基于五次样条函数的基坑土层等效参数反演方法

Inversion method of equivalent parameters of foundation pit soil based on quintic spline function

根据五次样条函数的性质,利用弹性支点法,将土压力视为不连续的分布载荷集度,对支护结构的变形进行五次样条函数拟合,并通过逐次求导反演支护结构上的受力,最后结合工程情况反演基坑土层的等效参数。本文基于上述研究思路,成功反演了支护结构的分布载荷集度,提出了一种基于五次样条函数的基坑土层等效参数反演方法,反演的土层等效参数可用于基坑工程的动态化设计、施工方案优化和变形预测,并为邻近类似土层区域的基坑设计提供土层抗剪强度指标参考。

In the foundation pit engineering,the elastic fulcrum method is usually used to predict the deformation of the row pile supporting structure.The shear strength index of soil layer is the key factor affecting the deformation.Due to the uneven distribution of the actual soil thickness,it is usually assumed that the earth pressure action of the uniform soil layer with a certain thickness.The shear strength index of the soil layer is the equivalent shear strength index of the soil layer(referred to as the soil equivalent parameter).The existing researches using spline function inversion only get the bending moment of the supporting structure and how to invert the load concentration of the supporting structure is always in the bottleneck state.According to the properties of the quintic spline function,this paper uses the elastic fulcrum method,takes the earth pressure as the discontinuous distributed load concentration,carries on the quintic spline function fitting to the deformation of the supporting structure,and informs the force on the supporting structure by successive derivative,and finally gets the equivalent parameters of the foundation pit soil combining with the engineering situation.This paper successfully inverses the supporting structure distributed load set,and puts forward a way to inverse soil layer equivalent parameter based upon the quintic spline function.The equivalent parameters of soil can be used in foundation pit engineering of dynamic design and construction scheme optimization and deformation prediction,and provide the soil shear strength index of foundation pit design in similar soil adjacent area.