赣北红土区工程堆积体坡面水动力特性

为探明锥状工程堆积体坡面薄层水流剥蚀率与水力要素之间的关系, 室内模拟赣北红土区散乱锥状工程堆积体。通过人工降雨试验, 设计4种降雨强度(1.0~2.5mm/min)和3种砾石含量(10%~30%)完全组合。采用灰色关联度分析法, 评估坡面水力参数与土壤剥蚀率之间的关联度。结果表明:① 在试验条件下, 坡面水流功率与土壤剥蚀率呈幂函数关系;② 当堆积体砾石含量一定时, 以降雨强度为变量能反映堆积体坡面水力参数与土壤剥蚀率之间的关联度;③ 当降雨强度一定时, 大雨强下(≥1.5mm/min)堆积体砾石含量不宜作为灰色关联度分析的变量。综上所述, 水流功率是描述赣北红土区锥状工程堆积体侵蚀过程的最佳水力参数, 可用于建立堆积体侵蚀物理模型。     

库车前陆褶皱-冲断带前缘盐构造分段差异变形特征

库车前陆褶皱-冲断带前缘秋里塔格构造带发育大量盐构造,其类型丰富多样。根据野外露头、钻井和地震资料识别出的盐构造样式主要有盐推覆、盐枕、盐墙、盐焊接、鱼尾构造、盐撤凹陷、突发构造、断层传播褶皱、断层转折褶皱和三角带构造等。秋里塔格构造带盐构造变形表现出明显的分段差异变形特征,其中西段却勒地区以古隆起(盐下)—盐枕(盐层)—逆冲推覆构造(盐上)为主;中段西秋地区以构造斜坡(盐下)—盐墙(盐层)—断层传播褶皱、向斜(盐上)为主;东段东秋地区则以断层转折褶皱(盐下)—盐推覆(盐层)—断层传播褶皱(盐上)为主。造成这种盐构造分段差异变形的主要控制因素包括基底断裂、含盐层系、构造转换带和变形空间等方面的差异性,其中基底构造和含盐层系的差异性起主导作用。     

Depositional System of the Carboniferous Huanglong Formation, Eastern Sichuan Basin: Constraints from Sedimentology and Geochemistry

Using analyses of the lithology, sequences, paleoenvironment, and tectonic setting, the depositional system of the Carboniferous Huanglong Formation in the eastern Sichuan Basin was identified. The lithological characteristics of the Lower Member, Middle Member, and Upper Member were analyzed and classified. Before the use of carbon, oxygen, and strontium isotopes in the analysis, all of the geochemical data were tested for validity. On the basis of the Z values obtained from carbon and oxygen isotopes, the paleoenvironments of the three members were elucidated. Lower Member was dominantly an enclosed marine environment with intense evaporation and little freshwater input into the sea. Middle Member developed in a semi-enclosed to normal marine environment with many rivers. Upper Member was formed in a normal marine environment. The east Sichuan Basin was enclosed by paleouplifts before the deposition of the Huanglong Formation, forming a relatively enclosed depositional setting. Paleogullies developed in the Silurian strata that underlie the Carboniferous rocks; these paleogullies can be identified. On the basis of a comprehensive analysis, we propose that the Huanglong Formation developed in a platform system. Four microfacies were identified: supratidal flat, dolostone flat, grain shoal, and shelf microfacies. The high-permeability and high-porosity characteristics of the grain shoal microfacies are favorable for hydrocarbon accumulation, while the supratidal flat and shelf microfacies developed very few high-quality reservoirs. The paleogullies, in which increased amounts of grain shoal microfacies developed, controlled the distribution of high-quality reservoirs.     

高压相变晶体化学:Ⅰ.高压下SiO_2物相氧硅离子的半径变化和迁移行为

高压下随着压力增加,氧化物及硅酸盐矿物中的阳离子会发生从配位数低的多面体向配位数高的多面体迁移的现象,这种迁移是由于阴阳离子半径的比值发生改变引起的。对SiO2在高压下形成的各种多形的氧和硅的离子半径进行计算,发现氧离子半径是随压力增加及相变的发生而逐渐缩小,但硅离子半径随压力增加及相变的发生而有明显的增大。这种现象可能是在高压下离子化合物逐渐向金属相化合物转变引起的。     

南宁盆地第三系泥岩物理性质与强度关系的研究

根据南宁几大工程的泥岩物理试验参数,分析了南宁盆地第三系泥岩物理指标与强度的关系,得出物理指标与强度之间具有近似的单一关系,抗剪强度随含水量、孔隙比的减小而增大,而随干重度趋势的增大而增大。     

