抗剪强度分项系数的标准差反馈标定法

基于可靠度理论的分项系数极限状态设计方法是当今岩土工程设计的一个趋势，分项系数的标定是确定设计参数的关键。岩土材料强度分项系数需反映材料参数的变异性，现有理论方法如安全系数校核法、一次二阶矩校核法、验算点校核法等理论标定方法，没有明确说明分项系数如何降低参数不确定性的影响，理论基础有待进一步完善。因此，提出岩土材料强度分项系数的标准差反馈标定法，该方法在目标可靠度的基础上，通过观察均值的调整对标准差调整的抵消作用，确定材料强度分项系数，由此确定的分项系数能充分反映强度参数的离散性。通过算例对该标定方法的实现进行了说明，并与验算点校核法进行了对比分析，指出标准差反馈标定法比验算点校核法更加合理。

Calibration of partial factors of shear strength parameters using standard deviation feedback method

Limit state design method based on reliability theory is a trend of modern geotechnical design. Calibration of the partial factors is a key to determine the design strength parameters. Although there are safety factor calibration methods, first order second moment method and designed points method to calibrate the partial factor theoretically, the mechanism of how the partial factors reflect the variance of the geotechnical materials is still unknown. The standard deviation feedback calibration method is then proposed to solve this problem. The core concept of this method is to adjust the mean value of the strength parameters to offset the influence of the standard deviation adjustment. A case study is given to illustrate the method. A comparison between this method and the design points method is taken out to see their different effects on the design strength parameters. The results show that the standard deviation feedback calibration method is more reasonable and the design points method will lead to a conservative design which would raise the budget ultimately.