深中通道沉管隧道深层水泥搅拌桩复合地基沉降计算分析  

Calculation and analysis of settlement of deep cement mixing pile composite foundation for Shenzhen-Zhongshan Link immersed tunnel

作　　者：陈卓杰 周佳锦 陈伟乐 刘健 龚晓南[1] CHEN Zhuojie;ZHOU Jiajin;CHEN Weile;LIU Jian;GONG Xiaonan(College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China;Shenzhen-Zhongshan Link Management Center,Guangzhou 510600,China)

机构地区：[1]浙江大学建筑工程学院,浙江杭州310058 [2]深中通道管理中心,广东广州510600

出　　处：《浙江大学学报（工学版）》2024年第7期1397-1406,共10页Journal of Zhejiang University：Engineering Science

摘　　要：基于深中通道沉管隧道深层水泥搅拌(DCM)桩复合地基现场试验结果,考虑厚垫层和高置换率DCM桩对复合地基荷载传递机理及沉降特性的影响,将碎石垫层、DCM桩复合地基和桩端下卧层作为协同作用的系统,考虑系统各部分在接触面上的应力与变形协调,通过分析典型单元体,推导海底DCM桩复合地基桩土应力比和沉降的理论计算公式.将理论计算得到的DCM桩复合地基荷载-位移曲线和桩土应力比变化曲线与现场静载试验实测曲线进行对比,相对误差均不超过±10%,验证了所提理论计算公式的合理性.分析置换率和垫层柔度系数对海底DCM桩复合地基的荷载传递机理及沉降特性的影响规律,结果表明:复合地基沉降随垫层柔度系数的增大而增大,随置换率的增大而减小;复合地基桩土应力比随置换率的增大而增大,随垫层柔度系数的增大而减小;置换率对复合地基沉降和桩土应力比的影响较垫层柔度系数更大.Based on the on-site test results of the deep cement mixing(DCM)pile composite foundation of the immersed tunnel in Shenzhen-Zhongshan Link,the influence of thick cushion and high replacement rate of DCM piles on load transfer mechanism and settlement characteristics of the composite foundation were considered.The gravel cushion,DCM pile composite foundation,and underlying layer at the pile end were regarded as a synergistic system,and the stress and deformation coordination of each part of the system on the contact surface were considered.The theoretical calculation formulas for the pile-soil stress ratio and settlement of submarine DCM pile composite foundation were derived by analyzing a typical unit.The load-displacement curve and pile-soil stress ratio variation curve of the DCM pile composite foundation obtained from theoretical calculation were compared with the measured curve of the on-site static load test,and the relative errors of both were within±10%,verifying the rationality of the proposed theoretical calculation formulas.Further analysis was conducted on the influence of replacement rate and cushion flexibility coefficient on the load transfer mechanism and settlement characteristics of submarine DCM pile composite foundation.Results show that the settlement of composite foundation increases with the increase of cushion flexibility coefficient and decreases with the increase of replacement rate,the pile-soil stress ratio of composite foundation increases with the increase of replacement rate and decreases with the increase of cushion flexibility coefficient.Replacement rate has a greater impact on settlement and pile-soil stress ratio of composite foundation than cushion flexibility coefficient.

关 键 词：沉管隧道 海底深层水泥搅拌桩复合地基 碎石垫层 置换率 沉降计算 

分 类 号：TU472.6[建筑科学—结构工程]