考虑级配影响的粗粒土−格栅最优网格尺寸试验研究  

Experimental study on optimal grid size of coarse-grained soil-grid considering the effect of gradation

作　　者：蒋明杰 李泽懿 吉恩跃 刘宇菠 梅国雄 JIANG Ming-jie;LI Ze-yi;JI En-yue;LIU Yu-bo;MEI Guo-xiong(Laboratory of Disaster Prevention and Structural Safety of Ministry of Education,Guangxi University,Nanning,Guangxi 530004,China;Guangxi Key Laboratory of Disaster Prevention and Structural Safety,Guangxi University,Nanning,Guangxi 530004,China;Geotechnical Engineering Department,Nanjing Hydraulic Research Institute,Nanjing,Jiangsu 210024,China;Ocean College,Zhejiang University,Zhoushan,Zhejiang 316021,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]南京水利科学研究院岩土工程研究所,江苏南京210024 [4]浙江大学海洋学院,浙江舟山316021

出　　处：《岩土力学》2024年第9期2565-2572,2582,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.52108309,No.52178321);广西科技计划项目(No.2021AC18008);广西自然科学基金(No.2021GXNSFBA196091)。

摘　　要：土工格栅作为土石坝常用的加筋材料,根据颗粒级配采用适合的格栅网格尺寸可显著提高土石坝抗震性能,探究级配影响下最优网格尺寸变化规律具有工程意义。基于连续级配的级配方程,通过改变最大粒径d_(max)和级配面积S,设计15组级配土料,采用4组不同网格尺寸L_(a)对各个土料加筋,做成60组加筋试样。利用大型直剪仪对各个试样进行循环剪切试验,从而定量研究级配与能使加筋粗粒土抗震性能达到最优的土工格栅网格尺寸之间的关系。试验发现,当d_(max)及L_(a)一定时,级配面积存在一个最优值使抗震性能达到最佳,将此定义为最优级配面积S_(opt);当网格尺寸一定时,S_(opt)随d_(max)增大而增大,两者之间呈明显的对数关系;当d_(max)一定时,S_(opt)随L_(a)增大而减小,两者之间也呈明显的对数关系。建立定量描述d_(max)和L_(a)对最优级配面积S_(opt)的耦合影响的计算模型,并结合工程实际,提出基于室内试验结果预测现场粗粒土原级配对应最优网格尺寸的经验公式。Geogrid,commonly used for reinforcement in rockfill dams,significantly enhances seismic performance when appropriate grid dimensions are selected based on particle size distribution.Investigating the variations in optimal grid dimensions influenced by particle size distribution is of great engineering importance.By employing the continuous grading equation,15 sets of graded soils were developed by varying the maximum particle size d_(max) and grading area S.Creating 60 reinforced specimens by using four different grid sizes L_(a) to reinforce each soil.Subsequently,large-scale direct shear tests were performed on each specimen to quantitatively analyze the correlation between grading area and geogrid dimensions,aiming to optimize the seismic performance of reinforced coarse-grained soil.The experimental results show that there is an optimal grading area,S_(opt),that maximizes seismic performance when d_(max) and L_(a) are fixed.When the grid size remains constant S_(opt) increases logarithmically as d_(max) increases.Conversely,when d_(max) is constant,S_(opt) decreases logarithmically as L_(a) increases.A quantitative model is developed to d_(max) describe the combined effects of d_(max) and L_(a) on S_(opt).This model is integrated with engineering practices to propose an empirical formula based on indoor test results for predicting the optimal grid dimensions for the original grading of coarse-grained soil on-site.

关 键 词：粗粒土 土工格栅 颗粒级配 循环剪切 最优网格尺寸 

分 类 号：TU411[建筑科学—岩土工程]