砂卵石地层冻结法施工融沉效应研究

本文针对富水砂卵石地层联络通道应用冻结法进行施工时的融沉特性进行研究,在数值模拟软件ANSYS中采用间接法进行热力耦合计算,模拟地铁联络通道冻结法施工的全过程,探讨富水砂卵石地层融沉阶段地表变形、双线隧道管片及联络通道结构的变形与受力特性,为实际工程施工提供有效的参考与建议。结果表明:随着砂卵石地层的逐渐解冻,地表沉降呈逐渐增大的趋势,但砂卵石地层的融沉效应小,融沉变形仅有1.85 mm;管片和联络通道结构的沉降变形值随砂卵石地层的解冻逐渐增大,在此过程中管片和联络通道结构的拉应力减小,压应力增大;实际施工中,应该重点监测管片结构在与联络通道结构连接处顶部的沉降变形、底部的受压情况以及联络通道结构底板处的沉降变形和受压情况。

Study on Thaw-Settlement Effect of Sandy Cobble Ground under Freezing Construction

The whole freezing process construction of the metro liaison channel is simulated using the indirect method to realize thermal-mechanical coupling by ANSYS to highlight the thaw-settlement characteristics in the freezing structure of the liaison channel on water-rich sandy cobble ground. The discussion of the surface settlement, deformation, and stress characteristics in the thaw-settlement stage of segment structure and liaison channel structure of the double-line tunnel in water-rich sandy cobble ground provides a valuable reference for the construction of the practical project. The results show that the surface settlement increases gradually with the thawing of sandy cobble ground. However, the thaw-settlement effect of sandy cobble ground is small, and the thaw-settlement deformation of the stratum is only 1.85 mm. The settlement value of the segment and the liaison channel structure increases gradually with the thawing of sandy cobble ground. At the same time, the tensile stress of the segment and the liaison channel structure decreases, and the compressive stress increases. The settlement deformation at the top of the connection between the segment structure and the liaison channel structure, the segment's compressive stress at the bottom of the connection, and the settlement deformation and compressive stress at the floor of the liaison channel should be well-monitored in actual construction.