富钴结壳中贵金属元素的特征

对太平洋CL、CM海山调查时获取9个富钴结壳样品,采用化学处理及ICP-MS法进行分析。对贵金属元素含量分布特征、富集因子、标准化模式以及来源进行探讨和研究。结果表明：海山结壳中贵金属元素Ag、Au、Ru、Rh、Pd、Pt等的平均含量分别为： 1.05×10^-6、2.3×10^-6、15.6×10^-9、22.3×10^-9、2.39×10^-9和432×10^-9。与结核、洋壳及陆地矿石的Pd/（Pt+Pd）、Pt/（Pt+Pd）和Pd/Pt等贵金属元素的比值相比,大洋富钴结壳的 Pd/（Pt+Pd） 比值最低,为0.006;其次是结核,为0.06;洋壳为0.08;陆地矿石的Pd/（Pt+Pd）比值较大,为0.35～0.65。结壳的Pt/（Pt+Pd）比值最高,为0.99;其次是结核,为0.95;洋壳为0.93;陆地矿石的Pt/（Pt+Pd）比值相对较低,为0.33～0.65。统计分析显示了不同区域、不同环境中贵金属元素的特征参数变化,并且说明富钴结壳中富铂、金、钌、铑,而贫钯。贵金属元素标准化显示,海山富钴结壳均存在着Pt、Au正异常和Pd的负异常,其中Au异常幅度与结核的Au异常一致。     

Granite fracture index to check suitability of granite outcrops for quarrying

A correct knowledge of fracture patterns previous to quarrying is important for economical exploitation. This work comprises the general characterization of the discontinuities of 10 granite rock masses in NE Portugal. During the study some discontinuity characteristics such as orientation, persistence, aperture, trace length and spacing were evaluated. The differences in the characteristics of the selected granites were described, and the most important exploration factors were identified. In the granites studied, most of the joints are oriented from N10°E to N50°E, which is compatible with the regional fracture pattern. Concerning joint termination, the XX type is common, while the RR type is rare; the persistence index ranges from 3.5% to 25.4%. Closed joints are predominant in the granites studied (> 72.4%), and openings of the others are about 1–2 mm as a result of superficial displacement of the granite blocks. The percentage of filled joints, usually by quartz and pegmatite, is different from one granite to another, but most are < 20%. The average joint length ranges from 11.1 m in post-tectonics granites to 4.6 m in syntectonic granites. Joint spacing varies from 0.98 to 2.8 m with higher values in post-tectonic granites. Joint-space distributions of the granites studied are close to log-normal and exponential distributions. Volumetric joint count (Jv) ranges from 0.8 to 2.1 joints/m³ and is used for categorizing the places of each granite. The relationships between Jv and other joint characteristics, such as length, spacing and number of joint sets, were investigated. A Granite Fracturing Index (GFI) is introduced, computed on the basis of volumetric joint count, number of joint sets and true joint spacing. The GFI classification of studied places allows us evaluate the suitability for profitable exploitation.     

黄土高原西部土壤水分时空变化模拟研究——以安家坡流域为例

土壤水作为陆地水循环和水量平衡的一个重要组成部分,在土壤-植被-大气连续体物质与能量转化中起着重要的作用,成为陆面过程研究中的重要参量.选择黄土高原西部的安家坡流域,采用多点长序列观测方法,对该区域土壤水分的时空变化规律进行研究.结果表明:坡向和土地利用类型是小流域土壤水分变异的重要影响因素,得出了不同立地条件下土壤水分的剖面变化与时间的动态规律.在此基础上,利用土壤湿度指数结合主要影响因素预测土壤水分的时空变化,旨在为黄土高原大中尺度的土壤水分模拟提供思路.     

测井曲线概率分布法识别四川盆地火山岩气水层

火山岩的矿物成分复杂,主要矿物有石英、正长石、斜长石、云母、角闪石、辉石和橄榄石.不同岩性的储层物性和孔隙结构类型各不相同,这给火山岩气水层判别造成很大困难.基于测井资料,首先采用中子-密度交会图的方法求取孔隙度,然后结合实验室的岩电参数以及测井的电阻率曲线,构建P1/2概率分布曲线,根据概率曲线的分布形态来识别火山岩...     

浅基础竖向极限承载力的可靠度分析

结合各种地基土的原始载荷板试验资料,用太沙基理论公式、汉森理论公式和魏西克理论公式进行了浅基础极限承载力的计算,对计算模式的不确定性、土性固有的变异性及由其引起的极限承载力的不确定性等进行了研究;根据以上计算结果,计算了各类地基土承载力的可行度指标;结合上部结构的荷载标准及分项系数,计算了各类地基土承载力的分项系数。     

荧光有机组分指数与烃源岩生烃性能研究

荧光有机组分是各类低熟-成熟烃源岩的重要的有机显微组分。本文在研究吐哈与准噶尔盆地早中侏罗世烃源岩时,提出荧光有机组分指数概念。它作为主要生烃指标之一,并配合其他有机岩石学参数,在评价低熟-成熟烃源岩有机质类型、丰度等方面均取得了良好效果。      

