浅埋条件下并行立交隧道施工安全性的三维数值模拟

以长沙市营盘路湘江隧道东岸并行立交段施工为研究对象，对浅埋条件下并行立交隧道施工安全性进行三维数值模拟分析。研究结果表明：隧道施工结束后地表沉降最大值为39．66mm，并位于隧道上下立交区域，地表沉降不能满足安全要求，还需对地表采取加固措施，如采取地表锚杆、地表袖阀管注浆或旋喷桩加固；下部隧道初期支护变形及受力受上部隧道施工影响不大，安全系数均大于1，结构能满足安全要求，但施工中仍不能忽视对初期支护变形及内力的监测，视情况采取加固措施，或改变施工工艺，如可以先行贯通下部隧道二次衬砌。其研究结果可为类似地质条件和施工方法的同类工程提供借鉴。

Three- dimensional numerical simulation of construction safety on the parallel and cross tunnel in condition of the shallow

Taking the parallel and cross section on the east coast of Xiangjiang river crossing tunnel on Yingpan road in Changsha City for example, the construction safety was analyzed by using the three - dimensional numeri- cal simulation method. The results show that the maximum of ground surface settlement would be 39.66 mm and is situated at the interchange area after the tunnel construction completion. So the settlement can＇ t meet the safe- ty requirements and it needs still strengthening measurements to be taken, such as surface anchor, surface sleeve valve tube or jet grouting pile. The upper tunnel construction influence on the initial support deformation and stress of the lower tunnel is small, and the safety factors all are greater than 1 which means that the structure can meet safety requirements. However, monitoring the deformation and internal force of initial support can still not be ignored in construction. If the deformation or the internal force is too large, reinforcement measures need to be taken, or the construction technology should be changed, such as building the secondary lining of the lower tun- nels first. The research can give a reference for tunnel projects which have similar geological conditions and con- struction methods.