郑西高速铁路豫西段黄土现场浸水自重湿陷特征研究

通过现场浸水试验，研究了郑西高速铁路豫西段典型黄土场地浸水后的自重湿陷特征，分析了湿陷土层深度随浸水时间的演化规律，判定了浸水水平向影响范围。研究表明：浸水边界对沉降的影响十分明显，浸水后的湿陷速率呈现出慢-快-慢直至稳定的特点，在浸水10 d后已完成总沉降量的60%，浸水30 d时完成总沉降量的约90%；该场地实测因地区土质而异的修正系数 为1.30，大于规范推荐的0.9，说明该地区黄土的湿陷程度比以往认识地更为强烈；该场地自重湿陷土层下限深度室内试验值是19 m，而现场实测值是16 m，前者是后者的1.2倍。通过综合判定，该场地浸水后的湿陷变形范围为距试坑边缘20 m，与试坑的直径相当，建议在郑西高速铁路沿线此类黄土场地，线路两侧20 m范围内不得积水。该研究成果已在郑西高速铁路建设中得到应用，也可为该地区类似工程提供参考。

Study of immersion collapsible characteristics under overburden pressure of Western Henan loess along Zhengzhou-Xi'an high-speed railway

This paper makes a study of the collapsible characteristics under overburden pressure of the Western Henan loess along Zhengzhou-Xi’an high-speed railway by field experiment.The developing process in the depth of loess collapsibility under overburden pressure and the collapsible horizontal distance have also been analyzed.The results show that: the influence of soaking boundary on collapse is very clear;but collapsible rate shows a slow-fast-slow-until-stable tendency,with 60% of the total settlement immersed for 10 days and 90% for 30 days.The 0of the site is 1.30,greater than the recommended 0.9 by the code.The results show that the extent of collapsibility of this region is more intense than that of general knowledge.In the site,loess collapse under overburden pressure maximum depth laboratory test value is 19 m;and field test value is 16 m,the former is 1.2 times the latter.The collapsible horizontal distance out of the test pit is 20 m,similar with the diameter of the test pit.Therefore,no water should be kept within 20 m from the embankment toe.The research results have been applied to the Zhengzhou-Xi’an high-speed railway construction,and can be taken as reference for similar projects in this region.