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111.
易门式大型铜矿床构造成矿动力学模型 总被引:5,自引:1,他引:5
针对金属矿床隐伏矿定位预测的关键问题,在提出构造成矿动力学的分支学术方向的基础上,以易门式大型铜矿床为例,从成矿地质背景、矿田构造、构造地球化学和成矿构造应力场等方面进行构造成矿动力学研究,阐述在构造应力场控制下成矿流体运移和聚集的规律。构造地球化学研究认为,构造地球化学异常反映矿体的原生晕;构造地球化学异常受构造控制,其分带特征可指示成矿流体的流向,并提供矿床成因和隐伏矿(化)体相对埋深的信息。构造应力场的控矿特征主要表现在:构造应力场导致控矿构造的形成,并驱动成矿流体的运移;构造应力场控制了成矿能量场;应力和能量的高值集中区分布特点可反映某些构造型式。在此基础上建立构造成矿动力学模型,概括隐伏矿成矿预测准则,据此提出若干重点找矿靶区和靶位,其中部分靶区得到工程验证,表明构造成矿动力学方法对隐伏矿定位预测和评价具有重要的指导意义。 相似文献
112.
Motivated by the development of performance‐based design guidelines with emphasis on both structural and non‐structural systems, this paper focuses on seismic vulnerability assessment of block‐type unrestrained non‐structural components under sliding response on the basis of seismic inputs specified by current seismic codes. Two sliding‐related failure modes are considered: excessive relative displacement and excessive absolute acceleration. It is shown that an upper bound for the absolute acceleration response can be assessed deterministically, for which a simple yet completely general equation is proposed. In contrast, fragility curves are proposed as an appropriate tool to evaluate the excessive relative displacement failure mode. Sample fragility curves developed through Monte‐Carlo simulations show that fragility estimates obtained without taking into account vertical base accelerations can be significantly unconservative, especially for relatively large values of the coefficient of friction. It is also found that reasonable estimates of relative displacement response at stories other than the ground in multistorey buildings cannot in general be obtained by simply scaling the ground acceleration to the peak acceleration at the corresponding storey. Failure modes considered in this study are found to be essentially independent of each other, a property that greatly simplifies assessment of conditional limit states. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
113.
This article presents a numeric comparative study of the inelastic structural response of base isolated buildings. The comparative study includes the following isolation systems: laminated rubber bearings, New Zealand one, pure friction and the frictional pendulum ones. The study is based on obtaining non‐linear response spectra for various design parameters using six earthquake records. Usually the base isolation of a new building seeks to maintain the structure in the linear elastic range. The response of old weak buildings or the response of new ones subjected to extreme earthquakes may not be, necessarily, in the aforementioned ideal elastic range. Consequently, it is important to characterize the response of isolated buildings responding inelastically. A conclusion from this research is that the isolators affect significantly the structural response of weak systems. Rubber isolators seem slightly less sensitive to plastification that may occur in the structure compared to friction isolators. Ductility demands in the structure are affected significantly by friction and neoprene protected systems, in particular sliding ones where larger demands are obtained. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
114.
吐哈盆地中央构造带正反转演化特征 总被引:5,自引:3,他引:5
吐哈盆地中央构造带由火焰山构造和七克台构造组成。中央构造带形成于三叠纪晚期至侏罗纪早期,表现为伸展构造特征,生长断层上盘地层厚度明显大于下盘,并于断层上盘所在的台北凹陷形成沉降中心。晚侏罗世,由于拉萨陆块与欧亚大陆的碰撞作用导致吐哈盆地由伸展盆地转变为挤压盆地,中央构造带也于此时发生构造反转,由早期的伸展正断层转变为挤压逆断层。发生于55Ma的喜山构造事件对天山地区产生了深刻的影响,但影响时间略有滞后,大致发生在晚渐新世至早中新世,中央构造带即在此次构造事件中强烈变形,逆冲出露于地表。 相似文献
115.
Stochastic Structural Modeling 总被引:3,自引:0,他引:3
Lars Holden Petter Mostad Bjørn Fredrik Nielsen Jon Gjerde Chris Townsend Signe Ottesen 《Mathematical Geology》2003,35(8):899-914
A consistent stochastic model for faults and horizons is described. The faults are represented as a parametric invertible deformation operator. The faults may truncate each other. The horizons are modeled as correlated Gaussian fields and are represented in a grid. Petrophysical variables may be modeled in a reservoir before faulting in order to describe the juxtaposition effect of the faulting. It is possible to condition the realization on petrophysics, horizons, and fault plane observations in wells in addition to seismic data. The transmissibility in the fault plane may also be included in the model. Four different methods to integrate the fault and horizon models in a common model is described. The method is illustrated on an example from a real petroleum field with 18 interpreted faults that are handled stochastically. 相似文献
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119.
山东省龙卷风发生的气候特征 总被引:9,自引:0,他引:9
根据藤田-皮尔森强度分类法对1950年~2000年山东省出现的351次龙卷风进行分类,其中F0级61次,F1级256次,F2级34次。山东半岛、鲁中、鲁南出现次数较多,鲁西北较少。1950~1972年发生次数明显高于1973~2000年。龙卷风发生存在明显的季节变化,夏季发生较多。龙卷风主要发生于午后至傍晚,多数龙卷风仅能维持几分到十几分钟。 相似文献
120.
天山北坡牧草生长季节土壤水分变化特征探讨 总被引:1,自引:0,他引:1
通过对牧业气象试验站多年土壤水分观测资料的整理分析,认为夏季土壤水分比较丰富,其随深度分布呈降水型;春季土壤水分含量最少,秋季次之,其随深度分布呈蒸发、降水型。旬土壤水分含量在牧草生长期呈两峰三谷型。 相似文献