水平应力差对砂岩起裂破坏规律的声发射试验研究
|
摘要
煤矿坚硬顶板的压裂对防止冲击矿压以及保证矿井的安全开采具有重大的意义。对于深部矿井而言,坚硬顶板预制裂缝定向压裂技术的研究尤为重要。通过声发射试验研究不同预制裂缝方位角条件下水平应力差对裂缝起裂以及扩展的影响规律。实验结果表明:在裂缝开裂扩展过程中,岩石的强度和完整性逐步降低,裂缝开裂所需要的能量和压力不断减小;随着水平应力差的增加,砂岩从稳定到破坏所需的能量愈大;当水平应力差固定时,预制裂缝方位角为60°时,砂岩发生破坏所需的能量要高于裂缝方位角为30°时砂岩发生破坏所需的能量;随着RA和AF之间的比例的增大,剪切破坏所占比例不断提高。
The fracturing of hard roofs in coal mines is of great significance in preventing rock bursts and ensuring the safe mining of mines.For deep mines,the research on the directional fracturing technology of prefabricated cracks in hard roofs is particularly important.Therefore,the acoustic emission test was used to study the influence of horizontal stress difference on crack initiation and propagation under different prefabricated fracture azimuth angles.The test results were concluded as follows.First of all,the strength and integrity of the rock gradually reduced during crack propagation,and the energy and pressure required for cracking kept decreasing.Secondly,with the increase of the horizontal stress difference,the energy required for the sandstone from stabilization to failure was increasing.Then,when the horizontal stress difference was fixed,the energy required for the sandstone to break at the prefabricated fracture azimuth of 60°was higher than that at prefabricated fracture azimuth of 30°.Finally,as the ratio between RAand AFincreased,the proportion of shear damage continued to increase.
The fracturing of hard roofs in coal mines is of great significance in preventing rock bursts and ensuring the safe mining of mines.For deep mines,the research on the directional fracturing technology of prefabricated cracks in hard roofs is particularly important.Therefore,the acoustic emission test was used to study the influence of horizontal stress difference on crack initiation and propagation under different prefabricated fracture azimuth angles.The test results were concluded as follows.First of all,the strength and integrity of the rock gradually reduced during crack propagation,and the energy and pressure required for cracking kept decreasing.Secondly,with the increase of the horizontal stress difference,the energy required for the sandstone from stabilization to failure was increasing.Then,when the horizontal stress difference was fixed,the energy required for the sandstone to break at the prefabricated fracture azimuth of 60°was higher than that at prefabricated fracture azimuth of 30°.Finally,as the ratio between RAand AFincreased,the proportion of shear damage continued to increase.
引文
[1]窦林名,刘贞堂,曹胜根,等.坚硬顶板对冲击矿压危险地影响分析[J].煤矿开采,2003,8(2):58-60.
[2]李志伟,郤保平,郭庆华,等.煤储层水力压裂裂隙沿井孔起裂扩展的影响因素试验研究[J].矿业研究与开发,2015,35(3):13-15.
[3] Freeman C M,Moridis G,Ilk D,et al.A numerical study of performance for tight gas and shale gas reservoir systems[J].Journal of Petroleum Science and Engineering,2013,108(8):22-39.
[4] ZHAI Cheng,LI Min,SUN Chen,et al.Guiding-controlling technology of coal seam hydraulic fracturing fractures extension[J].International Journal of Mining Science and Technology,2012,22(6):831-836.
[5] Ohno K.,Ohtsu M.Crack classification in concrete based on acoustic emission[J].Construction and Building Materials,2010(24):2339-2346.
[6] Mao R B,Feng Z J,Liu Z H,et al.Laboratory hydraulic fracturing test on large-scale pre-cracked granite specimens[J].Journal of Natural Gas Science&Engineering,2017,44.
[7]郭建春,何颂根,邓燕.弹塑性地层水力压裂起裂模式及起裂压力研究[J].岩土力学,2016,37(2):407-414.
[8]严成增,郑宏,孙冠华,等.基于FDEM-Flow研究地应力对水力压裂的影响[J].岩土力学,2016,37(1):237-246.
[9]孙可明,张树翠.水力裂缝遇斜交层理弱面的扩展规律解析分析[J].岩石力学与工程学报,2016(S2):3535-3539.
[10]李芷,贾长贵,杨春和,等.页岩水力压裂水力裂缝与层理面扩展规律研究[J].岩石力学与工程学报,2016,34(1):12-20.
[2]李志伟,郤保平,郭庆华,等.煤储层水力压裂裂隙沿井孔起裂扩展的影响因素试验研究[J].矿业研究与开发,2015,35(3):13-15.
[3] Freeman C M,Moridis G,Ilk D,et al.A numerical study of performance for tight gas and shale gas reservoir systems[J].Journal of Petroleum Science and Engineering,2013,108(8):22-39.
[4] ZHAI Cheng,LI Min,SUN Chen,et al.Guiding-controlling technology of coal seam hydraulic fracturing fractures extension[J].International Journal of Mining Science and Technology,2012,22(6):831-836.
[5] Ohno K.,Ohtsu M.Crack classification in concrete based on acoustic emission[J].Construction and Building Materials,2010(24):2339-2346.
[6] Mao R B,Feng Z J,Liu Z H,et al.Laboratory hydraulic fracturing test on large-scale pre-cracked granite specimens[J].Journal of Natural Gas Science&Engineering,2017,44.
[7]郭建春,何颂根,邓燕.弹塑性地层水力压裂起裂模式及起裂压力研究[J].岩土力学,2016,37(2):407-414.
[8]严成增,郑宏,孙冠华,等.基于FDEM-Flow研究地应力对水力压裂的影响[J].岩土力学,2016,37(1):237-246.
[9]孙可明,张树翠.水力裂缝遇斜交层理弱面的扩展规律解析分析[J].岩石力学与工程学报,2016(S2):3535-3539.
[10]李芷,贾长贵,杨春和,等.页岩水力压裂水力裂缝与层理面扩展规律研究[J].岩石力学与工程学报,2016,34(1):12-20.