级配对粗粒土-格栅界面循环剪切特性影响试验研究  

Experimental study of gradation effect on interfacial cyclic shear behavior between coarse-grained soils and geogrid

作　　者：蒋明杰 石竣允 栗书亚 胡荣峰 梅国雄 JIANG Mingjie;SHI Junyun;LI Shuya;HU Rongfeng;MEI Guoxiong(Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education,Guangxi University,Nanning 530004,Guangxi,China;Guangxi Key Laboratory of Disaster Prevention and Structural Safety,Guangxi University,Nanning 530004,Guangxi,China;Key Laboratory of Urban Security and Disaster Engineering,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]广西大学工程防灾与结构安全教育部重点实验室,广西南宁530004 [2]广西大学广西防灾减灾与工程安全重点实验室,广西南宁530004 [3]北京工业大学城市减灾与防灾防护教育部重点实验室,北京100124

出　　处：《水利水电技术（中英文）》2024年第3期162-172,共11页Water Resources and Hydropower Engineering

基　　金：国家自然科学基金(1878185,52178321,52108309);广东省海洋土木工程重点实验室开放基金(LMCE202103);水利部土石坝破坏机理与防控技术重点实验室开放基金(2020ZDK003);广西自然科学基金(2021GXNSFBA196091)。

摘　　要：【目的】为研究级配对粗粒土-土工格栅界面动力剪切特性的影响规律,【方法】基于连续级配方程,通过改变试样的最大粒径d_(max)和级配面积S,制备了18组不同级配试样,对各组试样分别进行设置土工格栅和不设置土工格栅的循环直剪试验,分析d_(max)和S对界面循环剪切特性的影响,并引入了加筋剪切刚度系数α_(K)和加筋阻尼比系数α_(D),来评价土工格栅对动剪切强度参数的影响效果。【结果】结果显示:当小于格栅网孔尺寸的粗粒含量较高时,剪切刚度K随着d_(max)的增大而增大,阻尼比D随着d_(max)的增大而减小;反之,则表现出相反的趋势。K和D均与d_(max)呈对数函数关系;K和D与S的关系均可用二次多项式表示。此外,给出了α_(K)和α_(D)与粒孔比的关系,即随着粒孔比的增大,α_(K)先增大后减小,α_(D)呈先减小后增大的规律。当粒孔比取0.073左右时,土工格栅对粗粒土循环剪切特性的加筋效果最好。【结论】结果表明:颗粒与土工格栅间的互锁机制对粗粒土-格栅界面的循环剪切特性有重要影响,当大部分颗粒粒径小于格栅网格尺寸时,颗粒与格栅间的互锁机制充分发挥;当颗粒最大粒径及格栅网格尺寸相同时,存在一个最优级配面积,使得粗粒土-格栅界面的抗震性能最好。[Objective]In order to study the effect of gradation on the dynamic shear behavior of coarse-grained soil-geogrid interface,[Methods]18 groups of different gradation samples were prepared by changing the maximum particle size(d_(max))and gradation area(S)of the samples based on the continuous gradation equation,the cyclic direct shear tests with and without geogrids were carried out for each group of specimens,and the effects of d_(max) and S on the cyclic shear properties of interface were analyzed,the shear stiffness coefficientα_(K) and the damping ratio coefficientα_(D) are introduced to evaluate the effect of geogrids on dynamic shear strength parameters.[Results]The experimental result show that the shear stiffness K increases with the increase of d max,and the damping ratio D decreases with the increase of d max.Conversely,the opposite trend is observed.K and D are logarithmically related to d max.The relations of K/D with S can be expressed by quadratic polynomials.In addition,the relationship betweenα_(K)/α_(D) and aperture ratio is given,that is,with the increase of aperture ratio,α_(K) increases first and then decreases,andα_(D) decreases first and then increases.When the aperture ratio is about 0.073,the geogrid has the best reinforcement effect on the cyclic shear behavior of coarse-grained soil.[Conclusion]The result show that the interlock mechanism between particles and geogrids has an important effect on the cyclic shear behavior of the coarse-grained soil-geogrid interface.When the particle size of most particles is smaller than the size of the grid,the interlock mechanism between particles and the grid is brought into full play.When the maximum particle size and the grid size are the same,there is an optimal gradation area,which makes the coarse-grained soil-grid interface have the best seismic performance.

关 键 词：粗粒土 土工格栅 颗粒级配 模型试验 土石坝 变形 抗剪强度 影响因素 

分 类 号：TU411[建筑科学—岩土工程]