哈大高铁路基用掺水泥级配碎石冻胀特性试验研究

摘要

The Harbin-Dalian high-speed railway runs through the northeastern China,where seasonal frozen soil is widely distributed,the temperature difference between summer and winter is very large and the frost heaving problem is very serious. The frost heaving problems which are not treated properly could easily result in roadbed and track deformation and affect the high-speed railway safe operation. The transition sections of bridge-subgrade and culvert-subgrade are filled with graded gravel mixed with cement in Harbin-Dalian high speed railway. For understanding the impact of fines and cement content of graded gravel on its frost heaving characteristics,this paper carried out an experimental study of the frost heaving characteristics of graded gravel mixed with cement. The test results showed that the frost heaving ratio of graded gravel is from 1% to 1. 65% with no cement capacity,hardened graded gravel with more than 5% cement capacity basically eliminates the frost susceptibility of fine soil and the frost heaving ratio is below 0. 2%,graded gravel mixed with cement may be damaged by frost in 50 freeze-thaw cycles, the surface crackes but not into powder and the frost heaving ratio does not significantly increase,which could provide a reference for economic and reasonable design scheme of the Harbin-Dalian high-speed railway.%哈大高铁纵贯我国季节性冻土广泛分布的东北地区，该地区冬夏季温差大，冻胀问题突出，处理不当易造成路基和轨道变形，从而影响高铁的运营安全。哈大高铁路桥、路涵过渡段采用级配碎石掺水泥进行填筑，为了解级配碎石中细粒含量和水泥掺量对其冻胀特性的影响，对掺水泥级配碎石的冻胀特性进行了试验研究。结果表明：不掺水泥级配碎石冻胀率可达1.00%～1.65%，而5%以上水泥掺量级配碎石硬化后基本消除了细粒土冻胀敏感性，冻胀率＜0.2%；在50次冻融循环作用下，掺水泥级配碎石有被冻坏可能，表层冻裂但并未成粉状，冻胀率也没有显著增大。