湿陷性黄土地区新建铁路与水渠合理避让距离研究

Study on the Reasonable Avoidance Distance Between Railway and Canal in the Collapsible Loess Area

黄土具有垂直节理发育、透水性好、遇水易湿陷和较强水敏性工程特征。本文在对比分析中兰铁路典型不同成因黄土物理力学性质的基础上,开展现场浸水试验,对不同成因黄土场地新建铁路与长大干渠合理避让距离进行研究。试验结果表明:当黄土渗透系数大于10^(-4)cm/s、砂粒含量较大且结构疏松、孔隙发育时,铁路路基边坡外缘与水渠合理避让距离不小于20 m,对沉降敏感的高速铁路安全避让距离原则上需大于30 m;当黄土渗透系数小于10-5cm/s、砂粒含量较少且黏粒含量较高时,铁路路基边坡外缘与水渠合理避让距离不小于15 m。该研究结论对湿陷性黄土地区铁路工程地质选线具有一定参考价值。

Loess has the engineering characteristics of developed vertical joint,good water permeability,water collapsibility and strong water sensitivity.Based on the comparative analysis of the physical and mechanical properties of the loess of different origin in the Sino-Lanlanian Railway,this paper carried out a field immersion test to study the reasonable avoidance distance between the newly-built railway and the canal in the loess sites with various genesis.The test results show that when the permeability coefficient of loess is above 10^(-4)cm/s and with large sand content,loose structure and developed pores,the reasonable avoidance distance between the outer edge of the railway subgrade slope and the canal should not be less than 20 m,and the safe avoidance distance of settlement-sensitive high-speed railway should be over than 30 m in principle.When the permeability coefficient of loess is below 10-5 cm/s and with less sand content and high clay content,the reasonable avoidance distance between them should not be less than 15 m.The conclusion of this study provides certain reference value for railway track selection in collapsible loess region.