钻孔多参量指标预测冲击地压危险性的试验研究

为准确预测预报冲击地压危险性,提出一种通过监测钻孔过程中钻杆推力、钻杆扭矩与钻屑量等钻孔多参量指标变化规律来预测冲击危险性的方法。利用自主研制的钻孔多参量一体化测试装置,在实验环境下对不同煤体应力状态下的多参量指标进行测试分析,发现钻杆扭矩与钻屑量均随着煤体应力的增大而增大,钻杆推力随着钻进时间的增加呈现先增大再减小,并出现波谷随后增大最后减小的规律。在相同钻机及钻具条件下,进行井下原位钻孔试验,结果表明：随着钻进深度增大,钻杆扭矩与钻屑量变化规律呈现较好一致性,在5 m深度前均先增大随后减小;钻杆推力在1~4 m内呈上升趋势,在5 m处下降至波谷位置,随后推力值再次上升,最后呈稳定趋势。对此区域应力分布带情况进行划分,可确定应力峰值点大致在孔深5 m处,并利用SPSS数据分析软件初步确定此试验点钻杆推力临界指标为7.5 kN,钻杆扭矩临界指标为50.0 N·m。研究结果可为冲击地压等煤矿动力灾害危险性的预测预报提供理论基础与工程指导。     

小秦岭太峪水系沉积物重金属污染生态危害评价

以金矿开发影响的黄河二级支流太峪水系沉积物为研究对象,沿河采集16个表层沉积物样品,分层采集垂向剖面10件水库沉积物样品,测定了样品中重金属元素Hg、Pb、Cd、Cr、As、Cu和Zn的含量,采用Hakanson潜在生态指数法和Tomlinson污染负荷指数法评价重金属元素污染程度和潜在生态风险。结果表明,矿业活动是太峪水系沉积物重金属元素污染的主要因素;变异系数、富集系数和最高污染系数均反映Hg、Pb、Cd是太峪水系沉积物的特征污染重金属元素,Cr和As的质量分数接近地区背景值;太峪水系表层沉积物受到重金属元素的极强污染,山区段污染较山外更严重;整个流域的Hg、Pb、Cd具有很强的潜在生态危害,Cr、As、Zn的潜在生态危害轻微;太峪水系沉积物垂向各层沉积物都受到重金属元素的极强污染,生态问题以Hg、Pb、Cd的潜在生态危害为主,其污染和生态危害程度都高于流向上的沉积物。潜在生态危害指数评价突出了不同元素的毒性和危害程度,而污染负荷指数法侧重于样本空间上的污染程度,二者互补使用有利于实际问题的全面评价。     

北京平原区软弱黏性土次固结系数的试验研究

次固结系数通常被认为是一个常数,然而,大量的实验数据表明,随着时间的改变次固结系数也发生着变化。同样,大量的试验表明次固结系数与固结压力、压缩指数、含水率以及塑性指数有着一定的相关性。本文在着重研究北京平原区软弱黏性土次固结特性的基础上,对其规律进行了总结和分析。结果表明:对超固结土,次固结系数随荷载的增大而增大; 对正常固结土,次固结系数随荷载增大而减小。次固结系数亦随着土样含水率和塑性指数的增长呈线性增长趋势,且Cα/Cc比值为常数。     

Migration and dispersion of trace elements in the rock–soil–plant system in areas underlain by black shales and slates of the Okchon Zone, Korea

The Okchon black shale in Korea provides a typical example of natural geological materials enriched with potentially toxic elements. The Chung-Joo, Duk-Pyung, Geum-Kwan, I-Won, Bo-Eun and Chu-Bu areas are underlain by these black shales and slates of the Guryongsan Formation or the Changri Formation, which are parts of the Okchon Group in the central part of the southern Korean Peninsula. In order to investigate the enrichment levels and dispersion patterns of potentially toxic elements in the rock–soil–plant system, environmental geochemical surveys were undertaken in the above six study areas in the Okchon Zone. After appropriate preparation, rock and soil samples were analyzed for potentially toxic elements by instrumental neutron activation analysis (INAA) and inductively coupled plasma atomic emission spectrometry (ICP-AES), and plant samples by atomic absorption spectrometry (AAS). In particular, Ba, Cd, Mo, V and U in Okchon black shales are highly enriched, and their mean concentrations are significantly higher than those in black slates. These elements are geochemically associated, and might be enriched simultaneously. The highest mean concentrations of 42.0 μg g⁻¹ As, 2100 μg g⁻¹ Ba, 10.9 μg g⁻¹ Cd, 213 μg g⁻¹ Mo, 83 μg g⁻¹ U, 938 μg g⁻¹ V and 394 μg g⁻¹ Zn are found in black shales from the Duk-Pyung area. Mean concentrations of As, Mo and U in soils overlying black shales occurring in the Duk-Pyung area (30 μg g⁻¹ As, 24 μg g⁻¹ Mo and 50 μg g⁻¹ U) and Chu-Bu area (39 μg g⁻¹ As, 15 μg g⁻¹ Mo and 27 μg g⁻¹ U) are higher than the permissible level. Enrichment index values of the six study areas decrease in the order of Duk-Pyung > Chu-Bu > Bo-Eun > Chung-Joo > Geum-Kwan = I-Won areas. Relationships between trace element concentrations in soils and plants are significantly correlated, and the biological absorption coefficients (BAC) in plants are in the order of Cd > Zn = Cu > Pb, which suggests that Cd is more bioavailable to plants than the other elements. Cadmium concentrations in plant species decrease in the order of chinese cabbage > red pepper > soybean = sesame > rice stalk > corn > rice grain. From the result of sequential extraction analysis of soils, relatively high proportions of Cu, Pb and Zn are present as residual fractions, and that of Cd as non-residual fractions. Cadmium occurs predominantly as exchangeable/water-acid soluble phase in soils, and this is in agreement with the findings of high Cd concentrations in plants.