基坑端头井联结隧道冻结过程应力应变分析

Stress and Strain Analysis of Freezing Process of End-shaft Connection Tunnel of Foundation Pit

为分析冻结法对盾构隧道施工过程中的加固作用,以合肥市轨道交通2号线大东门站到达端盾构工程为依托,对无限大区域内单根冻结管稳态温度场公式进行推导,并根据工程实际情况建立了三维数值模型并进行热-力耦合计算。结果表明:冻结帷幕内温度场是以各冻结孔为中心圆形发展,各孔之间出现交圈之后再向四周发散;冻结法加固能显著降低由施工导致的地层沉降,降低幅度最大约为50%,加固效果较好;左线隧道较右线隧道后施工,其管片应力较大,应及时施作衬砌,尽快闭合支护体系,保证施工安全顺利进行。

In order to analyze the reinforcement effect of freezing method in shield tunnel construction,the steady temperature field around a single freezing pipe is analyzed based on the shield tunneling project of Dadongmen Station of Hefei Rail Transit Line 2 and a three-dimensional numerical model is established according to the actual situation of the project.The results show that the temperature field in the freezing curtain develops circularly around the freezing holes and diverges around them after the intersection of the holes occurs.And the freezing method has a better reinforcement effect that the ground settlement of tunneling construction can be significantly reduced with a maximum 50% reduction.Besides,the left tunnel has larger segment stress after the construction of the right tunnel,so the lining should be put into effect in time and the supporting system should be closed timely to ensure the safe and smooth construction.