考虑盾构隧道渗水的富水软弱#br# 地层地表长期沉降计算研究

富水软弱地层中盾构隧道渗水的情况时有发生，对盾构施工引起超孔隙水压力的消散造成影响。在地表长期沉降的计算中，隧道渗水的工况是不容忽视的。对此，以富水软弱地层盾构隧道渗水为背景，将超孔隙水压力的消散视为地下水向低水头位置和向隧道渗流共同作用的结果，在前人研究的基础上推导了长期沉降计算式。针对3个实际工程，采用提出的计算方法与不考虑隧道渗水的方法、实测结果进行对比，结果表明：对于黏土占比较高的地层，不考虑隧道渗水的方法计算结果偏小，与实测值存在一定的偏差；隧道渗水量越大，引起的地表沉降量越大；考虑隧道渗水可有效提高长期沉降的计算精度，验证了所提计算方法的可靠性。

Calculation model of the long-term settlement in the weak #br# watery stratum considering leakage of shield tunnel

Seepage of shield tunnel occurs occasionally in the weak and water-rich stratum after long-term use, which has impact on the dissipation of excess pore water pressure caused by shield construction. Thus, tunnel seepage conditions cannot be ignored in the calculation of long-term surface settlement. On the basis of the previous research, a calculation method that can evaluate long-term consolidation settlement in the weak and water-rich stratum was proposed, considering that the dissipation of excess pore pressure is caused by the seepage of groundwater towards the lower head position in stratum and the position of shield tunnel. For three actual projects, the proposed calculation method is compared with the method that does not consider the tunnel seepage as well as the actual measurement results. The results show that computed result by the method without considering tunnel leakage is smaller than the measured value in the stratum with high clay content. Additionally, the larger the seepage volume, the greater the surface settlement; Considering tunnel seepage can effectively improve the calculation accuracy of long-term settlement, which verifies the reliability of the proposed calculation method.