管片衬砌结构可靠度分析的优化方法

STUDY ON RELIABILITY OPTIMIZATION OF SEGMENTS LINING IN SHIELD TUNNEL

从结构可靠度指标的几何意义出发,推导了管片衬砌结构可靠度指标计算的优化模型,在此基础上研制了基于复形优化思想的数值计算程序。算例表明,管片衬砌结构可靠度指标优化模型无需功能函数对变量求偏导数,将当量标准正态变量在验算点上的值用原始变量统计特征值和验算点的坐标来表示,就避免了每次迭代时要进行R-F变换,提高了计算效率,且精度较高。该优化模型对功能函数非线性程度高、隐式表示的管片衬砌结构可靠度分析比较适用,为地下结构可靠度分析提供了一种新的选择。

Based on the geometrical meaning of structural reliability index, the reliability optimization model of segments lining in shield tunnel is proposed. Furthermore, the program is developed according to complex optimization algorithm. The numerical example is provided to demonstrate the better efficiency and accuracy of the optimization model, which avoids the performance function＇s partial derivative to the random variable, than those of first-order approximation methods. The value of equivalent standard normal distribution variable at checking point is expressed with the checking point coordinates and the statistics value of original random variable, which avoid the R-F（Rackwitz R. and Fiessler B.） equivalent normal transformation of each iterative calculation at checking point. In the example analysis, the optimization model is very suitable to acquire the reliability index of segments lining in shield tunnel where the performance function is highly nonlinear and implicit： and the optimization is a new approach to analyzing of underground structure reliability.