Hydrogeochemistry of mine, surface and groundwaters from the Sanggok mine creek in the upper Chungju Lake, Republic of Korea

 The Sanggok mine used to be one of the largest lead-zinc mines in the Hwanggangri mining district, Republic of Korea. The present study characterizes the heavy metal contamination in the abandoned Sanggok mine creek on the basis of physico-chemical properties of various kinds of water samples (mine, surface and groundwater). Hydrochemistry of the water samples is characterized by the relatively significant enrichment of Ca²⁺, HCO₃ ^–, NO₃ ^– and Cl^– in the surface and groundwaters, whereas the mine water is relatively enriched in Ca²⁺, Mg²⁺, heavy metals, and HCO₃ ^– and SO₄ ^2–. The more polluted mine water has a lower pH and higher Eh, conductivity and TDS values. The concentrations of some toxic elements (Al, As, Cd, Cu, Fe, Mn, Pb, Se, Sr, Pb and Zn) are tens to hundreds of times higher in the mine water than in the unpolluted surface and groundwaters. However, most immobile toxic pollutants from the mine drainage were quickly removed from the surface water by the precipitation of Al and Fe oxyhydroxides. Geochemical modeling showed that potentially toxic heavy metals might exist largely in the forms of MSO₄ ^2– and M²⁺ in the mine water. These metals in the surface and groundwaters could form M²⁺, CO₃ ^2– and OH^– complex ions. Computer simulation indicates that the saturation indices of albite, alunite, anhydrite, chlorite, fluorite, gypsum, halloysite and strontianite in the water samples are undersaturated and have progressively evolved toward the saturation condition. However, barite, calcite, chalcedony, dolomite, gibbsite, illite and quartz were in equilibrium, and only clay minerals were supersaturated. Ground and mine waters seemed to be in equilibrium with kaolinite field, but some surface water were in equilibrium with gibbsite and seceded from the stability field of quartz. This indicates that surface water samples in reaction with carbonate rocks would first equilibrate with carbonate minerals, then gibbsite to kaolinite. Investigations on water quality and environmental improvement of the severely polluted Sanggok creek, as well as remediation methods on the possible future pollution of the groundwater by the acid mine drainage from the abandoned metal mines, are urgently required. Received: 4 February 2000 · Accepted: 9 May 2000     

深厚覆盖层建坝土体利用研究

本文通过深厚覆盖层基坑开挖现场原位试验及室内试验论证了覆盖层沉积时代越早、埋深越大和在有上覆盖重情况下力学性能和抗渗性能均有明显提高,总结了国内外覆盖层建坝土体利用经验,提出了覆盖层土体利用原则,以达到充分利用坝基下覆盖层、节约工期及降低造价目的。同时本研究可推动深厚覆盖层建坝技术发展,可供水利水电工程技术人员借鉴。     

浅议苏鲁造山带基底大地构造属性--以荣成-威海地区为例

苏鲁造山带的基底在大地构造上是归属华北板块还是扬子板块,抑或二者兼而有之还是二者都不是?存在着不同意见.依据造山带变质表壳岩的区域性对比和岩浆演化序列,特别是通过Nd同位素示踪所提供的信息,文章从事件演化的角度综合研究分析认为,苏鲁造山带基底的大地构造属性,既不应归于华北板块,也不宜归于扬子板块,而应作为一个独立的大地构造单元划出为宜.     

