Geological and Geotechnical Characteristics of Marine Clays at the Busan New Port   总被引：1，自引：0，他引：1  

S. G. Chung  C. K. Ryu  K. Y. Jo  D. Y. Huh 《Marine Georesources & Geotechnology》2005,23(3):235-251

Despite a number of geotechnical investigations that have been carried out in the Busan new port area of South Korea, the local practicing engineers have been unable to deduce successfully the geotechnical properties of the clays due to their spatial variation. In the area, clay deposits, so-called Pusan clays, are unusually thick, varying from 20 m to 70 m in thickness. For this study, comprehensive geological and geotechnical investigations were carried out with sophisticated sampling techniques, in situ and laboratory tests as well as geological analyses at an additional three locations. As a result of the investigations, it was found that depositional environments are closely related to the relative changes in sea level and have different features depending on location and depth. The clays consist of soft and stiff clays in the upper and the lower layers, respectively, which are classified as normally consolidated and cemented clay. Moreover, most of the geotechnical properties undergo small changes due to their depositional environment. Information about these effects would be quite helpful to understand the spatial variation of geotechnical properties as well as the effect of sample disturbance. Some correlations which reflect the geological history of the deposts were conducted for physical indexes and mechanical properties.  相似文献   

Contaminant transport modeling in marine clays   总被引：1，自引：0，他引：1  

G. Rajasekaran  K. Murali  S. Nagan  V. Amoudhavally  V. Santhaswaruban   《Ocean Engineering》2005,32(2):117-194

The need to develop various offshore containment systems encourages the contaminant transport study in marine clays. In the present investigation, an attempt has been made to examine six cases of contaminant transport in marine clays. Adequate literature background on the chemical diffusion of soils, and the earlier reported modeling techniques relevant to the present work have been highlighted. These methods enable a rapid examination of the impact of contaminant physical properties on the environment over a period of time. The numerical results of this study help to understand the chemicals transport phenomena in the marine environment especially at sea bed.  相似文献   

Voltammetric characterization of Boda Albitic Claystone. Comparison with previous Mössbauer spectroscopy results     

《Applied Geochemistry》2016

We used ‘Voltammetry of MicroParticles’ to investigate electrochemically samples from the Boda Albitic Claystone, a potential site for deep underground disposal of nuclear waste in Hungary. The samples were collected near the surface and at a depth of 1050 m. The electrochemical characterization in acidic media allowed the identification of Fe²⁺ and Fe³⁺ ions associated with clays, hematite and pyrite. The cathodic detection of pyrite does not raise special difficulties, but the anodic one is complex and depends on the time of the samples exposure to the atmosphere. This work completes a previous Mössbauer spectroscopy study by clarifying the presence, or absence, of extremely small amounts of pyrite in some samples.  相似文献   

A new approach to anisotropic,bounding surface plasticity: general formulation and simulations of natural and reconstituted clay behaviour     

A. Gajo  D. Muir Wood 《国际地质力学数值与分析法杂志》2001,25(3):207-241

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土壤腐殖物质特征及其对有机碳长时间尺度稳定性的指示：以陕西洛川黄土剖面为例          下载免费PDF全文

孙旭辉  李福春  师焕芝  代静玉  吴枫  金章东 《地学前缘》2011,18(6):117-124

在长时间尺度上研究土壤中腐殖物质的组成和腐殖化特征对于正确评价土壤有机质的稳定性具有重要意义。文中对洛川黄土/古土壤剖面S8以上的17个黄土和古土壤样品中的胡敏酸（HA）、富里酸（FA）和胡敏素（HM）进行定量研究,并对HA和FA的E465、E665值等进行了测定。结合该课题组对矿物组成、总有机碳（TOC）及其各组分含...  相似文献   

Composition and geochemistry of clay sediments offshore the northeastern Sicilian coast (Southeastern Tyrrhenian Sea,Italy)     

Carmelo Saccà  Domenica SaccàPreziosa Nucera  Anna De Fazio 《Estuarine, Coastal and Shelf Science》2011

Grain-size, mineralogical and chemical analyses were carried out on fine fraction of sediments collected in the Gulfs of Patti and Milazzo, two borderland basins in the Southern Tyrrhenian extending offshore the northeastern Sicilian coast.  相似文献   

Probing deep weathering in the Shale Hills Critical Zone Observatory,Pennsylvania (USA): the hypothesis of nested chemical reaction fronts in the subsurface   总被引：1，自引：0，他引：1  

Susan L. Brantley  Molly E. Holleran  Lixin Jin  Ekaterina Bazilevskaya 《地球表面变化过程与地形》2013,38(11):1280-1298

