三峡井网的布设与观测井建设
|
摘要
介绍了我国第 1个以监测水库诱发地震的地下水前兆为目标的三峡井网布设与观测井建设的科学思路及其实施结果。由于水库蓄水引发一定震级的诱发地震时 ,会引起含水层应力应变状态及与其相关的孔隙压力变化 ,并导致观测井水位的异常变化 ,为此利用震级 (MS)、孕震断层长度(L)与应力应变场变化范围 (R)的关系确定了井数与井间距 ;井位的选择 ,主要依据了地下水动态为映震灵敏条件的科学认识 ,选择了断裂带及其应力易集中的端点、拐点与交点等特殊构造部位 ;井深与井孔结构的确定 ,遵循了在有限投资的前提下 ,尽可能揭露封闭性好的承压含水层 (带 )和尽可能减少地表水文气象因素干扰的原则。按照上述思想与原理 ,在坝区和库首区各布设了 4口井 ,井深为10 0～ 2 0 0m ,均揭露出封闭性较好的承压含水层 (带 )。初步观测结果表明 ,三峡井网的布设与观测井的建设较为成功 ,为诱发地震前兆监测奠定了良好的基础
The Three Gorges well network is the first well network in China established specially for the purpose of monitoring the groundwater precursors of reservoir induced earthquake. The basic consideration of the establishment of this well network is based on the fact that the seismic event of certain magnitude induced by the storage of reservoir may cause the changes of stress and strain states of the aquifer, as well as the corresponding pore water pressures. The number and spacing of the wells are determined according to the magnitude of earthquake ( M S), the length of seismogenic fault ( L ) and the variation range of stress strain field ( R ). The selection of well locations is based on the groundwater behaviors sensitive to earthquakes. Such peculiar tectonic sites as the termination, inflection and junction of fault zones are selected for well location. The depth and structure of the wells are decided according to the requirement that the well may reveal well enclosed confined aquifer and minimize the influence of surface water and hydro atmospheric factors on the premise of limit funds. According to the afore mentioned considerations, 4 wells are drilled at the dam site and 4 wells at the head of the Three Gorges Reservoir. The depths of the wells are between 100～ 200m, and all the wells expose well enclosed confined aquifer. Primary observations show that the arrangement of the Three Gorges well network and the establishment of the observation wells are relatively successful. They form a good base for monitoring the precursor of reservoir induced earthquake.
The Three Gorges well network is the first well network in China established specially for the purpose of monitoring the groundwater precursors of reservoir induced earthquake. The basic consideration of the establishment of this well network is based on the fact that the seismic event of certain magnitude induced by the storage of reservoir may cause the changes of stress and strain states of the aquifer, as well as the corresponding pore water pressures. The number and spacing of the wells are determined according to the magnitude of earthquake ( M S), the length of seismogenic fault ( L ) and the variation range of stress strain field ( R ). The selection of well locations is based on the groundwater behaviors sensitive to earthquakes. Such peculiar tectonic sites as the termination, inflection and junction of fault zones are selected for well location. The depth and structure of the wells are decided according to the requirement that the well may reveal well enclosed confined aquifer and minimize the influence of surface water and hydro atmospheric factors on the premise of limit funds. According to the afore mentioned considerations, 4 wells are drilled at the dam site and 4 wells at the head of the Three Gorges Reservoir. The depths of the wells are between 100～ 200m, and all the wells expose well enclosed confined aquifer. Primary observations show that the arrangement of the Three Gorges well network and the establishment of the observation wells are relatively successful. They form a good base for monitoring the precursor of reservoir induced earthquake.
引文
郭增建,秦保燕.1979.震源物理〔M〕.北京:地震出版社.
GUOZeng jian,QINBao yan.1979.EarthquakeSourcePhysics〔M〕.SeismologicalPress,Beijing(inChinese).
国家地震局震害防御司.1990.地震工作手册附录Ⅰ〔Z〕.北京:地震出版社.603─604.
DepartmentofEarthquakeHazardPrevention,StateSeismologicalBureau.1990.ManualofSeismologicalWork(AppendixⅠ)〔Z〕.SeismologicalPress,Beijing.603─604(inChinese).
