广东云浮硫铁矿矿床多因复成富集机制   总被引：1，自引：0，他引：1  

曾晓东  吴延之 《大地构造与成矿学》1998,22(3):242-251

从历史-因果论出发,运用陈国达教授提出的多因复成成矿理论,对广东云浮硫铁矿的成矿作用重新进行了研究和解剖。首次研究并论证了矿床形成的裂谷背景,提出了本矿床是一种经历了晚元古代裂谷期海底喷流初始沉积,加里东期裂谷回返动力变质过程中的矿体塑性流动和剪切固态迁移集中富集（有混染了的变质热液的叠加）,印支或岩浆热液叠加富化的多因复成矿床的新观点。  相似文献   

模拟岩石节理试样剪切变形特征和破坏机制研究   总被引：11，自引：3，他引：8  

李海波  刘博  冯海鹏  张磊奇 《岩土力学》2008,29(7):1741-1746

通过RMT－150C电伺服试验机,利用人工浇注素混凝土节理试样进行了不同剪切变形速率、法向应力和起伏角情况下的剪切试验,研究了节理破坏模式和刚度特征及其与起伏角、剪切变形速率和法向应力之间的关系。研究结果表明,试样破坏模式主要受起伏角控制,小起伏角情况下节理呈现磨损破坏模式,大起伏角情况下节理呈现剪断破坏模式,法向应力和剪切变形速率对节理破坏模式有一定的影响;节理的剪切刚度随剪切变形速率和起伏角的增大而增大,增大幅度随变形速率的增大有减小趋势;节理的剪切刚度随法向应力的增大而增大,基本呈线性关系。提出了考虑剪切速率和起伏角度影响的节理剪切刚度公式,并根据试验结果对剪切刚度公式进行了拟合。  相似文献   

煤矿区地质环境承载能力及其评价指标体系研究   总被引：4，自引：2，他引：2  

夏玉成 《煤田地质与勘探》2003,31(1):5-8

煤矿区的地质环境受自然地质作用控制和人类工程活动的扰动,其地质环境又具有一定的抗扰动能力。本文提出煤矿区地质环境承载能力的概念及其评价指标体系,并举例介绍地质环境承载能力的评价方法。   相似文献   

基于传递系数法的滑带土抗剪强度参数反分析研究          下载免费PDF全文

尚瑾瑜  李松  李新生 《甘肃地质》2012,(3):85-88

滑坡滑带土抗剪强度参数的合理选取是进行滑坡稳定性分析和治理设计的关键。本文结合滑坡的发育阶段,合理选取滑坡稳定性评价指标,基于反分析的基本原理,利用至少两个反分析剖面,采用试算、插值和图解法求解滑带土的抗剪强度参数,对比室内剪切试验数据,该方法最终所得参数基本满足工程要求,可为其它滑坡的稳定性分析及治理工程设计提供借鉴。  相似文献   

上海重塑粘性土的直剪特性研究   总被引：1，自引：0，他引：1  

陈敏  管飞 《上海国土资源》2012,33(1):79-82

上海地区浅层广泛分布的淤泥质粉质粘土、淤泥质粘土和粘土具孔隙比大、含水量高、压缩性大、强度低等特点,容易对工程造成严重不良影响。对这三种土重塑样的直剪特性进行了系统研究,试验方法包括固结快剪和固结慢剪,剪切过程中量测剪切位移和竖向压缩量,剪切结束后量测了破坏面上的土样含水率。结果显示,固结慢剪试验中土样均硬化,剪切位移达6mm时仍未破坏;而固结快剪试验中,除粉质粘土外另两类土在0.2mm的位移下就达到剪切强度。通过试验得到了剪切应力与剪切位移关系、剪缩变形量和抗剪强度参数等。结合试验结果,对粉质粘土与粘土的不同结构导致直剪特性的差异进行了分析讨论。可为上海重塑土的结构及力学特性研究提供依据和借鉴。  相似文献   

冻融作用对饱和粉质黏土抗剪性能的影响   总被引：4，自引：0，他引：4  

于琳琳  徐学燕  邱明国  闫自利  李鹏飞 《岩土力学》2010,31(8):2448-2452

为研究季节冻土地区冻融作用对道路边坡土体抗剪性能的影响规律,在不同冻结和融化温度、不同冻融循环次数、开放和封闭体系条件下对冻融饱和原状粉黏土试样进行了不固结、不排水剪切试验。试验结果表明:饱和原状粉质黏土冻融后,黏聚力降低,内摩擦角增大,冻结温度越低,冻融作用对黏聚力和内摩擦角的影响越小,随着冻融循环次数的增加,5～7次冻结循环后二者的变化逐渐趋于稳定。水分补给会强化冻融作用对试验土抗剪性能的影响;融化温度对试验土的抗剪性能影响很小。  相似文献   

