INFLUENCE OF PUMPING ON FOUR-COMPONENT BOREHOLE STRAIN AT TAI'AN SEISMIC STATION AND ITS INTERFERENCE MECHANISM          下载免费PDF全文

JIA Yuan  GAN Wei-jun  LI Jie  ZHU Cheng-lin  YIN Hai-tao  LU Shuang-ling  JU Jia-bin 《地震地质》2019,41(6):1429-1443

Four-component borehole strainmeter (FCBS) is one kind of high-precision borehole strain observation instruments invented in China. As a kind of near-surface deformation observation instrument, FCBS is also easily disturbed by the external environment factors. As a common factor, pumping has significant influence on FCBS observation. Existing studies mostly identify the pumping interference from the perspective of observation curve morphology, relatively few studies focus on its interference mechanism. In order to truly capture earthquake precursor information, it is necessary to study the interference mechanism. In recent years, RZB-3 type FCBS at Tai'an seismic station has been seriously affected by pumping, so it is necessary and also feasible to study the interference mechanism of pumping. Since the influence of pumping interference on borehole strainmeter is common, this work would be very practical and be used for reference by other borehole strain observation stations. We find that the original observation curves and observed surface strain, shear strain from RZB-3 type FCBS at Tai'an seismic station have the characteristics of synchronous change with the borehole water level, in which the linear correlation coefficient between the two observed shear strain curves and borehole water level reached 0.70 and 0.82 respectively. We further find that the principal strain direction of borehole and borehole water level after normalization meet the nonlinear function as y=1.217arctan(x)^0.224-0.284. The above phenomenon indicates that the observation of RZB-3 type FCBS at Tai'an seismic station is significantly affected by the borehole water level, and the influence is more obvious and the gradient is larger at the stage of low water level. Pumping interference often appears in low water level stage and changes the rock pore pressure state. Statistics show that pumping interference affects the borehole strain state. To investigate the interference mechanism of pumping to RZB-3 type FCBS at Tai'an seismic station, we take a known pumping as an example, in which we study the principal strain state of the borehole in three periods of normal pumping, interruption of pumping and resuming pumping respectively. During each period, we solve 3 parameters of the principal plane strain state, i.e. the maximum principal strain rate, the minimum principal strain rate and the maximum principal strain direction from four observation equations of FCBS by nonlinear iterative least squares algorithm. On the other hand, concentrated load model (CLM) is used to simulate the mechanical mechanism of pumping. Firstly, the depth of FCBS relative to pumping source and the concentrated load at pumping source are inversed, then, the strain state surrounding the pumping well, including the state at RZB-3 borehole, is simulated by forward modeling. By comparing these results, we find that: (1)The concentrated load at pumping source inversed by CLM during periods of normal pumping and resuming pumping are both located at or near the bottom of the pumping well, which is consistent with the actual situation, indicating that mechanism and degree of the influence of pumping on borehole strain are well simulated by CLM. (2)The observed strain state is consistent with the simulation result of pumping interference by forward modeling, indicating that the principal strain state of borehole calculated based on observation of FCBS reflects the true strain state of borehole under different pumping states.(3)The inversed concentrated load at pumping source during pumping periods is significant greater than the load of the pumped water, indicating that the pumping process has more significant influence on the pore pressure of rocks than the load of the pumped water. Even though CLM is an approximate simulation since it's based on some elastic assumptions, the interference mechanism of pumping on RZB-3 type FCBS at Tai'an seismic station is well explained, which is maybe very helpful for studying the influence of pumping interference on other deformation instruments, locating the unknown pumping source and studying the characteristics of pore pressure of rocks.  相似文献   

2019年甘肃张掖M5.0地震余震序列重定位          下载免费PDF全文

鞠慧超  张元生  刘旭宙 《地震工程学报》2019,41(6):1396-1401

本文使用祁连山主动源台网和甘肃省数字测震台网记录到的地震资料,应用双差定位方法和遗传算法对2019年甘肃张掖M5.0地震及其余震进行重定位,获得了30个地震事件的重定位结果,双差定位显示主震位置为38.502°N,100.254°E,震源深度14.7 km。重定位结果显示余震分布在昌马—俄博断裂,较为集中,震源深度主要分布在5～15 km范围内,余震序列沿SW—NE向空间分布。  相似文献   

