基于岩石变形声发射实验结果讨论岩石失稳的可预测性
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摘要
根据室内岩石变形声发射实验结果,计算了声发射序列的地震非均匀度GL值,并以此探讨了岩石破裂失稳的可预测性。在双轴压缩、等速率加载条件下,含障碍体断层、挤压雁列断层和Ⅲ型剪切断层等非连续岩石标本在临近滑动失稳前,声发射活动均出现了显著的均匀—非均匀的状态变化,表现为GL值出现持续大于1的异常变化,GL值异常的位置与破裂成核部位相重合,并与断层走向一致;改变统计窗长、窗内分割数及能级统计下限计算声发射序列的GL值,结果表明,GL值计算结果具有一定的稳定性。综合分析认为,地震非均匀度(GL值)可以较好地刻画岩石失稳前夕因破裂成核导致的声发射活动在时间分布上的状态变化,GL值持续异常是岩石失稳的显著性标志,对预测岩石失稳具有较好的指示意义。
Based on experiment result of sound emission as rock distortion indoors,the earthquake non-uniformity GL value of sound emission sequence is calculated and thus the predictability of rock steady failure is discussed.Under the condition of double axes compressing and equal velocity loading,nearly before slide steady failure of non-continuous rock samples,such as fault containing obstacle,compressive en echelon fault and Ⅲ-model shear fault etc.,all the sound emission activities appear obvious change in state,from uniformity to non-uniformity.It shows that the GL values vary abnormally,which is continuously larger than 1.The location of anomaly of GL value superposes with the position of rupture in core nucleating,with the same strike of the fault.The result indicates that the calculated results of GL value are steady in some degree,no matter the GL values of sound emission sequence are calculated at with different statistic window lengths,division number within the window or lower statistic limit of energy level.It is thought,through synthetic analysis,that earthquake non-uniformity(GL value)can well describe the state change on time distribution of sound emission activities,caused by rupture in core nucleating,just before steady failure of rock.Continuous anomaly in GL value is a notable indication to rock steady failure and useful for predicting rock steady failure.
Based on experiment result of sound emission as rock distortion indoors,the earthquake non-uniformity GL value of sound emission sequence is calculated and thus the predictability of rock steady failure is discussed.Under the condition of double axes compressing and equal velocity loading,nearly before slide steady failure of non-continuous rock samples,such as fault containing obstacle,compressive en echelon fault and Ⅲ-model shear fault etc.,all the sound emission activities appear obvious change in state,from uniformity to non-uniformity.It shows that the GL values vary abnormally,which is continuously larger than 1.The location of anomaly of GL value superposes with the position of rupture in core nucleating,with the same strike of the fault.The result indicates that the calculated results of GL value are steady in some degree,no matter the GL values of sound emission sequence are calculated at with different statistic window lengths,division number within the window or lower statistic limit of energy level.It is thought,through synthetic analysis,that earthquake non-uniformity(GL value)can well describe the state change on time distribution of sound emission activities,caused by rupture in core nucleating,just before steady failure of rock.Continuous anomaly in GL value is a notable indication to rock steady failure and useful for predicting rock steady failure.
引文
[1]M og i K.S tudy of e lastic shocks caused by the fracture ofheterogeneous m ateria ls and its re lation to earthquakephenom ena[J].Bu ll.E arthq.R es.Inst.T okyo U n iver.,1962,40:125-173.
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[3]Scho lz C H.T he frequency-m agn itude re lation ofm icrofracturing in rock and its re lation to earthquakes[J].Bu ll.Se ism o l.Soc.Am.,1968,58:399-415.
[4]耿乃光.b值模拟实验的进展和我国b值模拟实验的开端[J].地震学报,1986,8(3):330-333.
[5]W ang T F,B raceW F.T herm a l expans ion of rocks:Som em easurem en ts at h igh pressure[J].T ectonophys ics,1979,57:95-117.
[6]Chen Y ong,W ang G Y,T herm a lly induced acousticem iss ion in W esterly gran ite,G eophys[J].R es.L ett.,1980,7:1089-1092.
