南岭钨矿“五层楼模式”的结构与构式——以粤北始兴县梅子窝钨矿为例   总被引：4，自引：1，他引：3  

汪劲草  韦龙明  朱文凤  万方良  莫志明 《地质学报》2008,82(7):894-2008-01-30

南岭脉状钨矿的“五层楼模式”,在纵剖面上具正扇形结构,横剖面上具树形分叉结构,平面上沿构造带呈定向脉组（群）分布。从上往下,矿脉分布的分维值（平均1.10）从大变小。认为燕山期含矿岩浆流体沿构造带发生定向的周期性地震泵吸、液压致裂与裂开愈合。对于同一条矿脉,矿脉的扩展速率与扩展时间决定了脉幅的大小：脉幅越大,扩展速率就越小,扩展时间就越长,起始时间也就越早;而脉幅越小,扩展速率也就越大,扩展时间就越短,起始时间也就越晚。认为脉的扩展速率与液压、围压的相对大小有关：当液压一定时,围压越大,则脉的扩展速率就越小;而围压越小,脉的扩展速率就越大。由于各处围压及扩展时间长短的差异,“五层楼”模式中的中部、深部、侧部、上部的矿脉构式、脉幅具有明显的差异：中部单脉出现分支复合,脉幅稳定;侧部单脉出现自然尖灭或单侧分支尖灭、双则分支尖灭;上部则出现复杂的树形分支,分支自然尖灭或分支与分支之间的复合尖灭,深部可能为自然尖灭。  相似文献   

U/Th dating of fissure ridge travertines from the Kirsehir region (Central Anatolia Turkey): structural relations and implications for the Neotectonic development of the Anatolian block     

《Geodinamica Acta》2013,26(4):201-213

Travertines exposed in several locations in Central Anatolia are the important lithological product for the interpretation of local neotectonics. The fissure-type travertines provide significant information about stress orientation during deposition. Two travertine masses cropping out in the Kirsehir region have been studied and dated by the U-series method to obtain new chronological constraints, determine dilation rates and contribute to studies on the recent tectonic evolution of the area. The Kusdili and Kayabasi travertine masses are located on the hanging wall of the Kirsehir Fault, similar to numerous fissure ridge banded travertine deposits which are inactive today in the region. While individual fissures of the Kusdili travertine mass (Late Pleistocene-Holocene) have been dilated at rates of between 0.303 and 0.386 mm yr–1 during deposition, the Kayabasi travertine mass (Late Pleistocene) produced measured dilation rates of between 0.136 and 0.187 mm yr–1. The central fissures, filled by banded travertine, roughly follow the ridge crests. While the ridge crest has a NNE-SSW trend in the Kayabasi travertine mass, the ridge crest of the Kusdili travertine mass shows a NE-SW trend. This difference may be related to the clockwise rotation of the stress tensors from Late Pleistocene to Late Pleistocene-Holocene in the region.  相似文献   

闽西南马坑矽卡岩型铁矿床扩容构造控矿机制及深部找矿意义   总被引：1，自引：0，他引：1  

高孝巧  张达  冯海滨  潘天望  王森  易锦俊 《矿床地质》2016,35(3):605-617

文章基于岩石力学及分形统计分析,结合野外地质调查,探讨了扩容构造控矿机制及其在福建马坑铁矿床成矿过程中的作用。指出马坑铁矿床成矿过程与构造变形作用造成的扩容机制密切相关,其中,锯齿状断裂扩容构造及流体超压作用扩容是马坑铁矿床除接触交代作用外成矿的关键因素。锯齿状断裂扩容构造形成于伸展剪切作用,造成矿体沿倾向的尖灭再现。成矿流体超压扩容主要是由于流体沸腾作用引起,使岩石发生角砾岩化,其中大规模角砾岩是矿体的有利赋存部位。福建马坑矿区深部及外围找矿,应重点关注大规模高强度的汇流扩容区。  相似文献   

离散目标群的边界搜索     

王延亮  刘登杰 《测绘科学》2007,32(5):101-102

搜索离散目标群的边界是地理信息系统(GIS)和地图学中一个重要问题,传统的算法是基于矢量数据的。本文提出了基于栅格数据搜索离散目标群的边界的新方法,并用两个点群算例介绍了用闭运算搜索边界的方法与流程,为数字高程模型生成、地图学等提供一种新的边界搜索方法。  相似文献   

黄土坡滑坡滑带土非饱和力学特性试验研究     

王君鹭  唐辉明  倪卫达 《工程地质学报》2015,23(2):211-218

以三峡库区黄土坡滑坡临江I号崩滑体的滑带土为研究对象,研究基质吸力对非饱和滑带土的强度与变形等力学性质的影响。利用GDS非饱和反压直剪仪对滑带土进行了不同净法向应力和基质吸力组合下的直剪试验。试验结果表明:相同的基质吸力作用下,滑带土抗剪强度随着净法向应力的增大而增大。当滑带土试样中基质吸力较小时(50kPa),试样剪切过程中的应力-应变曲线,随着净法向应力的增大表现为应变硬化型。之后随着基质吸力的增加,当吸力大于净法向应力时,剪切应力-应变曲线表现为较明显的达到峰值后软化。反之,应力-应变曲线表现为应变硬化型。相同净法向应力下,抗剪强度随着吸力的增大而增大,剪切应力-应变曲线由低法向应力下的达到峰值后软化向高法向应力下的应变硬化转变。剪切过程的轴向位移表现为:当吸力大于净法向应力时,表现为剪胀; 反之,表现为剪缩。滑带土固结排水剪切条件下得到的黏聚力随着基质吸力呈线性增长关系。得到了滑带土的吸力摩擦角b为13.7,有效内摩擦角有较小增长,平均有效内摩擦角15.9。  相似文献   

