中文摘要：

对砂土中隧道施工引起管线性状变化进行了室内模型试验，分析了管土相互作用的一些宏观特性，为进一步进行三维颗粒流细观模拟提供必要的参数和宏观依据。在室内模型试验的基础上，建立了隧道垂直下穿既有管线颗粒流分析模型，验证了室内模型试验的宏观现象。在此基础上分析了隧道施工过程中管土相互作用的机理、管周土体的应力与位移以及管线的剪应变和弯矩。分析结果可为工程实践中确定管线加固位置提供理论依据。

英文摘要：

A series of lg physical model tests are carried out to investigate the tunnelling effects on existing pipelines. A tunnel is excavated directly underneath the existing pipeline. The tunneling-induced pipeline deformation mechanism and the stress field around the pipeline are studied. In addition, three-dimensional discrete element back-analyses （PFC3D） are conducted to improve the understanding of soil-pipe interaction problem. Based on the measured and computed results, change of the tunneling-induced stress, displacement, shear strain and bending moment in the existing pipeline are analyzed. The findings in this study can give theoretical basis for the reinforcement design of pipelines.