不同加载速率Ⅰ型预制裂纹花岗岩断裂特征研究
|
摘要
以CCD相机配合高速相机搭建试验变形观测系统,开展不同加载速率下含Ⅰ型预制裂纹花岗岩试件的三点弯试验。利用数字散斑相关方法对试验过程采集的数字散斑图像进行分析,对不同加载速率作用下含Ⅰ型预制裂纹花岗岩试件裂纹扩展过程中的变形演化特征、裂纹扩展速率、裂纹尖端张开位移、裂纹张开角以及初始断裂应力强度因子进行研究,研究结果表明:(1)花岗岩试件初始裂纹扩展速率随着加载速率的增加总体呈线性增加趋势;最大扩展速率随着加载速率增加呈现先较快增加后缓慢增加的变化趋势。(2)不同加载速率作用下,花岗岩试件预制裂纹尖端张开位移均呈现非线性缓慢增长-迅速增长-线性增长的变形趋势,且线性增长阶段曲线斜率随着加载速率的增加而增大。(3)随着加载速率的增加,花岗岩试件初始裂纹张开角先逐渐减小后稳定在0.1o～0.13o。(4)随着加载速率的增加,花岗岩试件初始断裂应力强度因子呈指数增长。
The deformation measurement system was built with a CCD camera and a high-speed camera. Experimental tests were conducted on rectangular granite specimens with pre-cracks of mode-Ⅰ under different loading rates. The speckle images captured in the process of experiments were analysed by the digital speckle correlation method(DSCM). We studied the speed of crack growth, crack-tip opening displacement, crack tip opening angle and crack stress intensity factor(SIF) of granite specimens with pre-cracks of mode-Ⅰ under different loading rates. The initial speed of the crack growth of granite specimens increases linearly with the loading rate. With the increase of loading rate, the maximum speed crack increased rapidly at first and then slowly. At different loading rates, the crack-tip opening displacement of granite specimens showed three stages of evolution: nonlinear slow growth,rapid growth, and linear growth. In the linear growth stage, the slope of the curve increased with the increase of loading rate. With the increase of loading rate, the initial crack opening angle of granite specimen decreases gradually and then stabilises to 0.1°～0.13°. Before the initial fracture of granite specimens, the SIF value increased exponentially with the increase of loading rate.
The deformation measurement system was built with a CCD camera and a high-speed camera. Experimental tests were conducted on rectangular granite specimens with pre-cracks of mode-Ⅰ under different loading rates. The speckle images captured in the process of experiments were analysed by the digital speckle correlation method(DSCM). We studied the speed of crack growth, crack-tip opening displacement, crack tip opening angle and crack stress intensity factor(SIF) of granite specimens with pre-cracks of mode-Ⅰ under different loading rates. The initial speed of the crack growth of granite specimens increases linearly with the loading rate. With the increase of loading rate, the maximum speed crack increased rapidly at first and then slowly. At different loading rates, the crack-tip opening displacement of granite specimens showed three stages of evolution: nonlinear slow growth,rapid growth, and linear growth. In the linear growth stage, the slope of the curve increased with the increase of loading rate. With the increase of loading rate, the initial crack opening angle of granite specimen decreases gradually and then stabilises to 0.1°～0.13°. Before the initial fracture of granite specimens, the SIF value increased exponentially with the increase of loading rate.
引文
[1]许江,刘义鑫,刘婧,等.双面剪切荷载作用下岩石断裂过程声发射特性研究[J].岩石力学与工程学报,2015,34(增刊1):2659-2664.XU Jiang,LIU Yi-xin,LIU Jing,et al.Study of characteristics of rock acoustic emission fracture process of double shear loading effect[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(Supp.l):2659-2664.
[2]岳中文,杨仁树,孙中辉,等.含倾斜边裂纹岩石冲击断裂模拟试验[J].煤炭学报,2010,35(9):1456-1460.YUE Zhong-wen,YANG Ren-shu,SUN Zhong-hui,et al.Simulation experiment of rock fracture containing inclined edge crack under impact load[J].Journal of China Coal Society,2010,35(9):1456-1460.
[3]李术才,朱维申.复杂应力状态下断续节理岩体断裂损伤机理研究及其应用[J].岩石力学与工程学报,1999,18(2):142-146.LI Shu-cai,ZHU Wei-shen.Fracture damage mechanism of discontinuous jointed rock mass under the state of complex stress and its application[J].Chinese Journal of Rock Mechanics and Engineering,1999,18(2):142-146.
