Face supporting pressure of slurry shield tunnel under high hydraulic pressure

Face supporting pressure has great influence on face stability and ground deformation under high hydraulic pressure during slurry shield tunneling. Based on the under-river tunneling project of Nanjing Metro Puzhulu-Binjianglu interval, a numerical model is established to simulate the process of instability, the relation between face supporting pressure and soil deformation and the impact of relevant parameters are studied. The results show that, compared the case without no hydraulic pressure, the limit supporting pressure is reached when smaller soil displacement has occurred and the value the much greater under high hydraulic pressure. The ratio of the limit supporting pressure increases and the face stability decreases with the increase of the internal friction angle, water levle and tunnel diameter. The relation curve of the limit supporting pressure and the internal friction angle (water level) is parabola, and that of the limit supporting pressure and tunnel the diameter is power function. The ratio of the limit supporting pressure decreases and the face stability increases with the increase of the cohesion and tunnel depth. The relation curve of the limit supporting pressure and cohesion (tunnel depth) is parabola (power function). The elastic modulus has almost no effect on the face stability. The research may provide a reference for the determination of face supporting pressure during slurry shield tunneling under high hydraulic pressure.