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441.
以新疆西准噶尔包古图Ⅴ号岩体为例,系统论述了包古图Ⅴ号含矿岩体的围岩蚀变分带和蚀变期次。结合ETM+数据的特征,选择多种遥感图像预处理方法组合,建立了基于典型蚀变矿物的特征光谱拟合技术的多光谱遥感蚀变信息提取模型,即遥感数据的归一化处理(Calibration )+掩膜(Mask)+混合像元分解(Endmember Unmixing)+波谱拟合(Spectral Feature Fitting)+ SAM+分类(分割)的CES模型。据此模型对岩体进行信息提取,并与化探资料叠加验证了该方法的可行性,取得了较满意的效果。 相似文献
442.
徐州市区地面塌陷与岩溶水开采关系研究 总被引:4,自引:0,他引:4
岩溶水是徐州城市供水的主要水源。由于对岩溶水的长期不合理开采,诱发了地面塌陷。论文概述了该地区水文地质条件及地下水开采状况。较系统地分析地面塌陷的形成机制及诱发因素并提出了防治措施。 相似文献
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在反倾层状边坡内,开挖边坡并修筑隧道洞口后,出现岩体从隧道掌子面整体挤出和洞顶塌方现象,并导致边坡出现后缘拉裂、坡体内出现多处裂缝和岩块崩塌等坡体失稳迹象。通过对该边坡失稳和隧道塌方的勘察和机制分析,确定该坡体的变形破坏模式,提出针对性治理方案。 相似文献
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Meysam Fadaee I. Anastasopoulos G. Gazetas M.K. Jafari M. Kamalian 《地震工程与工程振动(英文版)》2013,12(3):473-486
When seismic thrust faults emerge on the ground surface,they are particularly damaging to buildings,bridges and lifelines that lie on the rupture path.To protect a structure founded on a rigid raft,a thick diaphragm-type soil bentonite wall(SBW) is installed in front of and near the foundation,at sufficient depth to intercept the propagating fault rupture.Extensive numerical analyses,verified against reduced–scale(1 g) split box physical model tests,reveal that such a wall,thanks to its high deformability and low shear resistance,"absorbs" the compressive thrust of the fault and forces the rupture to deviate upwards along its length.As a consequence,the foundation is left essentially intact.The effectiveness of SBW is demonstrated to depend on the exact location of the emerging fault and the magnitude of the fault offset.When the latter is large,the unprotected foundation experiences intolerable rigid-body rotation even if the foundation structural distress is not substantial. 相似文献
448.
The local design and construction practices in the United Arab Emirates(UAE),together with Dubai’s unique rate of development,warrant special attention to the selection of Lateral Force-Resisting Systems(LFRS).This research proposes four different feasible solutions for the selection of the LFRS for tall buildings and quantifies the impact of these selections on seismic performance and cost.The systems considered are: Steel Special Moment-Resisting Frame(SMRF),Concrete SMRF,Steel Dual System(SMRF with Special Steel Plates Shear Wall,SPSW),and Concrete Dual System(SMRF with Special Concrete Shear Wall,SCSW).The LFRS selection is driven by seismic setup as well as the adopted design and construction practices in Dubai.It is found that the concrete design alternatives are consistently less expensive than their steel counterparts.The steel dual system is expected to have the least damage based on its relatively lesser interstory drifts.However,this preferred performance comes at a higher initial construction cost.Conversely,the steel SMRF system is expected to have the most damage and associated repair cost due to its excessive flexibility.The two concrete alternatives are expected to have relatively moderate damage and repair costs in addition to their lesser initial construction cost. 相似文献
449.
Base isolated buildings subjected to extreme earthquakes can exceed their design displacements and impact against the surrounding moat wall. To better understand the consequences of impact on the superstructure, an impact element considering moat wall flexibility is proposed based on impact theory and observations during experimental simulations. It is demonstrated that numerical simulations using the proposed impact element can capture the dominant characteristics of the contact force observed in experiments of base isolated buildings impacting various moat wall configurations including concrete walls with soil backfill and rigid steel walls. The contact force is dependent on impact velocity, geometry, and material properties at the contact surface, and the global dynamic characteristic of the moat wall. Properties of the moat wall impact element are derived based on mechanics‐based models considering material properties and geometric measurements of the experimental setup. For this purpose, the moat wall is modeled as a flexural column with a concentrated nonlinear hinge at its base and soil backfill considered through a damped elastic foundation then generalized into a single degree of freedom system. The resulting impact element is shown to accurately capture both local deformation and the vibration aspects of impact observed in experiments and the effects of impact on superstructure response. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
450.
In this report, the capabilities of the adaptively shifted integration (ASI)‐Gauss code in the analysis of the seismic responses of framed structures are verified and validated by comparing the results with detailed numerical simulations performed by the parallel finite element analysis code, E‐Simulator, and with experimental results obtained by E‐Defense. The numerical results obtained by both codes showed good agreement with the experimental results obtained by E‐Defense. Furthermore, seismic waves with unnaturally large magnitudes are applied to a high‐rise building model to demonstrate the ability of the ASI‐Gauss code to analyze the collapse behaviors of building frames. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献