直剪试验方法对轻量土抗剪强度的影响规律研究  

Study on the influence of direct shear test methods on shear strength of lightweight soil

作　　者：郭鹏斐 侯天顺[1] 刘茜 骆亚生[1] GUO Pengfei;HOU Tianshun;LIU Qian;LUO Yasheng(College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,Shaanxi,China;Hanjiang to Weihe River Valley Water Diversion Project Construction Co.,Ltd.,Shaanxi Province,Xi′an 710011,Shaanxi,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100 [2]陕西省引汉济渭工程建设有限公司,陕西西安710011

出　　处：《水利水电技术（中英文）》2023年第4期161-170,共10页Water Resources and Hydropower Engineering

基　　金：国家自然科学基金项目(51509211);中国博士后基金项目(2016M602863);陕西省留学人员科技活动择优资助项目(2018031);陕西省社会发展科技攻关项目(2015SF260);陕西省博士后基金项目(2017BSHYDZZ50);陕西省自然科学基础研究计划引汉济渭联合基金项目(2021JLM-51);西安市岩土与地下工程重点实验室开放基金项目(XKLGUEKF21-02);中央高校基本科研业务费专项资金项目(2452020169)。

摘　　要：【目的】为了快速、准确地获取轻量土抗剪强度相关指标,确定不同直剪试验方法对轻量土抗剪强度的差异,【方法】通过快剪、固结快剪以及慢剪试验,分析了轻量土剪应力-剪切位移曲线、黏聚力和内摩擦角在不同剪切方法及不同配比下的变化规律。【结果】结果显示:轻量土的抗剪强度及抗剪强度指标随着其配比不同表现出一定的差异,其中,随着EPS颗粒体积比的增大,剪应力-剪切位移曲线由应变软化型转变为应变硬化型,轻量土抗剪强度大幅降低。随着水泥掺量的增加,轻量土抗剪强度总体呈现增大的趋势,同时轻量土黏聚力随EPS颗粒体积比增大而大幅减小,随水泥掺量的增大略有增大;内摩擦角随EPS颗粒体积比的增大急剧减小,随水泥掺量增大略微减小。其中以快剪试验为例,当水泥掺量为15%、EPS颗粒体积比由20%增长至40%和60%时,轻量土黏聚力相对减少量为22.20%、44.73%。【结论】结果表明,不同EPS颗粒体积比下,慢剪方法对轻量土试样黏聚力的变化较为敏感,而快剪方法对轻量土试样内摩擦角的变化较为敏感。与素土相比,三种直剪方法下得到的不同配比轻量土剪应力-剪切位移曲线形态、抗剪强度值均比较相近,实际工程中可用直剪快剪方法获取轻量土抗剪强度。[Objective]In order to obtain relevent parameters of light weight soil shear strength quickly and accurately,the influence of different direct shear method on the shear strength of light weight soil is studied.[Methods]Through the quick shear test,consolidated quick shear test and slow shear test,the variation laws of shear stress-shear displacement curve,cohesion and internal friction angle of the light weight soil under different shear testing method and different proportions.[Results]The result show that with the increase of EPS particle volume ratio,the shear strength and shear strength index of light weight soil show certain differences with its different ratio.The shear stress-shear displacement curve changes from strain softening type to strain hardening type,and the shear strength of light weight soil decreases significantly.With the increase of cement content,the shear strength of light weight soil shows an increasing trend generally.The cohesion of light weight soil decreases greatly with the increase of EPS particle volume ratio,and increases slightly with the increase of cement content.The internal friction angle decreases sharply with the increase of EPS particle volume ratio,and decreases slightly with the increase of cement content.Taking the quick shear test as an example,when the cement content is 15%and the EPS particle volume ratio increases from 20%to 40%and 60%,the cohesion of light weight soil decreases from 44.24 kPa to 34.42 kPa and 24.45 kPa,the absolute reduction is 9.82 kPa and 19.79 kPa,and the relative reduction is 22.20%and 44.73%.[Conclusion]Under different EPS particle volume ratios,the slow shear test method is sensitive to the cohesion change of light weight soil samples,while the quick shear test method is more sensitive to the internal friction angle change of light weight soil samples.Compared with soil,the shear stress-shear displacement curves and shear strength values of light weight soil in different proportion ratios obtained under the three different direct shear method

关 键 词：轻量土 直剪试验 抗剪强度 黏聚力 内摩擦角 

分 类 号：TU431[建筑科学—岩土工程]