Groundwater is a common problem in the design and construction of underground structures in water-rich strata. In order to explore the influence of groundwater on the shallow buried excavation of double-cavern vertical overlapping tunnels, this study first reveals the essence of the seepage-stress coupling and the change of the permeability coefficient during the coupling process, assigns the dynamic permeability coefficient to the soil element. Based on the actual seepage coupling analysis, simulates the seepage-stress coupling process with the double-cavern overlapping tunnels by shallow buried excavation in the Guomao-Laojie section, 3C tender section of Shenzhen metro as the project background, and analyzes and verifies the influences of seepage-stress coupling on the deformation characteristics of surrounding rock and pore water pressure during the excavation of overlapping tunnels. Studies have shown that the impact of seepage-stress coupling cannot be ignored during the excavation of double-cavern overlapping tunnels in the case of upper soft and lower hard strata. In order to reduce the amount of surface settlement, the necessary support is required before the excavation of the upward tunnel. Excavation is the main factor for the increase of tunnel deformation. After excavation, the stress concentration will occur in the vicinity of the tunnel vault, floor and left and right side walls. This method can provide reference for hydraulic coupling simulation and analysis of similar projects.
vertical overlapping tunnel, seepage-stress coupling, shallow burying, coefficient of permeability
This work is supported by Natural Foundation of Shandong Province, China [Grant No. ZR2017MEE069]. Thank you for the support of Natural Foundation of Shandong Province.
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