基于MODIS NDVI时序数列的柴达木盆地土地覆盖分类研究

以2003年柴达木盆地的MODIS卫星遥感影像为基础数据,结合野外实地考察资料,综合分析了2003年柴达木盆地的植被指数时间变化与空间分布特征,提取了该年度该区域各主要土地覆盖类型NDVI的时序数列曲线,采用NDVI时序数列变化曲线形状匹配方法对柴达木盆地进行了土地覆盖类型分类.在此基础上使用了将以月为单位的变化曲线转换为十二维空间中的单位向量,比较向量夹角以决定其相似度的先进算法,取得了良好的分类效果,获得了2003年柴达木盆地比较精确的土地覆盖分类图.提出了利用MODIS卫星遥感影像进行土地覆盖分类的新方法.     

地震断层摩擦残余热异常测量方法探讨———以WFSD- 1钻孔温度测量为例

以汶川地震断裂带科学钻探工程WFSD-1钻孔高精度相对温度梯度测量确定汶川地震断层为例,探讨了地震断裂带断层摩擦残余热温度测量方法。利用WFSD-1钻孔相对温度梯度温度测量取得的科学数据进行分析,发现在400~500 m、580~610 m及620~750 m三个测量段内存在温度正异常。结合地质资料综合分析,判定400~500 m、620~750 m段温度异常可能由地层热导率差异引起,并非断层摩擦残余热异常,判定位于不透水断层泥中温度异常深度580~610 m范围为断层主滑移带位置。      

湿位涡分析在河北东北部暴雨预报中的应用

应用湿位涡理论,对2008年6月25日发生在河北省东北部的1次局地暴雨天气进行了诊断分析。结果表明,暴雨产生在θse线陡立密集区附近,θse线陡立密集区附近对流稳定度较小,有利于湿斜压涡度发展,MPVI“高层正值区低层负值区垂直迭加”的配置是暴雨发生、发展的有利形势,暴雨区位于850hPa上MPVI零线附近,湿位涡在850hPa上具有MPV1〈0,MPV2〉0的特征,在夏季可以作为河北省北部预报暴雨的一个有效辅助工具。     

黄土地区公路崩塌危险性简易快速评价方法探讨马保成,范丽晓,田伟平

公路黄土崩塌灾害在陕北黄土地区多发、易发,给当地公路交通建设和运营造成严重危害。结合陕北$302（榆林至佳县）沿线典型路段黄土边坡的现场调研,研究公路崩塌灾害简易快速评价方法,对灾害科学评判及减灾具有重要的工程意义。首先,分析了影响黄土崩塌灾害的因素,并通过专家咨询法和相对比较评分法提取了4个关键因子作为识别指标,即破坏阶段、坡度、崩塌规模和坡高;其次,给各个识别指标赋以相应权重,对公路黄土崩塌危险性进行初步综合评价,并以K66＋100～K66＋650路段为例进行实例检验,为快速识别评价公路黄土崩塌提供了一种方法。     

青藏铁路设计与建设——第六届国际冻土工程会议回顾

The 6^th International Symposium on Permafrost Engineering was successfully held in China in September 2004. About 150 scientists and engineers from 7 countries attended the symposium in Lanzhou on 5～7 September, and about 35 people from 6 countries participated in the field trip along the QinghaiTibet Highway/Railway on 8～13 September and the seminar in Lhasa on 14 September 2004. During the Symposium, the latest progress on permafrost engineering and the surveys, design and construction of the Qinghai-Tibet Railway were exchanged and inspected. Fifty-eight technical papers in English from the Symposium were published in the first volume of the Proceedings of the Symposium, as a supplement of the Journal of Glaciology and Geocryology, before the symposium. About 6 papers from the symposium are published in the second volume in the volume 27(1) of the Journal of the Glaciology and Geocryology, after the symposium. The Qinghai-Tibet Railway (QTR) under construction will traverse 632 km of permafrost, and the engineers are facing unprecedented engineering and environmental challenges. With the QTR under construction and to be completed in 2007, permafrost engineering has become the research focus of permafrost scientists and engineers in China. Many encouraging and promising achievements in permafrost engineering have been obtained during the past three years. However, there are still numerous engineering and environmental problems needing to be solved or resolved. In the discussions, some experts pointed out that methods, such as removal of snow cover on the embankments and toe areas, light-color embankments and side slope surfaces, awnings for shading the solar radiation, hairpin or tilted thermosyphons, could be applied to actively cool the roadbed of the QTR. Some new ideas on utilization of the natural cold reserves were proposed to protect the QTR permafrost roadbed from thawing. Many questions and answers on the survey, design, construction, operations, maintenance and environmental protection were exchanged in situ and in the Lhasa seminar with participation by some major railway designers, regulators and administrators.