热应力与膨胀力耦合作用下岩石破裂机理的数值模拟研究
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摘要
基于静态破碎剂破岩机理,运用数值模拟方法研究了内部含圆孔的方形岩样在热应力与膨胀力耦合作用下的破坏过程,重点分析了热应力对材料破坏机理的影响,并与物理实验进行了比较。结果表明:在内部热应力与膨胀力耦合作用下,模型中的两条裂纹萌生于垂直于模型边缘的孔径方向上的某个位置,而不是圆孔周围或者模型边缘,并同时向内和向外扩展至模型的内壁和外壁。随着模型热传导系数的增大,起裂位置向模型边缘移动;随着静态破碎剂膨胀系数的增大,起裂位置向圆孔周围移动。同时也研究了相同模型在只有热应力与只有膨胀力作用时的应力场,发现在此模型中热应力对起裂位置和减少裂纹数量有重要影响,耦合作用下的模型破坏是只有热应力作用和只有膨胀力作用的一种综合作用结果。
Based on the mechanism of rock failure induced by static cracking agent(SCA), a numerical simulation test was carried out to study the failure process of a square rock sample containing an internal round hole under the coupling effect of thermal stress and inner pressure, with a focus on the effect of thermal stress on the material's failure mechanism. The failure process of the model was then compared with that observed in a physical experiment. The results indicate that under coupling effect of thermal stress and inner pressure, two cracks started at positions between the surface of the hole and the edge of the model, rather than around the two boundaries,and then propagated radially in two directions: inward to the hole's surface and outward to the edge of the model. The initial locations of the cracks got closer to the edge of the model as the thermal conductivity of the model increased. As the expansive coefficient of static cracking agent increased, the initial locations gradually approached the hole. Moreover, the stress field of the model subjected to only thermal stress or inner pressure respectively was investigated. The results suggest that the thermal stress has an important impact on the initial locations and number of cracks. And the failure of the model under coupling effect was the result of the combined effect of individual thermal stress and inner pressure.
Based on the mechanism of rock failure induced by static cracking agent(SCA), a numerical simulation test was carried out to study the failure process of a square rock sample containing an internal round hole under the coupling effect of thermal stress and inner pressure, with a focus on the effect of thermal stress on the material's failure mechanism. The failure process of the model was then compared with that observed in a physical experiment. The results indicate that under coupling effect of thermal stress and inner pressure, two cracks started at positions between the surface of the hole and the edge of the model, rather than around the two boundaries,and then propagated radially in two directions: inward to the hole's surface and outward to the edge of the model. The initial locations of the cracks got closer to the edge of the model as the thermal conductivity of the model increased. As the expansive coefficient of static cracking agent increased, the initial locations gradually approached the hole. Moreover, the stress field of the model subjected to only thermal stress or inner pressure respectively was investigated. The results suggest that the thermal stress has an important impact on the initial locations and number of cracks. And the failure of the model under coupling effect was the result of the combined effect of individual thermal stress and inner pressure.
引文
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[2]周克群,楚泽涵,张元中,等.岩石热开裂与检测方法研究[J].岩石力学与工程学报,2000,19(4):412-416.Zhou K Q,Chu Z H,Zhang Y Zh,et al.Research of the detection method and thermal cracking of rock[J].Chinese Journal of Rock Mechanics and Engineering,2000,19(4):412-416.(in Chinese)
[3]吴晓东,刘均荣.岩石热开裂影响因素分析[J].石油钻探技术,2004,31(5):24-27.Wu X D,Liu J R.Factors on the thermal cracking of rocks[J].Petroleum Drilling Techniques,2004,31(5):24-27.(in Chinese)
[4]Ranc N,Palin-L T,Paris P C.Thermal effect of plastic dissipation at the crack tip on the stress intensity factor under cyclic loading[J].Engineering Fracture Mechanics,2011,78(6):961-972.
[5]Nabavi S M,Shahani A R.Thermal stress intensity factors for a cracked cylinder under transient thermal loading[J].International Journal of Pressure Vessels and Piping,2009,86(2):153-163.
[6]杨更社,张全胜,蒲毅彬.冻结温度对岩石细观损伤扩展特性影响研究初探[J].岩土力学,2004,25(9):1409-1412.Yang G Sh,Zhang Q Sh,Pu Y B.Preliminary study on meso-damage propagation characteristics of rock under condition of freezing temperature[J].Rock and Soil Mechanics,2004,25(9):1409-1412.(in Chinese)
[7]康健.随机介质固热耦合数学模型与岩石热破裂数值实验[D].阜新:辽宁工程技术大学,2004.Kang J.Random non-homogeneous solid-head coupled model and numerical tests on hot cracking of rock[D].Fuxin:Liaoning Technical University,2004.(in Chinese)
[8]武晋文.固-热耦合作用下岩体破裂及声发射特征试验研究[D].太原:太原理工大学,2012.Wu J W.Experimental study on fracture and acoustic emission characteristics of rock mass under the action of mechanical-thermo coupling[D].Taiyuan:Taiyuan University of Technology,2012.(in Chinese)
[9]唐世斌.混凝土温湿型裂缝开裂过程细观数值模型研究[D].大连:大连理工大学,2009.Tang Sh B.Mesoscopic numerical model of thermo-hygro cracking process in concrete[D].Dalian:Dalian University of Technology,2009.(in Chinese)
[10]王建鹏.静态破剂碎破岩机理研究[J].中国矿业,2008,17(11):90-92.Wang J P.Research on broken rock mechanism of static state dose[J].China Mining Magazine,2008,17(11):90-92.(in Chinese)
[11]杨仁树,孙中辉,佟强,等.静态破碎剂膨胀作用下试件裂纹扩展试验研究[J].工程爆破,2010,16(3):7-11.Yang R Sh,Sun Zh H,Tong Q,et al.Experiment of crack propagation in test specimen under expansive action of static cracking agent[J].Engineering Blasting,2010,16(3):7-11.(in Chinese)
[12]郝兵元,黄辉,冯子军,等.单轴应力状态下石灰岩体静态破碎裂纹演化规律及应用[J].煤炭学报,2014,39(12):2397-2404.Hao B Y,Huang H,Feng Z J,et al.Crack evolution of limestone induced by static demolition at axial stress and its application[J].Journal of China Coal Society,2014,39(12):2397-2404.(in Chinese)
[13]Hinze J,Nelson A.Enhancing performance of soundless chemical demolition agents[J].Journal of Construction Engineering and Management,1996,122(2):193-195.
[14]Gambatese J A.Controlled concrete demolition using expansive cracking agents[J].Journal of Construction Engineering and Management,2003,129(1):98-104.
[15]Arshadnejad S,Goshtasbi K,Aghazadeh J.A model to determine hole spacing in the rock fracture process by non-explosive expansion material[J].International Journal of Minerals,Metallurgy and Materials,2011,18(5):509-514.
[16]Laefer D F,Ambrozevitch-C N,Huynh M P,et al.Expansive fracture agent behaviour for concrete(?)acking[J].Magazine of Concrete Research,2010,62(6):443-452.
[17]Tang C.Numerical simulation of progressive rock failure and associated seismicity[J].International Journal of Rock Mechanics and Mining Sciences,1997,34(2):249-261.
[18]Ishida T,Suemune K,Fukui H,et al.Effect of thermal stress in fracturing by expansive cement agent in comparison with a borehole pressurizing test and a heater test[C]//Proceedings of the 40th U.S.Symposium on Rock Mechanics:Rock Mechanics for Energy,Mineral and Infrastructure Development in the Northern Regions.Alaska:American Rock Mechanics Association,2005.