摘要
收集统计了国内32个在既有隧道上方进行基坑开挖的实际工程案例,根据土质分为含砂细粒土和含砾细粒土两类地层,将相关的数据进行整理归纳,统计基坑平面尺寸、相对位置以及常用的控制措施等,分析了影响隧道最大隆起位移的主要因素。在此基础上,提出含砂细粒土和含砾细粒土地层基坑开挖引起最大隧道隆起位移的预测算式,并与其他预测算式和实际案例工程进行对比分析验证。研究表明:基坑开挖面积A越大,卸荷率R越大、基坑形状因子α越大、隧道穿越基坑长度L_(t)越长,则基坑开挖引起的隧道最大隆起位移w_(max)也越大,但是单个影响因素与隧道最大隆起位移相关性不强,因此须综合考虑主要影响因素才能科学地预测基坑开挖引起的隧道变形;采用αR(lg A+ln L_(t))作为表征基坑开挖引起隧道最大隆起位移的整体影响因子,发现w_(max)与αR(lg A+ln L_(t))呈现较好线性关系。
Based on the statistics on 32 cases of actual underground engineering projects in China where the foundation was excavated above existing tunnels,according to the composition of site soils,they could be divided into two types of strata:fine-grained soil containing sand and fine-grained soil containing gravel.Sorting and summarizing the relevant information including the plane sizes of excavated areas,the relative position and conventional control measures,etc.,the main factors induced the maximum uplift displacement of tunnels were analyzed.On the basis,the prediction formula for the maximum uplift displacement of tunnels caused by deep excavation in the strata of fine-grained soil containing sand and fine-grained soil containing gravel were proposed,which were compared and analyzed with other prediction formula and actual engineering cases for verification.The results indicated that the larger the excavated area A,unloading ratio R and the shape factor of excavated areasα,and the longer the longth of tunnels passing under excavated areas L_(t),the larger the maximum uplift displacement of tunnels caused by deep excavation w max was,but the correlation between a single influencing factor and the maximum uplift displacement of tunnels was not strong.Thus,it was necessary to comprehensively consider the main influencing factors to scientifically predict tunnel deformation caused by foundation excavation.Eventually,αR(lg A+ln L_(t))was used as the overall influence factor to characterize the maximum uplift displacement of tunnels induced by deep excavation of foundation,and it was found that w_(max) showed a good linear relation withαR(lg A+ln L_(t)).Collecting statistics about 32 cases of actual underground works in China where foundation excavation was carried out above existing tunnels.According to the soil quality is divided into two types of stratum,powdery clay and gravelly clay,the relevant data will be sorted and summarized,including the pit plane size,relative position and common control measures,etc.,to
作者
吕林海
蒋明杰
谢忠铭
王炳华
黄钟晖
LYU Linhai;JIANG Mingjie;XIE Zhongming;WANG Binghua;HUANG Zhonghui(College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education,Guangxi University,Nanning 530004,China;Nanning Rail Transit Construction Co.,Ltd.,Nanning 530029,China;Nanning Rail Transit Investment Co.,Ltd.,Nanning 530029,China)
出处
《工业建筑》
2024年第11期24-32,共9页
Industrial Construction
基金
国家自然科学基金项目(52108309)。
关键词
工程案例
基坑开挖
下卧隧道
隆起位移
预测算式
engineering case
foundation excavation
displacement by heave of underlying tunnel
uplift displacement
prediction equation
