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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。
Using the theory of stress release and stress transfer theory, the formula for calculating the peak value of excess pore water pressure caused by shield construction at any point around the soil is deduced. The case study shows that the peak value of excess pore water pressure near the lining is approximately circular (the bottom is greater than the top), and the peak value of excess pore water pressure is concave curve attenuation as the distance from the tunnel center increases. At the same time, it is found that the effect of shield diameter and buried depth on the excess pore water pressure peak is opposite. When the diameter decreases or the depth increases, the difference between the bottom of the excess pore water pressure peak near the lining and the tunnel center horizontal line will be more obvious, and vice versa. The contour at the bottom of the tunnel is the most dense, that is, the change is fastest; the contour of the tunnel above the area gradually becomes larger, that is, changes slowly. At a certain depth, the peak value of excess pore water pressure is the maximum above the tunnel axis and decreases away from the tunnel axis. As the depth increases, the maximum value of pore pressure increases.