[4]李战鲁,王启智.加载速率对岩石动态断裂韧度影响的实验研究[J].岩土工程学报,2006,28(16):2116-2120.LI Zhan-lu,WANG Qi-zhi.Experimental research on effect of loading rate for dynamic fracture toughness of rock[J].Chinese Journal of Geotechnical Engineering,2006,28(16):2116-2120.
[5]宫凤强,陆道辉,李夕兵,等.动力扰动下预静载硬岩断裂的增韧和减韧效应[J].岩石力学与工程学报,2014,33(9):1905-1915.GONG Feng-qiang,LU Dao-hui,LI Xi-bing,et al.Toughness increasing or decreasing effect of hard rock fracture with pre-static loading under dynamic disturbance[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(9):1905-1915.
[6]宋义敏,何爱军,王泽军,等.冲击载荷作用下岩石动态断裂试验研究[J].岩土力学,2015,36(4):965-970.SONG Yi-min,HE Ai-jun,WANG Ze-jun,et al.Experiment study of the dynamic fractures of rock under impact loading[J].Rock and Soil Mechanics,2015,36(4):965-970.
[7]代树红,马胜利,潘一山,等.数字散斑相关方法测定岩石I型应力强度因子[J].岩石力学与工程学报,2012,31(12):2501-2507.DAI Shu-hong,MA Sheng-li,PAN Yi-shan,et al.Evaluation of mode I stress intensity factor of rock utilizing digital speckle correlation method[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(12):2501-2507.
[8]COSTIN L S.Static and dynamic fracture behavior of oil shale[M]//Fracture Mechanics for Ceramics,Rock and Concrete.[S.l.]:[s.n.],1981:169-184.
[9]WU M B.Effects of laoding rates on fracutre toughness of rock[J].Mech Practice,1986,10(2):21-24.
[10]BAZANT Z P,BAI S P,GETTU R.Fracture of rock:Effect of loading rate[J].Engineering Fracture Mechanics,1993,45(3):393-411.
[11]左建平,柴能斌,周宏伟.不同深度玄武岩的三点弯曲细观破坏实验研究[J].岩石力学与工程学报,2013,32(4):689-695.下转第4384页ZUO Jian-ping,CHAI Neng-bin,ZHOU Hong-wei.Investigation on failure behavior of basalt from different depths based on three-point bending mesoexperiments[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(4):689-695.
[12]杨圣奇,蒋昱州,温森.两条断续预制裂纹粗晶大理岩强度参数的研究[J].工程力学,2008,25(12):127-134.YANG Sheng-qi,JIANG Yu-zhou,WEN Sen.Study on the strength parameters of coarse marble with two preexisting cracks[J].Engineering Mechanics,2008,25(12):127-134.
[13]张盛,王启智,梁亚磊.裂缝长度对岩石动态断裂韧度测试值影响的研究[J].岩石力学与工程学报,2009,28(8):1691-1696.ZHANG Sheng,WANG Qi-zhi,LIANG Ya-lei.Research on influence of crack length on test values of rock dynamic fracture toughness[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(8):1691-1696.
[14]朱万成,黄志平,唐春安,等.含预制裂纹巴西盘试样破裂模式的数值模拟[J].岩土力学,2004,25(10):1609-1612.ZHU Wan-cheng,HUANG Zhi-ping,TANG Chun-an,et al.Numerical simulation on failure process of precracked Brazilian disk specimen of rock[J].Rock and Soil Mechanics,2004,25(10):1609-1612.
[15]代树红,马胜利,潘一山.数字图像相关法测定岩石Ⅰ-Ⅱ复合型裂纹应力强度因子[J].岩土工程学报,2013,35(7):1362-1368.DAI Shu-hong,MA Sheng-li,PAN Yi-shan.Evaluation of mixed-modeⅠ-Ⅱstress intensity factors of rock utilizing digital image correlation method[J].Chinese Journal of Geotechnical Engineering,2013,35(7):1362-1368.
[2]岳中文,杨仁树,孙中辉,等.含倾斜边裂纹岩石冲击断裂模拟试验[J].煤炭学报,2010,35(9):1456-1460.YUE Zhong-wen,YANG Ren-shu,SUN Zhong-hui,et al.Simulation experiment of rock fracture containing inclined edge crack under impact load[J].Journal of China Coal Society,2010,35(9):1456-1460.
