含水率和冻融循环对筋土界面剪切特性的影响  

Influence of water contents and freeze-thaw cycles on shear behavior of geogrid-soil interface

作　　者：孟亚 徐超[1,2] 贾斌 左彬澧 MENG Ya;XU Chao;JIA Bin;ZUO Bini(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China;East China Electric Power Design Institute Co.Ltd.,China Power Engineering Consulting Group,Shanghai 200063,China)

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]中国电力工程顾问集团华东电力设计院有限公司,上海200063

出　　处：《中南大学学报（自然科学版）》2024年第2期586-594,共9页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(41772284);安徽省交通运输行业重点科技项目(2022-KJQD-008);中国电力工程顾问集团华东电力设计院有限公司科研项目(30-K2023-G01)。

摘　　要：制作了一套可实现温度控制的筋土界面直剪试验设备。为了研究含水率、界面温度、冻融循环次数对筋土界面剪切特性的影响,开展11组土工格栅-砂土界面直剪试验。研究结果表明,筋土界面的黏聚力和摩擦角均随含水率的增加而减小,当含水率提高时,筋土间的抗剪强度减弱。加筋可显著提高冻土的抗剪强度,当界面温度为-10℃时,土工格栅-砂土界面剪应力峰值较冻结后砂土的剪应力增加了约20%。筋土界面剪应力随着界面温度的降低而增大,当界面温度在0℃以下时,剪应力较大且剪应力-剪切位移曲线会出现峰值强度和残余强度,而在无冻结情况下,筋土界面剪应力稳定值基本相同。冻融循环后筋土界面的抗剪强度减小,筋土界面的黏聚力和摩擦角均随着冻融循环次数的增加而减小,但在4次冻融循环后趋于稳定。研究成果可为冻土地区土工格栅加筋土结构的设计和应用提供理论依据。A set of temperature-controlled direct shear test apparatus for the interface of reinforced soil was developed.Eleven groups of direct shear tests were conducted to study the influence of water contents,interface temperatures,and freeze-thaw cycles on the shear behavior of the geogrid-soil interface.The results show that the cohesion and friction angle of the geogrid-soil interface both decrease with the increase of water contents,as does the shear strength at the geogrid-soil interface.The reinforcement can obviously improve the shear strength of the frozen soil.When the interface temperature is-10℃,the peak shear stress at the geogrid-soil interface increases by about 20%relative to the unreinforced soil.The reinforcement provided by the geogrid increaes as the interface temperature drops.The shear stress is higher and the shear stress-shear displacement will show the peak strength and residual strength when the interface temperature drops below 0℃,whereas in a non-frozen state,the interface exhibits lower shear stress with a consistent stable value.The shear strength of the geogrid-soil interface decreases after freeze-thawing.Furthermore,both the cohesion and friction angle of the geogrid-soil interface decrease with the increase of freeze-thaw cycles number but tend to stabilize after four freeze-thaw cycles.The research results have reference for the design and application of geogrid reinforced soil structures in permafrost and seasonal frozen regions.

关 键 词：土工格栅 直剪试验 筋土界面 剪切特性 冻融循环 

分 类 号：TU445[建筑科学—岩土工程]