反复一维冲击下钙质砂动力特性SHPB试验研究  

SHPB tests on the dynamic characteristics of calcareous sand under repeated one-dimensional impact loading

作　　者：戴国亮[1,2] 欧阳浩然 秦伟 朱文波[1,2] 龚维明[1,2] 张程锋[1,2] DAI Guoliang;OUYANG Haoran;QIN Wei;ZHU Wenbo;GONG Weiming;ZHANG Chengfeng(Key Laboratory of Concrete and Prestressed Concrete Structure of Ministry of Education,Southeast University,Nanjing 211189,China;School of Civil Engineering,Southeast University,Nanjing 211189,China;College of Civil Engineering and Architecture,Wenzhou University,Wenzhou 325027,China)

机构地区：[1]东南大学混凝土及预应力混凝土结构教育部重点实验室,南京211189 [2]东南大学土木工程学院,南京211189 [3]温州大学建筑工程学院,浙江温州325027

出　　处：《振动与冲击》2022年第14期264-270,279,共8页Journal of Vibration and Shock

基　　金：国家自然科学基金(51878160,52078128)。

摘　　要：南海岛礁建设桩基工程面临钙质砂地层问题,利用改进的分离式霍普金森压杆(split Hopkinson pressure bar,SHPB)试验装置研究钙质砂在反复冲击荷载作用下的动力特性。共进行28次反复一维冲击试验,得到钙质砂和石英砂的应力-应变、一维压缩特性以及吸能效率曲线,以探讨反复一维冲击荷载作用下冲击次数、含水率和相对密实度等因素对两种砂样动态力学响应的影响。结果表明:钙质砂由于颗粒形状和矿物组成的不同,其动态表观模量(动刚度)在首次冲击以及反复冲击多次后都约为石英砂的10%;随着反复冲击的进行,两种砂样不断密实,表现为刚度增大、可压缩性减弱;首次冲击下钙质砂和石英砂的屈服应力分别约为3.20 MPa和9.33 MPa,此后颗粒开始大量破碎,压缩指数分别约为0.87和0.41,反复冲击后两种砂样的屈服应力分别增加到6.14 MPa和12.54 MPa;钙质砂的吸能效率高于石英砂,不同含水率和不同相对密实度钙质砂样吸能效率在多次冲击后趋于接近。In order to solve the problems about the calcareous sand layer in the construction of pile foundation in the South China Sea,a modified split Hopkinson pressure bar(SHPB)apparatus was used to investigate the dynamic characteristics of calcareous sand under repeated impact loading.A total of 28 times of repeated 1D impact tests were conducted to obtain the stress-strain curves,1D compression curves and energy absorption efficiency curves of calcareous sand and silica sand,so as to explore the influences of impact times,moisture content and relative density on the dynamic characteristics of the two types of sand specimens under repeated 1D impact loading.The test results show that the dynamic apparent modulus(dynamic stiffness)of calcareous sand is approximately 10%of that of silica sand after the first impact or repeated impacts due to the difference in particle shape and mineral compositions;with repeated impacts,both sand specimens continue to be compacted,showing an increase in stiffness and a decrease in compressibility;the yield stresses of calcareous sand and silica sand under the first impact are about 3.20 MPa and 9.33 MPa respectively,and then a large number of particles begin to break,and the compression index is about 0.87 and 0.41 respectively.After repeated impacts,the yield stress of the two kinds of sand samples increases to 6.14 MPa and 12.54 MPa respectively;the energy absorption efficiency of calcareous sand is higher than that of silica sand,and the energy absorption efficiency of calcareous sand specimens with different moisture content and relative density tends to be similar after repeated impacts.

关 键 词：钙质砂 分离式霍普金森压杆(SHPB)试验 冲击次数 应力-应变关系 一维压缩特性 吸能特性 

分 类 号：U416.1[交通运输工程—道路与铁道工程]