层间软弱夹层发育的切向边坡失稳模式及稳定性研究     

赵晓  赵建军  巨能攀  肖华波 《地质灾害与环境保护》2006,17(3):110-114

通过系统分析边坡工程地质条件及岩体结构,采用定性分析结合有限元模拟研究了边坡变形破坏模式,并采用块体理论及极限平衡法系统分析边坡局部及整体稳定性。结果表明,切向边坡的变形破坏模式可以分为两类:深层变形破坏为受层间软弱夹层空间展布特征控制的块体失稳,浅表层破坏为局部块体失稳及强风化强卸荷带岩体沿最大剪应力带的滑移-拉裂变形。稳定性分析结果认为边坡浅表层岩体稳定性差,但发生深层破坏的可能性较小。  相似文献   

天山乌一号冰川物质平衡特征的统计分析   总被引：5，自引：1，他引：4  

鞠远江  魏遐  刘耕年 《干旱区地理》2006,29(1):76-80

利用天山乌鲁木齐河源一号冰川物质平衡的多年观测资料,通过数学统计方法提取主成分,获得影响该冰川物质平衡的主要因素,通过成分矩阵的旋转获得表示冰川物质平衡特征的两个主因子,其中第一主因子为影响冰川物质平衡的常年因子,代表该冰川的多年持续变化方向与趋势,第二主因子为影响冰川物质平衡的年际因子,代表该冰川在平衡年内的物质平衡变化特征。常年因子的持续下降反映了冰川持续后退的现实,年际因子在上世纪80年代中期以后突然强劲上升,实际上是冰川物质平衡水平提高,平衡年内积累量和消融量都增加的表现,清晰地指示了西北地区气候由暖干向暖湿的转型。常年因子是冰川物质平衡变化的主导因子,控制了冰川变化的方向。常年因子具有较好的周期性,以6年周期最为明显,但其形成原因尚不明。年际因子周期性不明显,但可以看出其周期与太阳黑子变化具有相关性,同时受到常年因子的影响。  相似文献   

河流相砂体精细描述在西湖凹陷某气田的应用     

张锡楠  程超  鞠颢  黄启彰 《中国地质调查》2020,7(5):25-32

西湖凹陷某气田钻井资料少,传统陆上利用多井点资料描述河流相储层展布的方法不适用该气田。前人关于该区为浅水三角洲平原分流河道沉积、储层横向上连片分布的认识过于宏观,不能指导气田的开发生产。研究从已钻井资料出发,充分利用海上高分辨率三维地震资料对河流相储层横向识别精度高、单一河道边界刻画清晰的特点,开展地震沉积学研究和单河道精细解释,识别出4期目的层单河道砂体,形成横向上逐渐向东迁移摆动、纵向上相互叠置的沉积演化模式。这一认识指导了地质模型优化,解决了生产井动静储量差异矛盾,能够有效指导气田开发生产。在海上少井条件下,利用地震沉积学方法进行河流相砂体精细描述的方法有较强的适用性。  相似文献   

东海黑潮PN和TK断面流量的多时间尺度变化特征          下载免费PDF全文

许达  马超  鞠霞 《海洋科学进展》2020,38(3):400-411

根据日本海洋数据中心提供的1972—2017年PN断面共181个航次和1987—2010年TK断面共92个航次的CTD调查资料,利用动力高度法估算了这2个断面的流量,分析了其季节、年际和长期变化特征。主要结果表明,PN断面流量季节变化为冬、春和夏季大而秋季小,TK断面流量季节变化为冬、夏季大而春、秋季小,二者共同点为最大(小)流量均出现在夏(秋)季。PN断面年平均流量的年际变化不明显,但冬季和夏季流量分别具有准3 a和准2 a的显著变化周期;TK断面年平均流量具有准4 a和准6 a的显著变化周期,冬季流量具有准4 a和准7 a的显著变化周期,但夏季流量无显著变化周期。此外,PN断面流量在1976年附近出现了一次较大幅度的增加。PN断面流量具有较大的长期增加趋势,增长率约为0.3 Sv/a,在1972—2017年增加了约13 Sv,结合NCEP海面风应力资料,结果显示,北太平洋更高纬度带(35°N和40°N)的风应力旋度对PN断面流量的影响更强。  相似文献   

