考虑岩土参数空间变异性的盾构隧道地表沉降分析  

Ground surface settlement of shield tunnels considering spatial variability of multiple geotechnical parameters

作　　者：王长虹 朱合华[2] 徐子川[2] 李建高[3] 

机构地区：[1]上海大学土木工程系,上海200444 [2]同济大学地下建筑与工程系,上海200092 [3]中铁隧道集团三处有限公司,广东深圳518052

出　　处：《岩土工程学报》2018年第2期270-277,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家重点基础研究发展计划项目(2011CB013800-G);国家自然科学基金项目(51208303);上海市教委科技创新重点项目(14ZZ162)

摘　　要：现有随机场理论能够较好地描述单一岩土参数的天然随机性、空间结构性和局部奇异性。当前面临的挑战是如何考虑多个土层、多元及统计相关的岩土参数空间变异性对岩土工程的影响。考虑岩土参数如黏聚力、内摩擦角和压缩模量等具有明显的空间变异性,将随机场理论引入盾构隧道地表沉降可靠指标分析。主要研究工作包括：（1）采用局部均值方法将多个非平稳土层同一岩土参数转化为平稳各向异性随机场变量,并给出随机场的统计特征;（2）简化岩土参数的空间变异性为一般变异性,直接采用响应面方法计算盾构隧道地表沉降可靠指标;（3）提出协同序贯高斯离散算法,在空间网格上实现多元岩土参数随机场的同步离散化,并基于经典Monte-Carlo随机模拟原理和盾构隧道数值计算,直接统计地表沉降的可靠指标;（4）引入子集Monte-Carlo随机模拟加速算法。将以上方法应用于天津-#5、-#6地铁环湖西路站—宾馆西路站区间盾构隧道四线交叠工程,结果表明,采用经典随机理论描述岩土参数的变异性,所得到的盾构隧道地表沉降可靠指标小于基于随机场理论的对应值。该结论为复杂盾构隧道的施工控制与设计优化提供了理论依据。The existing spatial random field theories can better depict the uncertainty of a single geotechnical parameter, including the intrinsic randomness, global variability and local singularity. The current challenge is how to analyze the correlated variables in multiple soil layers for soil-tunneling mechanics. The coefficient of cohesion, internal friction angle and compression modulus are considered in the reliability index analysis of ground surface settlement due to excavation of shallow-buried tunnels. At first, the geotechnical parameters of multiple non-stationary soil layers are converted into unified anisotropic spatial random field using the local detrending method, and the statistical parameters are defined. Then, the uncertainty is simplified into aleatory randomness, and the response surface method is introduced into the reliability index analysis. The co-sequential Gaussian discretization is designed for the spatial random field and numerical analysis. Finally, the failure probability（i.e., reliability index） of ground surface settlement is calculated stochastically by using the classical and subset Monte-Carlo simulations, respectively. This approach is applied into the four shield tunnel paralleling zones of the 5-（th） and 6-（th） metro lines between West Huanhu Road station and West Binguan Road station in Tianjin of China. The results show that the reliability index considering geotechnical parameters as the classically probabilistic variables is smaller than that of spatial random field assumption. It may support substantially the construction control and design optimization in complex shallow-buried shield tunneling projects.

关 键 词：岩土参数 空间变异性 随机模拟 地表沉降 可靠指标 

分 类 号：TU454[建筑科学—岩土工程]