近距离叠层的盾构隧道施工扰动问题研究

Study on Disturbance Problem of Overlapped Shield Tunnel Construction at Short Range

针对上海某新建越江隧道与新建轨交区间隧道立体交叉重叠施工的情况,采用BC-3位移边界条件分析了不同开挖次序以及不同土体损失率下的施工扰动影响。结果表明:在“先上后下”工况下,后开挖对先开挖隧道的影响较大,但对地表沉降的影响较小;在“先下后上”工况下,施工扰动影响与“先上后下”相反;若能将盾构施工的土体损失率控制在一个较小值,则无论采用“先上后下”还是“先下后上”,施工扰动都相对较小。

In view of the spatial overlapped construction of a newly built river-crossing tunnel and a rail transit interval tunnel in Shanghai,the BC-3 displacement boundary conditions are used to analyze the influences of construction disturbance under different excavation sequences and soil loss rates.The results show that under the condition of"first up,then down",the later excavation has a greater impact on the first excavation tunnel,but it has little influence on ground surface settlement.While under the condition of"first down,then up",the influence of construction disturbance is opposite to that of"first up,then down".If the soil loss rate of shield construction can be controlled to a small value,the construction disturbance is relatively small whether it is"first up,then down"or"first down,then up".