双线盾构隧道下穿既有建筑物诱发地表变形规律分析

Analysis of ground deformation caused by two track shield tunnelling under existing building

盾构下穿建（构）筑物施工不可避免对地层及上层建筑产生影响，而双线隧道穿越同一建筑物同时存在着二次扰动，且同时由于建筑物与地层之间的作用，诱发的地表变形影响更为复杂。以南京地铁三号线常府街～夫子庙区间双线隧道下穿刘公巷7号楼具体工况为例，结合经验公式和数值模拟进行对比分析，研究存在建筑物情况下的地表变形规律。研究结果表明：建筑物的存在使得地表沉降曲线呈非对称形式，且存在建筑物范围内沉降曲线相对平缓，而 PECK 预测地表沉降槽为对称曲线，且相对数值模拟结果偏大，表明地面建筑物对地层变形具有直接的约束作用；采用 peck 公式预测存在地面建筑物的地表沉降时，应根据现场实测数据反算确定经验参数，从而考虑建筑物刚度的影响。

The shield constructions beneath the building will inevitably have impacts on the surrounding soils and the superstructures,and the double track tunnel beneath the same building will cause secondary perturbation.So the surface deformation will be more complex with the interaction between the soil and the superstructure.Taking the Confucius Temple to Chang Fu Street interval Line subway tunnel of shield excavation beneath Liu Gong lan in Nanjing,as an example,the patlern of surface settlement with existing building was analyzed by comparing the results of the theoretical formula and numerical simulation.The results indicate that because of the existence of building the surface settlement curve is non -symmetric form,and the settlement curve is relatively flat within the scope of building,but the surface settlement calculated by PECK formula is symmetric and larger than the re-sult of numerical simulation,which indicates that the building have directly restriction effect on the surface de-formation.When using the PECK formula to predict the surface settlement with existing building,should inverse calculate the parameters according to the measured data,in order to get the empirical parameters in consideration of the influence of the stiffness of the building.