Abstract:

Based on the current status of frequent ground collapse during the urban tunneling, the catastrophe mechanism and control technology of ground collapse induced by urban tunneling are studied combined with ground collapse accident cases. The statistics of 44 safety accidents induced by Beijing Metro tunneling show that there are 16 ground collapse accidents out of the 44 cases, accounting for high percentage (36%). The statistics of 29 ground collapse accidents induced by urban tunneling show that pipeline leakage and unfavorable geologic bodies are the main inducing factors to cause ground collapse, accounting for 69% of all the inducing factors. So the pipeline leakage and unfavorable geologic bodies are the key factors to prevent and control ground collapse accidents. According to the statistical analysis results, the ground collapse forms are divided into three categories as follows: ground collapse directly induced by instability of overlying strata in tunneling, ground collapse indirectly induced by failure of unfavorable geologic bodies in strata in tunneling, and ground collapse indirectly induced by pipeline leakage or damage in tunneling.The catastrophe mechanism and evolution law of ground collapse induced by urban tunneling are introduced by using theoretical analysis and numerical simulation, and then the corresponding measures are put forward to control ground collapse in urban tunneling.

Key words: urban tunneling, ground collapse, safety accidents, catastrophe mechanism, statistical analysis