缩尺效应对粗颗粒土静止侧压力系数影响规律试验  

Experimental Investigation on Scale Effect of the At-rest Earth Pressure Coefficient of Coarse-grained Soil

作　　者：蒋明杰 朱俊高[3] 张小勇[1,2] 梅国雄 赵辰洋 JIANG Mingjie;ZHU Jungao;ZHANG Xiaoyong;MEI Guoxiong;ZHAO Chenyang(Key Lab.of Disaster Prevention and Structural Safety of Ministry of Education,Guangxi Univ.,Nanning 530004,China;Guangxi Key Lab.of Disaster Prevention and Structural Safety,Guangxi Univ.,Nanning 530004,China;Key Lab.of Ministry of Education for Geomechanics and Embankment Eng.,Hohai Univ.,Nanjing 210098,China;Key Lab.of Oceanic Civil Eng.,Sun Yat-sen Univ.,Zhuhai 510275,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]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [4]中山大学广东省海洋土木工程重点实验室,广东珠海510275

出　　处：《工程科学与技术》2023年第2期259-266,共8页Advanced Engineering Sciences

基　　金：国家自然科学基金项目(51878185,52178321,52108309);国家自然科学基金委员会–雅砻江流域水电开发有限公司雅砻江联合基金(U1865104);长江水科学研究联合基金重点支持项目(U2040221);广西防灾减灾与工程安全重点实验室开放基金资助项目(2020ZDK003);广东省海洋土木工程重点实验室开放基金资助项目(LMCE202103)。

摘　　要：准确把握粗颗粒土静止侧压力系数K_(0)对分析及设计土石坝等岩土工程具有十分重要的作用。由于缩尺效应的存在,粗颗粒土室内K_(0)试验结果往往无法正确反映其真实值。本文利用自行研制的大型K_(0)测试仪对某砂卵砾石料及堆石料进行大量试验,以研究分析缩尺效应对粗颗粒土K_(0)影响规律,找出消除缩尺效应影响的方法。通过改变试样颗粒的最大粒径d_(M)、缩尺方法、初始相对密实度D_(r0)等初始条件,设置24组试样,利用大型K_(0)测试仪对各组试样进行直剪试验,定量研究d_(M) 、缩尺方法和D_(r0)对粗粒土K_(0)的影响规律,并探讨以室内试验数据推求现场粗粒土K_(0),从而消除缩尺效应的方法。结果表明:D_(r0)及缩尺方法不变时,粗颗粒土K_(0)随着d_(M) 的增加而显著减小,因此,缩尺效应会导致粗颗粒土K_(0)显著增高,且缩尺后土料d_(M) 越小,其K_(0)受影响程度越高;D_(r0)及d_(M)相同时,缩尺方法对粗颗粒土K_(0)有一定影响,采用等量替代法缩尺后,试样K_(0)值增加最小,因此,采用等量替代法缩尺可减小缩尺效应对粗颗粒土K_(0)的影响;相比d_(M) ,D_(r0)对粗粒土K_(0)的影响更为显著,D_(r0)越大的土样,d_(M)对粗粒土K_(0)影响更明显。基于砂卵砾石料K_(0)试验结果及前人的研究,建立根据室内试验结果反推现场粗颗粒土料K_(0)的公式,以消除缩尺效应对粗颗粒土K_(0)的影响。利用堆石料K_(0)试验结果验证了该经验公式的准确性及适用性。The accurate measurement of the at-rest earth pressure coefficient K_(0) for coarse-grained soil is important in the analysis and design of geotechnical engineering such as the earth rockfill dam. The laboratory K_(0) test results of the coarse-grained soil usually cannot accurately reflect its K_(0) value due to scale effects. To investigate the scale effect of K_(0) for coarse-grained soil, and propose a method to eliminate its influence, several K_(0) tests for the sandy gravel and the rockfill were performed by using a special large-size K_(0) testing apparatus. By changing the maximum grain size d_(M) , scale method, and relative density D_(r0), 24 groups of specimens were designed. K_(0) tests for all specimens were conducted by a largesize K_(0) apparatus, to quantitatively study the multiple influences of d_(M) , scale method and D_(r0)on the K_(0) of coarse-grained soils, and investigate the method that can predict the K_(0) behavior of sandy gravel in situ based on the laboratory test results and eliminate the influence of scale effects on K_(0) . The test data show that: when the scale method and D_(r0)are the same, K_(0) for coarse-grained soil trend to decrease observably with increasing d_(M) , therefore scale effect results in the obvious increasing value of K_(0) for coarse-grained soil, and the smaller d_(M) for reducing scale soil, the stronger influence of scale effect on its K_(0);Scale method have some influence on K_(0) for coarse-grained soil with the same d_(M) and D_(r0), and the increasing value of K_(0) for test specimens prepared by replacement technique is the least, therefore adopting the replacement technique to prepare test specimen can reduce the influence of scale effect on K_(0) for coarse-grained soil;Compared with d_(M) , D_(r0)have a stronger influence on K_(0) for coarse-grained soil, and the larger D_(r0), the stronger influence of d_(M) on K_(0) for coarse-grained soil. Based on the K_(0) test data of sandy gravel and previous research results, an empire equation, which co

关 键 词：粗颗粒土 静止侧压力系数 缩尺效应 颗粒最大粒径 缩尺方法 相对密实度 

分 类 号：TU443[建筑科学—岩土工程]