共查询到20条相似文献，搜索用时 93 毫秒
1.
中浅成岩浆的隐爆机制及其成矿动力学意义 总被引：5，自引：0，他引：5
借助爆炸动力学理论讨论了隐爆作用的机制，提出隐爆作用的本质是因超压导致相变而发生的一种快速物理反应；而岩浆上侵至低围压的中浅层环境→气水组分分离并产生气泡→后续岩浆提供高压力梯度导致超压，即为隐爆作用得以发生的主要条件。模拟实验则进一步表明，在隐爆发生的瞬间，岩浆中的多相组分因密度差和粘度差而发生分离流动，围岩则在隐爆时的热冲击下局部碎裂并气化、液化，从而使相关的热液活动及多种成矿作用得以进行，并由此形成相应的隐爆角砾岩系列及矿床组合 相似文献
2.
3.
山西灵丘支家地热液隐爆银（多金属）矿床成矿机制 总被引：3，自引：0，他引：3
本文从矿床学的角度，对支家地银（多金属）矿床的地质特征、成矿条件及成矿机制进行了系统研究，提出了热液隐爆矿床概念以及与它有关的隐爆构造及引爆热液概念，认为该矿床是一种含矿热液通过隐爆作用而形成的银矿床，即热液隐爆银矿床。 相似文献
4.
赣中相山地区是我国重要的铀资源生产基地,铀矿化产于相山火山侵入杂岩体中,主要由早白垩世熔结凝灰岩、流纹英安斑岩、碎斑熔岩、花岗斑岩、英安玢岩、煌斑岩等组成,杂岩体中还分布大量隐爆作用遗迹——隐爆碎屑岩,隐爆作用发生的时间与火山侵入杂岩活动时间一致或稍后。文章通过对隐爆碎屑岩野外地质调查及室内镜下观察,将隐爆碎屑岩划分为岩浆隐爆碎屑岩和热液隐爆碎屑岩,相应地将隐爆作用划分为岩浆隐爆作用和热液隐爆作用。岩浆隐爆作用主要指流纹英安斑岩侵入活动之后发生的隐爆活动和碎斑熔岩的隐爆侵入活动,发生在早白垩世早期; 热液隐爆作用主要指英安玢岩侵入活动之后发生的、与铀成矿密切相关的热液隐爆活动,发生在早白垩世晚期或晚白垩世初期。从早白垩世早期到晚白垩世初期,隐爆作用呈现“弱—强—弱”的演化趋势。铀成矿作用与晚白垩世初期的热液隐爆作用有关,该隐爆作用与铀成矿时间同步,形成年龄约为90 Ma,铀成矿是一种突发事件。 相似文献
5.
闽西北地区隐爆作用与火山岩型铀矿化 总被引：1，自引：0，他引：1
隐爆角砾岩体对火山岩型铀矿化的控制作用已为实践所证明，并引起高度重视。本文阐述了闽西北地区隐爆角砾岩形成的时空条件、与围岩的关系、分带性及其鉴别要素。以实例说明隐爆角砾岩体对铀矿化起控制作用的３种主要形式，指出了寻找隐爆角砾岩体的方法。 相似文献
6.
7.
8.
浙西火山岩区隐爆岩与铀矿化 总被引：1，自引：0，他引：1
周家志 《华东地质学院学报》1996,19(3):211-217
本文在阐述浙西中生代铀火山岩区隐爆岩产出地质背景的基础上，根据隐爆岩脱结物种类及结构构造特征等综合因素，将该区隐爆岩划分为４大类９个亚类，文章还讨论了它们的形成机理，强调了碎屑型及气热型爆裂角砾岩和爆裂岩类对铀矿的控制作用，并指出了隐爆岩型铀矿的找矿方向。 相似文献
9.
以某杂货码头和集装箱重力式码头水下地基处理工程为例，介绍了其地基处理的爆夯试验过程，得出了一次性爆破夯实厚层块石抛石基床的爆夯参数，并对其施工过程进行了监测。总结了类似工程施工的经验与教训。 相似文献
10.
在拉尔玛金铀矿床研究中鉴别出一种新的金矿控矿构造──热液隐爆机构。该机构在平面上呈近椭圆形,剖面上呈漏斗状,顶部为一由热液硅岩构成的“硅盖”,中心部位为热液隐爆角砾岩,其分布范围与金矿体吻合。热液隐爆机构的形成机制为：在硅岩与板岩的交界处形成的热液硅岩“盖”阻塞了热液系统,导致出现过压的地热环境,约49．5Ma时,由于东西向断裂复活,使脆性的硅岩发生破裂,最终导致了热液隐爆作用的发生。热液隐爆作用促使金元素从热液中沉淀,而热液隐爆机构则为金矿化提供了赋存空间。 相似文献
11.
