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61.
研究底板突水的结构力学方法   总被引:1,自引:0,他引:1  
介绍了研究底板突水的结构力学方法,并用极限弯矩的理论计算得出确定底板隔水层有效厚度之计算公式。  相似文献   
62.
块状岩体边坡地震滑动位移分析   总被引:13,自引:3,他引:13  
岩体边坡在强震作用下往往会产生滑动残余位移。这种位移是边坡稳定性评价的重要参量。本文利用块体动力学原理推导出层状和块状岩体边坡地震滑动位移微分方程式, 并编制了相应的计算程序, 给出了实例的计算结果。  相似文献   
63.
朱燕 《内陆地震》2004,18(2):162-168
通过分析、比较1996--2003年喀什地震台站记录到的新疆伽师及附近地区发生的多次6级地震的地磁前兆异常特征,发现在这几组地震活动过程中喀什地震台的地磁表现出不同的异常特征,说明与地震破裂特征有更深层次的相关性,且地磁响应比异常和总强度差值异常在一定程度上反映了台站周围小范围的震源区介质电性结构的变化。巴楚-伽师6.8级地震前地磁异常特征并不十分突出,有别于1996—1998年伽师强震群震前地磁异常量较丰富的特点。  相似文献   
64.
刘伯 《中国煤田地质》2004,16(6):36-37,60
开滦矿区煤系地层上覆由于防水煤柱留设过大,造成了大量的煤炭储量呆滞。为了提高煤炭资源回收率,确保安全生产,开滦林南仓矿在西二采区进行了工作面采后的导高观测试验研究,测量导水裂隙带岩层的漏失情况,为提高开采上限提供了地质依据,防水煤柱由原来的65m缩小到53m,成功地在1221上工作面进行了试验开采。  相似文献   
65.
The paper introduces the horizontal crustal movement obtained from GPS observations in the regional networks (including the basic network and the fiducial network) of the Crustal Movement Observation Network of China (CMONOC) carried out in 1999 and 2001. This paper is characterized by the acquisition of the horizontal displacement velocities during the period from 1999 to 2001 at the observation stations in the regional networks with datum definition of a group of stable stations with small mutual displacements in east China. Based on the most detailed map of horizontal crustal movement in Chinese mainland, the division of blocks, their displacements and deformations are studied. An approach to analysis of the intensity of the horizontal crustal deformation is proposed. The general characteristics of the recent horizontal crustal movement in Chinese mainland and that before the Kunlunshan earthquake of M=8.1 on November 14, 2001 are analyzed. Foundation item: The National Development and Programming Project for Key Basic Research (95-13-03-07).  相似文献   
66.
Abstract Several differently scaled strike‐slip faults were examined. The faults shared many geometric features, such as secondary fractures and linkage structures (damage zones). Differences in fault style were not related to specific scale ranges. However, it was recognized that differences in style may occur in different tectonic settings (e.g. dilational/contractional relays or wall/linkage/tip zones), different locations along the master fault or different fault evolution stages. Fractal dimensions were compared for two faults (Gozo and San Andreas), which supports the idea of self‐similarity. Fractal dimensions for traces of faults and fractures of damage zones were higher (D ~1.35) than for the main fault traces (D ~1.005) because of increased complexity due to secondary faults and fractures. Based on the statistical analysis of another fault evolution study, single event movements in earthquake faults typically have a maximum earthquake slip : rupture length ratio of approximately 10?4, although this has only been established for large earthquake faults because of limited data. Most geological faults have a much higher maximum cumulative displacement : fault length ratio; that is, approximately 10?2 to 10?1 (e.g. Gozo, ~10?2; San Andreas, ~10?1). The final cumulative displacement on a fault is produced by accumulation of slip along ruptures. Hence, using the available information from earthquake faults, such as earthquake slip, recurrence interval, maximum cumulative displacement and fault length, the approximate age of active faults can be estimated. The lower limit of estimated active fault age is expressed with maximum cumulative displacement, earthquake slip and recurrence interval as T ? (dmax /u) · I(M).  相似文献   
67.
