保温法结合弃渣换填防治季节冻土山区软基冻害的适用性  

Applicability of Prevention of Soft Subgrade from Frost Damage with the Insulation and Replacement Filling Measures in Seasonally Frozen Ground Mountain Areas

作　　者：武立波[1,2] 刘惠阳 牛富俊 林占举 商允虎 WU Li-bo;LIU Hui-yang;NIU Fu-jun;LIN Zhan-ju;SHANG Yun-hu(School of Civil Engineering and Water Conservancy,Ningxia University,Yinchuan 750021,China;State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;School of Civil Engineering and Transportation,South China University of Technology,Guangzhou 510000,China)

机构地区：[1]宁夏大学土木与水利工程学院,银川市750021 [2]中国科学院西北生态环境资源研究院冻土工程国家重点实验室,兰州市730000 [3]华南理工大学土木与交通学院,广州市510000

出　　处：《公路》2024年第5期65-75,共11页Highway

基　　金：国家自然科学基金地区科学项目,项目编号41961011;宁夏重点研发计划(引才专项)项目,项目编号2019BEB04010。

摘　　要：为更好地解决季节冻土山区突出的软基冻害难题,提出在弃渣碎石换填层上铺设保温板的“保温换填法”。基于工程实例,运用带冰水相变的考虑路基阴阳坡效应的有限元数值解法,模拟分析XPS保温板在不同的埋深、厚度,以及考虑冻融循环作用和地下水对XPS保温板导热系数不利影响(最不利工况)的条件下,路基不同部位最大季节冻深和路基阴、阳坡路肩横向热差异在30年内随时间的变化。结果表明:“保温换填法”在抬升路基不同部位的最大季节冻深和控制路基阴、阳坡路肩横向热差异方面都具有良好的效果,但具体效果与路堤高度有关,路堤高度越小效果越好;综合考虑经济性和长期保温效果,路面下0.8 m是XPS保温板合理的埋设深度,8 cm厚是合理的铺设厚度,按《公路路基设计手册》公式确定的6 cm厚在季节冻土山区路基中偏于不安全;同时,“保温换填法”也适用于季节冻土山区地下水位埋深浅的地段。In order to solve the outstanding issue of soft subgrade frost damage in seasonally frozen ground mountain regions in a better way,the new measure is put forward,which is replacing filling with gravels from a tunnel excavation,and laying certain thickness insulation board on the replacement layer(the new Thermal Insulation and Replacing measure).Relying on a project practice,2-D finite element analysis of temperature field with phase change is conducted to simulate the thermal state of the subgrade.Based on the predicted maximum seasonal freezing depth and the differences of maximum seasonal freezing depth of subgrade on the shade and sunny slopes for the following 30years,firstly,the rational position and thickness of the insulation are discussed,secondly,the suitability of the Thermal Insulation and Replacing measure is analyzed under the most unfavorable conditions,which XPS insulation board is soaked with groundwater and under freezing-thawing cycles simultaneously.The results show that the new Thermal Insulation and Replacing measure can reduce the maximum seasonal freezing depth obviously and control the difference in thermal state of subgrade on the shade and sunny slopes well.The specific effect is related to the embankment height,the low embankment performs better than the high embankment.The appropriate position of XPS insulation board is 0.8mbelow the road surface,and the reasonable thickness is 8cm considering economy and long-term insulation effect.As far as the subgrade in study area is concerned,the 6cm thickness of XPS insulation board is less securable,which is determined by the formula of insulation board's thickness in the Handbook of Highway Subgrade.Moreover,as for the road section with shallower ground water level in seasonally frozen ground mountain regions,the new Thermal Insulation and Replacing measure is also applicable.

关 键 词：季节冻土山区 软基冻害 弃渣换填 保温法 合理埋设深度 合理厚度 阴阳坡 

分 类 号：U416.1[交通运输工程—道路与铁道工程] P642.14[天文地球—工程地质学]