基于渗流分析的湿陷性黄土地区城际轨道地基处理范围

通过一维渗流土柱试验和数值模拟分析,开展了压实黄土渗流特性及湿陷性黄土地区城际轨道地基处理范围研究。试验结果表明:压实系数对非饱和黄土的渗流影响显著。湿润峰随着时间的变化有两个阶段,快速入渗和缓慢入渗。对压实系数较大的黄土,当湿润峰推进到50 cm后,水分入渗速率进入缓慢阶段。当入渗边界水头较小时,不同的边界水头对压实的黄土渗流规律影响不大。综合分析试验结果及数值分析得到:城际轨道地基采用挤密桩处理时,外放尺寸可按规范取最小值2 m,不必按处理深度的一半取值。对于乙、丙类建筑物或非高等级的线性工程,在满足承载力要求下可采用减小地基处理深度、增大地基处理宽度的处理方式。研究成果可为优化深厚湿陷性黄土地区城际轨道工程地基处理范围提供参考。

Study on Ground Treatment Scope of Intercity Rail in Collapsible Loess Area Based on Seepage Analysis

Through one-dimensional seepage soil column test and numerical simulation analysis the seepage characteristics of the compacted loess and its application in intercity orbital foundation were studied. The experimental results show that the compaction coefficient has a significant influence on the seepage of unsaturated loess. The wetting front has two phases with the change of time, rapid infiltration and slow infiltration. For the loess with greater compaction coefficient, when the wetting front is pushed to 50cm, the water infiltration rate enter a slow phase. When the water head of the infiltration boundary is smaller, the different boundary water head have little effect on the seepage law of the compacted loess. Through test results analysis and numerical analysis, it are concluded that when the intercity rail foundation adopts the compacting pile, the size of the outer space is the minimum value of 2m by the standard, and is not half of the foundation treatment depth. For class B and C buildings or non-high-grade linear projects, the treatment methods of reducing the depth of foundation treatment, increasing the width of foundation treatment can be adopted when the requirements of bearing capacity is meet.The research results can provide reference for optimizing the foundation treatment scope of Intercity Track Engineering in deep collapsible loess area.