构造活动地区工程构造稳定性研究     

刘行松  钟嘉猷 《工程地质学报》1995,3(1):1-9

拟建的新疆喀拉喀什河乌鲁瓦提水电站位于现代地壳运动十分活跃的区域。野外证据显示出，坝区的Ｆ＿（１２）断层新活动延续到晚更新世，电站附近的石门北断层在第四纪有活动。对采自坝区及附近几条断层的断层物质样品进行了变形显微构造、石英颗粒表面形貌和微结构类型、ＴＬ年龄的分析测定，结果表明，Ｆ＿（１２）最新活动的上限时间不晚于３万年，Ｆ＿（３０）和石门断层的活动持续到晚更新世，石门北断层最新的活动的上限时间约２万年。根据区域断裂的分布和应力场的情况，进行了构造模拟实验，预测出工程区在区域应力场的继续作用下，应力集中在远离坝址的部位，坝址附近不会出现新的应力集中点。总体看，所选坝址是地壳活动区中相对较稳定的地段。  相似文献   

Long-term erosion on granitic roadcuts based on exposed tree roots     

Walter F. Megahan  Kathleen A. Seyedbagheri  Patrick C. Dodson 《地球表面变化过程与地形》1983,8(1):19-28

Exposed roots were used to estimate soil and bedrock erosion on the cut slopes of a 45-year-old road constructed in granitic soils of the Idaho Batholith. The original roadcut surface was defined by projecting a straight line from the toe of the cut past the end of the exposed root to the intersection of a straight line projected along the surface of the hillslope. A cross-sectioning technique was then used to determine erosion to the present roadcut surface. A total of 41 exposed root sites were used to estimate erosion on a 1350 m-long section of road. Average erosion was 1·0 and 1·1 cm/year for soil and bedrock respectively. Buttressing by tree roots caused lower erosion rates for soil as compared to bedrock. Both soil and bedrock erosion rates showed statistically significant correlations with the gradients of the original cut slope. The bedrock erosion data provide a reasonable estimate of the disintegration rate of exposed granitic bedrock exhibiting the weathering and fracturing properties common to this area. The road is located in a study watershed where long-term sediment yield data are available. Sediment data from adjacent study watersheds with no roads were compared to sediment data from the roaded watershed to estimate the long-term increase in sediment yield caused by the road. The increase amounts to about 2·4 m³/year. This figure, compared to the average annual on-site road erosion, provides an erosion to sediment delivery ratio of less than 10 per cent. Based on study results, road construction and maintenance practices are suggested for helping reduce roadcut erosion.  相似文献   

混合沉积和混积岩的讨论   总被引：36，自引：6，他引：30  

沙庆安 《古地理学报》2001,3(3):63-66

混合沉积物是指陆源碎屑与碳酸盐(包括异化粒等)在沉积上的混合。混合沉积可分为狭义的和广义的,狭义的是指陆源碎屑与碳酸盐组份的混合(在同一岩层内),而广义的混合则包括了狭义的和陆源碎屑与碳酸盐层构成交替互层或夹层的混合。混合沉积很早就引起了人们的注意,尽管碎屑岩和碳酸盐岩的研究与应用已很成熟,但对混积岩的研究多被忽视了。对狭义的混合沉积物有必要起一成因名称——混积岩。当人们接触到混合沉积时,除了分析研究它们的组分和结构特征外,还必须去思考,它们为什么能经常频繁地交互出观,或是直接混合在一起?倒底是：①陆源碎屑跑到碳酸盐的沉积背景里?②碳酸盐跑到陆源碎屑的沉积背景里?③二分别从各自的源地跑到第三种沉积背景里?还是④二本来就在同一沉积背景里?接下来就要思考是什么动力条件使它(们)能从这个沉积背景(环境)“跑”到另一个沉积背景(环境)里去?是水?是风?是自身?还是别的什么力量?那么,又是怎样的水动力或风动力条件呢?是正常条件,还是突发事件?很明显,要分析研究混合沉积和混积岩。这些问题就不得不细细加以考虑,深入进行研究。  相似文献   

Digital Image Based Approach for Three-Dimensional Mechanical Analysis of Heterogeneous Rocks   总被引：2，自引：0，他引：2  

S. Chen  Z. Q. Yue  L. G. Tham 《Rock Mechanics and Rock Engineering》2007,40(2):145-168

Summary This paper presents a digital image based approach for three-dimensional (3-D) numerical simulation and failure analysis of rocks by taking into account the actual 3-D heterogeneity. Digital image techniques are adopted to extract two-dimensional (2-D) material heterogeneity from material surface images. The 2-D image mesostructures are further extrapolated to 3-D cuboid mesostructures by assuming the material surface as a representation of the inner material heterogeneity within a very small depth. The iterative milling and scanning system is set up to generate the 3-D rock mesostructures. A Hong Kong granite specimen is used as an example to demonstrate the procedure of 3-D mesostructure establishment. The mechanical responses and failure process under the conventional Brazilian tensile test condition are examined through numerical analyses. The stress distribution, crack propagation process and failure model of heterogeneous material cases are simulated with a finite difference software. The numerical results indicate that material heterogeneity plays an important role in determining the failure behavior of rocks under external loading.  相似文献   

