Study on Penetration Damage Caused by Leakage of Earth Pressure Balance Shield Machine Tail Skin in Water-rich Silty Fine Sand Stratum

Abstract

In order to study the principle of stratum seepage damage caused by shield tail leakage during the EPB shield tunneling in water-rich silty fine sand stratum, a targeted-designed device is used. The results of this research are as follows: (1) The soil loss after leakage could be divided into three stages: initial, rapid growth, and destruction. Besides, the proportions of water leakage and sand leakage in these stages are significantly different; (2) The process of stratum seepage damage caused by tail skin leakage is divided into two stages: the first stage is the formation of subsurface cavities, and the second stage is the instability and destruction of subsurface cavities; (3) When the leakage point is under the tunnel, two flow areas were formed toward the leakage point. When the leakage point is above the tunnel, one flow area is formed at the crown area of the tunnel. Based on the test results, in the actual project, the seepage damage stage and the development of subsurface cavities can be judged based on the amount of water and soil leakage to provide a certain basis for construction risk control and emergency disposal.