运用应力释放理论及应力传递理论,推导了盾构施工引起周边土体任一点的超孔隙水压力峰值的计算公式。并通过算例分析表明:与衬砌相邻的土体超孔隙水压力峰值呈近似圆形(底部大于顶部);随着离隧道中心距离的增加,土体超孔隙水压力峰值呈凹曲线衰减。同时发现盾构直径及埋深对土体超孔隙水压力峰值的影响是相反的。当直径减小或是埋深增大,均会使得与衬砌相邻周边土体超孔隙水压力峰值的底部与隧道中心水平线处的差异更加明显,反之亦然。隧道底部的等值线最密,即变化最快;隧道上方区域的等值线间距逐渐变大,即变化变缓。在一定深度处,超孔隙水压力峰值在隧道轴线上方为最大,远离隧道轴线则减小;随深度增大,其最大值有增大趋势。
Based on the stress relief theory and the stress transfer theory, a formula for the peak value of the excess pore water pressure at any point induced by shield construction is deduced. Case studies show that the distribution of the peak value of the excess pore water pressure around shield lining is similar to a circular shape. With the increase of the distance from the central axis of shield tunnel, the peak value of the excess pore water pressure decreases in a concave curve. The effect of shield diameter is opposite to the depth of the shield tunnel on the peak value of the pore water pressure of the soil. The isopleth map of the peak value of the excess pore water of the soil changes fastest at the bottom of the shield tunnel, but it increases gradually at the top of the shield tunnel. At a certain depth, the largest peak value of the excess pore water pressure is above the tunnel axis, and it decreases with the increase of the distance away from the axis. With the increase of the depth, the maximum value of the peak value of the excess soil pore water has an increasing trend.