岩石中柱状装药爆炸能量分布 总被引：21，自引：0，他引：21
岩石中装药爆炸产生的爆破能量可分为爆炸冲击波能量和爆生气体膨胀能量。对爆炸能量分布的理论分析有助于改善爆破效果,提高爆破质量。在柱状耦合装药情况下,分析了冲击波作用下岩石变形和破坏的特点、爆生气体对爆腔的扩腔作用,考虑了在岩体的损伤情况下爆生气体对裂纹的驱裂作用。计算结果表明：埋深在临界深度以下时,岩石中柱状装药爆破冲击波做功消耗的能量约占爆炸总能量的40 %,剩余爆生气体能量中用于扩腔和扩展主要裂隙的能量约占总能量的23 %,剩余大约37 %的能量中有小部分能量用于新增裂纹数目,而大部分损失掉了。 相似文献
12.
13.
Ali Mortazavi P. D. Katsabanis 《Fragblast: International Journal for Blasting and Fragmentation》2000,4(3):175-197
The objective of this paper is to introduce the development of a dynamic blasthole expansion model, which is coupled to the discontinuous deformation analysis (DDA) code of Shi (1988). The developed model considers the effects of blast geometry (blasthole shape, angle, and location), the physical properties of the intact rock and existing discontinuities, the distribution and orientation of pre-existing discontinuities, and the blasthole pressure on the processes of burden breakage, fragment throw and muckpile formation. The newly modified DDA code (DDA_BLAST) describes the expansion of the blasthole as a function of blast chamber volume and time. It is assumed in the code that the rock is already fragmented in-situ due to the intersection of pre-existing discontinuities and the passage of stress wave. Hence, the model only considers the gas pressurization phase of the blasting process. Moreover, the proposed model for the blasthole expansion assumes an adiabatic expansion of explosion products and variations in the explosion pressure upon expansion of the blast chamber are calculated from an equation of state. Accordingly, the newly modified DDA_BLAST code was used to simulate typical blasting problems in jointed media and delve into the mechanisms involved (in a macro scale) in the gas pressurization phase of the blasting process, burden breakage, and the effects of the discontinuity properties on the process of rock breakage by blasting. 相似文献
14.
鄂尔多斯盆地下古生界奥陶系碳酸盐岩生烃能力研究 总被引：2，自引：0，他引：2
产率比是有机质在某一成熟度下的气态烃类产物的产率与其最终气态烃产率的百分比,对相同类型有机质的不同阶段的产率比进行分析可建立该类型有机质的产率比与成熟度的关系.元素平衡法是指有机质及其生成物、残留物间存在的一种物质平衡关系.应用产率比法和元素平衡法对鄂尔多斯盆地下古生界奥陶系碳酸盐岩的生烃能力进行了讨论,指出下古生界奥陶系泥质碳酸盐岩具有一定的生烃能力,其气态烃最终产率可达420～430 m3/T*有机碳,相当于Ⅱ型干酪根的生烃能力;纯碳酸盐岩的生烃能力相对较低,气态烃产率只有120 m3/T*有机碳. 相似文献
15.
Supernovae and gamma-ray bursts (GRBs) are among the brightest events in the universe. Excluding Type Ia supernovae and short GRBs, they are the result of the core collapse of a massive star with material being ejectedwith speeds of several 1000 km/s to nearly the speed of light, and with a neutron star or a black hole left over as the compact remnant of the explosion. Synchrotron radiation in the radio is generated in a shell when the ejecta interact with the surrounding medium and possibly also in the central region near the compact remnant itself. VLBI has allowed resolving some of these sources and monitoring their expansion in detail, thereby revealing characteristics of the dying star, the explosion, the expanding shock front, and the expected compact remnant. We report on updates of some of the most interesting results that have been obtained with VLBI so far. Movies of supernovae are available from our website. They show the evolution from shortly after the explosion to decades thereafter, in one case revealing an emerging compact central source, which may be associated with shock interaction near the explosion center or with the stellar corpse itself, a neutron star or a black hole. 相似文献
16.