韩晓光,李容川.1984.三峡地区地壳应力场与地震活动〔J〕.华北地震科学,2(1):53─57.
HANXiao guang,LIRong chuan.1984.ThecrustalstressfieldandtheearthquakeactivitiesinSanxiaregion〔J〕.NorthChinaEarthquakeSciences,2(1):53─57(inChinese).
胡毓良,杨清源,陈献程.1998.长江三峡工程周边地区的采矿诱发地震〔J〕.地震地质,20(4):349─360.
HUYu liang,YANGQing yuan,CHENXian cheng.1998.Mining inducedearthquakesintheareaaroundtheYangtzeGorgeProject〔J〕.SeismologyandGeology,20(4):349─360(inChinese).
李安然.1984.长江三峡地区地震地质环境与水库诱发地震问题〔J〕.地震科学研究,2(1):8─14.
LIAn ran.1984.TheseismologicalconditionsofSanxia,Changjiangregionandinducedearthquakesbyreservoir〔J〕.JournalofEarthquakeStudies,2(1):8─14(inChinese).
严尊国.1994.长江三峡及邻近区地震活动研究〔J〕.地壳形变与地震,14(2):47─55.
YANZun guo.1994.StudyonseismicityintheYangtzeGorgesanditsvicinity〔J〕.CrustalDeformationandEarth quakes,14(2):47─55(inChinese).
周明礼,荣建东,周坤根.1981.试论长江三峡地区的地壳运动与地震〔J〕.地壳形变与地震,1(4):65─74.
ZHOUMing li,RONGJian dong,ZHOUKun gen.1981.DiscussiononcrustalmovementsandearthquakesinThreeGorgesareas,YangtzeRiver〔J〕.CrustalDeformationandEarthquakes,1(4):65─74(inChinese).
GUOZeng jian,QINBao yan.1979.EarthquakeSourcePhysics〔M〕.SeismologicalPress,Beijing(inChinese).
国家地震局震害防御司.1990.地震工作手册附录Ⅰ〔Z〕.北京:地震出版社.603─604.
DepartmentofEarthquakeHazardPrevention,StateSeismologicalBureau.1990.ManualofSeismologicalWork(AppendixⅠ)〔Z〕.SeismologicalPress,Beijing.603─604(inChinese).
韩晓光,李容川.1984.三峡地区地壳应力场与地震活动〔J〕.华北地震科学,2(1):53─57.
HANXiao guang,LIRong chuan.1984.ThecrustalstressfieldandtheearthquakeactivitiesinSanxiaregion〔J〕.NorthChinaEarthquakeSciences,2(1):53─57(inChinese).
胡毓良,杨清源,陈献程.1998.长江三峡工程周边地区的采矿诱发地震〔J〕.地震地质,20(4):349─360.
HUYu liang,YANGQing yuan,CHENXian cheng.1998.Mining inducedearthquakesintheareaaroundtheYangtzeGorgeProject〔J〕.SeismologyandGeology,20(4):349─360(inChinese).
李安然.1984.长江三峡地区地震地质环境与水库诱发地震问题〔J〕.地震科学研究,2(1):8─14.
LIAn ran.1984.TheseismologicalconditionsofSanxia,Changjiangregionandinducedearthquakesbyreservoir〔J〕.JournalofEarthquakeStudies,2(1):8─14(inChinese).
严尊国.1994.长江三峡及邻近区地震活动研究〔J〕.地壳形变与地震,14(2):47─55.
YANZun guo.1994.StudyonseismicityintheYangtzeGorgesanditsvicinity〔J〕.CrustalDeformationandEarth quakes,14(2):47─55(inChinese).
周明礼,荣建东,周坤根.1981.试论长江三峡地区的地壳运动与地震〔J〕.地壳形变与地震,1(4):65─74.
ZHOUMing li,RONGJian dong,ZHOUKun gen.1981.DiscussiononcrustalmovementsandearthquakesinThreeGorgesareas,YangtzeRiver〔J〕.CrustalDeformationandEarthquakes,1(4):65─74(inChinese).
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心