固结过程对冻土应力-应变特性的影响

选用四种不同固结方式,并在－５０℃条件下,对冻结砂土样进行三轴压缩试验,试验发现固结过程对冻土的强度与变表有明显影响。经历Ｋ０ＤＣＦ的冻土其强度最大,友坏变形最小,经历ＦＣ的试样强度最小,破坏变形最大;经历ＥＤＣＦ和ＥＵＤＣＦ的产介于中间。     

非均质土壤饱和稳定流中盐分运移的传递函数模拟

对室内人工构造的两种非均质土柱,以传递函数模型作为模拟手段,研究了稳定流场中饱和非均质土壤盐分优先运移的随机特征。首先计算了模型参数μ和σ2,获得了氯离子在非均质土壤中迁移时间的概率密度函数,然后应用传递函数模型对土柱中氯离子的出流浓度动态进行了随机模拟,并对非均质土壤中氯离子的均值和中值迁移时间及相应的运移体积与可动体积进行了分析和讨论,还依据质量守衡原理获得了土壤溶液中氯离子平均驻留浓度的变化。     

吸附对土壤水环境中有机污染物生物降解过程的影响研究

在土壤水环境系统中,吸附作用是影响有机污染物生物降解过程的主要制约因素。污染物的吸附性越强,则其存在于土壤水溶液的重量百分比就越小,生物降解可能性也就越低。本文建立了定量描述吸附作用对有机污染物在土壤颗粒内部传输过程影响的数学模型。通过模型计算发现,有机污染物的土壤-水吸附分配系数Kd越大,则其从土壤颗粒内部传输到外部水溶液的速率就越小,总的降解速率也就越低。     

核地球物理和化探综合测量在上海市区工程地质调查中的应用

本文介绍在上海市区断裂构造调查中 ,核地球物理测量和化探的应用效果。应用α卡、地面伽马能谱U、Th、K和总量 (Σ)及壤中气汞等测量方法 ,采用组合指标推断断裂构造 ,推断出的断裂构造与地震推断的结果相比较 ,具有较好的一致性。这些方法经济、快速、有效 ,有着广泛的应用前景     

Indigenous knowledge of landscape–ecological zones among traditional herbalists: a case study in Keiyo District, Kenya

Object of study is the insight of traditional herbalists in the landscape-ecological factors wich control the growth of the plants they use for healing their patients. The extent of this insight determines their capacity to adapt to environmental changes such as deforestation and soil degradation. This paper deals with the landscape-ecological perception of herbalists who live in an area with sharp landscape contrasts and drastic changes in landuse: the Keiyo Escarpment in the Rift which links the cool and humid Uasin Gishu Plateau at a level of more than 2600 m above sea level, with the warm and semi-arid Kerio Valley at 1250 m. The landuse changes of the last 50 years are caused by growing population density, loss of traditional attitudes towards the value of the land, and changes in forest cover. Data on local knowledge are acquired through interviews and field visits. The corresponding western knowledge is derived from aerial photographs and existing reports and maps. Six landscape-ecological zones are recognized. They are named after topography (wareng, mosop, soin), vegetation (teguming, korget) or landuse (tumdo). These zones coincide with the units of the agro-climatic map of Kenya. Apart from geology, all the factors of the hierarchical model used in western-based landscape ecology (climate, geology, relief, water, soil, vegetation and fauna) are included in the indigenous perception of the landscape, but the hierarchical order is not necessarily the same: e.g. the herbalists assume that rock grows in the soil instead of the other way around, and that forests attract rain. From the herbalists' point of view, deforestation and the establishment of small-holder agriculture is less serious for their trade than the replacement of indigenous trees by plantations with exotic species. They adapt to the loss of the forest by travelling to areas with comparable landscape-ecological conditions or, especially in the case of women and older male herbalists, by planting the required species in the garden. According to the herbalists, good climate and fertile soil stimulate species diversity, but best medicinal performance give plants on soils which are periodically dry.     

Mobility of Al, Co, Cr, Cu, Fe, Mn, Ni and V in sulphide-bearing fine-grained sediments exposed to atmospheric O2: an experimental study

