喷层混凝土-围岩组合体的循环冲击压缩试验研究  

Experimental research on the sprayed concrete-surrounding rock combined body subjected to cyclic impact loadings

作　　者：郭东明[1,2] 闫鹏洋 张英实 张伟[1] 丁莹莹 赵黎明 GUO Dongming;YAN Pengyang;ZHANG Yingshi;ZHANG Wei;DING Yingying;ZHAO Liming(School of Mechanics and Civil Engineering,China University of Mining & Technology (Beijing),Beijing 100083,China;State Key Laboratory for Geomechanics and Deep Underground Engineering,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)力学与建筑工程学院,北京100083 [2]深部岩土力学与地下工程国家重点实验室,北京100083

出　　处：《振动与冲击》2019年第10期105-111,共7页Journal of Vibration and Shock

基　　金："十三五"国家重点研发计划(2017YFC0804200);国家自然科学基金(51274204);国家重点基础研究发展计划(2016YFC0600903)

摘　　要：针对巷(隧)道爆破开挖施工中,喷层混凝土和围岩黏结面近区双层介质动态力学问题,利用Φ75 mm SHPB试验装置,对龄期为3 d,7 d,10 d的混凝土-岩石组合体试件进行不同冲击气压的循环冲击试验。结果表明,早龄期混凝土对组合体试件的动力特性影响较大,在0.52 MPa冲击气压下,循环冲击2次后,组合体试件力学特性由塑性转变为脆性,峰值应变减小,弹性模量增大,随着循环冲击次数的增加,组合体试件力学性能被劣化,峰值应变增大,弹性模量降低;循环冲击后,混凝土与岩石端面均出现张拉损伤裂纹,混凝土损伤较岩石严重。对比0.54 MPa和0.56 MPa试验结果,发现试件耗散能与损伤值呈负相关关系,低入射能条件下组合体试件损伤更小,这对现场施工具有重要的指导意义。In order to explore the dynamic properties of the medium around the adhesive surface formed by the adherence of early age concrete on rock during the blasting excavation in a tunnel,cyclic impact compression tests were conducted with a split Hopkinson pressure bar(SHPB)of 75 mm diameter on the early age concrete-rock combined bodies at the age of 3 d,7 d and 10 d respectively.The results show the early age concrete has great influence on the dynamic characteristics of combined bodies.The mechanical characteristics of the combined body change from ductility to brittleness after twice impacts with the impact pressure of 0.52 MPa.Its peak strain decreases,while the elastic modulus increases.The mechanical characteristics of the combined body are deteriorated along with the increasing of impact times,the peak strain presents the trend of increasing,but the elastic modulus is contrary.Tensile cracks appear at the ends of concrete and rock and the damage of the concrete is more serious than that of rock after the cyclic impacts on the combined body.There is a negative correlation between the damage and dissipated energy according to the results of 0.54 MPa and 0.56 MPa,which indicates that the lower impact energy condition would improve the ability of resistance against the cyclic impacts.The test results have an important guide significance for the site construction.

关 键 词：喷层混凝土-围岩组合体 霍普金森压杆试验装置 循环冲击 动力特性 累计损伤 

分 类 号：TU45[建筑科学—岩土工程]