The bending mutation model of urban shallow tunnel collapse

based on the catastrophic theory

was established which took the overlying strata of the urban shallow tunnel as the quantity of state

and took the tunnel buried depth

the diameter of the excavation

underground water level

the thickness of the overlying strata etc as the control quantities to reveal the relationship between shallow tunnel ground landslide and its various influencing factors（For example

for shallow tunnels

the probability of collapse is greatly increased with the increase of the water table）.The critical value of land subsidence in the overlying strata can be got by using the model

when urban shallow tunnel collapse occurs.The rationality and accuracy of the model can be verified by taking the critical value of the subsidence threshold in the overlying strata as the basic condition for the landslide

combined with the FLAC3 Dnumerical simulation and the field condition of a shallow tunnel engineering in Dongguan-Huizhou railway

the predicted subsidence thresholds by the model are coincident with the field data and numerical simulation results.