基于多目标综合评价法的边坡抗滑桩桩位优化设计
Optimization design of pile location on slope based on multi-objective comprehensive evaluation method

抗滑桩-边坡体系设计中,安全系数、桩后滑坡推力和桩身长度是影响桩位确定的主要因素。利用多目标综合评价法将上述因素综合考虑，建立用于桩位选取的多因素优化模型，分别计算出不同桩位的优属度，比较优属度大小后确定最合理的桩位。研究结果表明：在边坡中部设桩时桩前土体抗力较大，桩身将滑移面分为前后2个部分，边坡安全系数、桩后滑坡推力和桩身长度较大，加固效果明显，但经济性相对较差；在坡顶或坡脚处设桩时桩前土抗力小，坡体内部容易形成新的贯通滑移面，安全系数、桩后滑坡推力和桩身长度较小，但安全性相对较差。由于不同桩位上桩前土抗力差别较大，桩后滑坡推力曲线在边坡中部出现一个平台，桩后土推力呈现抛物线形式。利用多目标综合评价法将上述因素值进行建模计算，发现将抗滑桩设置在边坡中下部，距坡脚水平距离6 m处的桩位优属度最大，这与实际工程经验相符。
The safety factor, the landslide thrust behind the pile and the length of the pile are the main factors affecting the determination of pile location in the design of the system of anti-pile slope. The method of multi-objective comprehensive evaluation was employed to consider the above three main factors comprehensively. A model of multi-factor optimization was established and the value of optimization of piles at different locations was calculated to determine the most desirable pile location. By formulating a pile location at intervals of a fixed horizontal distance on the slope, the finite element model was established for analysis. The results were compared with the calculation which was calculated with a traditional limit equilibrium method in order to verify the correctness of the results. It is found that the soil resistance in front of the pile, the safety factor, the landslide thrust behind the pile and the length of the pile are large when the pile is set in the middle of the slope, and the slip surface is divided into two parts by the pile, but it could not meet economic demand; The soil resistance, safety factor, the landslide thrust behind the pile and the length of the pile are relatively small when the pile location is in the toe or top of the slope, and it does not dissatisfy secure request. It is shown that a plateau region appears in the curve of the lateral force due to the soil resistance in front the pile is quite different on the slope, and the lateral force acting on the pile is a parabola. The calculated data of the pile were modeled and calculated by using multi-objective comprehensive evaluation method and then it is found that the location of 6 m away from the toe of the slope in horizontal distance is the most desirable, and it is concordant with practical situation