砂土地基的黏性特性及其有限元模拟

采用非线性弹塑黏性有限元法模拟了砂土地基变速率加载室内试验,再现了砂土地基荷载-沉降曲线对加载速率突变、砂土蠕变以及应力松弛等加载情况下的响应和瞬时黏性中砂土黏性随加载进行的衰减现象。在有限元分析中,以非线性三要素模型为理论框架构建了可以综合考虑砂土黏性特性的弹塑黏性本构模型,用动态松弛法进行有限元求解,最后通过有限元与室内试验的对比分析研究了砂土地基所具有的黏性特性,同时验证了非线性三要素弹塑黏性模型用于模拟砂土黏性特征的合理性和正确性。     

日本MW 9.0级大地震前后华北和东北地区现今构造应力作用调整过程与研究意义探讨

为了探讨日本M_W 9.0级大地震前后华北和东北地区现今构造应力作用调整过程与研究意义,对华北和东北地区进行原位现今地应力绝对测量与实时监测、GPS测量,结果表明：日本大地震在山东半岛、华北北部地区和东北地区所诱发同震位移引起的张性效应调整周期分别约为6个月(即调整结束时间大约在2011年9月)、15个月(即调整结束时间大约在2012年6月)和26个月(即调整结束时间大约在2013年5月),张性效应调整周期与同震位移大小成正比。在这种调整过程中,往往表现出区域现今构造应力作用方式和构造应力场转换,并可能伴随重大地质事件(如地震等)的发生。2012年5月28日和29日、6月18日、8月26日及2013年1月11日在唐山及其周围地区分别发生的4.8级、3.2级、4.0级、3.3级和3.0级地震与华北北部地区构造应力作用方式和构造应力场转换有关,而2013年10月31日以来在吉林省松原市发生的地震群应与东北地区构造应力作用方式和构造应力场转换有关,而非一个大地震前的小震群。     

湘黔新晃-天柱重晶石矿床微量稀土元素和硫同位素研究

湘黔新晃-天柱地区的早寒武世重晶石成矿带是世界上最大的重晶石矿集区,在全球范围内具有代表性,对其进行 研究具有重要的科学意义。本文通过对新晃-天柱地区的重晶石矿床微量稀土元素和硫同位素研究表明：所有样品的 、比值以及重晶石含矿岩系稀土元素具有明显的负异常表明重晶石矿床形成时处于缺氧还原环境;重晶石矿石 表现出明显的正异常,反映了成矿过程受到了较强的海底热液物质的影响,表明钡可能主要来自于海底热液喷流物质; 重晶石的δ3值主要分布在,表现出重硫富集的特征,且重晶石硫同位素呈塔式分布,表明硫源来源单一,主 要来自同期海水硫酸盐。黄铁矿δ3值低于同期海水硫同位素组成,表明生物细菌对海水硫酸盐的还原起到了很大作用, 并且反映了矿床形成于海水交换有限的滞留的海盆系统。综合以上分析认为重晶石成矿时期为海底缺氧、热液活动频繁、 封闭半封闭的台地泻湖环境。     

时空数据的组织与应用研究

时空数据是智慧城市各个领域实现智能化的关键性支撑技术,智慧城市的建设离不开时空数据。本文以智能应用为导向,提出了时空数据的组织模型,构建了智慧城市时空大数据计算、分析、服务框架,实现了时空数据全生命周期的高效管理与智能应用。     

Crystallization conditions of peraluminous charnockites: constraints from mineral thermometry and thermodynamic modelling

Most igneous charnockites are interpreted to have crystallized at hot and dry conditions, i.e. at >800?°C and <3 wt.% H₂O and with an important CO₂ component in the system. These charnockites are metaluminous to weakly peraluminous and their formation involves a significant mantle-derived component. This study, in contrast, investigates the crystallization conditions of strongly peraluminous, metasediment-sourced charnockites from the Qinzhou Bay Granitic Complex, South China. To constrain the temperature-melt H₂O crystallization paths for the studied peraluminous charnockites, petrographic characterization was combined with fluid inclusion compositional data, mineral thermometry, and thermodynamic modelling. The uncertainties of the thermodynamic modelling in reconstructing the crystallization conditions of the granitic magmas have been evaluated by comparison between modelled and experimental phase relations for a moderately evolved, peraluminous granite (~70 wt.% SiO₂). The comparison suggests that the modelling reproduces the experimentally derived phase saturation boundaries with uncertainties of 20–60?°C and 0.5–1 wt.% H₂O for systems with ≤1–2 wt.% initial melt H₂O at ~0.2 GPa. For the investigated natural systems, the thermometric estimates and modelling indicate that orthopyroxene crystallized at relatively low temperature (750–790?±?30?°C) and moderately high to high melt H₂O content (3.5–5.6?±?0.5 wt.%). The charnockites finally solidified at relatively “cold” and “wet” conditions. This suggests that thermodynamic modelling affords a possible approach to constrain charnockite crystallization as tested here for peraluminous, moderately low pressure (≤0.3 GPa), and overall H₂O-poor systems (≤1–2 wt.% H₂O total), but yields results with increasing uncertainty for high-pressure or H₂O-rich granitic systems.     

