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1.
黄土的粒度组成和分布既能够反映其沉积环境,又在很大程度上决定了黄土的物理力学及水理性质。粒度分析表明黄土的粒度频率分布曲线包含多峰分布和单峰分布两种形式。对比研究发现:粒度具多峰分布的黄土其粘粒含量相对较高,微结构一般为镶嵌微孔半胶结结构或絮凝状胶结结构,比表面积大,平均孔径小,微孔隙和小孔隙含量高,一般超过孔隙总量的60%,其工程地质性质明显优于具单峰分布的黄土,且多峰分布特征愈明显即细粒部分的次峰愈高,其工程地质性质愈稳定,渗透系数的各向异性愈低。 相似文献
2.
含粘粒量黄土抗震陷性能的试验研究 总被引：1，自引：0，他引：1
对甘肃含粘粒黄土粘粒含量不同的原状土样进行了室内动三轴试验、激光粒度分析试验、化学分析和电镜扫描试验,对比分析试验结果后得出,粘粒含量不同,可引起黄土动力稳定性的变化;动剪应力强度与粘粒含量并非呈单调增加关系,而呈抛物线型;含粘粒的黄土,在同一固结比时,抗震陷性能最低点在粘粒含量16%~17%之间。 相似文献
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不同粘土矿物水敏性特征 总被引：2，自引：2，他引：0
通过改变砂样中的粘土矿物的种类和含量,结合咸淡水之间的单一和驱替实验,研究不同粘土矿物的水敏性特征。在单一的咸水和淡水情况下,当砂柱中的粘粒含量≤1.5%(重量比)时,其渗透系数基本不发生改变,即使粘粒含量从1.5%增加10%,其渗透系数也仅下降约一个数量级。各种粘土矿物中,蒙脱石导致含水介质渗透系数的下降最为明显,高岭土和伊利石约是其影响值的一半。咸淡水驱替实验中,加入蒙脱石颗粒的砂柱的渗透系数急剧下降,当蒙脱石含量达3~4%时,渗透系数已经下降的极低,可以看作不透水层,而加入高岭土和伊利石的砂柱的渗透系数没有急剧变化。对于这种现象的解释是:不同类型的粘土颗粒吸附不同数量的水分子,形成数量和大小不同的胶体团,使得介质渗透系数的变化量不同。 相似文献
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以陕北神府地区二郎山和清凉山晚更新世以来黄土剖面为例,应用粒度分析和扫描电子显微镜对陕北地区晚更新世黄土的微结构进行分析研究,探讨黄土微结构特征与其形成环境的关系。分析结果表明粒度小于0.005 mm的粘粒级含量在黄土与古土壤中差异最大,S1古土壤达30.4%,而L1黄土为24.7%;S1古土壤中大量出现铁质粘粒胶膜并呈流胶状,结构密实;L1黄土粘粒胶结物含量较少,土质疏松;陕北地区晚更新世S1古土壤形成于湿热的森林环境,L1黄土形成于凉偏湿的草原环境,S0黑垆土形成于暖湿的气候环境。 相似文献
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河床沉积物中有机质对其垂向渗透系数的影响分析 总被引：1，自引：1，他引：0
采用水头下降立管法对渭河5个区域的河床渗透系数进行测定,并在室内分析其粒径分布及有机质含量。运用SPSS18.0软件分析不同类型的沉积物中有机质含量与其垂向渗透系数的关系。结论为:有机质主要通过改变黏土的结构从而改变沉积物的结构,进而影响垂向渗透系数值的大小;有机质对垂向渗透系数的影响关系与沉积物中有机质含量及黏土含量的组合关系密切相关。 相似文献
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“治沟造地”修建水库,导致土地盐渍化,而盐渍土的渗透性是影响工程设计、施工安全的重要因素,因此阐明不同盐分含量及类型条件下的重塑黄土渗透性至关重要。通过制备不同盐分含量的钠、钙盐重塑黄土试样,开展一系列室内变水头饱和渗透试验,探析重塑黄土渗透系数随盐分含量的变化规律。结果表明：随盐分含量增加,重塑黄土饱和渗透系数逐渐减小,两者呈负指数相关,含盐重塑黄土渗透系数与不含盐重塑黄土相比均有不同程度减小;同一盐分含量条件下,钙盐黄土的渗透系数小于钠盐黄土的渗透系数。采用核磁共振（nuclear magnetic resonance,NMR）技术,测取重塑黄土的孔隙水赋存状态与孔隙结构随盐分含量与类型的变化;当盐分含量小于2%时,随盐分含量增加,孔隙水赋存状态与孔隙结构的变化使重塑黄土渗透系数迅速减小;当盐分含量大于2%时,随盐分含量增加,孔隙水赋存状态变化使重塑黄土渗透性增加,而孔隙结构变化使重塑黄土渗透性减小且对渗透性的影响占主导,因此重塑黄土的渗透系数缓慢减小;同一盐分含量条件下,钙盐重塑黄土的孔隙水赋存状态和孔隙结构的变化比钠盐重塑黄土更显著。 相似文献
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软弱夹层粘粒含量与抗剪强度参数的关系分析 总被引：6，自引：1，他引：5
分析表明,赋存环境相同、粘土矿物成分以伊利石为主的软弱夹层,在相同稠度状态下粘粒含量与抗剪强度参数具有很好的相关性。通过现场和大量的室内试验成果,建立了各种稠度状态下粘粒含量和抗剪强度参数之间的相关关系式,揭示了在研究粘粒含量对抗剪强度参数影响时,还应当考虑软弱夹层所处的天然状态。结合《温凝土重力坝设计规范》中提出的用粒度成分定量指标选取软弱结构面抗剪强度参数,对软弱夹层抗剪强度参数取值问题进行了探讨。 相似文献
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地下水资源是长江三角洲地区社会经济发展的重要后备资源.根据江苏宝应境内钻取的145m深的By1孔岩芯,沉积物粒度分析显示,钻孔20m之下有5个主要的含水层,主要是粉砂质砂层,其间是粘土质粉砂层隔水层;在钻孔60m之下有3个厚度超过10m的含水层,显示该区域深部地下水资源十分丰富,具有较大的开发价值.宝应钻孔揭示的地下含水层上覆广泛分布末次冰盛期的硬质粘土层,对地下水资源起到明显的保护作用,未来地下水资源开发中应重视"硬枯土层"的保护和防止海水内侵,并加强深层地下水资源的科学调查与开发管理. 相似文献
