Classification of inorganic natural fine-grained soils in Korea based on modified plasticity chart     

Juhyun Kim 《Marine Georesources & Geotechnology》2018,36(5):579-588

Classification of fine-grained soils is typically conducted using plasticity charts. The typically used plasticity chart proposed by Casagrande was questioned by Polidori proposing different classification criterion in separating clayey and silty soils. Using natural clayey and silty soils sampled from four different coastal sites in Korea, applicability of both Casagrande’s and Polidori’s plasticity charts was evaluated. Classification results of Korean natural soils based on the Casagrande’s and Polidori’s plasticity charts did not match well with those based on the soils’ behavior reported in the previous publication. The disagreement in classification of Korean natural fine-grained soils may result from disregard of considerable silt fraction effect on plastic and liquid limits for Polidori’s chart. Consequently, revised proposal of Polidori’s plasticity chart was tentatively made for further classification of fine-grained soils suitable for Korean natural soils by accounting the effect of silt fraction on soil classification.  相似文献   

Explicit stress–strain equations for modeling frictional materials     

Kenneth J. Xu  Martin D. Liu  Buddhima Indraratna 《Marine Georesources & Geotechnology》2018,36(6):722-734

In this paper, a comprehensive study on simulating the shearing behavior of frictional materials is performed. A set of two explicit equations, describing the relationship among the shear stress ratio and the distortional strain and the volumetric strain, are formulated independently. The equations contain three stress parameters and three strain parameters and another parameter representing the nonuniformity of stress and strain during softening. All the parameters have clear physical significance and can be determined experimentally. It is demonstrated that the proposed equations have the capacity of simulating the complicated shearing behavior of many types of frictional materials including geomaterials. The proposed equations are used to simulate the stress–strain behavior for 27 frictional materials with 98 tests. These materials include soft and stiff clays in both reconstituted and structured states, silicon sands and calcareous sands, silts, compacted fill materials, volcanic soils, decomposed granite soils, cemented soils (both artificially and naturally cemented), partially saturated soils, ballast, rocks, reinforced soils, tire chips, sugar, wheat, and rapeseed. It has been demonstrated that the proposed explicit constitutive equations have the capacity to capture accurately the shearing behavior of frictional materials both qualitatively and quantitatively. A study on model parameters has been performed.  相似文献   

A 3D finite element simulation model for TBM tunnelling in soft ground     

Thomas Kasper  Günther Meschke 《国际地质力学数值与分析法杂志》2004,28(14):1441-1460

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Techniques to measure grain-size distributions of loamy sediments: a comparative study of ten instruments for wet analysis   总被引：2，自引：0，他引：2  

DIRK GOOSSENS 《Sedimentology》2008,55(1):65-96

Ten instruments for measuring the grain‐size distribution of loamy sediments in water were tested in a comparative study. Instruments tested were: the Malvern Mastersizer S, the Coulter LS 200, the Fritsch Analysette 22 (version C), the Horiba Partica LA‐950, the Sedigraph 5100, the Atterberg cylinder, the Coulter Multisizer 3, the CIS‐100, the EyeTech and the image analysis software Histolab. The first four instruments use laser diffraction. The Sedigraph and Atterberg cylinder are based on sedimentation. The Coulter Multisizer 3 uses impedance measurements and the last three instruments use optical techniques. Grain‐size analyses were carried out on four sediments with median grain diameters of approximately 35, 30, 12 and 9 μm, respectively, and with no particles >90 μm. The laser diffraction instruments produced the best results for the various criteria considered in this study, followed by the Coulter Multisizer 3 (electrical sensing zone technique), the sedimentation techniques and the optical methods. However, the study also showed that there is no such thing as an ‘ideal’ method because techniques may score differently according to the criterion tested. An appropriate evaluation thus requires that various criteria be considered. Issues to be taken into account are: type of sediment, quantity of sediment available, speed of measurement, complexity of the measurement protocol, processing of the data, reproducibility of the results and the specific aims of the study undertaken.  相似文献   

Diagenesis, palaeoclimate and tectono-sedimentary influences on clay mineralogy and stable isotopes from Upper Cretaceous marine successions of the Basque-Cantabrian Basin (N Spain)     

lvaro Jimnez Berrocoso  Maria Cruz Zuluaga  Javier Elorza 《Cretaceous Research》2008,29(3):386-404

Clay mineralogy and whole-rock stable isotopes (δ¹⁸O and δ¹³C) of Upper Cretaceous marly sediments on the Basque-Cantabrian Basin have been integrated to determine the main effects of diagenesis, palaeoclimate and tectono-sedimentary factors in sections belonging to deep- (Barrika) and platform-marine (Isla de Castro, Villamartín and Olazagutía) settings.The mean values for the clay assemblages and δ¹⁸O exhibit notable differences among the sections, partially explainable by the influence of diagenesis. The Barrika sediments, with more diagenetically advanced illite-smectite (I-S) mixed-layer (R1, 70% illite), authigenic chlorite, and low δ¹⁸O (−4.05‰ PDB), experienced higher diagenetic grade than Isla de Castro and Olazagutía, which have R0 I-S (20% illite) and heavier δ¹⁸O. Villamartín was also affected by higher diagenesis than Isla de Castro and Olazagutía, given the occurrence of R1 I-S (60% illite) and low δ¹⁸O (−4.11‰ PDB). However, the absence of other clays in Villamartín (e.g. authigenic chlorite) is indicative of less diagenetic grade than Barrika. These results show the useful integration of clay mineralogy and stable isotopes to detect different diagenetic grades in distinct marine successions of the same basin.Despite being influenced by diagenesis, the clay mineralogy partially preserves its inherited signature. This allows detection of major contents of I-S and mica, and minor kaolinite, interpreted as indicative of warm palaeoclimatic conditions. High kaolinite content in Villamartín and absence of kaolinite in Isla de Castro, though, are considered to be a product of neither diagenesis nor palaeoclimatic influences. Instead, tectono-sedimentary causes, related to unsuitable conditions for clay formation and transport from the local source areas, contributed to original clay differences. The inferred effects of diagenesis, palaeoclimate and tectono-sedimentary factors make this work important to show the potentially great variety of controls on the clay mineralogy of marine sections, which are often uncritically treated in studies concerning the Late Cretaceous.  相似文献   

