为了研究基坑开挖对周围管道、建筑、道路的影响,2个狭长形地铁车站深基坑不同位置处土体的侧向位移、土体沉降、管道沉降、建筑沉降等资料的监测数据在开挖过程中被记录.通过分析现场监测资料发现,地表沉降与监测点基坑围护结构距离的关系呈三折线模型,管道沉降与土体沉降有一定的相关性,燃气管道、给水管道和污水管道的沉降平均值占地表沉降平均值的比例分别为94.3%、58.7%、65.3%.管道沉降和地表沉降的变化趋势相似且均呈一定的空间效应,随着L/He的增大,土体沉降及管道沉降的平面应变比(PSR)呈先增大后变化缓慢的趋势,刚度较小的燃气管道的三维效应与土体沉降的三维效应变化相似.距离基坑15m处桥台的最大沉降差发生在距离开挖边缘-5~5m处,差异沉降为0.88×10-3,桥台最大沉降值发生在靠近基坑中心位置处,最大达24.32mm.随着时间的增长,管道沉降和地表沉降均呈现先增大后保持稳定的趋势,底板完成时,管道沉降和地表沉降占最终沉降的比例分别为85%和80%.
A series of field monitoring exercise including lateral displacement,soil settlement,pipeline settlement and building settlement were conducted into two similar subway station deep foundation pit in order to analyze the effect of excavation on the surrounding pipelines,buildings and roads.Field monitored data indicate that concave pattern was proposed for the surface settlement profiles and the pipeline settlement has a relevance to the surface settlement.The proportion of the average gas pipelines settlement,water pipeline,sewer line to the average surface settlement is 94.3%,58.7%,65.3%,respectively.Pipeline settlements and surface settlements showed a three-dimensional(3D)effect and the values of plain strain ratio(PSR)of pipelines settlements and surface settlements increased first and then changed slowly as L/Heincreases.The three-dimensional effects of gas pipeline settlement were similar to that of surface settlement because of its smaller stiffness.The maximum differential settlement occured between-5mto 5m from the excavation face and reached the value of 0.88mm/m.The maximum settlement occured near the centre of the excavation and reached the value of 24.32mm.The pipeline settlement and surface settlement increased first and then maintained stable.The proportion of the pipeline settlement and surface settlement to the final settlement was 85%and 80% when the base slab was completed.