建筑物对盾构隧道施工引起地面沉降模式的影响

Influence of existing structures on ground movement induced by shield tunnel

本文以盾构隧道施工引起的地面沉降为对象,研究邻近地表建筑物的存在对其发生发展的影响。以具体工程为依托,以实际工程监测和数据分析为主要手段,研究得出:在有邻近地表建筑物存在时,地表沉降曲线形状与无建筑物存在时相似,均符合高斯曲线的形式;区别在于有建筑物存在时,地表沉降曲线的峰值要比无建筑物存在时小,曲线的反弯点离隧道轴线的距离要比无建筑物存在时远;说明了地表建筑物的存在以及建筑物基础与地基相互作用提高了盾构隧道穿越地基土层的刚度,对盾构隧道引起的地表沉降有控制作用。在盾构隧道施工及监测的过程中,可依据该特点合理布设有无地表建筑物存在情况下的监测测点,并对盾构隧道引起的建筑物及地标开裂现象做出合理的预测。

The present paper, in which a practical project has been taken as an example, aims at studying the influence of adjacent surface structures on the occurrence and development of ground movement profile caused by shield tunnel excavation. Field data monitoring and data analysis have been employed as the main methodology during the analysis. The results show that the ground movement profiles caused by shield tunnel excavation for Greenfield condition and condition with the influence of surface structures are shaped like Gaussian curve. The differences lie in that the maximum settlement of the profile with structure influence is mitigated compared with Greenfield condition with the inflection point deviated further away from the tunnel axis. The results show that the existence of the surface structures and the interaction between structure foundation and surrounding soil improve the rigidity of the underlying strata which the shield tunnel goes through and accordingly mitigates the settlement of the ground. These features are suggested to be better understood by the engineers engaged in tunnel excavation and engineering monitoring for reasonable prediction of the cracks in buildings and ground surface associated with shield tunnel excavation.