model for mechanics analysis of the engineering practice of is established.2. Three-dimensional finite difference method is used for the simulation of the typical site of the slope. The support mechanism of anti-slide piles with different type and pile spacing are analyzed and studied.3. Two-dimensional finite element method is used for the simulation of the typical section. Reasonable anti-slide pile length and reasonable site of pile are obtained after the simulation. The mechanism law and supporting effect of the slope as well as the slope after supporting is achieved.Results and conclusions of the study are:1. Through the analysis of slope safety factor calculation results, the practical engineering channel slope of expansive soil is stable in the absence of expansive force, but as long as the expansion force is active, the slope will tend to be unstable.2. Choice of pile spacing:Less spacing of the d=1.0m circular anti-slide pile will have more supporting capacity, but the d=0.75m rectangle pile will have more supporting capacity than the circular one when the pile spacing is the same. Choice of pile location:The best location of the pile is at the middle of the slope surface. Choice of pile length:the longer the pile, the higher safety coefficient. During the design of the anti-slide pile, both safety requirement and economic benefit should be taken into account.3. Considering the expansion force, the anti-slide pile usually can control the shallow expansion force occurred above the half length of the anti-slide pile. The greater and longer the pile is, the deeper the pile supporting will control the range. When at the same engineering situation, scheme of several lines of small diameter piles is a better choice for expansive soil slope, which will have a good supporting effect.