Initial excess pore water pressures induced by tunnelling in soft ground

LIANG Rong-zhu(梁荣柱)^{1, 2}, XIA Tang-dai(夏唐代)^{1, 2}, LIN Cun-gang(林存刚)³, YU Feng(俞峰)⁴, WU Shi-ming(吴世明)⁵

(1. College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China;
2. Research Center of Coastal and Urban Geotechnical Engineering, Zhejiang University, Hangzhou 310058, China;
3. College of Civil, Construction and Environmental Engineering, Ningbo University, Ningbo 315211, China;
4. School of Civil Engineering and Architecture, Zhejiang Sci-Tech University, Hangzhou 310018, China;
5. Insigma Group Co., Ltd., Hangzhou 310002, China)

Abstract:Tunnelling-induced long-term consolidation settlement attracts a great interest of engineering practice. The distribution and magnitude of tunnelling-induced initial excess pore water pressure have significant effects on the long-term consolidation settlement. A simple and reliable method for predicting the tunnel-induced initial excess pore water pressure calculation in soft clay is proposed. This method is based on the theory of elasticity and SKEMPTON’s excess pore water pressure theory. Compared with the previously published field measurements and the finite-element modelling results, it is found that the suggested initial excess pore water pressure theory is in a good agreement with the measurements and the FE results. A series of parametric analyses are also carried out to investigate the influences of different factors on the distribution and magnitude of the initial excess pore water pressure in soft ground.

Key words:initial excess pore water pressure; geostress relief; tunnel; soft clay; ground settlement