河西走廊地区盐渍土路基换填层水盐迁移试验研究  

Experimental study on water and salt migration of replacement layer saline soil subgrade in Hexi Corridor

作　　者：李萍[1] 杨熙 王英 LI Ping;YANG Xi;WANG Ying(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China;School of Civil Engineering and Architecture,Xi’an University of Technology,Xi’an 710048,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050 [2]西安理工大学土木建筑工程学院,陕西西安710048

出　　处：《武汉大学学报（工学版）》2024年第5期582-592,共11页Engineering Journal of Wuhan University

基　　金：国家自然科学基金项目(编号:52268070);甘肃省重点科技攻关项目(编号:NO.20YF3GA017);甘肃省优秀研究生“创新之星”项目(编号:No.2021CXZX-492);兰州理工大学研究生科研探索项目(编号:256017)。

摘　　要：我国河西走廊地区大量分布以粉砂质土为主的盐渍土,其毛细水作用现象明显,对公路路基造成了严重的破坏。为了明确路基换填层的水盐迁移特性,采用自主设计的水盐迁移试验装置开展室内试验研究,并结合扫描电镜从微观层面解析盐渍土破坏机理。试验结果表明:在掺入风积沙的黄土与盐渍土换填层中,水盐迁移主要集中在试验前期,随着风积沙掺量增加,换填层水盐迁移速率先增大后减小,最快迁移速率出现在掺沙率为30%的土样。电镜结果表明:盐渍土土样在水盐迁移试验结束后会析出盐分晶体填充于土颗粒之间,形成胶结体和团聚物,从而导致土体开裂;在盐渍土中掺加50%的风积沙可以减少土体由盐胀引起的裂隙与孔隙,能有效降低水盐迁移引起的破坏。There are a lot of silty saline soils in Hexi Corridor of China,and its capillary action is obvious,which has caused serious harm to highway subgrade.Based on the above reasons,in order to clarify the water and salt migration characteristics of the replacement subgrade,this paper uses the self-designed water and salt migration test device to carry out indoor experimental research,and analyzes the failure mechanism of saline soil from the micro level by means of scanning electron microscope(SEM)test.The test results show that in the replacement functional layer of loess and saline soil mixed with aeolian sand,the water and salt migration is mainly concentrated in the early stage of hydration.With the increase of aeolian sand content,the water and salt migration rate of the replacement layer first increases and then decreases,and the fastest migration rate occurs in the soil sample with sand content of 30%.The results of SEM show that after the migration of water and salt,salt crystals will be precipitated and filled between soil particles to form cements and agglomerates,resulting in soil cracking;when 50%aeolian sand is added to saline soil,the cracks and pores caused by salt expansion can be reduced,and the damage caused by water salt migration can be effectively reduced.

关 键 词：路基工程 盐渍土 风积沙 水盐迁移 换填层 

分 类 号：TU448[建筑科学—岩土工程] U416[建筑科学—土工工程]