新建盾构隧道上穿对既有隧道的变形影响分析

针对上海地铁11号线上、下穿越既有地铁4号线的多线叠交复杂工况，构建三维弹塑性有限元模型，研究在不同净距、不同土仓压力、不同注浆量下新建隧道盾构穿越对既有隧道管片变形的影响。根据模拟结果和实测数据，结合因素正交分析，提出多线叠交隧道施工影响系数的概念。研究结果表明，在新建隧道穿越既有隧道的过程中，新旧隧道之间的净距在影响系数中所占权重最大，土仓压力次之，注浆量权重较小。研究成果可为多线叠交盾构隧道施工微扰动控制技术以及隧道变形计算提供一定的理论基础。

Deformation effect on existing tunnels overlapped by new tunnel in lower-region

Aiming at the Shanghai metro tunneling line No.4, that is, a tunnel within ultra-near distance crossed through the adjacent operating metro line No.11, the three-dimensional finite element method was applied to analyze the deformation distribution of the existing tunnel. The deformation analysis is based on three elements: different clearance distance, earth pressure of the chamber, injecting quantity of grout. Based on the results of the numerical modeling and theory of orthogonal analysis, the concept of influence coefficient for the overlapping tunnel is inferred. Through the results of orthogonal analysis, it was shown that: in the procession of overlapping, the distance affects the displacement field of the existing tunnel evidently; the influence on the earth pressure is secondary, injecting quantity effects slightly. These results could provide valuable preference to the technology of micro-perturbation control in the construction of overlapping tunnels.