冻融循环作用下二灰盐渍土无侧限抗压强度研究  

Study on unconfined compressive strength of two ash saline soil under freeze-thaw cycle

作　　者：王润泽 孙静[1] 季雨航 刘宇轩 WANG Runze;SUN Jing;JI Yuhang;LIU Yuxuan(School of Civil Engineering,Heilongjiang University,Harbin 150080,China)

机构地区：[1]黑龙江大学建筑工程学院,哈尔滨150080

出　　处：《黑龙江大学工程学报(中英俄文)》2024年第3期78-87,共10页Journal of Engineering of Heilongjiang University

基　　金：国家自然科学基金项目(52178514);黑龙江省自然科学基金项目(LH2023D022)

摘　　要：我国盐渍土分布较广,盐渍土在冻结状态下的工程性能随冻融循环的发展逐渐恶化,影响盐渍土地区工程的安全运营及其耐久性。以黑龙江省大庆市盐渍土为研究对象,通过无侧限抗压试验,研究不同冻融循环次数下石灰、稻壳灰掺量对盐渍土无侧限抗压强度的影响。结果表明:冻融循环使应力-应变曲线的轴向应力峰值对应的应变变大,为应变软化型,弹性模量变小,0次和1次冻融循环弹性阶段突出,3次冻融循环后压密阶段明显。随着冻融循环次数的增加,原状土和二灰土的无侧限抗压强度均先小幅提升后大幅降低,1次冻融循环时强度最大,1~5次冻融循环处于快速劣化阶段,5次冻融循环后达到稳定阶段,建议将5次冻融循环的无侧限抗压强度作为强度稳定值。石灰6%和稻壳灰8%时无侧限抗压强度提升效果最大,在0、1、3、5、7和9次冻融循环下的无侧限抗压强度加强系数分别为4.32、3.50、4.83、3.63、3.39和3.31,二灰的提升效果优于单灰,单稻壳灰优于单石灰。Saline soil is widely distributed in China,and the engineering performance of saline soil in frozen state deteriorates gradually with the development of freeze-thaw cycle,which affects the safe operation and durability of engineering in saline soil area.The influence of lime and rice husk ash(RHA)content on the unconfined compressive strength(UCS)of saline soil under different freeze-thaw cycles was studied through unconfined compressive test in Daqing City,Heilongjiang Province.The results show that the strain corresponding to the peak axial stress of the stress-strain curve increases during freeze-thaw cycle,which is a strain softening type.The elastic modulus becomes smaller,and the elastic stage of 0 and 1 freeze-thaw cycles is prominent,and the compaction stage after 3 freeze-thaw cycles is obvious.With the increase of the number of freeze-thaw cycles,the UCS of both natural and lime-RHA-stabilized soilds initially rises slighthy and then decreased significantly.The strength was the highest during the first freeze-thaw cycle,and the first to fifth freeze-thaw cycle was in the rapid deterioration stage,and the fifth freeze-thaw cycle reached the stable stage.It is suggested that the UCS of the fifth freeze-thaw cycle should be taken as the stable strength value.The greatest UCS improvement is achieved with 6%lime and 8%RHA,with strength enhancement factors of 4.32,3.50,4.83,3.63,3.39,and 3.31 after 0,1,3,5,7 and 9 freeze-thaw cycles,respectively.The lime-RHA combination is more effective than lime alone,and RHA alone outperforms lime alone.

关 键 词：冻融循环 二灰盐渍土 无侧限抗压强度 应力-应变曲线 

分 类 号：TU44[建筑科学—岩土工程]