广西大瑶山-西大明山金银成矿系统研究   总被引：10，自引：0，他引：10       下载免费PDF全文

崔彬  翟裕生  蒙义峰  黄方方  树皋  刘光华 《地球科学》2000,25(4):352-355

大瑶山-西大明山是广西主要的金银产地和重要的成矿远景区.区内金银矿床主要产于寒武系中.矿床形成与加里东和燕山期构造活动和岩浆作用密切相关, 形成与同熔型花岗岩类有关的Au-Ag-Cu成矿系列, 并建立了挤压构造条件下的岩浆-热液成矿系统.   相似文献   

基于SMP准则的土的平面应变强度公式   总被引：31，自引：6，他引：25  

罗汀  姚仰平  松冈元 《岩土力学》2000,21(4):390-393

基于SMP准则和佐武的平面变变条件,推导了磨擦材料的平面就变强度公式。通过引入粘结应力σ0,推导出适应于C－Φ材料的平面应变强度公式。各种试验结果证明了所提强度公式是合理的。  相似文献   

计算机网络通讯和小波数据压缩技术在地震勘探领域的联合应用     

张绍红  樊佳芳 《物探与化探》1999,23(1):60-63

分析目前三维地震勘探中产生的数据量庞大、采集处理周转时间延长及勘探成本增加等问题,指出高速网络通讯技术和小波数据压缩技术的利用是解决这些问题的有效手段,介绍这种方法的经济效益,并进行了前景展望.  相似文献   

四川某水库大坝左坝肩边坡变形破坏机制及整治对策探讨   总被引：8，自引：0，他引：8  

王士天 《地质灾害与环境保护》1999,10(3):1-5

以现场考察和变形监测资料为依据,探讨一个下部有软弱基底,上部为硬脆性坡体的“二元结构”边坡的变形破坏问题,揭示这类边坡的变形总是以下部软弱岩体的不均匀压缩流变为先导,进而引起上部硬脆性坡体的拉裂与倾倒,最终通过渗入水的作用,使下部承载状况已进一步恶化了的软弱岩体,沿剪应力集中带发生剪切破坏而导致整个变形坡体的下滑。  相似文献   

方钢管混凝土柱-不等高钢梁框架节点抗剪承载力分析          下载免费PDF全文

许成祥  费建宝  简齐安  彭胜 《世界地震工程》2020,(4):053-61

为研究方钢管混凝土柱-H型不等高钢梁框架节点的抗剪承载力,分析其破坏机理,建立适用于不等高钢梁节点的抗剪计算模型,提出了节点的抗剪承载力计算公式,比较了基于不同抗剪模型建立的抗剪承载力计算值与试验值的差异性。结果表明:节点域的破坏模式主要为上核心区的剪切斜压破坏;节点域抗剪承载力主要由钢管腹板、核心区混凝土主斜压杆及约束斜压杆共同承担。对比分析表明:提出的节点屈服抗剪承载力和极限抗剪承载力理论公式计算值更为接近试验值,验证了方钢管混凝土柱-不等高钢梁框架节点传力机理和承载力计算公式的正确性。  相似文献   