193nmLA-ICPMS对国际地质标准参考物质中42种主量和微量元素的分析   总被引：31，自引：16，他引：31  

柳小明  高山  袁洪林  Bodo HATTENDORF  DetlefGNTHER  陈亮  胡圣红 《岩石学报》2002,18(3):408-418

本文采用配备有 193nm Ar F准分子 (excimer)激光器的 Geo L as2 0 0 M剥蚀系统和 Elan6 10 0 DRC ICP- MS对 4个美国地质调查所 (USGS)玻璃标准参考物质以及 3个美国国家标准技术研究院 (NIST)人工合成硅酸盐玻璃标准参考物质中几乎覆盖整个质量数范围 (从 7L i到 2 38U)的 38个微量和 4个主量 (Na、Mg、Ti和 Mn)元素进行了分析。分析结果表明 ,无论是对 USGS还是 NIST玻璃 ,元素分析的相对标准偏差 RSDs和分析值与参考值之间的相对偏差 (RDs)一般优于 10 % ,RSD和RD较大的元素主要出现在含量很低或不均匀样品中。稀土元素的 RSD显示 ,除 AGV- 2 G可能存在不均匀现象外 ,其它所测样品在 6 0 μm尺度上 ,元素分布是均匀的。本研究证明 ,由于 ICP- MS具有 10 8cps(每秒计数 )的动态线性范围 ,本实验室的L A- ICPMS系统可定量分析含量在百分之几的主量元素及微量元素。分析精密度和准确度可与常规溶液雾化进样 ICP- MS方法相媲美  相似文献   

对山西应县木塔采用纳米复合纤维加固的建议   总被引：9，自引：0，他引：9  

李大华  徐扬  郑鹄 《山西地震》2001,(4):24-25

山西应县木塔是古人留给我们的稀世珍宝，如何妥善地保护好这一珍贵的遗产，使之在加固时尽量保持原有的风貌，是一项复杂而艰巨的任务。根据长期的研究成果和实际工作的经验，提出了用纳米复合纤维加固应县木塔的建议，介绍了纳米复合纤维材料的特点，分析讨论了加固时的一些具体技术问题。  相似文献   

Health Risks and Environmental Inequity: A Geographical Analysis of Accidental Releases of Hazardous Materials     

Florence Lansana Margai 《The Professional geographer》2001,53(3):422-434

This study examines the spatial distribution and impact of nonroutine accidental releases of hazardous materials relative to the demographic composition of residents in nearby communities. First, atmospheric dispersion modeling methods are used to delineate the impact zones of worst‐case accidents in two New York counties over the last ten years. Next, using accidental reports for 1997, GIS and statistical operations are used at the census tract level of the two counties to determine whether these incidents disproportionately affected disadvantaged neighborhoods. The results suggest that the areas of high‐impact from accidental releases of hazardous materials are best characterized by a large proportion of families below the poverty line, Hispanics, and other minorities.  相似文献   

贵池铜山铜矿床成因探讨   总被引：6，自引：6，他引：6       下载免费PDF全文

俞沧海 《地质与勘探》2001,37(2):12-16

铜山铜矿床矿化类型可划分为层状含铜黄铁矿型，含铜角砾岩型，含铜夕卡岩型和含铜班岩型，控矿因素为地层，岩浆岩及构造，其中层间断裂与接触带构造是主要的容矿构造，铅，硫，氢，氧同位素特征及成矿温度研究表明矿物质和热液主要来源于铜山岩体，矿床成因为层控夕卡岩型铜矿床。  相似文献   

新型环境矿物材料——堇青石质泡沫陶瓷的研制   总被引：5，自引：0，他引：5  

李金洪  鲁安怀  宋庭兵  黄英 《矿物学报》2001,21(3):481-484

以聚氨脂泡沫塑料为前驱体，高岭土、铝土矿和滑石为原料，经配方和工艺设计，制备了以堇青石为主晶相的泡沫陶瓷，制成品密度为0．310－0．447g/cm^3，气孔率为81．7％－87．6％，孔径为0．2－0．5mm,平均抗压强度为0．98MPa。探讨了烧成温度对材料气孔率、抗压强度和吸水率等性能的影响。  相似文献   

环境矿物材料基本性能：无机界矿物天然自净化功能   总被引：53，自引：23，他引：53       下载免费PDF全文

鲁安怀 《岩石矿物学杂志》2001,20(4):371-381

重点阐述环境矿物材料基本性能，包括矿物表面吸附、孔道过滤、结构调整、离子交换、化学活性、物理效应、纳米效应及与生物交互作用等，旨在发掘、凝炼并新提出物理方法和化学方法之后与有机界生物同效的无机界矿物天然自净化功能的基础理论与应用方法，以发展和完善无机矿物与有机生物所共同构筑的自然界中存在的天然自净化系统，并就目前笔者在黄铁矿、锰钾矿、金红石、蛭石、蒙脱石、苋铁铁钒等天然矿物方面已经完成和正在开展的一系列环境矿物材料研究工作进行了举例说明。  相似文献