基于新型随机响应面法的改进基坑支护体系可靠度分析  

Reliability Analysis of Improved Retaining and Protection for Excavations System Based on New Stochastic Response Surface Method

作　　者：张伟 ZHANG Wei(China Railway 19th Bureau Group Guangzhou Engineering Co.Ltd.,Guangzhou Guangdong 511400,China)

机构地区：[1]中铁十九局集团广州工程有限公司,广东广州511400

出　　处：《铁道建筑技术》2025年第2期118-122,共5页Railway Construction Technology

基　　金：中铁十九局集团有限公司科技研究开发项目(2024-B04)。

摘　　要：现有基坑支护体系多采用四面支护结构,存在出渣、运料慢,效率低下等问题。依托跨柳南客专转体桥主墩承台基坑工程,提出三面灌注桩支护、单面放坡开挖的改进基坑支护体系。采用有限元法分别对长度为12 m和15 m的灌注桩进行模拟及变形分析,并针对现有设计方法未考虑参数不确定性的问题,构建基坑稳定性分析随机响应面模型,结合Cox-Lasso回归方法,得到回归系数和回归函数,可有效处理具有多重共线性数据。采用随机响应面法对基坑支护体系进行可靠度分析。结果表明:采用12 m桩长满足结构要求且更为经济;多重共线性对基坑失效概率具有重要影响,忽略共线性可能导致结果保守问题。The current retaining and protection for excavations system typically employ a four-sided support structure,which is associated with issues such as slow debris removal and material transportation,as well as low efficiency.Leveraging the excavation project of the main pier for the turntable bridge spanning the Liuzhou-Nanning Passenger Dedicated Line,an improved retaining and protection for excavations system has been proposed,featuring three-sided grouting pile support and one-sided slope excavation.Finite element analysis was conducted to simulate and analyze the deformation of grouting piles with lengths of 12 meters and 15 meters,respectively.Moreover,addressing the existing design methods′oversight of parameter uncertainty,a stochastic response surface model for the stability analysis of the foundation pit was developed.This model was integrated with the Cox-Lasso regression method to derive precise regression coefficients and functions,effectively managing data with multicollinearity.The reliability of the retaining and protection for excavations system was then assessed using the stochastic response surface method.The findings indicate that a pile length of 12 meters satisfies the structural requirements and is more cost-effective.Importantly,multicollinearity significantly influences the probability of foundation pit failure,and its disregard could result in overly conservative outcomes.

关 键 词：基坑支护 多重共线性 Cox-Lasso 随机响应面法 可靠度指标 

分 类 号：U445.55[建筑科学—桥梁与隧道工程]