颗粒粒径和密实度对砂土K0值影响的离心模型试验研究  

Effect of particle size and compaction on K value of sand by centrifugal model test

作　　者：蔡正银[1] 代志宇 徐光明[1] 任国峰[1] CAI Zheng-yin;DAI Zhi-yu;XU Guang-ming;REN Guo-feng(Geotechnical Engineering Department,Nanjing Hydraulic Research Institute,Nanjing,Jiangsu 210024,China)

机构地区：[1]南京水利科学研究院岩土工程研究所,江苏南京210024

出　　处：《岩土力学》2020年第12期3882-3888,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51879167)。

摘　　要：静止土压力系数K0在挡土墙土压力计算中尤为重要,采用离心模型试验的方法,针对不同粒径和密实度的砂土K0值展开研究。试验首先通过砂雨法制备土样,利用自制的撒砂装置对不同出砂口和落距下砂土的制样密实度进行了测定;然后通过合理设计土压力测量模型结构,利用离心模型试验同时测量了土体的压缩量和铝合金板上的水平土压力;最后,通过计算和分析得到了不同粒径和密实度砂土的K0值变化规律。试验结果表明:在砂雨法制样时,针对不同的土样需要采用不同的出砂口和不同的落距;在砂土K0值的离心模型试验中,土体沉降量1#砂>3#砂>2#砂,且1#砂与3#砂的土体沉降量较为接近;对同种粒径的砂土,K0值随着土样相对密实度的增加而逐渐增加;对于不同粒径的土样,相同密实度下,砂土粒径越大K0值越小。The coefficient of earth pressure at rest K0 is particularly important in the calculation of earth pressure of retaining wall. In this paper, the K0 value of sand with different particle sizes and compactions was studied by centrifugal model tests. Firstly, soil samples were prepared by sand pluviation method, and the designed compactions of sand samples under different types of sand outlets and drop distances were measured by self-made sanding device. Then, through reasonable design of earth pressure measurement model structure, the centrifugal model test was used to simultaneously measure the soil compression and the horizontal earth pressure on the aluminum alloy plate. The variation of the K0 value of sand with different particle sizes and compactions was finally obtained by calculation. The test results showed that, when using the sand pluviation method to prepare the samples, different types of sand outlets and drop distances should be adopted for different soil samples. In the centrifugal model test on the K0 value of sand, the order of soil settlement was #1 sand > #3 sand > #2 sand, and the settlement of #1 sand and #3 sand was close to each other. For sand with the same particle sizes, the K0 value increased gradually with the increase of the relative compaction of soil sample. For sand with different particle sizes, under the same compaction, the larger the sand particle size is, the smaller the K0 value is.

关 键 词：相对密实度 砂雨法 离心模型试验 静止土压力系数 

分 类 号：TU432[建筑科学—岩土工程]