应力-干湿-冻融循环下膨胀土力学特性试验研究  

Experimental study on mechanical properties of expansive soil under stress-wet-dry-freeze-thaw cycle

作　　者：杨博文 李凯[2] 张方祺 段正中 YANG Bowen;LI Kai;ZHANG Fangqi;DUANG Zhengzhong(School of Science,Qingdao University of Technology,Qingdao,Shandong 266525,China;Qingdao Engineering Research Center for Underground Unconventional Energy(Qingdao University of Technology),Qingdao,Shandong 266525,China)

机构地区：[1]青岛理工大学理学院,山东青岛266525 [2]青岛市地下非常规能源开发工程研究中心(青岛理工大学),山东青岛266525

出　　处：《中国科技论文》2025年第2期137-145,共9页China Sciencepaper

基　　金：国家自然科学基金资助项目(51808306);山东省自然科学基金资助项目(ZR2023ME214)。

摘　　要：为了研究复杂的环境因素对季节性冻土区(季冻区)膨胀土工程破坏的主要原因,选定临沂市沂河地区膨胀土,开展室内基本土工试验,量测膨胀土的基本物理力学性质指标;通过膨胀土应力-干湿-冻融循环(stress-wet-dry-freeze-thaw,L-WDFT)试验,量测出膨胀土剪切强度及土-水特征曲线,分析L-WDFT循环对季冻区膨胀土水力-力学特性的影响。结果表明:L-WDFT循环作用对膨胀土力学特性的衰减有显著影响;内摩擦角有波动但幅度不大,可以忽略;剪切强度和黏聚力均有所降低,但第3次循环后基本趋于稳定,且随着上覆应力的增大,整体衰减幅值减小。在L-WDFT循环作用过程中,各组膨胀土水分特征曲线趋势大致相同,随着上覆应力的增加,土-水特征曲线呈现整体上移的趋势,在较小吸力范围内,膨胀土土-水特征曲线下移区间较小。In order to investigate the main causes of engineering damage to expansive soil in seasonally frozen soil areas(seasonally frozen regions)due to complex environmental factors,expansive soil from the Yihe river area in Linyi city were selected for laboratory basic geotechnical tests to measure the basic physical and mechanical property indicators of the expansive soil.The shear strength and soil-water characteristic curve of expansive soil were measured by the experiment of stress-wet-dry-freeze-thaw(L-WDFT)cycle,and the influence of L-WDFT cycle on the hydromechanical characteristics of expansive soil in seasonally frozen region was analyzed.The results show that the L-WDFT cycle has a significant effect on the attenuation of mechanical properties of expansive soil.Specifically,the internal friction angle fluctuates,but the amplitude is relatively small and can be negligible.The shear strength and cohesion both decrease but tend to be stable after the third cycle,and the overall attenuation amplitude decreases with the increase of the overlying stress.In the process of L-WDFT cycling,the trends of soil-water characteristic curves of all groups of expansive soil remainded similar.With the increase of overlying stress,the soil water characteristic curve shows a trend of overall upward shift.In the range of relatively low suction,the downward shift interval of the soil-water characteristic curve of expansive soil is relatively small.

关 键 词：季冻区 应力-干湿-冻融循环作用 膨胀土 剪切强度 土-水特性 

分 类 号：TU432[建筑科学—岩土工程]