玉龙雪山西麓冰碛(水)砾岩的工程地质特性研究

作为滇西北、川西和西藏地区最重要的第四纪堆积物类型之一,冰川堆积物的工程性质及其相关的地质灾害和工程问题研究日益受到工程界的关注。通过对上述地区大量冰碛物和冰水沉积物的现场调查发现,冰碛物和冰水沉积物是一类成分、结构和性质都十分复杂的第四纪堆积物,其工程性质主要与母岩成分和充填胶结物的矿物成分密切相关。发育在石灰岩地区的冰碛物和冰水沉积物因钙质（方解石）的次生胶结,而成为单轴抗压强度达10.94～14.22 MPa的岩石,作者称其为“冰碛（水）砾岩”。结合滇藏铁路滇西北段线路比选和优化工作,对云南玉龙雪山西麓第四纪冰川堆积物的类型和分布特征进行了详细的野外调查;在室内物理力学试验的基础上,着重研究了冰碛（水）砾岩的胶结物成分与胶结作用、水稳性、力学性质、声波速度等方面的特性,这不仅可以丰富现代岩石力学的研究内容,而且对本区铁路工程建设和水力资源的开发具有重要的实际价值。     

Landowner Attitudes Toward Conservation Easements: Balancing the Private and Public Interest in Land

Private land conservation provides an opportunity to address problems of habitat fragmentation and biodiversity loss caused by an increase in the development and parcelization of private land. Conservation easements (CEs) are used to protect significant natural qualities of private land. In this study, we explore landowner attitudes toward CEs through the implementation of a mixed-mode survey to private landowners in the Whychus Creek Watershed (Deschutes County, Oregon). The results of an exploratory factor analysis suggest there are two dimensions to landowner attitudes toward CEs, an internal dimension and an external dimension. We found that positive external attitudes are primarily influenced by environmental beliefs, whereas positive internal attitudes are influenced by a suite of factors, including financial beliefs and perceived risk to private ownership. Awareness of CEs may also play a role in attitude development. Through this research, we argue that CEs may be beneficial in reintegrating the public good into private property.     

地壳介质各向异性电性本构关系讨论

讨论了地壳介质中常见的两类电性各向异性。推导了长波长条件下薄中向异性电导率张量;提出了一种新的电导率物理模型并由此推导了与ＥＤＡ裂隙相适应的各向异性电导率张量。从直流电法和大地电磁测深法的角度分别讨论了这两种电性各向异性所显现的地表视电阻率、阻抗和电位特征。     

景洪5.1,5.5级地震地下水动态预报启示

本动态追踪了１９９７年景兴５．１、５．５级中强震的孕震－发震的整个过程,异常阶段属性清楚,异常发展层次分明,有动态感,过程清晰完整,表明中强地震亦有孕震过程。震前异常阶段的属性和异常的准同步是地震预测的主要依据。跟踪各类异常,掌握地震孕育发展的进程,把握时机有可能预报一些地震。本是“八五”、“九五”攻关成果运用的结果之一。     

Recursive evaluation of interaction forces and property matrices from unit-impulse response functions of unbounded medium based on balancing approximation

Starting from the unit-impulse response matrix of the unbounded medium, a discrete-time formulation permitting the recursive evaluation of the interaction forces and a continuous-time formulation yielding property matrices corresponding to a model with a finite number of degrees of freedom are discussed. This is achieved using the balancing approximation method which is easily automated, guarantees stability and leads to highly accurate results. © 1998 John Wiley & Sons Ltd.     

CFG24型桩机的研制

认述了CFG24型桩机的设计原则，整机结构及工作原理，对该桩机的设计特点进行了重点介绍。     

Spectral Analysis of Nonlinear Drag Forces

The spectral properties of nonlinear drag forces of random waves on vertical circular cylinders are analyzed in this paper by means of nonlinear spectral analysis. The analysis provides basic parameters for estimation of the characteristic drag forces. Numerical computation is also performed for the investigation of the effects of nonlinearity of the drag forces.The results indicate that the wave drag forces calculated by linear wave theory are larger than those calculated by the third order Stokes wave theory for given waves. The difference between them increases with wave height. The wave drag forces calculated by use of hnear approximation are about 5% smaller than their actual values when measured in the peak values of spectral densities. This will result in a safety problem for the design of offshore structures. Therefore, the nonlinear effect of wave drag forces should be taken into comidemtion in design and application of important offshore structures.