Geostatistical methods to identify and map spatial variations of soil salinity

The problem of estimating and predicting spatial distribution of a spatial stochastic process, observed at irregular locations in space, is considered in this paper. Environmental variables usually show spatial dependencies among observations, with lead one to use geostatistical methods to model the spatial distributions of those observations. This is particularly important in the study of soil properties and their spatial variability. In this study geostatistical techniques were used to describe the spatial dependence and to quantify the scale and intensity of spatial variations of soil properties, which provide the essential spatial information for local estimation. In this contribution, we propose a spatial Gaussian linear mixed model that involves (a) a non-parametric term for accounting deterministic trend due to exogenous variables and (b) a parametric component for defining the purely spatial random variation due possibly to latent spatial processes. We focus here on the analysis of the relationship between soil electrical conductivity and Na content to identify spatial variations of soil salinity. This analysis can be useful for agricultural and environmental land management.     

瓦里关大气降水的化学特征

利用2007—2009年瓦里关本底台降水化学观测资料,分析了瓦里关降水的pH值、电导率及Cl-、NO-3、SO2-4、NH+4、K+、Na+、Ca2+、Mg2+等离子成分的分布特征。结果表明,瓦里关pH值和电导率的年平均值分别为6.60和21.26μs/cm,2007—2009年呈逐年升高趋势。根据pH值,瓦里关降水以中性降水为主,占总降水的65.13%,其次为碱性降水,酸雨最少。离子浓度大小排序依次为Ca2+SO2-4Na+NH+4Cl-Mg2+NO-3K+,且存在明显的季节变化特征,K+、Na+、Ca2+、Mg2+有相似的来源。瓦里关降水中SO2-4/NO3-的范围为0.35~16.48,平均值为3.07;2007—2009年SO2-4/NO-3值呈逐年下降趋势;SO2-4/NO-3全年存在两个峰值,分别在4月和9—10月。     

Accounting for mineralogical composition and origin of soils and sedimentary rocks in thermal property predictions

A methodology for calculating the thermal conductivity of soils and rocks is developed which takes into account their origin and mineralogical composition.This method utilizes three approaches.One is founded on the structural modeling of contact heat interaction between particles and fills and estimates the statistical probability distribution of the particles in the volume of the medium.The second approach analyses perturbation to the temperature field of the matrix medium by ellipsoidal inclusions.The third approach is to find the mean thermal conductivity of the solid skeleton in the universal model at different composition of rock-forming minerals.     

岩土体导热系数研究进展

岩土体导热系数在与地热有关的地质基础研究和生产应用中有重要作用.首先介绍了导热系数的概念,然后分析了导热系数的受控因素,最后探讨了导热系数的测定方法.导热系数的受控因素包括地层岩性、孔隙率、含水率、温度以及各向异性.导热系数随地层岩性从大到小排列为海相碳酸盐岩、陆相碎屑岩、火成岩,变质岩导热系数与母岩和变质程度有关;同...     

EH4方法在辽宁本溪大台沟铁矿勘查中的应用

EH4连续电导率剖面测量是近年来地质勘察中采用的新方法,可以推断隐伏铁矿体的埋深、宽度、规模及产状。本溪大台沟铁矿勘查中进行了EH4连续电导率剖面测量,经钻探验证。取得了较好的效果。寻找深部隐伏铁矿体,磁法测量和EH4测量2种方法综合运用,为后续钻探工作提供更充分的依据。     

EH-4在江西省仙姑台铜多金属矿勘查中的应用

为实现仙姑台矿区找矿突破,在矿区采用EH-4连续电导率成像技术进行探测,通过寻找斑岩型隐伏岩体来寻找铜多金属矿。发现在电阻率反演断面图上,花岗闪长斑岩有三种异常标志:从高阻到低阻过渡带出现扭曲变形地段、低阻区局部高阻地段和高阻区局部低阻地段;对3条典型剖面进行了异常解释及钻探验证,取得了较好的地质效果。结果表明:在矿区内开展EH-4连续电导率剖面测量,可获得丰富的异常信息,为寻找斑岩型铜多金属矿提供地球物理依据。     

不同电法组合在找水中的应用

针对河南省新乡市凤泉区严重缺水的现状,利用高密度电阻率法、EH-4电导率测深和激发极化对称四极测深不同电法组合,在水文地质条件复杂的松散岩和基岩干旱地区找水取得显著的效果,总结出针对不同水文地质条件下的不同电法找水组合模式,不同电法组合模式的应用能为地下水勘查定井位提供可靠的科学依据,为机井工程成功率提供重要保障。     

北京平原区地源热泵换热能力现场测试研究

岩土体不仅决定地温场的展布形态,而且也是浅层地温能资源评价和工程设计的关键因素,掌握区域岩土体的热物性及换热性能,是保障热泵高效稳定运行的关键。根据北京地区在施地源热泵工程对现场换热能力测试结果,系统地研究了地层结构及岩性、水文地质条件、回填材料等因素对综合热导率的影响。研究结果表明:在相同条件下选择适当回填材料有利于提高系统换热性能,膨润土和水泥基作为回填材料,比中细砂作为回填材料的换热性能分别提高了17.6%和19.7%;岩土体和地下水是热能赋存和传播的物质基础,地下水与地层结构决定着地温场分布形态和换热效率,地埋管换热器的换热能力与土壤颗粒、地下水位、地下水渗流存在直接关系,土壤颗粒越大,地下水位埋深越浅,渗流越快,对地埋管换热器换热能力具有明显的强化作用。     

黄土高原北部坡面尺度土壤饱和导水率分布与模拟

为探明黄土高原北部坡面土壤饱和导水率(K_s)空间分布特征,为土壤水文过程模拟与预测提供理论依据,采用经典统计学和地统计学的空间变异分析方法,分析了坡面尺度土壤K_s的空间变异特征,并用一阶自回归状态空间模型对K_s的空间分布进行了模拟.研究区坡面尺度K_s的变异为中等程度变异,具有中等程度空间依赖性,变程为42 m.K_s与容重、砂粒、粉粒和黏粒含量在不同滞后距离下均具有自相关关系和交互相关关系.容重和土壤颗粒是影响坡面K_s空间分布的主要因素.状态空间模拟结果表明,基于容重和土壤颗粒的状态空间方程可以很好地解释坡面K_s的变异状况(R2>0.9).一阶自回归状态空间模型可用于田间条件下坡面尺度K_s分布特征的预测.     

The Effect of Flow on Pollution and Remediation in Groundwater

1IntroductionFlow is the key mechanism by which pollutants are transmitted from one point to another in hydro-geologic systems. Groundwater flow is not indepen-dent of the geological formation within which it occurs. Hydraulic conductivity which is a measure of groundwater flow is strongly related with the am-bient geologic properties such as texture,porosity and topography. These properties do not only con-trol the rate of groundwater flow but also limit the occurrence,hence the dispersion of…