隔离桩及盾构近接施工对高铁桩基的影响分析

针对饱和砂土地区盾构隧道超近接高铁桥墩摩擦桩的工程问题，采用钻孔灌注桩及高压旋喷桩组合隔断隧桩间位移。分别对钻孔灌注桩、高压旋喷桩及盾构上下行线近接高铁桥梁桩基引起的高铁桩基的变形及变位开展现场试验，对现场实测数据及规律进行分析。结果表明，钻孔灌注桩施工使高铁桥墩产生沉降，占施工过程最大沉降量的 75%～125%；高压旋喷桩施工导致桥墩产生隆起，占施工过程最大沉降量的-50%，旋喷桩施工完成后将持续一段时间；盾构施工对高铁桥墩竖向变形产生影响，距离高铁桩基越近影响越大，同时累计沉降跟盾构施工控制有较大关系。

Analysis of impact of isolation piles and shield tunnelling on adjacent high-speed railway pile foundation

In light of the adjacent high-speed railway pile foundation problem induced by the process of shield tunnelling in the saturated sandy stratum, the isolation piles, including bored pile and jet grouting pile, were applied to resist the displacement of the pile foundation. An experiment was investigated in order to determine the effect on high-speed railway piles by the adjacent construction of bored pile, jet grouting pile and shield tunnel. The monitoring in-situ was carried out. The results shows that the settlement of high-speed railway piles is induced by the performance of bored pile, the settlement value may account for almost 75%-125% of maximum ones. The heave of the high-speed railway is induced by the performance of jet grouting piles; the heave value may account for the -50% of the maximum settlement. Meanwhile, the process of the heave can last for a long time. The specific operation of shield tunnel machine affects the magnitude of the adjective high-speed railway piles subsidence; the closer the distance between the shield tunnel and the piles, the larger the influence; the cumulative settlement is associated with operation of the shield tunnelling.