Weathering is both an acid‐base and a redox reaction in which rocks are titrated by meteoric carbon dioxide (CO₂) and oxygen (O₂). In general, the depths of these weathering reactions are unknown. To determine such depths, cuttings of Rose Hill shale were investigated from one borehole from the ridge and four boreholes from the valley at the Susquehanna Shale Hills Observatory (SSHO). Pyrite concentrations are insignificant to depths of 23 m under the ridge and 8–9 m under the valley. Likewise, carbonate concentrations are insignificant to 22 and 2 m, respectively. In addition, a 5–6 m‐thick fractured layer directly beneath the land surface shows evidence for loss of illite, chlorite, and feldspar. Under the valley, secondary carbonates may have precipited. The limited number of boreholes and the tight folding make it impossible to prove that depth variations result from weathering instead of chemical heterogeneity within the parent shale. However, carbonate depletion coincides with the winter water table observed at ~20 m (ridge) and ~2 m depth (valley). It would be fortuitous if carbonate‐containing strata are found under ridge and valley only beneath the water table. Furthermore, pyrite and carbonate react quickly and many deep reaction fronts for these minerals are described in the literature. We propose that deep transport of O₂ initiates weathering at SSHO and many other localities because pyrite commonly oxidizes autocatalytically to acidify porewaters and open porosity. According to this hypothesis, the mineral distributions at SSHO are nested reaction fronts that overprint protolith stratigraphy. The fronts are hypothesized to lie subparallel to the land surface because O₂ diffuses to the water table and causes oxidative dissolution of pyrite. Pyrite‐derived sulfuric acid (H₂SO₄) plus CO₂ also dissolve carbonates above the water table. To understand how reaction fronts record long‐term coupling between erosion and weathering will require intensive mapping of the subsurface. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

考虑渐近状态特性的超固结土本构模型   总被引：1，自引：0，他引：1  

罗汀  侯伟  姚仰平 《岩土力学》2010,31(3):683-688

基于超固结土的UH模型,结合渐近状态概念,将适用于饱和砂土的渐近状态本构模型推广为考虑渐近状态特性的超固结土本构模型,用于描述土的超固结性和渐近状态特性。通过采用变换应力方法实现了模型的三维化。新提出的本构模型简单、参数较少,与剑桥模型相比,仅增加了一个材料参数,即伏斯列夫面斜率。该模型能够合理反映超固结土的硬化、软化、临界状态、剪缩、剪胀、应力路径依赖性、渐近状态等特性。  相似文献   

动荷载作用下结构性软土微结构变化的分形研究   总被引：1，自引：0，他引：1  

姜岩  雷华阳  郑刚  杨雄建 《岩土力学》2010,31(10):3075-3080

为探讨天津滨海新区典型结构性软土的动力特性,采用动三轴试验和压汞试验,对交通荷载作用下结构性软土微观结构变化进行了研究。取原状土和动荷载作用后的土样进行压汞测试,用分形理论对压汞测试数据进行分析,探讨孔隙分布特征,提出孔径划分的方法,给出了卓越频率与土体孔隙变化的规律。研究结果表明：在动荷载作用后,天津滨海新区典型软土的孔隙分布发生改变,可分为3种类型;利用Menger海绵模型研究交通荷载作用下结构性软土的孔隙分布特性是可行的;用孔隙分维数可实现对卓越频率的预测以及路基土体变形行为的机制分析。  相似文献   

Assessment of Compressibility Behavior of Naturally Cemented Soft Clays     

S. G. CHUNG  K. NAGENDRA PRASAD  T. S. NAGARAJ  J. G. CHUNG  K. Y. JO 《Marine Georesources & Geotechnology》2013,31(1-2):1-20

It Naturally cemented soft clays have components of strength and stiffness, which cannot be accounted for by classical soil mechanics (Leroueil and Vaughan 1990). This stems from the influence of structure caused by cementation due to environmental factors. It is necessary to evaluate the cementation bond strength at preyield and postyield stress levels of loading, to understand comprehensively the observed response from micromechanic considerations. This helps to better understand and evolve approaches to model the constitutive behavior in a consistent manner, according to the physical phenomenon of formation of cementation as an additional component to what is otherwise normally regarded as frictional behavior arising only from particulate nature of clays. Comparing the behavior of deep deposits of Pusan soft clays under stress with corresponding response of the same clay in its remolded state, it has been possible to take into account particulate and nonparticulate responses. The evolution of cementation bonding is modeled for different Pusan clays with the yield stress in oedometer compression as a normalizing parameter for obtaining the generalized relationship of cementation bonding with increase in stress. The already established model for determining the remolded behavior is appropriately modified to assess the behavior influenced by cementation. The model proposed consists of parameters, which are determined in routine investigations.  相似文献