喷层混凝土-围岩组合体的循环冲击压缩试验研究
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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.
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.
引文
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[17] 邓国强,杨秀敏.静力循环加载与动力重复冲击下岩石破坏全过程对比试验研究[J].岩石力学与工程学报,2014,33(3):581-585.DENG Guoqiang,YANG Xiumin.Comparative experimental investigation on damage process of rock under static cyclic loading and repeated dynamic impact[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(3):581-585.
[18] 李夕兵,古德生,赖海辉.冲击载荷下岩石动态应力-应变全图测试中的合理加载波形[J].爆炸与冲击,1993,13(2):125-130.LI Xibing,GU Desheng,LAI Haihui.On the reasonable loading stress waveforms determined by dynamic stress-strain curves of rocks by SHPB[J].Explosion and Shock Waves,1993,13(2):125-130.
[19] 王世鸣.冲击荷载下早龄期混凝土力学和损伤特性的试验研究[D].长沙:中南大学,2014.
[ 2 ] 单仁亮,黄博,耿慧辉,等.爆破动载作用下新喷射混凝土累积损伤效应的模型实验[J].爆炸与冲击,2016,36(3):289-296.SHAN Renliang,HUANG Bo,GENG Huihui,et al.Model experiment to study cumulative damage effects of young shotcrete under blasting load[J].Explosion and Shock Waves,2016,36(3):289-296.
[ 3 ] 闫长斌,徐国元,杨飞.爆破动荷载作用下围岩累积损伤效应声波测试研究[J].岩土工程学报,2007,29(1):88-93.YAN Changbin,XU Guoyuan,YANG Fei.Measurement of sound waves to study cumulative damage effect on surrounding rock under blasting load[J].Chinese Journal of Geotechnical Engineering,2007,29(1):88-93.
[ 4 ] 颜峰,姜福兴.爆炸冲击载荷作用下岩石的损伤实验[J].爆炸与冲击,2009,29(3):275-280.YAN Feng,JIANG Fuxing.Experiment on rock damage under blasting load[J].Explosion and Shock Waves,2009,29(3):275-280.
[ 5 ] 赖建中,孙伟,戎志丹.活性粉末混凝土在多次冲击荷载下的力学行为[J].爆炸与冲击,2008,28(6):532-538.LAI Jianzhong,SUN Wei,RONG Zhidan.Dynamic mechanical behaviour of reactive powder concrete subjected to repeated impact[J].Explosion and Shock Waves,2008,28(6):532-538.
[ 6 ] 李胜林,刘殿书,杨俊,等.碳纤维包裹下混凝土的动态力学性能研究[J].公路交通科技,2010,27(4):22-27.LI Shenglin,LIU Dianshu,YANG Jun,et al.Study on dynamic mechanical properties of CFRP wrapped concrete[J].Journal of Highway and Transportation Research and Development,2010,27(4):22-27.
[ 7 ] 李夕兵,王世鸣,宫凤强,等.不同龄期混凝土多次冲击损伤特性试验研究[J].岩石力学与工程学报,2012,31(12):2465-2472.LI Xibing,WANG Shiming,GONG Fengqiang,et al.Experimental study of damage properties of different ages concrete under multiple impact loads[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(12):2465-2472.
[ 8 ] 李夕兵,王世鸣,周韬,等.不同冲击条件下早龄期混凝土的力学特性[J].中国有色金属学报,2015,25(6):1672-1677.LI Xibing,WANG Shiming,ZHOU Tao,et al.Mechanical properties of early ages concrete underdifferent impact loading conditions[J].The Chinese Journal of Nonferrous Metals,2015,25(6):1672-1677.
[ 9 ] LI X B,LOK T S,ZHAO J.Dynamic character-istics of granite subjected to intermediate loading rate[J].Rock Mechanics and Rock Engineering,2005,38(1):21-39.
[10] 李地元,孙小磊,周子龙,等.多次冲击荷载作用下花岗岩动态累计损伤特性[J].实验力学,2016,31(6):827-835.LI Diyuan,SUN Xiaolei,ZHOU Zilong,et al.On the dynamic accumulated damage characteristics of granite subjected to repeated impact load action[J].Journal of Experimental Mechanics,2016,31(6):827-835.
[11] 梅年峰.循环动荷载作用下脆性岩石疲劳损伤力学特性研究[D].武汉:中国地质大学,2014.
[12] 朱晶晶,李夕兵,宫凤强,等.单轴循环冲击下岩石的动力学特性及其损伤模型研究[J].岩土工程学报,2013,35(3):531-539.ZHU Jingjing,LI Xibing,GONG Fengqiang,et al.Dynamic characteristics and damage model for rock under uniaxial cyclic impact compressive loads[J].Chinese Journal of Geotechnical Engineering,2013,35(3):531-539.
[13] 李胜林,刘殿书,张慧,等.石灰岩的SHPB试验研究[J].北京理工大学学报,2013,33(12):1224-1228.LI Shenglin,LIU Dianshu,ZHANG Hui,et al.Split hopkinson pressure bar test on limes-tone[J].Transactions of Beijing Institute of Technology,2013,33(12):1224-1228.
[14] 许金余,吕晓聪,张军,等.循环冲击作用下围压对斜长角闪岩动态特性的影响研究[J].振动与冲击,2010,29(8):60-63.XU Jinyu,Lü Xiaocong,ZHANG Jun,et al.Research on dynamic mechanical performance of amphibolite under cyclic impact loadings at different confining pressures[J].Journal of Vibration and Shock,2010,29(8):60-63.
[15] 刘少赫,许金余,王鹏,等.围压条件下砂岩循环冲击损伤的力学与超声分析[J].振动与冲击,2015,34(1):190-194.LIU Shaohe,XU Jinyu,WANG Peng,et al.Mechanical and ultrasonic analysis on damage of sandstone under cyclical impact loading with confining pressure[J].Journal of Vibration and Shock,2015,34(1):190-194.
[16] 唐礼忠,王春,程露萍,等.一维静载及循环冲击共同作用下矽卡岩力学特性试验研究[J].中南大学学报(自然科学版),2015,46(10):3898-3906.TANG Lizhong,WANG Chun,CHENG Luping,et al.Experimental study of mechanical characteristics of skarn under one-dimensional coupled static and cyclic impact loads[J].Journal of Central South University (Science and Technology),2015,46(10):3898-3906.
[17] 邓国强,杨秀敏.静力循环加载与动力重复冲击下岩石破坏全过程对比试验研究[J].岩石力学与工程学报,2014,33(3):581-585.DENG Guoqiang,YANG Xiumin.Comparative experimental investigation on damage process of rock under static cyclic loading and repeated dynamic impact[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(3):581-585.
[18] 李夕兵,古德生,赖海辉.冲击载荷下岩石动态应力-应变全图测试中的合理加载波形[J].爆炸与冲击,1993,13(2):125-130.LI Xibing,GU Desheng,LAI Haihui.On the reasonable loading stress waveforms determined by dynamic stress-strain curves of rocks by SHPB[J].Explosion and Shock Waves,1993,13(2):125-130.
[19] 王世鸣.冲击荷载下早龄期混凝土力学和损伤特性的试验研究[D].长沙:中南大学,2014.