基坑圆环支撑体系水平刚度系数计算方法研究

A method for calculating horizontal stiffness coefficient of ring supporting system for foundation pit

由受力根据刚度分配的原则,引入受力分配系数,对圆环支撑体系水平刚度系数的计算进行了解析式的推导,提出了圆环支撑体系水平刚度系数的简易计算方法,并给出了解析式的修正式。并以某超深基坑圆环支撑体系为例,应用所提出的公式计算该圆环支撑体系的水平刚度系数,并与三维有限元分析结果进行对比,同时分析了不同封闭环梁、发射梁对水平刚度的影响,结果表明:二者误差较小,圆环支撑体系水平刚度主要由受力杆件封闭环梁决定,与发射梁等传力杆件关系不大,依据所提出的解析式进行计算,结果精确且简单易行,可为基坑圆环支撑体系水平刚度系数的取值提供依据。

The force distribution coefficient is introduced according to the principle of the stiffness distribution; a method of calculating the horizontal stiffness coefficient of the ring support system is developed, and its analytical solutions are derived; furthermore, the revised analytical solutions are given. The procedure is employed to calculate the horizontal stiffness coefficient of the ring support system of an extra deep foundation pit with ring support. The influence of different closed ring beams and transmitting beams on the horizontal stiffness is also analyzed. The calculated results by proposed procedure are compared with those by three-dimensional finite element method. The results show that the error with the two methods is small, and the horizontal stiffness of the ring support system is mainly determined by the closed beam of the force bar, and is trivially affected by the force beam of the transmitting beam. According to the proposed analytical formula, the result is accurate and simple, which can provide the basis for determining the design values of the horizontal stiffness coefficient of the foundation ring support system.