Degradation in Cemented Marine Clay Subjected to Cyclic Compressive Loading   总被引：1，自引：0，他引：1  

G. Gerald Moses  S. Narasimha Rao 《Marine Georesources & Geotechnology》2003,21(1):37-62

The influence of cyclic loading on the strength and deformation behavior of cemented marine clay has been studied. This marine clay is of recent Pleistocene origin and deposited in a shallow water marine environment. Open pits were dug in sheeted enclosures and from these pits, undisturbed samples were taken for strength testing. A series of standard triaxial shear tests and stress controlled one-way cyclic load tests were conducted at consolidation stress ranges below and above the preconsolidation pressure. For the stress levels below the preconsolidation pressure, the cyclic loading has brought about the collapse of the cementation bond through an increase in strains, and at higher pressure ranges, the soil behaves like typical soft clay. This experiment studied the rate of development of strain and pore water pressure and shows that rate is a function of number of cycles, applied stress, and stress history. In addition, soil degradation during cyclic loading is studied in terms of Degradation Index. Attempt has been made to predict stain, pore water pressure, and degradation index through an empirical model.  相似文献   

柴达木盆地第三系咸水湖相生油岩古沉积环境地球化学特征   总被引：9，自引：0，他引：9  

叶爱娟  朱扬明 《海洋与湖沼》2006,37(5):472-480

在系统分析柴达木盆地西部第三系咸水湖相生油岩样品的微量元素、有机物、粘土矿物组成的基础上,揭示了研究区生油岩的无机元素和有机质组成特征;并结合沉积环境的无机与有机地球化学指标,重建了生油岩沉积时的古沉积环境。生油岩的B、Cl-及伽玛蜡烷含量表明,沉积时的水介质条件是半咸水—咸水环境,并伴随湖盆沉积中心北迁过程各层位地层的盐度发生规律性时空]化;生油岩的Fe2 /Fe3 、S2-、Pr/Ph比值、藿烷碳数分布模式及黄铁矿含量反映其沉积时的沉积环境为强还原性;粘土矿物组合特征及含量揭示这些生油岩的沉积相带介于中心咸湖相和边缘咸湖相之间。  相似文献   

Petroleum geochemistry of the Kimmeridge Clay of onshore Southern and Eastern England     

Paul F. V. Williams 《Marine and Petroleum Geology》1986,3(4)

The Kimmeridge Clay is considered a major oil source rock for the North Sea hydrocarbon province. The formation is also developed onshore in an organic-rich mudstone facies. This paper examines the possibility of onshore oil generation from the Kimmeridge Clay. Geochemically, onshore basin margin sediments contain rich, potential source horizons with mainly Type l/Type ll oil-prone kerogen, but are immature. Some deeper Cleveland Basin sediments have reached marginal maturity. Burial history reconstruction suggests significant formation palaeoburial depths in central areas of the Cleveland and Wessex Basins. Computed vitrinite isoreflectance contours show the Wealden and Isle of Wight Kimmeridge Clay to be thermally mature. Basin modelling suggests an early Palaeogene onset of oil generation in parts of the Cleveland Basin, while maximum oil generation could have been reached by the formation base in the Isle of Wight area during the late Cretaceous. Although basin subsidence ceased in the Neogene, in the Weald and Isle of Wight, where the formation is still deeply buried, oil generation probably continued for some time during uplift. Thus significant quantities of oil could have been generated. Whether or not this oil is present today however, would depend on the correct timing of suitable migration and trap structures.  相似文献   

Effect of Pollutants on the Physical and Engineering Behavior of Lime-Treated Marine Clay     

G. Rajasekaran  S. Narasimha Rao 《Marine Georesources & Geotechnology》2001,19(1):17-35

Rapid industrial growth and increasing population has resulted in the discharge of wastes into the ocean, wastes which ultimately reach the seabed and contaminate the marine sediments. The soil-contaminants interaction, and their associated physico chemical properties with sediments control the behavior of marine clays. Marine clay deposits of low strength and high compressibility are located in many coastal and offshore areas. There are several foundation problems encountered in these weak marine clays. In this study, experimental work was carried out in the laboratory to stabilize soft marine clays using the lime column technique. Also the lime-induced effects on the physical and engineering behavior of marine clays in sulfate-contaminated marine environment was investigated. Consolidation tests indicate that compressibility of the lime-treated samples was reduced to 1/2-1/3 of the virgin soil after 45 days treatment. The test results also suggest that the lime column technique can be conveniently used to improve the behavior of contaminated marine clay deposits.  相似文献   

晚新生代洛川典型风尘堆积序列的延伸     

王先彦  鹿化煜  弋双文  邓成龙 《海洋地质与第四纪地质》2006,26(1):89-92

对中国黄土标准剖面———洛川黄土剖面之下的上新世红黏土进行了沉积特征和磁性地层学的研究,结果表明洛川红黏土堆积于约2.6~3.2 MaBP期间,从而确定世界惟一的黄土类地质公园的风尘开始堆积的年代约为3.2 MaBP。古气候替代性指标磁化率和粒度的分析表明,洛川风尘堆积序列记录了上新世到第四纪古气候的重大转型。  相似文献