土工格室与沙漠沙界面特性大型直剪试验  

Large-scale Direct Shear Test on Interface Characteristics Between Geocell and Desert Sand

作　　者：方济升 刘杰 张耀辉 赵阳 FANG Ji-sheng;LIU Jie;ZHANG Yao-hui;ZHAO Yang(College of Civil Engineering and Architecture,Xinjiang University,Urumqi,Xinjiang 830047,China;Xinjiang Traffic Planning Survey Design Research Institute Co.,Ltd.,Urumqi,Xinjiang 830006,China;School of Civil and Hydraulic Engineering,Huazhong University of Science and Technology,Wuhan,Hubei 430074,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China)

机构地区：[1]新疆大学建筑工程学院,新疆乌鲁木齐830047 [2]新疆交通规划勘察设计研究院有限公司,新疆乌鲁木齐830006 [3]华中科技大学土木与水利工程学院,湖北武汉430074 [4]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071

出　　处：《公路交通科技》2024年第6期65-73,共9页Journal of Highway and Transportation Research and Development

基　　金：新疆交通运输科技项目(KY2020050701)。

摘　　要：为探明土工格室与沙漠沙的筋土界面特性,开展了多项大型直剪试验研究,包括不同土工格室位置条件下、不同剪切速率条件下、不同温度条件下的土工格室加固沙漠沙界面直剪试验。结果表明:在50,100,150 kPa的法向应力条件下,以土工格室加筋层上界面或下界面作为剪切面,不同剪切速率(0.5,1.0,2.0 mm/min),不同温度(30,15,0,-15℃)影响下的筋土界面剪应力-剪切位移曲线均呈应变软化特征;纯沙漠沙对剪切速率的变化不敏感,剪切速率由0.5 mm/min升至3 mm/min时沙漠沙抗剪强度基本持平,而土工格室加固沙漠沙的界面对剪切速率的变化敏感,界面抗剪强度随剪切速率的增加而减小;在较低剪切速率0.5 mm/min下,土工格室提供的似黏聚力对抗剪强度的贡献更大;土工格室加固沙漠沙在30℃与15℃下峰值剪应力变化不大,区别在于峰值过后30℃抗剪强度存在更快的衰减至平稳阶段的情况;随着温度的降低,土工格室-土复合体呈现出更大的刚性,界面剪应力峰值提高并前移;土工格室刚性的增加使土工格室壁不易受拉变形,造成紧箍作用削弱而水平摩擦力作用增强,综合体现在加筋土剪切面的似黏聚力降低,而内摩擦角增大。Several large-scale direct shear tests were carried out to characterize the reinforcement-soil interface between geocell and desert sand,including direct shear tests on geocell-reinforced desert sand interface with different geocell positions,different shear rates,and different temperatures.The result indicates that under the normal stress of 50,100,150 kPa,taking the upper interface or lower interface of geocell-reinforced layer as the shear surface,the shear stress-shear displacement curves of reinforcement-soil interface under the influence of different shear rates(0.5,1.0,2.0 mm/min)and various temperatures(30,15,0,-15℃)are all characterized by strain softening.Pure desert sand is not sensitive to the variation of shear rate.The shear rate rises from 0.5 mm/min to 3 mm/min when the desert sand shear strength is flat.In contrast,the interface of geocell-reinforced desert sand is sensitive to the variation of shear rate,and the interface shear strength decreases with the increase of shear rate.At the lower shear rate of 0.5 mm/min,the contribution to shear strength from apparent cohesion provided by the geocell is greater.The peak shear stress of geocell-reinforced desert sand does not change much at 30℃and 15℃.The difference is that the shear strength at 30℃decreases more quickly to the stationary stage after the peak value.As the temperature decreases,the geocell-soil composite exhibits greater stiffness,and the peak interfacial shear stress increases and moves forward.The increase of geocell stiffness makes the geocell wall less susceptible to tensile deformation,resulting in the weakening of hoop action,and the enhancement of horizontal friction action.It comprehensively shows that the apparent cohesion of reinforced soil shear surface decreases,while the internal friction angle increases.

关 键 词：道路工程 界面特性 大型直剪试验 土工格室 剪切速率 温度 

分 类 号：U416.1[交通运输工程—道路与铁道工程]