三管并行盾构隧道近接施工纵向效应离心模型试验研究

结合上海轨道交通9号线R413标段三管并行盾构隧道下穿沪杭铁路段工程，通过模拟盾构隧道的地层损失的方法，进行了离心模型试验，研究了设置地层加固和不设置地层加固情况下三管并行盾构隧道近接施工时的衬砌内力纵向效应规律。试验结果表明，中间隧道施工时，受其影响左右隧道拱腰位置弯矩和轴力均出现较大变化，设置地层加固可以有效减小纵向效应的影响，但仍需注意在施工中加强盾构壁后注浆，设置纵向钢架以减小近接施工纵向效应对管片尤其是接头处的影响。

Study on longitudinal effect of three-tube parallel shield tunnel approaching constructed by centrifugal model test

Based on the three-tube parallel shield tunnel that cuts through under Hu-Hang Railway of R413 bid segment of the 9th route of Shanghai track traffic, two groups of centrifugal model tests ,with one group with stratum reinforced and another not, have been done by the method of simulating stratum loss. The longitudinal effect regularity of lining inner force caused by three-tube parallel shield tunnel approaching constructed, has been studiced. The test result shows that the moment of flexion and axial force appear major change at arch lumbus of the left and right tunnel lining when the middle tunnel constructed. The longitudinal effect can be controlled effetely by stratum reinforcement but the influence also should be paid attention to. In the process of construction such method as strengthen slip casting and install longitudinal steel frame can be used for decreasing the influence on the lining duct piece especially on the joint caused by the longitudinal effect.