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93.
Stylolites are rough surfaces, formed by localized rock dissolution, and prevalent in carbonates and other sedimentary rocks. Their impact on porosity and permeability, and capacity to accommodate compactive strain, are well documented. This paper presents a meso-scale field study on sedimentary stylolites in carbonates, characterizing large-scale distributions of stylolites, including measurements conducted on longer than kilometer-long stylolites. Our field study suggests that on large scales connections between stylolites become important. Since connectivity, and also lack of connectivity, are expected to play a significant role in strain accommodation and hydraulic rock properties, we suggest that large-scale analysis may require a new characterization scheme for “stylolite populations”, based on their connectivity. We therefore divide sedimentary stylolite populations into three end-member types, which are correlated with the three possibilities for percolation of such systems: isolated stylolites (with zero percolation/connectivity), long-parallel stylolites (with 2-dimensional percolation/connectivity), and interconnected stylolite networks (with 3-dimensional percolation/connectivity). New statistical parameters and measures are devised and used to quantitatively characterize the different population types. Schematic mechanistic models are then offered to explain the evolution of the three end-member connectivity-classes. In addition we discuss the effect on fluid flow of the different population types. 相似文献
94.
This paper presents a semi-analytical solution to one-dimensional consolidation of viscoelastic unsaturated soils with a finite thickness under oedometric conditions and subjected to a sudden loading. The solution is obtained by using Lee’s correspondence principle based on the semi-analytical solution to one-dimensional consolidation of elastic unsaturated soils. The boundary contains the top surface permeable to water and air and the bottom impermeable to water and air. A typical example is given to show the evolution of excess pore-air and pore-water pressures as well as the total degree of consolidation of the soil layer with time for different ratios of air–water permeability coefficient, elastic modulus and viscoelastic coefficient. The one-dimensional consolidation behavior of viscoelastic unsaturated soil is discussed according to the semi-analytical solution. These results contribute to a better understanding of the consolidation behavior of viscoelastic unsaturated soils. 相似文献
95.
This paper presents the analytical solutions for nonlinear consolidation of soft soil around a shield tunnel with idealized sealing linings. By introducing the empirical relation between permeability and compressibility, along with the conformal transformation, the governing equations of nonlinear consolidation are established, and the corresponding analytical solutions are derived. Then, the Terzaghi consolidation solutions are derived from the degenerate governing equation of nonlinear consolidation. Through the predictions of different consolidation theories in both completely permeable and impermeable lining conditions, the influences of a tunnel acting as a drain and impacting the dissipation of pore pressure, degree of consolidation, long-term ground settlements and ground settlement rates are investigated. During the early stages of consolidation, the case studies reveal that the predictions made by this study strongly agree with the field data when a completely permeable lining is applied. This study confirms that a tunnel acting as a drain can accelerate the consolidation of soil and enlarge soil deformation due to consolidation. During long term consolidation, a notable nonlinearity of the soil consolidation is exhibited by a small and gradually decreasing settlement rate, showing agreement with the tendency of field data from the impermeable conditions. 相似文献
96.
简要介绍了CORS系统的发展情况,分析了GPS C级控制网测量的精度,就GPS网的布设、基线解算、GPS网平差及检核进行有益的探讨,旨在发挥CORS的优势,解决GPS控制网测量中控制点缺乏的问题,提高CORS的应用水平。 相似文献
97.
Monica E. Erdman Cin‐Ty A. Lee Wenbo Yang Lynn Ingram 《Geostandards and Geoanalytical Research》2014,38(1):51-60
With implications for the origin of ore deposits, redox state of the atmosphere, and effects of volcanic outgassing, understanding the sulfur cycle is vital to our investigation of Earth processes. However, the paucity of sulfur concentration measurements in silicate rocks and the lack of well‐calibrated reference materials with concentrations relevant to the rocks of interest have hindered such investigations. To aid in this endeavour, this study details a new method to determine sulfur concentration via high mass resolution solution inductively coupled plasma‐mass spectrometry (ICP‐MS). The method is based on an aqua regia leach, involving relatively rapid sample preparation and analysis, and uses small test portion masses (< 50 mg). We utilised two independently prepared standard solutions to calibrate the analyses, resulting in 4% accuracy, and applied the method to eight geochemical reference materials. Measurements were reproducible to within ~ 10%. Sulfur concentrations and isotopes of six reference materials were measured additionally by elemental analyser‐combustion‐isotope ratio mass spectrometry to independently evaluate the accuracy of the ICP‐MS method. Reference materials that yielded reproducible measurements identical to published values from other laboratories (JGb‐1, JGb‐2 and MAG‐1) are considered useful materials for the measurement of sulfur. Reference materials that varied between studies but were reproducible for a given test portion perhaps suffer from sample heterogeneity and are not recommended as sulfur reference materials. 相似文献
98.
通过拉曼光谱、同步辐射X射线散射和密度泛函理论(DFT)模拟,研究了质量分数为1.0 %-28.0 %的NH4Cl水溶液的微观结构变化。同时在室温下测量了粘度、接触角和电导率。由拉曼光谱和密度泛函理论模拟结果可知,当溶质浓度升高至10.0 %时,在2900 cm-1和3100 cm-1附近出现了明显的N-H作用峰,且随着质量分数的升高,NH4Cl水溶液中的氢键类型发生了转变。X射线散射结果表明,当NH4Cl水溶液质量分数升高至10.0 %时,差值对分布函数G(r)在2.98 ?附近出现明显双峰,表明在该浓度下溶液中NH4+-Cl-接触离子对开始成为主要微观作用形式。对NH4Cl水溶液的宏观物性研究表明,粘度、接触角和电导率均随着NH4Cl水溶液质量分数的增加而增大。作者推断,NH4Cl水溶液中氢键类型的转变、O-H...N键占比增多以及逐渐增加的NH4+-Cl-接触离子对,是粘度和接触角随溶质浓度增加而增加的微观本质因素;电导率的增加与溶液中有效导电离子数量增加有关。 相似文献
99.
收集2 291个来源于NIED F-net宽频带地震台网中心MW≥3.0地震的震源机制解,采用MSATSI构造应力反演方法,得到反映应力相对大小的R值的量θ和3个主应力轴的方位角与倾伏角,同时反演出每个网格的极射赤平投影P、T轴。以3D应力反演为导向,采用矩阵网格分区的方法,以纬度、经度、深度为坐标,将发生在每一区域的震源机制解投射到相应的矩阵区中,并反演出每个矩阵网格点的应力场变化及分布情况。反演结果表明,与板块交接的浅部区域不仅受到太平洋板块的挤压俯冲,同时也受北美板块的斜插作用;东北区域的深震为Benioff带俯冲作用的结果。 相似文献
100.
矿业城市可持续发展困境原因探析 总被引:2,自引:0,他引:2
矿业城市是指由于矿业资源的开采而形成的城市。长期以来,矿业城市在我国的经济建设中做出了重大贡献。然而,随着矿产资源的耗减和体制改革的深化,矿业城市在目前发展中普遍存在资源衰竭、污染严重、管理体制不合理等问题。特别是在当今全球经济一体化的新形势下,矿业城市面临着更加严峻的挑战,如何合理有效地利用资源,确保矿业城市可持续发展,文章对矿业城市发展中存在的主要问题及目前出现困境的原因进行了分析,并提出了我国矿业城市摆脱困境的对策和建议。 相似文献