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Abstract The strata deformation of large section water-abundant soft rock shallow tunnel under unsymmetrical pressure passing through existing structures would be effected by several factors. This article considers the Jianfengding tunnel on the Wuhan—Guangzhou high-speed railway when electricity pylons are present on the ground surface. First，the article describes the engineering measures needed as in-situ measured data to control large strata deformation. Second，statistical and theoretical analyses comprehensively studies the relationship between strata deformation and the impact of the existing building as affected by terrain condition，attitude of stratum，tunnelling construction，tunnel cross-hole construction，ground load，and ground collapse. Third，quantitative analysis is performed on strata deformation brought about by several critical factors and based on coupled fluid-mechanical numerical computation. The main results include：(1) the strata deformation result for the attitude of the stratum is a major factor that affects the horizontal displacement and obliquity of the buildings for these large-section，water-abundant tunnels shallow-buried through soft rock under unsymmetrical pressure；(2) the additive effects on strata deformation have directional properties so that the critical factors with inverse direction can control the obliquity of the structures or buildings well；(3) the strata deformation distributes disymmetrically along the tunnel central line and the regions of greatest deformation occur at the hillside where the unsymmetrical large-span tunnel is excavated under a slope with soft-rock bedding；and (4) in a longer time，the strata deformation change with large fluctuations brought about by the tunnel excavation rapidly converges. However，the strata deformation change brought about by the attitude of the stratum shows a more persistent oscillation after tunnel excavation，and this has a lasting effect on building safety.
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Received: 19 December 2011
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2012, Vol. 31 
