基于响应面试验设计的深基坑降水开挖地表沉降特性  

Investigations into ground surface settlement characteristics of excavation under dewatering and excavating conditions using the response surface experimental design method

作　　者：程昊[1,2] 陈辉 张抒 贾瀚英[4] CHENG Hao;CHEN Hui;ZHANG Shu;JIA Hanying(Badong National Observation and Research Station of Geohazards,China University of Geosciences(Wuhan),Wuhan 430074,China;CCCC Second Harbor Consultants Co.,Ltd.,Wuhan 430071,China;The 7th Geological Brigade of Sichuan Province,Leshan Sichuan 614000,China;Hunan Electric Power Design Institute Co.,Ltd.,China Energy Engineering Group,Changsha 410007,China)

机构地区：[1]中国地质大学(武汉)湖北巴东地质灾害国家野外科学观测研究站,武汉430074 [2]中交第二航务工程勘察设计院有限公司,武汉430071 [3]四川省第七地质大队,四川乐山614000 [4]中国能源建设集团湖南省电力设计院有限公司,长沙410007

出　　处：《地质科技通报》2024年第5期181-196,共16页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(U2340230);湖北省自然科学基金项目(2023AFB933);中交第二航务工程勘察设计院有限公司重点科研课题(RP2024040998);湖北省重点研发项目(2023BCB117)。

摘　　要：受降水与开挖作用的共同影响,基坑周边土体会持续发生地表沉降变形,对基坑稳定以及周边环境都产生显著影响。为厘清基坑工程降水开挖过程中地表沉降的影响工况因素,并在此基础上建立经验模型,选取杭州地区典型江河阶地二元结构地层组合的深基坑为案例,开展了系统研究。首先,基于降水开挖作用下的土体变形机理,结合变形实测数据,提出了一种结合摩尔库伦(MC)与修正剑桥(MMC)本构关系开展基坑降水开挖沉降过程的数值分析方法。进一步采用响应面试验设计方法(RSM),考虑多种工况因素及其交互作用,建立了研究区内二元地质结构条件下基坑降水开挖地表沉降的经验模型,并分析了地表沉降分区特征。结果表明,地下水位降深(H_d)对地表沉降影响最为显著,其次为地下连续墙深度(H_w)与开挖宽度(B),其中B与H_d交互作用也较为显著。据此建立的回归模型可以较为准确地预测地表最大沉降量。本研究不仅为类似地层条件的基坑工程提供了经验模型,也为基坑设计、施工和监测提供了实用框架,对有效控制基坑及周边环境的沉降变形具有重要价值。The soil surrounding an excavation experiences continuous ground settlement due to the combined effects of dewatering and excavation,which significantly impacts both the stability of the excavation and its surrounding environment.[Objective]To elucidate the key factors governing ground settlement during the dewatering and excavation process,as well as to establish an empirical model based on these findings,this study systematically investigated a deep metro station excavation in Hangzhou,situated on a typical river terrace with a dual-layered geological structure.[Methods]Firstly,a numerical analysis method for settlement in braced excavations was proposed by incorporating a hybrid Mohr-Coulomb(MC)-Modified Cambridge(MMC)constitutive model,derived from the deformation mechanism of excavation soil and a comparison with actual monitoring data.Subsequently,the response surface method(RSM)was employed,to establish an empirical model for ground settlement caused by dewatering and excavation under dual-layer geological structure conditions in the study area,accounting for various operational factors and their interactions,and to analyze the zoning characteristics of ground settlement.[Results]The findings suggest that the drawdown of the groundwater table,H d,exerts the most significant influence on the surface settlement,followed by the depth of the underground diaphragm wall,H w,and excavation width,B.Additionally,there is a notable interaction between B and H d.The regression model developed based on these factors demonstrates high accuracy in predicting maximum surface settlement,H m.[Conclusion]This study not only presents an empirical model for excavation engineering under similar geological conditions but also provides a practical framework for excavation design,construction,and monitoring.These contributions are crucial for effectively managing settlement deformation in excavations and their surrounding environments.

关 键 词：基坑地表沉降 降水开挖 响应面试验设计方法 沉降分区 

分 类 号：TU753[建筑科学—建筑技术科学]