[3]李术才,朱维申.复杂应力状态下断续节理岩体断裂损伤机理研究及其应用[J].岩石力学与工程学报,1999,18(2):142-146.LI Shu-cai,ZHU Wei-shen.Fracture damage mechanism of discontinuous jointed rock mass under the state of complex stress and its application[J].Chinese Journal of Rock Mechanics and Engineering,1999,18(2):142-146.
[4]李战鲁,王启智.加载速率对岩石动态断裂韧度影响的实验研究[J].岩土工程学报,2006,28(16):2116-2120.LI Zhan-lu,WANG Qi-zhi.Experimental research on effect of loading rate for dynamic fracture toughness of rock[J].Chinese Journal of Geotechnical Engineering,2006,28(16):2116-2120.
[5]宫凤强,陆道辉,李夕兵,等.动力扰动下预静载硬岩断裂的增韧和减韧效应[J].岩石力学与工程学报,2014,33(9):1905-1915.GONG Feng-qiang,LU Dao-hui,LI Xi-bing,et al.Toughness increasing or decreasing effect of hard rock fracture with pre-static loading under dynamic disturbance[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(9):1905-1915.
[6]宋义敏,何爱军,王泽军,等.冲击载荷作用下岩石动态断裂试验研究[J].岩土力学,2015,36(4):965-970.SONG Yi-min,HE Ai-jun,WANG Ze-jun,et al.Experiment study of the dynamic fractures of rock under impact loading[J].Rock and Soil Mechanics,2015,36(4):965-970.
[7]代树红,马胜利,潘一山,等.数字散斑相关方法测定岩石I型应力强度因子[J].岩石力学与工程学报,2012,31(12):2501-2507.DAI Shu-hong,MA Sheng-li,PAN Yi-shan,et al.Evaluation of mode I stress intensity factor of rock utilizing digital speckle correlation method[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(12):2501-2507.
[8]COSTIN L S.Static and dynamic fracture behavior of oil shale[M]//Fracture Mechanics for Ceramics,Rock and Concrete.[S.l.]:[s.n.],1981:169-184.
[9]WU M B.Effects of laoding rates on fracutre toughness of rock[J].Mech Practice,1986,10(2):21-24.
[10]BAZANT Z P,BAI S P,GETTU R.Fracture of rock:Effect of loading rate[J].Engineering Fracture Mechanics,1993,45(3):393-411.
[11]左建平,柴能斌,周宏伟.不同深度玄武岩的三点弯曲细观破坏实验研究[J].岩石力学与工程学报,2013,32(4):689-695.下转第4384页ZUO Jian-ping,CHAI Neng-bin,ZHOU Hong-wei.Investigation on failure behavior of basalt from different depths based on three-point bending mesoexperiments[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(4):689-695.
[12]杨圣奇,蒋昱州,温森.两条断续预制裂纹粗晶大理岩强度参数的研究[J].工程力学,2008,25(12):127-134.YANG Sheng-qi,JIANG Yu-zhou,WEN Sen.Study on the strength parameters of coarse marble with two preexisting cracks[J].Engineering Mechanics,2008,25(12):127-134.
[13]张盛,王启智,梁亚磊.裂缝长度对岩石动态断裂韧度测试值影响的研究[J].岩石力学与工程学报,2009,28(8):1691-1696.ZHANG Sheng,WANG Qi-zhi,LIANG Ya-lei.Research on influence of crack length on test values of rock dynamic fracture toughness[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(8):1691-1696.
[14]朱万成,黄志平,唐春安,等.含预制裂纹巴西盘试样破裂模式的数值模拟[J].岩土力学,2004,25(10):1609-1612.ZHU Wan-cheng,HUANG Zhi-ping,TANG Chun-an,et al.Numerical simulation on failure process of precracked Brazilian disk specimen of rock[J].Rock and Soil Mechanics,2004,25(10):1609-1612.
[15]代树红,马胜利,潘一山.数字图像相关法测定岩石Ⅰ-Ⅱ复合型裂纹应力强度因子[J].岩土工程学报,2013,35(7):1362-1368.DAI Shu-hong,MA Sheng-li,PAN Yi-shan.Evaluation of mixed-modeⅠ-Ⅱstress intensity factors of rock utilizing digital image correlation method[J].Chinese Journal of Geotechnical Engineering,2013,35(7):1362-1368.