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[8]马胜利,蒋海昆,扈小燕,等.基于声发射实验结果讨论大震前地震活动平静现象的机制[J].地震地质,2004,26(3):426-435.
[9]马胜利,雷兴林,刘力强.标本非均匀性对岩石变形声发射时空分布的影响及其地震学意义[J].地球物理学报,2004,47(1):127-131.
[10]马胜利,刘力强,马谨,等.基于实验结果讨论断层破裂与强震物理过程的若干问题[J].地学前缘,2003,10(特刊):225-232.
[11]刘力强,马胜利,马谨,等.不同结构岩石标本声发射b值和频谱的时间扫描及其物理意义[J].地震地质,2001,23(4):481-492.
[12]李志雄,张国民,傅征祥,等.中强地震前地震频次-震级关系式拟合优度变化的研究[J].中国地震,1996,12(3):229-236.
[13]李志雄,高旭.地震非均匀度的研究及在强震中期预报中的应用[J].地震,1994(6):11-17.
[14]傅征祥.中国大陆东部强震活动时间过程的不均匀性[J].中国地震,1991,7(2):1-11.
[15]蒋海昆,张流,周永胜.不同围压条件下花岗岩的声发射序列特征及其地震学意义[J].地球物理学报,2000,43(6):812-826.
[16]刘力强,马胜利,马谨,等.岩石构造对声发射统计特征的影响[J].地震地质,1999,21(4):377-386.
[17]蒋海昆,马胜利,张流,等.含障碍体平直断层标本变形过程中群体微破裂事件的时空演化特征[J].地球物理学报,2003,46(2):209-216.
[2]M og i K.Source location of e lastic shocks in thefracturing process in rock(1)[J].Bu ll.E arthq.R es.Inst.T okyo U n iver.,1968,46:1103-1125.
[3]Scho lz C H.T he frequency-m agn itude re lation ofm icrofracturing in rock and its re lation to earthquakes[J].Bu ll.Se ism o l.Soc.Am.,1968,58:399-415.
[4]耿乃光.b值模拟实验的进展和我国b值模拟实验的开端[J].地震学报,1986,8(3):330-333.
[5]W ang T F,B raceW F.T herm a l expans ion of rocks:Som em easurem en ts at h igh pressure[J].T ectonophys ics,1979,57:95-117.
[6]Chen Y ong,W ang G Y,T herm a lly induced acousticem iss ion in W esterly gran ite,G eophys[J].R es.L ett.,1980,7:1089-1092.
[7]郝晋升,刘晓红,李纪汉.华北地区四种岩石在高压下的破坏特征[J].地震学报,1986,8(4):404-411.
[8]马胜利,蒋海昆,扈小燕,等.基于声发射实验结果讨论大震前地震活动平静现象的机制[J].地震地质,2004,26(3):426-435.
[9]马胜利,雷兴林,刘力强.标本非均匀性对岩石变形声发射时空分布的影响及其地震学意义[J].地球物理学报,2004,47(1):127-131.
[10]马胜利,刘力强,马谨,等.基于实验结果讨论断层破裂与强震物理过程的若干问题[J].地学前缘,2003,10(特刊):225-232.
[11]刘力强,马胜利,马谨,等.不同结构岩石标本声发射b值和频谱的时间扫描及其物理意义[J].地震地质,2001,23(4):481-492.
[12]李志雄,张国民,傅征祥,等.中强地震前地震频次-震级关系式拟合优度变化的研究[J].中国地震,1996,12(3):229-236.
[13]李志雄,高旭.地震非均匀度的研究及在强震中期预报中的应用[J].地震,1994(6):11-17.
[14]傅征祥.中国大陆东部强震活动时间过程的不均匀性[J].中国地震,1991,7(2):1-11.
[15]蒋海昆,张流,周永胜.不同围压条件下花岗岩的声发射序列特征及其地震学意义[J].地球物理学报,2000,43(6):812-826.
[16]刘力强,马胜利,马谨,等.岩石构造对声发射统计特征的影响[J].地震地质,1999,21(4):377-386.
[17]蒋海昆,马胜利,张流,等.含障碍体平直断层标本变形过程中群体微破裂事件的时空演化特征[J].地球物理学报,2003,46(2):209-216.
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