PUC固化路基融化夹层强度及耐冻融性能研究  

Study on strength and freeze-thaw resistance of PUC stabilized subgrade thawed layer

作　　者：王钰如 牛富俊 刘明浩 王子一 WANG Yu-ru;NIU Fu-jun;LIU Ming-hao;WANG Zi-yi(Key Laboratory of Cryospheric Science and Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,Gansu,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院西北生态环境资源研究院冰冻圈科学与冻土工程重点实验室,甘肃兰州730000 [2]中国科学院大学,北京100049

出　　处：《地基处理》2024年第S01期7-14,共8页Journal of Ground Improvement

基　　金：国家自然科学基金(42176224);甘肃省科技计划(22JR5RA059);中国科学院西部之光项目。

摘　　要：多年冻土退化导致路基融化夹层(SSLT)数量增加、范围扩大、埋深加剧,其含水量高、压缩性大、承载力低的特点,威胁多年冻土区基础设施安全运行。因此,开展融化夹层的处置研究工作,对寒区基础设施的维护和修复至关重要。为此,本文提出借鉴软土加固技术对其进行加固,采用亲水性聚氨酯(WPU)及改性水泥基地聚物材料(PUC)为固化剂,研究对SSLT的加固效果。结果表明,WPU固化SSLT试样呈弹性特征,压缩强度随WPU掺量增加而增大;当SSLT含水量分别为35%、40%和50%时,WPU最佳掺量分别为6%、10%和15%;冻融循环降低固化土无侧限抗压强度,冻融循环15次,掺入WPU和未掺入WPU固化土强度损失率分别为43.11%和49.38%;微观分析表明,PUC固化剂固化SSLT强度的增加,一部分是WPU充填、包裹、胶结土颗粒增加土体密实度,一部分来自水泥水化过程。本文为寒区老旧路基改造及提高其安全稳定运营提供一种新的解决思路。The degradation of permafrost leads to a large number of thawed layers(SSLT)that have high water content,high compressibility,and low bearing capacity,which threaten the stability of infrastructure in permafrost regions.Therefore,research on the disposal of thawed layer is crucial for the maintenance and repair of infrastructure in cold regions.This paper proposes a reinforcement technique for SSLT inspired by soft soil stabilization technology,in which hydrophilic polyurethane(WPU)and modified cement-based polymer material(PUC)were used as stabilizers to study their reinforcement effects on SSLT.The experimental results show that WPU-processed SSLT has elastic characteristic,and the compression strength increases with the increase of WPU content.When the water content of SSLT is 35%,40%,and 50%,the optimal WPU content is 6%,10%,and 15%,respectively.The freeze-thaw cycle reduces the unconfined compression strength of solidified soil.After 15 freeze-thaw cycles,the strength loss rates of solidified soil with and without WPU addition are 43.11%and 49.38%,respectively.Microscopic analysis indicates that the increase in strength of SSLT dealt with PUC curing agent is partly due to the filling,encapsulation,and cementation of soil particles by WPU,which increase the density of the soil,and partly due to the hydration process of cement.This study provides a new solution for the renovation of old subgrades in cold regions and the improvement of their safe and stable operation.

关 键 词：多年冻土 融化夹层 路基加固 亲水性聚氨酯 无侧限抗压强度 冻融循环 

分 类 号：TU472[建筑科学—结构工程]