Abstract: Double-shield tunnel boring machines(TBMs) always cause ground displacement and deformation when tunneling in complex rock strata in urban areas. To guarantee construction safety and minimize the influence on the surrounding environment, advanced deep geological layer monitoring methods are adopted for intact and fractured rock masses. Based on FLAC3D numerical simulation software, a real-time monitoring and simulation analysis of geological displacement during construction process of the double-shield TBM are conducted. The research results indicate the following: (1) In slightly-weathered granite formations, the displacement of the intact rock mass caused by double-shield TBM construction is within the range of －1－1 mm, belonging to elastic deformation. (2) In the fractured formations, the soil displacement pattern caused by double-shield TBM construction presents the characteristics of "one zone in horizontal direction, one layer in vertical direction, and two-stage in longitudinal direction". (3) The double-shield TBM has little influence on the intact rock mass in slightly-weathered granite formations, while measures should be taken to control ground displacement when it is applied in fractured formations.

Key words: double-shield tunnel boring machine, complex rock strata, ground displacement, displacement monitoring, deformation control