Yu. N. Efremov 《Astronomy Reports》2002,46(10):791-804
The nature of stellar complexes with peculiar populations and morphologies is investigated. The existence in the LMC of complexes made up of isolated stars, on the one hand, and consisting exclusively of clusters, on the other hand, could be due to different turbulence patterns in the initial gaseous medium. Arc-shaped stellar complexes are unlikely to be the result of star formation in a gaseous shell swept up by a central source of pressure, and instead probably reflect the shape of a bow shock that develops when a sufficiently dense cloud is subject to dynamical pressure. A peculiar arc-shaped complex in NGC 6946, which contains a young, massive cluster, may be the result of an oblique infall of a high-velocity cloud onto a region of the gaseous disk of the Galaxy with a strong, regular magnetic field; the properties of this complex can be explained as the result of a collision of the resulting shocks. The arc-shaped complexes in the LMC were also probably produced by high-velocity clouds moving obliquely through the more tenuous gas of the LMC disk. A similar complex in NGC 300 may owe its origin to the effect produced on a dense cloud by the shock from an extremely powerful external explosion, whose stellar remnant may have survived as an X-ray source now located along the line of symmetry of the arc of the complex. The rareness of such structures can be explained by the narrow range of conditions under which they can develop. 相似文献
17.
不同类型烃源岩气态烃的生成特征研究--来自差热-色谱联机热模拟实验方法的证据 总被引：2，自引：0，他引：2
运用差热-色谱联机分析仪对不同煤阶的标准煤样及泥岩和碳酸盐岩烃源岩的热模拟研究表明,低成熟的煤具有更强的放热反应和较大的失重量,其放热反应第一峰温度和失重温度相对较低。低煤阶煤在热模拟过程中比高煤阶煤具有更强的生烃能力。烃源岩气态烃的生成量和特征不仅受控于烃源岩中有机质的丰度而且与其岩石类型、干酪根类型、成熟度等存在着密切关系。成熟度较高的烃源岩属耗尽了的烃源岩,其生烃能力相对较弱。含Ⅰ、Ⅱ型干酪根烃源岩生成的气态烃中重组分含量普遍较高,含Ⅲ型干酪根烃源岩生成的气态烃中甲、乙烷等轻组分含量普遍较高。碳酸盐岩烃源岩在热模拟的高温阶段往往能生成比较大量的气态烃。 相似文献
18.
在原有有限元/离散元（FEM/DEM）耦合分析方法中,实现了一种新的爆破计算模型。该模型考虑了在爆生气体的作用下,随着裂隙的扩展,气体占据的体积不断增大,气体压力逐渐减小这一问题。同时考虑了气体嵌入与爆腔联通的裂隙对裂隙的作用力。克服了原有FEM/DEM方法中的爆破模型仅仅将压力施加于爆腔四周的岩壁上,无法考虑爆生气体嵌入生成的裂隙对裂隙的作用。提出了一种新颖的贯通裂隙网络形成的递归搜索算法,只需通过编写一个简单的递归函数,即可实现复杂裂隙网络的搜索,采用一种简洁的方法完成了对复杂问题的处理。最后通过一个爆破算例,结果表明FEM/DEM方法可以对爆炸过程中应力波的传播及岩体中裂纹的萌生、扩展进行全程捕捉,展现了该方法用于爆破模拟的潜力。 相似文献
19.
Numerical modeling of ground borehole expansion induced by application of pulse discharge technology
Pulse discharge technology (PDT) is an innovative technique that can be used to enhance bearing capacity of piles and resisting capacity of anchors. It enlarges the section area and compacts the surrounding soil by high-powered shock wave pressure induced by an underwater electrical discharge. This study aims to establish a suitable numerical model for the simulation and prediction of ground borehole expansion induced by PDT. In order to examine the relationship between electricity and the characteristics of shockwaves generated by PDT, laboratory pulse discharge tests were performed using PDT equipment used in current practice. Then, based on the underwater explosion (UNDEX) model and a coupled acoustic–structural analysis scheme, the results of laboratory PDT tests were analyzed and numerically benchmarked to determine the equivalent UNDEX model parameters for providing shock loading input in a ground borehole expansion simulation. A series of expansion simulations for undrained clayey and sandy soils were performed, and the predicted borehole expansion behaviors were compared with the test results. Moreover, a parametric study was conducted to examine the effects of soil properties on the expansion behavior. The results of the numerical work in this study appeared to be consistent with field test results published in the literature and showed that the soil characteristics related with packing, state of stresses, and degree of saturation were important when analyzing borehole expansion behavior. 相似文献
20.
The human and natural factors complicit in the driving forces of oasis change have always received considerable interest from the international research community. In this study, we used principal component analysis of natural and socio-economic statistical factors to quantitatively analyze the causal relationships and their contributions to the observed periodic expansion or shrinkage of the Minqin Oasis over almost 60 years. Our results show that human factors were the dominant factors governing expansion or shrinkage, with average contributions of 69.38% and 76.16%, respectively. Moreover, policy decisions have been the pivotal human factors. Under the influence of various policies, we have found that water resource utilization, land reclamation, population explosion, ecological protection and economic development have each played leading roles in different periods. This study provides a scientific basis for modelling the dynamics of an oasis for sustainable management. 相似文献