基于Hoek-Brown准则的岩石应变软化模型研究     

金俊超  佘成学  尚朋阳 《岩土力学》2020,41(3):939-951

基于Hoek-Brown（H-B）准则，根据大量试验数据，研究提出一种具有广泛适用性的岩石应变软化模型。利用40种硬岩和软岩三轴试验数据，验证了3参数幂函数型围压函数广泛适用于硬岩和软岩峰后临界塑性应变与围压的关系描述，并将其引入塑性内变量中；其次，比较分析当前基于H-B准则的岩石应变软化模型中软化参数的合理性，明确以GSI作为软化参数的方法最优，拟合结果正确且参数最少。然后，分析岩石峰后GSI随塑性内变量的演化规律，并建立一种普适的非线性演化模型。与其他演化模型相比，所建模型可更准确地描述不同种类岩石峰后H-B强度参数的非线性演化规律，同时参数较少。接着，采用非关联流动法则，将所建GSI演化模型嵌入有限元软件ABAQUS中，实现软化模型的数值求解。最后，对多种岩石的室内试验模拟结果表明，所建模型可正确描述不同围压下硬岩和软岩的峰后应变软化变形及剪胀变形，具备良好的适用性。与定临界塑性应变或定剪胀角的应变软化模型模拟结果相比，所建模型模拟曲线可一致性地与试验曲线接近。  相似文献   

大型GIS中方位距离的量算方法   总被引：1，自引：0，他引：1  

吕晓华  杨国平 《测绘学院学报》2004,21(2):138-140

摘要：方位、距离的量算是GIS开发、数字地图应用等空间分析中最基本的计算。沿用传统的局部投影平面上的各种分析、量算方法难以在大型GIS或大区域数字地图的空间分析中准确实施，距离、方位的量算应基于(B，L)2维场所决定的地球椭球面几何参考系依据大地线进行。文中给出了方位、距离的简化算法，计算精度高，展开级数收敛快，没有显著病态、停滞，对大型GIS及大区域数字地图的数据处理，对多分辨率、大区域或全球范围的数据无缝连续的定位分析有重要的实际应用价值。  相似文献   

The shear strength of rock joints in theory and practice   总被引：62，自引：10，他引：62  

N. Barton  V. Choubey 《Rock Mechanics and Rock Engineering》1977,10(1-2):1-54

SummaryThe Shear Strength of Rock Joints in Theory and Practice The paper describes an empirical law of friction for rock joints which can be used both for extrapolating and predicting shear strength data. The equation is based on three index parameters; the joint roughness coefficientJRC, the joint wall compressive strengthJCS, and the residual friction angle _r . All these index values can be measured in the laboratory. They can also be measured in the field. Index tests and subsequent shear box tests on more than 100 joint samples have demonstrated that _r can be estimated to within ± 1° for any one of the eight rock types investigated. The mean value of the peak shear strength angle (arctan/ _n ) for the same 100 joints was estimated to within 1/2°. The exceptionally close prediction of peak strength is made possible by performing self-weight (low stress) sliding tests on blocks with throughgoing joints. The total friction angle (arctan/ _n ) at which sliding occurs provides an estimate of the joint roughness coefficientJRC. The latter is constant over a range of effective normal stress of at least four orders of magnitude. However, it is found that bothJRC andJCS reduce with increasing joint length. Increasing the length of joint therefore reduces not only the peak shear strength, but also the peak dilation angle and the peak shear stiffness. These important scale effects can be predicted at a fraction of the cost of performing large scale in situ direct shear tests.With 20 Figures  相似文献   

The Gravitational Effects of a Celestial Body with Magnetic Charge and Moment     

Yong－JiuWang  Yi－BinHuang 《中国天文和天体物理学报》2001,1(2):125-128

The gravitational effects (precession of charge-less particles and deflec-tion of light)in the gravitational field of a celestial body with magnetic charge and moment(CM)are investigated.We found that the magnetic charge always weak-ens the pure Schwarzschild effects,while the magnetic dipole moment deforms the effects in a more complicated way.  相似文献   

腐蚀膨胀算法在三维重构中的应用   总被引：1，自引：0，他引：1  

张立朝  陈引川  曹广阔  张世全  余琳琳  郑海鹰 《测绘信息与工程》2006,31(5):12-13

分析了血管切片的样本图像,提出了一种基于图像腐蚀膨胀获得切片中心和边缘线的算法,真实快速地实现了血管的三维重构。  相似文献