软土基坑开挖对临近既有隧道变形影响研究  

Influence of excavation in soft soil foundation pit on deformation of adjacent existing tunnel

作　　者：韦宗科 陈健[1,2,3,4,5] 陈斌 黄珏皓[1,2,3,4] WEI Zongke;CHEN Jian;CHEN Bin;HUANG Juehao(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics of CAS,Wuhan 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Hubei Key Laboratory of Geo-Environmental Engineering,Wuhan 430071,China;The Soft Soil Research Center in Ningbo University of Technology,State Key Laboratory of Geomechanics and Geotechnical Engineering,Ningbo 315211,China;China-Pakistan Joint Research Center on Earth Sciences,Beijing 100049,China)

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049 [3]湖北省环境岩土工程重点实验室,湖北武汉430071 [4]岩土力学与工程国家重点实验室宁波工程学院工程软土实验中心,浙江宁波315211 [5]中国-巴基斯坦地球科学研究中心,北京100049

出　　处：《人民长江》2022年第6期198-206,共9页Yangtze River

基　　金：国家自然科学基金青年基金资助项目(51909259);宁波市公益类科技计划项目(2019C50012);中国科学院国际合作局国际伙伴计划项目(131551KYSB20180042);国家自然科学基金面上基金资助项目(52079135)。

摘　　要：基坑开挖后,地基由于应力卸载而回弹,导致临近基坑的隧道发生变形,其变形大小不仅受基坑开挖卸载程度的影响,还与隧道所处的位置有关。依托宁波市地铁1号线盾构隧道工程,基于土体小应变硬化模型和二维有限元数值方法,开展软土基坑开挖对临近既有盾构隧道管片变形影响的数值模拟,分别采用单因素分析法和多因素分析法,针对不同基坑宽度、基坑开挖深度、隧道拱顶埋深以及隧道与基坑距离等影响因素,分析了隧道管片竖向和水平位移随不同影响因素的变化规律。结果表明:①基坑开挖影响下,既有隧道管片竖向位移和水平位移均随基坑开挖深度的增大而逐渐增大,隧道管片竖向位移方向表现为沉降,水平位移方向表现为向基坑方向产生位移,管片呈“横鸭蛋”状变形。②单因素和多因素分析方法结果表明,基坑开挖深度、隧道与基坑距离、基坑宽度均为影响隧道沉降和水平位移的重要因素,而隧道拱顶埋深产生的影响相对较小。After excavation,the foundation rebounds due to stress unloading,which leads to the deformation of tunnels near the deep foundation.The deformation of the tunnel is not only related to the degree of excavation unloading,but also related to the location of the tunnel.Based on a shield tunnel project of Ningbo City Metro Line 1,the influence of soft soil foundation excavation on the segment deformation of adjacent existing shield tunnel is investigated by using the small strain hardening model and two-dimensional finite element numerical method.Single factor analysis and multiple factor analysis methods are used to analyze the effect of different influencing factors,namely,excavation width,excavation depth,buried depth of tunnel,and the distance between tunnel and foundation,on the vertical and horizontal displacements of tunnel segments.The results show that:①Under the influence of deep excavation,the vertical displacement and horizontal displacement of the existing tunnel segment increase gradually with the increase of the excavation depth.The tunnel segment displacements include vertical settlement and horizontal movement toward the foundation.The deformation of tunnel segment generally shows a‘horizontal duck egg shape.②The excavation depth,distance between the tunnel and the foundation,and the excavation width are important factors affecting the settlement and horizontal displacement of the tunnel,while the influence of the buried depth of the tunnel is relatively small.

关 键 词：临近既有隧道 深基坑开挖 隧道变形 敏感性分析 宁波市 

分 类 号：TU753[建筑科学—建筑技术科学]