Determining the cause of tunnel damages during tunneling in silty clay.

• The damage cause of ground surface and tunnel lining during tunneling is studied. • The tunnel damages during tunneling in silty clay can be reasonably simulated. • The field monitored softening soil body has much influence on tunnel damages. This paper presents a case study of investigating the cause of tunnel damages during tunneling in silty clay, in which the damages are existed in both ground surface and tunnel lining. The study is implemented by field investigation and numerical back analysis to determine the cause of tunnel damages, in which the field observed funnel-shaped surface subsidence of ground and surrounding soil moving to the tunnel are considered as softening soil body from ground surface until surrounding rocks in the numerical model, and the material parameters of the field monitored softening soil body are respectively taken as 0.8 times and 0.6 times of the original ones. This work confirms that the field observed tunnel damages during tunneling in silty clay can be numerically simulated, which is significantly influenced by the field monitored softening soil body from ground surface until surrounding rocks. [ABSTRACT FROM AUTHOR]