Large magnitude earthquakes generated at source–site distances exceeding 100km are typified by low‐frequency (long‐period) seismic waves. Such induced ground shaking can be disproportionately destructive due to its high displacement, and possibly high velocity, shaking characteristics. Distant earthquakes represent a potentially significant safety hazard in certain low and moderate seismic regions where seismic activity is governed by major distant sources as opposed to nearby (regional) background sources. Examples are parts of the Indian sub‐continent, Eastern China and Indo‐China. The majority of ground motion attenuation relationships currently available for applications in active seismic regions may not be suitable for handling long‐distance attenuation, since the significance of distant earthquakes is mainly confined to certain low to moderate seismicity regions. Thus, the effects of distant earthquakes are often not accurately represented by conventional empirical models which were typically developed from curve‐fitting earthquake strong‐motion data from active seismic regions. Numerous well‐known existing attenuation relationships are evaluated in this paper, to highlight their limitations in long‐distance applications. In contrast, basic seismological parameters such as the Quality factor (Q‐factor) could provide a far more accurate representation for the distant attenuation behaviour of a region, but such information is seldom used by engineers in any direct manner. The aim of this paper is to develop a set of relationships that provide a convenient link between the seismological Q‐factor (amongst other factors) and response spectrum attenuation. The use of Q as an input parameter to the proposed model enables valuable local seismological information to be incorporated directly into response spectrum predictions. The application of this new modelling approach is demonstrated by examples based on the Chi‐Chi earthquake (Taiwan and South China), Gujarat earthquake (Northwest India), Nisqually earthquake (region surrounding Seattle) and Sumatran‐fault earthquake (recorded in Singapore). Field recordings have been obtained from these events for comparison with the proposed model. The accuracy of the stochastic simulations and the regression analysis have been confirmed by comparisons between the model calculations and the actual field observations. It is emphasized that obtaining representative estimates for Q for input into the model is equally important.Thus, this paper forms part of the long‐term objective of the authors to develop more effective communications across the engineering and seismological disciplines. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
68.
红砂岩高陡岩质边坡稳定性分析及治理   总被引:2,自引:0,他引:2  
倪俊 《岩土力学》2004,25(6):981-983
充分利用边坡失稳前自身抗滑能力进行高陡边坡治理,结合工程实例,提出了主动性公路边坡治理的思路。分别利用极限平衡法和有限元数值法,综合考虑了两种方法的优缺点,对红砂岩高陡边坡进行了全面的稳定性分析,并针对性地提出了经济合理的治理方案。  相似文献   
69.
辽西医巫闾山地区中生代两期韧性变形的研究   总被引:3,自引:0,他引:3  
医巫闾山地区的韧性剪切构造是中生代两期韧性变形作用的产物。早期韧性变形中a线理发育,线理走向和糜棱面理走向基本一致,线理在xy面上的侧伏角绝大多数<30°;该期韧性变形是以左行走滑运动为主。晚期韧性变形中a线理发育,线理倾伏向和糜棱岩中糜棱面理倾向相近,线理在xy面上侧伏角主要在45°~90°之间;该期韧性变形是伸展作用的产物。医巫闾山中生代两期韧性剪切变形作用表明,在侏罗纪至早白垩世期间辽西地区不仅发生了强烈挤压推覆作用和伸展作用,也发生了大规模左行走滑作用。该韧性变形作用的发现对进一步研究辽西中生代的构造演化序列、期次和构造格架转换等问题有重要意义。  相似文献   
70.
结合西部地区某深埋长大公路隧道信息化施工 ,对深埋长隧地应力演化及围岩应力位移进行了弹塑性有限元数值模拟研究。研究结果表明 ,隧道轴线现代地应力状况与隧道埋深、地层岩性及构造发育程度有关 ,最大地应力为40 0MPa左右 ;隧道周边围岩应力在曲边墙底部最大 ,约 3 8 0MPa ,隧道开挖引起的围岩应力影响范围约 2 5 0m ;隧道水平收敛和拱顶下沉位移与隧道埋深近于成直线关系。这些研究结果为深埋长隧信息化设计和施工以及围岩稳定性分析提供了科学依据。  相似文献   
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