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高铁路基沉降控制是保证列车安全性和舒适性的重要因素。随着高铁运营时间增长,软土地区高铁路基长期沉降问题越来越引起关注。针对京沪高速铁路徐沪段某试验段,开展了桩网复合结构路基长期循环动态加载物理模型试验,获得了路基沉降、桩土应力分担及桩身轴力分布的变化规律。试验结果表明:在初始1000次加载时,路基沉降随加载次数增加明显,之后达到稳定;桩上部位置土体变形大于桩身变形,桩侧呈现负摩阻力,中性点位于距桩顶约2/3桩长位置;桩身轴力随加载次数增加而增大,说明桩分担荷载增加,当达到4万次加载后,轴力随加载次数增加不再明显。
Subsidence control of high-speed railway subgrade is an important factor to ensure train safety and comfort. With the growth of high-speed rail operation, the long-term settlement of high-speed railway subgrade in soft soil area has drawn more and more attention. Aiming at a certain test section of Xuhu section of Beijing-Shanghai high-speed railway, a long-term cyclic dynamic loading physical model test of subgrade with pile-net composite structure was carried out. The subsidence of subgrade, stress distribution of pile and soil and distribution of pile axial force were obtained. The test results show that the subgrade settlement increases obviously with the loading times in the first 1000 loadings and then reaches a steady state. The soil deformation at the upper part of the pile is larger than the deformation of the pile body, and the negative side friction resistance at the pile side. The neutral point is about 2 / 3 pile position; pile axial force increases with the increase in the number of loads, indicating that the share of pile load increases, when the load reaches 40,000, the axial force increases with the load is no longer obvious.