12.
济宁三号煤矿目前开采的煤层为上组煤的3煤(3上、3下煤),自投产以来,发生多次涌水,如13下01综放面侏罗系底部含水层最大涌水量达533.84m3/h,63下01综放3煤顶板砂岩最大涌水量527m3/h,曾一度出现工作面局部被淹而导致停产,对矿井的安全高效生产构成了极大的威胁。在综合分析研究上组煤顶板各含水层的水文地质特征和充水条件的基础上,认为上组煤(3上、3下煤)开采时的直接充水水源为3煤顶板砂岩含水层;间接充水水源是侏罗系含水层水以及局部地区对侏罗系含水层起补给作用的第四系含水层;部分地区侏罗系含水层被采动裂隙导通而成为直接充水水源,大部分地段第四系底部均为粘土,有效的阻隔了第四系与下伏侏罗系含水层的水力联系,对下伏含水层补给微弱;充水通道主要有断层、采动裂隙、封闭不良钻孔和破坏的井筒。为指导下一步煤矿生产预防水害事故提供了依据。 相似文献
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上海地区更新统承压含水层沉积机制（模式）探讨 总被引：3，自引：0，他引：3
区内更新世古河道变迁,具有暖期向南摆动,冷期向北摆动的规律。一、三期古河道暖期向南摆,河床中沉积的砂层形成了含水层,其间所夹持的隔水层(粘土、亚粘土)是二期古河道冷期向北摆动时的边滩或心滩沉积,从而形成了含水层与隔水层。无论是冷期或暖期的古河道都形成各自的含水砂层及隔水牯土、亚粘土层。对暖期形成含水层,冷期形成隔水层的看法,笔者认为值得商榷。 相似文献
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铝土矿的形成受到气候条件的严格限制。通过对黔北务川—正安—道真地区下二叠统铝土矿层钻孔岩心样品主量元素和黏土矿物的综合研究,探讨了铝土矿层形成时期黔北地区的古气候环境以及淋滤作用对矿层的改造。从下至上,铝土矿层化学蚀变指数(CIA)由80左右上升至大于90,成分分异指数(ICV)由0.8下降至0.1。X射线衍射分析发现,研究区铝土矿层中的黏土矿物组分为高岭石、伊利石与绿泥石,其中高岭石在各个钻孔中广泛存在且在大部分层位中含量较高,平均含量为34.2％,并呈机械碎屑或基质形态产出且有进一步风化成为铝矿物的现象;伊利石主要以机械碎屑形式产出,平均含量为21.5％,赋存于矿层的黏土质部分,结晶度变化范围为0.22°～0.71°;绿泥石多为基质,部分层位中含量极高且伴随ICV值上升,平均含量为44.3％,为后期成岩过程中由高岭石转化而成。矿层内极高的CIA值与广泛存在的高岭石证明,铝土矿形成时为炎热潮湿的古气候。而矿层内部ICV值的波动可能与淋滤作用所引起的矿层内元素迁移活动有关。 相似文献
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第四系第Ⅱ含水组地下水经长期开采,早已完成主固结过程;开采Ⅱ组地下水可使上覆咸水淡化越流,最终加快各类地表水的入渗,多年来在适宜地段大幅恢复Ⅱ组地下水的开采。经调查大部分水井水质恶化非含水层水质变化,绝大多数地区咸水底界没有下移趋势。笔者认为在滨海平原区能使咸、淡水保持数10万年高浓度差的粘土层,具有半透膜特性。由于部分观点与前人研究结果相左,澄清"井水咸化"与地下水咸化污染的区分就显得尤为重要。为此,将多年地下水水质调查资料进行分类,推进咸化污染机理研究推进。 相似文献
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G. V. Kharitonova S. E. Sirotskii N. P. Chizhikova N. S. Konovalova A. S. Manucharov Z. Tyugai E. V. Utkina 《Lithology and Mineral Resources》2014,49(3):201-212
The grain size distribution and fraction composition of bottom sediments (BS) in the Amur River are studied. The total composition of sediments, their clay subfractions—water-peptizable (WPC) and aggregated (AC) clays—and residue after clay elutriation were analyzed. It has been established that contents of Fe, Mn, Zn, and Cu in the clay subfractions are 2–4 times higher than in common bottom sediments and their residue left after the extraction of clay subfractions, confirming a significant role of clay minerals in the accumulation of elements mentioned above. It is shown that diatom algae participate in the accumulation and transport of Fe, Mn, Zn, and Cu in the river water-suspended matter-bottom sediments (clay minerals) system. It has been established that high Zr concentrations in bottom sediments are related to the presence of zircon therein. 相似文献