Deterministic and statistical size effect during shearing of granular layer within a micro‐polar hypoplasticity     

J. Tejchman  J. Górski 《国际地质力学数值与分析法杂志》2008,32(1):81-107

The paper deals with numerical investigations of a deterministic and statistical size effect in granular bodies during quasi‐static shearing of an infinite layer under plane strain conditions, free dilatancy and constant pressure. For a simulation of the mechanical behaviour of a cohesionless granular material during a monotonous deformation path, a micro‐polar hypoplastic constitutive relation was used which takes into account particle rotations, curvatures, non‐symmetric stresses, couple stresses and the mean grain diameter as a characteristic length. The proposed model captures the essential mechanical features of granular bodies in a wide range of densities and pressures with a single set of constants. In the paper, a deterministic and statistical size effect is analysed. The deterministic calculations were carried out with an uniform distribution of the initial void ratio for four different heights of the granular layer: 5, 50, 500 and 2000 mm. To investigate the statistical size effect, the Monte Carlo method was applied. The random distribution of the initial void ratio was assumed to be spatially correlated. Truncated Gaussian random fields were generated in a granular layer using an original conditional rejection method. The sufficient number of samples was determined by analysing the convergence of the outcomes. In order to reduce the number of realizations without losing the accuracy of the calculations, stratified and Latin hypercube methods were applied. A parametric analysis of these methods was also presented. Some general conclusions were formulated. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

三轴剪切总应力强度指标的回归求值   总被引：2，自引：0，他引：2  

王星辉 《地球科学与环境学报》2004,26(1):52-54

工程勘察三轴试验的总应力强度指标的计算,运用解析几何原理导出任意两个应力圆公切线切点坐标计算公式,尤其是直接计算切线斜率.各切点通过线性回归建立合切线(包线)的直线方程,进而计算凝聚力Cu和摩擦角φu.采用数据直接计算方法,替代了以前手工图解或计算机交互图解,计算速度快,精度高.  相似文献   

The Late Paleozoic fold-thrust structure of the Tunka bald mountains, East Sayan (southern framing of the Siberian Platform)     

A.B. Ryabinin  M.M. Buslov  F.I. Zhimulev  A.V. Travin 《Russian Geology and Geophysics》2011,52(12):1643-1661

According to the new geological, geochronological, and structural data, the Tunka bald mountains (East Sayan) have a nappe structure, which formed in the Late Carboniferous–Early Permian. The deformations have been dated by the ⁴⁰Ar–³⁹Ar method on the basis of syntectonic micas and amphiboles, whose structural and spatial positions have been determined in oriented thin sections. The geometrical analysis of macro- and microstructures has revealed three development stages of the structures, which followed one another in progressive deformation. The first (thrust-fault) stage (316–310 Ma) comprised a group of N-verging thrust sheets. In the second (fold deformation) stage (305–303 Ma), they were folded. The third (strike-slip fault) stage (286 Ma) comprised high-angle shears, along which V-shaped blocks were squeezed westward from the most compressed areas. All the structures developed under near-N–S-trending compression. The thrusting in the Tunka bald mountains was coeval with the major shear structures in the eastern Central Asian Fold Belt (Main Sayan Fault, Kurai, Northeastern, and Irtysh crumpled zones, etc.). Also, it was simultaneous with the formation of continental-margin calc-alkalic and shoshonite series (305–278 Ma) as well as that of the alkali and alkali-feldspar syenites and granites (281–278 Ma) of the Tarim mantle plume in the Angara–Vitim pluton, located near and east of the studied region. Thus, the simultaneous development of the Late Paleozoic structures, active-margin structures, and plume magmatism in southern Siberia might have resulted from the global geodynamic events caused by the interaction between the tectonic plates which formed the Central Asian Fold Belt.  相似文献   

结构性土固结不排水剪特性的一种描述方法   总被引：2，自引：0，他引：2  

王常明  匡少华  王钢城  邢玉东 《岩土力学》2010,31(7):2035-2039

针对结构性土的固结不排水剪性状,提出一种基于扰动状态概念的描述方法。通过三轴固结不排水剪试验,分析了结构性土固结不排水剪切过程中的剪应力、孔隙水压力与轴向应变的关系特点。根据扰动状态概念的原理,采用邓肯-张的非线性弹性模型描述相对完整状态的应力-应变关系,用孔隙水压力作为参量定义了一个新的扰动函数,构建了一种描述结构性土固结不排水剪性状的本构关系。经验证,模型计算结果与试验数据吻合较好,可统一描述应变软化型和应变硬化型应力-应变关系。  相似文献