特大暴雨条件下土质边坡入渗特征与微观结构试验研究

Experimental Study on Infiltration Characteristics and Microstructure of Soil Slopes Under Severe Heavy Rainfall Conditions

摘要:

降雨时铁路沿线土质的渗透能力对铁路路基的稳定性和安全性具有直接影响。为探究不同地区及坡度的影响,运用高精度工业CT微观设备、三维重构模型与现场人工模拟降雨试验,针对特大暴雨条件下土质边坡的入渗特征及土体孔隙微观性质展开深入分析。结果表明:在持续性降雨过程中,5°至50°坡度范围内,边坡雨水渗透吸水能力呈现缓慢下降直至平稳的趋势;石河口隧道处孔隙率约为29%,砂质土粒径较大;而温塘站地区孔隙率约为19%,粒径相对较小,石河口土质渗透能力较强。砂质土粒径越大、坡度越大,边坡对于雨水的渗透能力越强。从微观角度分析得知,在同等条件下,土体内部孔隙与孔喉等效半径越大,配位数越多,土体渗透系数越大;反之,孔喉长度越长,土体渗透系数越小。

Abstract:

The permeability of the soil along the railway during rainfall directly affects the stability and safety of the railway embankment. To investigate the influence of different regions and slopes, this study combined high-precision industrial CT microscopic equipment, three-dimensional reconstruction models, and on-site artificial rainfall simulation experiments to conduct in-depth analysis of the infiltration chara-cteristics of soil slopes under extreme rain conditions and the microscopic properties of soil pores. The results show that during continuous rainfall, within the range of 5° to 50° slopes, the infiltration and water absorption capacity of the slope gradually decreases and then stabilizes; the porosity at the Shiheshou Tunnel is approximately 29%, with larger sand particles, and the porosity in the Wen Tang Station area is approximately 19%, with relatively smaller particle sizes. The soil at Shiheshou has a stronger permea-bility. From a microscopic perspective, under the same conditions, the larger the equivalent radius of pores and pore throats in the soil and the greater the coordination number, the larger the soil permeability coefficient; the longer the pore length, the smaller the soil permeability coefficient.