Empirical Formula of Shear Strength of Rock Fractures Based on 3D Morphology Parameters

The prime objective of this work is to provide a reference to predict the peak shear strength of rock fractures. The paper studied some shear properties of rock fractures and proposed an empirical formula for the peak shear strength of rock fractures based on 3D morphology parameters. The rock fractures were induced in cylindrical sandstone and marble specimens by means of indirect tension. A rock direct shear apparatus (RDS-200) was adopted to conduct direct shear tests on five groups of rock fractures under different levels of normal load. Before the direct shear test, 3D morphology parameters of rock fracture surfaces were obtained using a 3D optical scanner. By analyses of direct shear test data, the relationships between peak shear strength, peak shear displacement, peak dilatancy angle, residual friction coefficient and peak normal stress were found. According to the evolution trends of peak shear strength and peak dilatancy angle along with the normal stress, an empirical formula was proposed to predict the peak shear strength of rock fractures in both sliding and cutting failure modes considering the 3D morphology parameters of rock fracture surfaces. The empirical formula could be commonly used for different types (sandstone and marble) and grain sizes (powder-grained, fine-grained, medium-grained and coarse-grained) of rock fractures.     

羌塘盆地石炭—二叠系烃源岩地球化学特征讨论

长期以来,羌塘盆地烃源岩的研究一直限于中生代地层,而对其古生代地层生烃能力一直缺乏系统研究。针对这一问题,本文选择羌塘盆地石炭—二叠系8条剖面的暗色泥岩及碳酸盐岩样品,对其从有机质丰度、有机质类型和热演化程度等方面进行了有机地球化学特征的分析。研究发现,石炭—二叠系可能烃源岩类型包括泥岩和碳酸盐岩两种,其分布总体上受沉积相的控制,碳酸盐岩烃源岩可能为局限台地相发育的泥晶灰岩,而泥质烃源岩主要为三角洲及斜坡相发育的暗色泥岩及凝灰质泥岩。石炭—二叠纪泥岩有机碳含量较高,具有较好生烃能力,大多达到烃源岩标准,尤其是刻莫石炭系剖面及贡日二叠系剖面,大多为中等—好烃源岩。碳酸盐岩有机碳含量总体比较低,为非烃源岩。石炭—二叠系碳酸盐岩烃源岩有机质类型为Ⅱ1型,泥质烃源岩有机质类型主要为Ⅱ2-Ⅲ型。石炭—二叠系烃源岩热演化程度总体较高,除盆地东部刻莫石炭系剖面处在成熟阶段外,大都处在高成熟—过成熟阶段,非常有利于天然气的生成,具备良好的天然气勘探前景。     

宜昌磷矿北部整装勘查项目深孔复杂地层钻探技术

宜昌磷矿北部整装勘查工程是湖北省大型磷矿资源勘查项目,由于地形复杂,工作量大,施工条件困难,钻孔深度达到1400 m,给钻探组织和施工带来更高的要求。本文就该项目的地质钻探工作进行简要总结,介绍了寒武系和震旦系地层中的钻探施工技术及应用效果。     

北京天竺地热田东坝凹陷南部地区地下热水富集的地热地质条件分析

以北京地区地热流体中温度和矿物质含量较高的东坝凹陷南部地区作为实例,在完整的地热钻孔及相关地质资料基础上,通过对研究区断裂构造、热储层、热储盖层、地温场、流体水化学特性和富水性等地热地质条件进行分析,研究造成该区地热流体中温度、矿物质含量升高的主要原因。研究表明：受太阳宫断裂北段、良乡—前门断裂和楼梓庄断裂的切割作用,东坝凹陷南部地区热储层下落近千米,形成了一个较为封闭的“黑箱子”区域。这种独特的地质结构导致东坝凹陷南部地区接受东南城区地热田侧向补给较少,长期处于较为封闭的还原环境;太阳宫断裂北段存在深部的热源通道,地层深部的高温热流顺断裂上涌在东坝凹陷南部地区的热储层富集,因此该区地热流体表现出温度高、矿物质含量高、富水性差的特征,该研究对我国今后地热资源的开发具有积极的借鉴意义。     

Trace Element Geochemistry of Devonian Strata in the Shizhuyuan Ore District, Hunan Province

<正>1 Introduction Both the Qiziqiao Formation and Shetianqiao Formation,which controls the occurrence and distribution of a great deal of metal mineral resources,are extensively developed in southern Hunan province(Liu et al.,1998),showing quite important indicative significance to deep concealed metal mineral resources(Yu et al.,2003).The geochemistry characteristics of Devonian strata could not affect the spatial occurrence shape of orebody