OPEN ACCESS
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.
[1] Ma CJ, Jiang YA, Jiang ZB. (2017). Analysis of water-force coupling simulation of shield tunnel based on element state index. Rock and Soil Mechanics 38(6): 1762-1770. https://doi.org/10.16285/j.rsm.2017.06.026
[2] Li DC, Ji S. (2006). Study on the design and construction technology of shenzhen metro overlapping tunnel. Modern Tunnelling Technology 43(4): 21-26.
[3] Terzaghi K. (1925). Soil mechanics based on soil physics. Vienna: Franz Deuticke.
[4] BIOT MA. (1941). General theory of three dimensional consolidations. Journal of Applied Physics 12(5): 155−164.
[5] BIOT MA. (1956). General solution of the equation of elasticity and consolidation for a porous material. Journal of Applied Mechanics 23(1): 91−96.
[6] Li JB, Chen JY. (2008). Fluid-structure coupling analysis of the effect of seepage field on the settlement and force of metro tunnels. Journal of Disaster Prevention and Mitigation Engineering 28(4): 441-446. https://doi.org/10.13409/j.cnki.jdpme.2008.04.007
[7] Zhao DP, Wang MN, Song NT. (2007). The shallow subsurface excavation of the subway overlapping tunnel near the subzone. China Railway Science 6(28): 65-68.
[8] Addenbrooke TI, Pons DM. (1996). Twin tunnels construction-ground movements and lining behavior. Int. Symp. On Geotechnical Aspects of Underground Construction in Soft Ground, City University, London 15-17.
[9] Ji XM, Yang CH. (2006). A coupled calculation model for rock mass structure and rock masses. Rock and Soil Mechanics 25(5): 763-768. https://doi.org/10.16285/j.rsm.2006.05.016
[10] Chen YM. (2008). Foundation and engineering example of FLAC/FLAC3D.M. Beijing: China Water Power Press.
[11] PUSCH R. (1989). Alteration of the hydraulic conductivity of rock by tunnel excavation. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts (26): 79-83.
[12] Kleinberg RL, Flaum C, Griffin DD. (2003). Deep sea NMR: Methane hydrate growth habit in porous media and its relationship to hydraulic permeability, deposit accumulation, and submarine slope stability. Journal of Geophysical Research 108: 2508-2522.
[13] Zhang CP, Zhang DL. (2014). Study on engineering properties and settlement characteristics after excavation in the rich water weak stratum of Shenzhen Metro. Modern Tunnelling Technology (04): 113-120. https://doi.org/10.13807/j.cnki.mtt.2014.04.017
[14] Huang H. (2016). Study on surface subsidence regularity of shallow buried subsurface excavation method in Shenzhen rich water weak stratum. D. Beijing Jiaotong University, Beijing, China.
[15] Li LS. (2012). Study on the design of overlapping lines of Shenzhen Metro Line 1. Journal of Railway Engineering Society (10): 101-105.