重型机械荷载作用下邻近高铁桥墩的扰动性分析

为了解重型机械施工期间邻近高铁桥梁及其周围土体的扰动情况，从而保障重型机械施工期间邻近高铁的运营安全，依托宁和城际轨道交通一期工程，基于PLAXIS 3D软件建立了高铁桥墩及相应土层的有限元模型，分析了重型机械荷载作用下周围土体的变形影响范围和高铁桥墩的变位值。在此基础上，对履带吊静置前后土体侧向应力，以及重型机械施工期间邻近高铁桥墩的竖向位移、水平位移和倾斜度进行了实时监测，并将数值计算与现场实测的结果进行了对比分析。结果表明:履带吊静压后，测试点处侧向土压力明显增大，但对深层土体无明显影响，履带吊就位后各测点土压力值均无明显变化；土体附加应力随着深度的增加而迅速衰减，且土体变形的水平影响范围不超过20 m；施工过程中高铁桥墩的竖向位移、倾斜度变位情况稳定，且均小于预警值（ 0.8 mm），但水平位移受重型机械施工影响相对较大，接近于预警值；所得结论可为今后类似邻近既有高铁线施工工程提供可靠参考。

Disturbance Analysis of Closed High-speed Railway Piers Under Heavy Mechanical Load

In order to understand the disturbance of heavy machinery closed the high-speed railway bridge and surrounding soil during the construction period, and ensure the operation safety of the high speed railway, the first-stage project of Nanjing-Hexian intercity rail transit was taken as the example, finite element model of high-speed railway piers and corresponding soil layer were developed based on PLAXIS 3D software. Furthermore, the deformation range of surrounding soil and the displacement value of high-speed railway pier under heavy machinery load were analyzed. The settlement, horizontal displacement and inclination of the closed high-speed railway bridge piers were also investigated during the construction. The numerical calculation and field monitoring results were compared and analyzed. The results show that after the static pressure of crawler crane, the lateral earth pressures at measuring points increase obviously, but have no obvious influence on the deep soil, and the earth pressure values at measuring points have no obvious change after the crawler crane is in place. The additional stress of the soil decreases rapidly with the increase of the depth, and the horizontal influence scope caused by heavy machine is less than 20 m. During the construction process, the settlement and inclination of the high-speed railway pier are stable and less than the warning value (0.8 mm). However, the horizontal displacement is relatively large and close to the warning value caused by heavy machinery. The results can provide a reliable reference for similar projects near the existing high-speed railways.