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981.
在统计、收集山西师范大学各类建筑物资料的基础上,对其各类建筑物进行了震害预测和经济损失估计,给出了各类建筑物在不同烈度下的破坏结果和经济损失值,为地震灾害的综合防御提供了科学依据。 相似文献
982.
通过对昆明经济技术开发区的地质构造,场地工程地质环境,砂土液化判别以震害预测的综合研究,进行了区内的场地地震易损性分析。根据计算出的地震易损性指数,结果表明,可将研究区划分为两个震害程度不同的区域。 相似文献
983.
984.
孙丕锋 《地震地磁观测与研究》1999,20(4):21-23
鲁西地处化北地台中南部,聊考察裂纵贯南北,自有历史记载以来,还未发生过7级以上大震,但中强地震发育,小震活动频率,具有较明显的周期性和条带分布特征。作者试图分析鲁西历史及现地震的时间序列和空间分布,以期鲁西地震形势有一个总体认识,对未来地震活动做一大致估计。 相似文献
985.
986.
《国际泥沙研究》2016,(4):291-298
As a result of the interaction between hydrodynamics and the effects of gravity, riverbank collapse is a common occurrence in the desert reach of the upper Yellow River (also called as Ningxia-Mongolia Inner reach), of which the riverbank may be divided into three types such as sandy riverbank in the wide-valley desert reach, silt-deposition riverbank on the fluvial plain and silt–sandy riverbank. The char-acteristics of both typical riverbank collapse and the particle size distributions (PSDs) for collapsed riverbanks of sandy, silt-deposition, and silt–sandy types were determined from analysis of data obtained from the field observations. It was found that particles from the silt-deposition riverbank had the smallest median size and those from the sandy riverbank the largest, with those from the silt–sandy riverbank being intermediate in size. The PSDs of the sandy and silt-deposition riverbanks exhibited double-peaked and single-peaked structures, respectively, while those of the silt–sandy riverbank exhibited multiple peaks. Furthermore, the corresponding to three kinds of riverbank collapse mechanisms were revealed. These results are significant with regard both to the understanding of river dynamics and to the planning of river harnessing projects. 相似文献
987.
988.
989.
The widespread preference for rockbolts in providing adequate rock stability in underground mines and man-made cavities make it necessary to obtain a better understanding of the response of these support systems. It is widely accepted that the fully grouted rockbolts provide better roof stability in areas of very poor roof condition which may be caused by high ground stress conditions. There is little information about the in situ behavior of these systems especially under dynamic loading. Hence, to study the behavior of fully grouted rockbolts under dynamic loading, a numerical modeling study was conducted using the FLAC3D code. In this study the behavior of three types of fully grouted rockbolts were compared with each other including rockbolts with and without head plate and a yielding type one. The results of analyses indicated that under dynamic loading the fully grouted rockbolts without the head plate are incapable of controlling the rock mass movement. Although fully grouted rockbolts with head plate damp a considerable amount of the dynamic energy through friction as these bolts slide within the grout, but the elongation of the rockbolt is not possible due to the rapid breakage of the rockbolt–grout interface. Yielding rockbolts are the best choice for the absorption of the dynamic stress wave and controlling of the rock mass movement. The obtained results show that the optimal design of yielding rockbolt should be in such a way that after dynamic loading, anchoring part of bolt has a limited movement to prevent stress concentration in the shaft of rockbolt and its breakage. 相似文献
990.