Abstract: A covert and curving zone,which is disturbed by trenchless pipeline engineering,is formed under the river and dyke stratum. Based on an actual engineering, a corresponding groundwater simulation model is proposed for evaluating the possibility of seepage failure induced by the disturbed zone Under the extremely unfavorable hydmlogy-weather conditions,the maximum groundwater flow gradient is estimated by the simulation model. Then, the possibility of seepage failure induced by engineeng can be quantitatively analyzed based on the critical hydraulic gradient method. The result shows that the maximum groundwater flow gradient is increasing gradually and its acceleration is decreasing corresponding to increasing river level. The maximum groundwater flow gradient is influenced obviously by the thin and low-permeability silt layer of river bed.