Abstract：
A tunnel in soft rock is affected by construction disturbances and the deformation is very obvious, with tunnel collapse occurring if any mistake is made. Based on the branched tunnel A of the Lianyue tunnel in Xiamen and the geological conditions, the deformation characteristics of the shallow tunnel in soft rock is studied by numerical simulation and site monitoring. The results show that the order of deformation magnitude is: extruded displacement at the work face, crown settlement, surface displacement and convergence around the tunnel for a tunnel in soft rock by full-face excavation or the bench construction method. Surrounding rock deformation is divided into antecedent deformation in front of the work face and deformation at the rear of the work face, and the more unfavorable the surrounding rock the larger the antecedent deformation, with antecedent deformation occupying 10%-30% of the total deformation. Bench construction reduces the affected scope and deformation in front of the work face. More strict pre- reinforcement measures should be taken to control deformation caused by tunnel construction if more strict requirements for control of surrounding deformation of the soft rock tunnel are specified, in order to ensure the safety of tunnel construction and its surroundings.
2018, Vol. 55 