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Problem of the distribution of clay minerals in water areas of the World Ocean and their relation to different (humid, arid, and volcanosedimentary) types of lithogenesis is considered. It is shown that layer silicates can be used as index minerals for distinguishing types of lithogenesis under conditions of marine sedimentation. Humid marine lithogenesis is represented by sediments of the White, Baltic, Black, and Mediterranean seas. Genetic link of marine clay formation with soil-climatic zones is clearly manifested in recent sediments of the World Ocean. Accumulation of statistic data on the mineral composition of clays allowed us to distinguish two modes of spatial-latitudinal distribution of clay minerals: maximal concentrations of illites and chlorites are confined to high latitudes, whereas kaolinite and smectite accumulate in the equatorial zone. In the arid lithogenesis, the dependence of clay formation on drainage areas is practically absent. The whole process is realized in surficial sediments and bottom waters: under conditions of intense evaporation, especially in closed water basins, the concentration of elements in the medium is enough for the synthesis of layer silicates, such as palygorskite and sepiolite. The processes were studied based on the Paleogene Fergana Bay and bottom sediments of the Sea of Aral, as well as DSDP core materials from the Atlantic (near the western coast of Africa) and Indian (the Arabian Peninsula area) oceans. The investigation of processes of volcanosedimentary lithogenesis was carried out within the East Pacific Rise (on the basis of core materials obtained during cruises of R/V Dmitry Mendeleev and Akademik Kurchatov). The results obtained made it possible to establish authigenic (primarily celadonite) K-Fe mineralization in the most active geothermal zones. The formation of clay minerals has specific features in each of the studied (humid, arid, and volcanosedimentary) types of lithogenesis. This should be taken into consideration during the lithological investigations and the study of clay mineralogy of past geological epochs. Clay minerals (particularly, unstable mixed-layered phases) are actively used as index minerals for paleogeographic and climatologic reconstructions. 相似文献
18.
