土压平衡盾构掘进参数关系及其对地层位移影响的试验研究

土压平衡盾构机施工过程中，正确地选择掘进参数可以有效地保持开挖面稳定、减少土体位移和地面沉降。通过对杭州地铁1号线盾构隧道施工进行现场监测，研究了盾构机参数关系及其对地层位移的影响。监测内容包括：地表沉降、土体侧向位移、超孔隙水压力以及记录盾构机实时工作参数。研究结果表明，盾构机总推力、土舱压力和刀盘扭矩变化基本同步；盾构机到达前，地表沉降主要受出土率的影响，施工沉降与盾构机土舱内外压力差值成反比；盾尾通过测点后0.5～1 d时间，超孔隙水压力快速下降，且在盾尾通过10 d左右完全消散；工后沉降分为加速沉降阶段和缓慢沉降阶段，占总沉降的 50% 以上，且在孔压计超孔隙水压力消散后继续缓慢发展。

Research of EPB shield tunneling parameter relations and their influence on stratum displacement

For EPB (earth pressure balance) shield tunneling, one must properly choose driving parameters to maintain face stability and reducing soil displacement and ground subsidence. In this paper, to research the relationship among shield machine parameters and its impact on the ground displacement by in-site monitoring of Hangzhou metro line shield tunnel construction. The work for in-situ monitoring a shield tunnel construction includes: measuring ground settlement, lateral displacement, excess pore pressure and recording the working parameters of the shield machine. The results show that: the fluctuation for the total thrust force, the earth pressure on chamber and the torque of cutter disc are basically synchronous; ground settlement are mainly influenced by soil removal efficiency before the shield machine arrivals; construction settlement are in inverse proportion to the pressure difference between the inside and outside of the soil chamber; the excess pore pressure begins to decrease rapidly after the shield tail passes through for 0.5 to 1 days; and it completely disappears after 10 days. Settlement after construction is divided into the accelerated subsidence stage and the slow subsidence stage. It accounts for more than 50% of the total ground settlement; and it continues to develop slowly after the dissipation of the excess pore pressure.