沉入式抗滑桩优化设计研究

Optimum design of deeply embedded anti-slide pile

沉入式抗滑桩是根据普通抗滑桩受力特点改进而成的一种新型抗滑桩,它能大幅度降低工程造价。作为一种新型边坡支护结构,由于设计理论不完善,严重影响其工程应用。其中合理沉入深度和最优设置位置是沉入式抗滑桩设计的关键,如果沉入深度过大可能导致上部坡体发生越顶破坏,形成新的次级滑动,沉入深度过小则起不到降低工程投资的目地。采用极限上限定理,在假设滑面为通过坡趾下端的对数螺旋曲线基础上,研究确保边坡稳定抗滑桩所需提供的最小抗力;在抗滑桩设置位置和沉入深度优化分析中,采用基于极限分析的扇形条分法,对可能出现的次级滑面形状及其稳定性进行预测研究。结合算例,分析沉入式抗滑桩设置位置、沉入深度对边坡稳定性及其抗力的影响,从而为沉入式抗滑桩的优化设计提供一种理论方法。

As a new anti-slide structure, the embedded anti-slide pile is often used in the treatment of landslide. There are two key issues in the design of embedded anti-slide pile, that is, the buried length of anti-slide pile and the placement location. In analysis of the anti-slide pile, the resistance can be estimated using the limit.theorem of plasticity mechanics by assuming typical failure mechanism for pile reinforced slopes. To determine the position and buried length of the ant-slide pile, the internal and external work is calculated respectively by dividing the entire slope body into small blocks and regarding the potential sliding surafce as a series of sectional planes. According to the upper bound theorem, the multivariate function for computing the critical height of slope is established and optimized by mathematical method. Based on numerical examples, the results show that the position of ant-slide pile and its buried length and some others may influence its resistance and the safety factor of slope to some extent.