基于响应面法的基坑支护可靠度优化

Foundation Pit Supporting Reliability Optimization Based on the Response Surface Method

为分析基坑支护结构在不确定性因素影响下的优化设计,针对土层参数大、小样本信息采用响应面法对基坑支护结构进行可靠度优化分析。由于土层参数c、φ间存在一定的互相关性,因此在优化分析中考虑了互相关性的影响;并采用响应面法对原设计及确定性优化设计进行了风险分析。结果表明,小样本条件下,是否考虑互相关性时,其优化结果与原设计相比,每延米土钉总长度可减少20.97%~32.58%;大样本条件下,是否考虑互相关性时,其优化结果与原设计相比:每延米土钉总长度可减少20.97%~35.01%;大、小样本条件下,考虑互相关性时比不考虑时每延米土钉总长度减少15.24%~17.76%,优化效果明显。

To analyze the optimum design of the foundation pit supporting structure under the influence of the uncertainty, reliability optimization analysis of the foundation pit supporting structure is realized based on the small and large sample information of soil parameters using the response surface method. At the same time, because the soil parameters c and φ have a certain correlation, the influence of cross correlation is considered in the reliability optimum analysis; And the method of the original scheme and deterministic optimization scheme is used for risk analysis. The results show that under the condition of small samples, whether considering cross correlation, compared with the optimization results of the original design, the length of soil nail per linear meter can reduce 20.97 % - 32.58 %; Under the condition of large samples, when considering cross correlation, the length of soil nail per linear meter can reduce 20.97 % - 35.01% compared with the optimization results of the original design; Under the condition of large and small samples, the total length of soil nail per linear meter considering the cross correlation decreased by 15.24 % - 17.76 % than that without considering, and the optimization effect is obvious.