吕宋海峡120°E断面水交换特征   总被引：5，自引：0，他引：5  

鲍献文  鞠霞  吴德星 《中国海洋大学学报(自然科学版)》2009,39(1)

利用2007年7～8月吕宋海峡120°E断面(18.5°N～21.5°N)CTD观测数据,分析了该断面的温度、盐度和密度分布特征,并用动力计箅方法计算了断面的流速,得到了通过该断面的海水体积通量.计算结果显示,通过断面的海水主要由南海向太平洋输送,总的交换量为3.15 Sv.19°30'N～20°30'N之间,南海水通过吕宋海峡进入太平洋,而19°30'N以南和20°30'N以北至21°30'N之间.海水由太平洋进入南海.此外,流出吕宋海峡的表层流速最大可达1.3 m/s,流入南海的表层流速最大可达60 cm/s,位于19°30'N以南.  相似文献   

附有限制条件的逐点压缩算法的设计与实现     

巨正平  王勇  郭广礼  齐建伟 《测绘通报》2009,(4)

讨论矢量数据压缩问题,着重介绍Douglas-Peucker算法,并分析该算法在矢量数据压缩过程中的局限性,提出附有限制条件的逐点压缩法.新的算法存满足给定限差的前提下,能够对曲线进行实时分析,并很好地考虑了目标曲线之间的相互关系.试验表明,该算法与Douglas-Peucker算法相比,不仪克服了后者在数据压缩过程中的局限性,且存数据压缩率和算法效率方面都得到了改进.  相似文献   

A Lagrangian mean theory on coastal sea circulation with inter-tidal transports I. Fundamentals   总被引：3，自引：1，他引：2  

FENG Shizuo  JU Lian  JIANG Wensheng 《海洋学报(英文版)》2008,27(6):1-16

A brief review is made on the theory of the Lagrangian residual circulation and inter-tidal transports in a convectively weakly nonlinear system. In the review the emphasis is put on the systematical development of the theory and its weakness of convectively weakly nonlinear approximation. The fundamentals of a Lagrangian tidally-averaged theory on circulation with inter-tidal transport processes have been proposed for a general nonlinear coastal/estuarine system. The Lagrangian residual velocity is strictly de- fined, and it has been verified to be able to embody the velocity field of circulation. A new concept of the concentration for inter- tidal transport processes is presented. The concentration describing the inter-tidal transport processes should be a ＂Lagrangian inter-tidal concentration＂ defined and named, but not the Eulcrian tidally-averaged concentration used traditionally. The circulation described here contains a set of infinite temporal-spatial fields of velocity/concentration, each of which corresponds to a specific value of tidal phases varying continuously over one tidal cycle. When the convectively weakly nonlinear condition（ with a smaller order of eddy diffusion and sources） is approximately satisfied, a set of infinite temporal-spatial fields of velocity/concentration can be reduced to a single one.. the mass transport velocity/the Eulerian tidally averaged concentration as exhibited traditionally.  相似文献   

两种激光粒度仪测量湖泊沉积物粒度结果的对比   总被引：4，自引：1，他引：3  

王君波  鞠建廷  朱立平 《湖泊科学》2007,19(5):509-515

湖泊沉积物粒度参数是湖泊沉积与环境演变研究中常用的环境指标,近年来激光粒度仪的发展和广泛使用更是促进了粒度指标的应用并在很大程度上提高了精度和效率.然而不同的激光粒度仪对于同一样品的测量会得到不同的结果,本文利用两种常见的激光粒度仪测量了西藏纳木错的两支岩芯,并对结果进行了对比分析.从仪器的重现性来看,Mastersizer2000型激光粒度仪要优于LS13320型激光粒度仪,而LS13320型激光粒度仪在对含量较少的细颗粒和粗颗粒的检测效果上优于Mastersizer2000型激光粒度仪;两种仪器得到的粒度参数d(0.1)和d(0.5)无论在变化趋势还是绝对数值上都较为相似,而d(0.9)的差异则较大.对比研究结果为利用湖泊沉积物粒度参数提取古环境信息研究提供了基础依据.  相似文献