关键词: 掘进速度, 软土地区, 水、土压力, 地表隆沉

Abstract: In view of shield tunnel projects in soft soil area of Shanghai, the advancing speed of the shield machine is adjusted, and the water pressure, soil pressure and strata stability are observed in the whole process of the shield crossing the monitoring section. According to the measured soil consolidation ratio, the pressure of artesian water and other strata soil properties, the influences of the varied advancing speeds are comprehensively evaluated by the mechanisms of soil disturbance. The analysis indicates that the shield tunneling in soft soil area is approximately 4 times of the diameter (D=6.2 m). By keeping the chamber earth pressure and grouting amount invariant in the shield advancing process, the change of the hoisting speed of the jack to great extent influences the soil pressure and deformation. Reducing the advancing speed results in the decrease of the disturbance range of water and earth pressures and then the disturbance is generated by the pressure increment, but leads to more stable values of the induced surface heave. The corresponding change value is determined by the ratio of depth to the advancing speed. Experiment results provide a certain valid reference to ensure the effect from the shield speed of the jack at the depth of 4D.

Key words: advancing speed, soft soil area, water and earth pressure, surface subsidence