 The major aim was to increase our knowledge on the behaviour of Al, Co, Cr, Cu, Fe, Mn, Ni and V in sulphide-bearing fine-grained sediments exposed to atmospheric oxygen. Samples of this type of sediment collected in a previous investigation at eight sites in western Finland were digested in HClO₄-HNO₃-HCl-HF at 200  °C and in HCl:HNO₃:H₂O at 95  °C (aqua regia), and subjected to extractions with ammonium acetate and hydrogen peroxide. Metals and S in the leachates were determined with ICP-AES. The results of the chemical analyses are compared with previously reported experimental data. The concentrations of Al and Fe in the sulphide-bearing fine-grained sediments are about 7% and 5%, respectively. Of the trace metals studied, Mn is most abundant followed in decreasing order by V>Cr>Ni>Cu>Co. On oxidation of the sediments, high proportions of Co, Mn and Ni, intermediate proportions of Cu but low proportions of Fe, Al, Cr and V are released. The extent of the release of a metal on oxidation is controlled either by (1) the level to which the pH of the sediments drops on oxidation (Al, Cu, Cr, V), (2) the amount of the metal associated with easily reduced phases (metal sulphides) in the sediments (Ni, Co) or (3) the sum of the amount associated with reduced phases and adsorbed on soil compounds (Mn). No control of the release of Fe on oxidation of the sediments was identified. Based on the results of the study it is argued that artificial drainage and the subsequent oxidation of sulphide-bearing sediments will result in extensive leaching of Co, Mn and Ni, moderate leaching of Cu and limited leaching of Cr and V into drainages. The major elements, Fe and Al, have the potential to be mobilised and leached in large amounts, though the proportions mobilised/leached will remain low. It is suggested that the identification of sulphide-bearing sediments with a high potential of metal release should be based on determination of metals in easily mobilised reduced compounds (dissolved e.g. in H₂O₂) and of the level to which the pH of the sediments drops on oxidation. Received: 16 October 1997 · Accepted: 9 March 1998     

Light hydrocarbons geochemistry of surface sediment from petroliferous region of the Mehsana block,North Cambay Basin

A study was carried out to test the usefulness of surface geochemical methods as regional evaluation tools in petroliferous region of the Mehsana block, North Cambay Basin. A suite of 135 soil samples collected from the depth of 2.5 m, were analyzed for adsorbed light gaseous hydrocarbons and carbon isotopes (δ¹³C_methane and δ¹³C_ethane). The light gaseous hydrocarbon analysis show that the concentration ranges 402 ppb, 135 ppb, 70 ppb, 9 ppb and 18 ppb of C₁, C₂, C₃, iC₄ and nC₄, respectively. The value of carbon isotopic ranges of methane −29.5 to −43.0‰ (PDB) and ethane −19.1 to −20.9‰ (PDB). This data, when mapped, indicates patterns coinciding with major known oil and/or gas field of Sobhasan/Linch in this study area. The existence of un-altered petroliferous microseeps of catagenetic origin is observed in the study area. A regional study, such as the one described here, can provide important exploration facts concerning the regional hydrocarbon potential in a block. This method has been confirmed and can be applied successfully in frontier basins.     

Characterization of an Area Polluted by Copper and Zinc:the Relation between Soil Texture,Mineralogy and Pollutant Concentration

Abstract: Twenty-four soil samples were collected at three depths from an approximately 2.5 acre contaminated site in southern Piedmont (Italy) and then analyzed. The main soil parameters determined were: pH, Cation Exchange Capacity (CEC), particle size distribution, total organic carbon (TOC) content and retained metal concentration. The mineral phases were identified by X-Ray Powder Diffraction (XRPD). All of the samples contained Zn and Cu resulting from industrial contamination during the last century, and those obtained at depths of 20-40 cm consistently showed the highest levels. To determine which size fraction was most active in the retention process, the samples were separated into four fractions (≤2 mm, ≤63 μm, ≤30 μm and ≤2 μm) and the amount of pollutant measured in each. It was found that metal retention was the highest in the clayey fraction, whose clay minerals were identified by XRPD after K+ and Mg2+ saturation, glycerol treatment and heating to 550°C. The clayey fraction was also the richest in TOC, and a direct correlation between TOC amount and metal retention was observed.     

Magnetic, Geochemical and Mineralogical Charac teristics of Soils in Qiangtang Basin, Tibet, China: Implications for Prospective Oil and Gas Land

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广西百色水电站边坡治理工程

文章通过广西右江百色水利枢纽地下发电厂房进水口与尾水洞高边坡的治理，介绍在此工程中具有特殊性的一些施工方法。该工程地质体为弱风化硅质泥岩夹泥化夹层、强风化含洞穴硅质泥岩石、强风化硅质岩及全强风化辉绿岩，地质条件非常复杂，对坡体的稳定极其不利。根据三维有限元的分析计算和国内有关权威专家的调查研究需施工1500kN、1000kN的锚索方能保证坡体的永久稳定。大吨位的锚索需锚固在强风化岩土体上，锚索设计采用能提高锚固力的防腐型压力分散锚索。通过现场锚索基本试验，其锚固力完全能满足工程需要。为保证进水口总体施工的进度，在施工进水口约30m高的垂直壁上的锚索时，笔者采用了通常施工中较少采用的垂直壁悬吊式施工法，满足了水电站的整体施工进度和要求。