Controls on the geotechnical response of sedimentary rocks to weathering     

S.J. de Vilder  M.J. Brain  N.J. Rosser 《地球表面变化过程与地形》2019,44(10):1910-1929

Weathering reduces the strength of rocks and so is a key control on the stability of rock slopes. Recent research suggests that the geotechnical response of rocks to weathering varies with ambient stress conditions resulting from overburden loading and/or stress concentrations driven by near-surface topography. In addition, the stress history experienced by the rock can influence the degree to which current weathering processes cause rock breakdown. To address the combined effect of these potential controls, we conducted a set of weathering experiments on two sedimentary lithologies in laboratory and field conditions. We firstly defined the baseline geotechnical behaviour of each lithology, characterising surface hardness and stress–strain behaviour in unconfined compression. Weathering significantly reduced intact rock strength, but this was not evident in measurements of surface hardness. The ambient compressive stress applied to samples throughout the experiments did not cause any observable differences in the geotechnical behaviour of the samples. We created a stress history effect in sub-sets of samples by generating a population of microcracks that could be exploited by weathering processes. We also geometrically modified groups of samples to cause near-surface stress concentrations that may allow greater weathering efficacy. However, even these pronounced sample modifications resulted in insignificant changes in geotechnical behaviour when compared to unmodified samples. The observed reduction in rock strength changed the nature of failure of the samples, which developed post-peak strength and underwent multiple stages of brittle failure. Although weakened, these samples could sustain greater stress and strain following exceedance of peak strength. On this basis, the multi-stage failure style exhibited by weaker weathered rock may permit smaller-magnitude, higher-frequency events to trigger fracture through intact rock bridges as well as influencing the characteristics of pre-failure deformation. These findings are consistent with patterns of behaviour observed in field monitoring results. © 2019 John Wiley & Sons, Ltd.  相似文献   

Improved numerical analysis for ultimate behavior of elastomeric seismic isolation bearings     

Ken Ishii  Masaru Kikuchi 《地震工程与结构动力学》2019,48(1):65-77

Elastomeric isolation bearings consist of multiple rubber layers with their top and bottom surfaces bonded to steel plates to restrict compressive deformation. Deformation constraints result in a variation of elastic modulus over the cross section of the rubber layers. In this paper, we describe a normalized compression modulus distribution on a circular rubber pad. The compressive and bending moduli of the rubber pad can be reproduced by applying the distribution to a series of axial springs. We also present a mechanical model for predicting the behavior of elastomeric seismic isolation bearings subject to large shear deformation and high compressive load. The mechanical model consists of a series of multiple shear springs at midheight and a series of axial springs at the top and bottom interfaces of the bearing. Simulation analyses of bearing tests were conducted to validate the proposed model. The analyses demonstrated that a model for circular lead-rubber bearings can successfully capture the influence of the axial load magnitude on the bearing shear behavior. The new model can simulate much more realistic behavior than prior models based on a uniform modulus assumption.  相似文献   

"北斗"导航系统在海洋水文、气象监测系统中的应用   总被引：7，自引：0，他引：7  

成方林  冯林强  张翼飞 《海洋技术学报》2004,23(3):70-73

“北斗”导航系统是具有我国自主知识产权的卫星导航系统,该系统具有快速定位、双向通信和精密授时三大功能．可以代替当前的Inmarsat-C和ARGOS系统在海洋监测平台中的应用。文章介绍了“北斗”系统在我国当前的海洋水文、气象监测平台的应用．并对“北斗”系统在我国海洋监测平台上的广泛应用提出了建设性意见。  相似文献   

大姚铜矿紫色砂岩的压拉变形特性试验研究     

谢强  余贤斌  张永兴  纳裕康 《岩土力学》2007,28(10):2155-2160

介绍了一种可对同一岩石试样分别进行单轴压缩和单轴拉伸实验的试验装置,该装置改变了因岩样不同而导致的压拉试验结果无法进行直接对比分析的现状,为岩石从受压转向受拉或从受拉转向受压的过渡特性的试验研究提供了可能。以云南大姚铜矿紫色砂岩为例,研究了其在压拉试验条件下的变形特性。结果表明：该种岩石从压缩到拉伸阶段弹模变化不大,但压缩泊松比与拉伸泊松比的变化较为复杂。试验同时证明该类岩石的压缩与拉伸并不是截然不同的两种过程,单轴压缩试验的卸载曲线与直接拉伸试验的加载曲线具有很好的连续性。  相似文献   

Elastic visco‐plastic consolidation modelling of clay foundation at Berthierville test embankment     

Guofu Zhu  Jian‐Hua Yin 《国际地质力学数值与分析法杂志》2000,24(5):491-508

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