Characterization on arsenic sorption and mobility of the sediments of Chia-Nan Plain, where Blackfoot disease occurred 总被引：1，自引：1，他引：0
Zhaohui Li Hanlie Hong Jiin-Shuh Jean Andria J. Koski Chia-Chuan Liu Selim Reza Jeffrey J. Randolph Stephan R. Kurdas Jonathan H. Friend Sarah J. Antinucci 《Environmental Earth Sciences》2011,64(3):823-831
Higher levels of arsenic in the aquifers of Chia-Nan Plain in southwestern Taiwan were attributed to the cause of Blackfoot
disease in the area half a century ago. Although extensive studies were conducted on the occurrence, speciation, mobility,
and transport of arsenic in the region, the relationship between arsenic adsorption by different aquifer materials and the
concentration and speciation of arsenic in these aquifers was poorly delineated. This study focused on characterization of
sediments in the region, as well as determination of relations between arsenic adsorption and other geochemical and clay mineralogical
properties of the sediments. The arsenic adsorption capacity was positively related to the clay minerals, Fe, and Mn contents
in the sediments. The higher arsenic adsorption capacity of the sediments served as a sink for the arsenic during its transport
from the central mountains to the coast and as a source for its release under reduced environment and in the presence of humic
substances. 相似文献
19.
地下水资源是长江三角洲地区社会经济发展的重要后备资源。根据江苏宝应境内钻取的145m深的By1孔岩芯,沉积物粒度分析显示,钻孔20m之下有5个主要的含水层,主要是粉砂质砂层,其间是粘土质粉砂层隔水层; 在钻孔60m之下有3个厚度超过10m的含水层,显示该区域深部地下水资源十分丰富,具有较大的开发价值。宝应钻孔揭示的地下含水层上覆广泛分布末次冰盛期的硬质粘土层,对地下水资源起到明显的保护作用,未来地下水资源开发中应重视“硬粘土层”的保护和防止海水内侵,并加强深层地下水资源的科学调查与开发管理。 相似文献
20.
《International Geology Review》2012,54(10):972-980
Soil materials used to construct the impervious core of the Camligöze dam consist of clay minerals, quartz, feldspar, and calcite. Smectite and chlorite + kaolinite appear to be the dominant clay minerals. Illite-smectite and illite also are present. The soils are predominantly of the CL (inorganic clays, silty clays, sandy clays of low plasticity) type, and to a lesser extent of the MH (inorganic silts of high plasticity) type and gravelly, sandy, and silty clay. The study-area soils are not active, provide low to medium swelling potential, and are impervious when compacted. According to the undrained shear strength when compacted, materials can be regarded as “soft.” Evaluation based on specific gravity, maximum dry unit weight, optimum water content, liquid limit, and the plasticity index results in an assessment rating of the relative desirability of the tested soils for core as 3 (very high level of desirability). For a small quantity (20%) of the soils that are of the MH type, the desirability is 9 (very low level of desirability). The materials are generally usable as impervious material for the clay core. 相似文献