Performance assessment of solute transport upscaling methods in the context of nuclear waste disposal

Stochastic simulations of solute transport in heterogeneous log₁₀ K random fields were conducted at two different support scales to assess solute transport upscaling methods in the context of nuclear waste disposal. A very fine grid-scale is used to obtain a reference solution of the real problem, which is based on data from the Sellafield site. A coarse-scale model is obtained by upscaling the heterogeneous grid-blocks onto equivalent homogeneous hydraulic conductivity tensors calculated using the Simple Laplacian Technique. Random fields were designed with different degrees of heterogeneity such that the standard deviation of log₁₀ K ranged between 0 and 1. It is shown that the early arrival time of particles at a control location, reflected in the lower limit of the 95% confidence interval of the mass flux cumulative density function stochastic process, associated with the upscaled model is strikingly similar to the one associated with the real solution for all heterogeneities. This is encouraging for the application of upscaled stochastic models to the design of nuclear waste repositories where the design of a nuclear waste disposal facility relies on the estimation of the early travel time of radionuclides arriving at a control location. On the contrary, the late arrival time of particles at the control location is largely underestimated by the upscaled model.     

城郊煤矿2201工作面底板改造技术

根据矿井水文地质、构造特征、工作面回采时突水规律，应用工作面底板改造技术，成功地对2201工作面40～70m段底板进行改造，效果显著。     

大兴安岭北部砂宝斯金矿水文地质特征及供水方向评价

砂宝斯金矿位于额尔古纳隆起的北东端，上黑龙江断陷盆地的边缘，共固定5条工业矿体，平均金品位1．19×10^-6，主要含水层为中侏罗统二十二站组砂岩、下寒武统额尔古纳组大理岩。通过分析矿区供水条件，指出矿区地下水贫乏、水质差，不能满足未来矿区生产、生活需要，需进行以地表水为主的供水，认为小东沟河可作为未来矿区首选供水源，开采时应注意钻孔封孔质量。     

Hydrogeological studies on the Tarkwa gold mining district,Ghana

The physical hydrogeology of the Tarkwa area has been evaluated with a view to improving the understanding of its groundwater characteristics. It has been inferred that aquifers in the Tarkwa area possess dual and variable porosity and heterogeneous permeability with predominantly limited storage properties. Both soil infiltration and pumping tests have shown that the Banket Series has the best hydraulic features, but the Banket rocks are host rocks for gold. The effect of mining on the groundwater regime is discussed, comparing groundwater recharge estimates obtained using the water balance method (299±72 mm year⁻¹) and the stream hydrograph method (192±30 mm year⁻¹).      

宜万铁路马鹿箐隧道水文地质分析及涌水预警

马鹿箐隧道是宜万铁路八座I级风险隧道之一,在DK255＋978发育大型高压富水充填溶腔。泄水洞揭穿该溶腔后,多次出现大规模突水突泥。介绍了马鹿箐隧道水文地质背景、水文专项监测、峰值涌水量预测及水文地质预警等相关情况,可为类似工程的水文地质分析和预警提供参考。     

Anthropogenic effects on the subsurface thermal and groundwater environments in Osaka, Japan and Bangkok, Thailand

Anthropogenic effects in both Osaka and Bangkok were evaluated to compare the relationships between subsurface environment and the development stage of both cities. Subsurface thermal anomalies due to heat island effects were found in both cities. The Surface Warming Index (SWI), the departure depth from the steady geothermal gradient, was used as an indicator of the heat island effect. SWI increases (deeper) with the magnitude of heat island effect and the elapsed time starting from the surface warming. Distributions of subsurface thermal anomalies due to the heat island effect agreed well with the distribution of changes in air temperature due to the same process, which is described by the distribution of population density in both Osaka and Bangkok. Different time lags between groundwater depression and subsidence in the two cities was found. This is attributed to differences in hydrogeologic characters, such as porosity and hydraulic conductivity. We find that differences in subsurface degradations in Osaka and Bangkok, including subsurface thermal anomalies, groundwater depression, and land subsidence, depends on the difference of the development stage of urbanization and hydrogeological characters.     

水文地质勘查技术在污染场地环境调查中的应用

随着社会经济的发展,不可避免的导致环境问题的逐渐恶化,土壤环境受到严重破坏、周边水资源也受到影响,可持续发展道路受到了严重的影响。国家也出台了相应得到法律法规,保护环境需要实际行动。鉴于以上问题,本文对污染场地环境调查及水文地质勘查进行了分析,探讨了水文地质勘查技术在污染场地环境调查中的应用,以便于在今后的场地污染调查中加强对水文地质勘查技术的研究。     

水文地质工程地质中基础地质调查的重要性

建筑工程建设是一项复杂工作,具体施工作业受多方面因素影响,而水文地质因素常被人们忽视,在具体施工中如果未重视该项内容,不仅会导致工程施工出现许多不便,甚至会引发安全事故,给工程建设造成严重影响。因此,应加强对水文地质工程地质工作中基础地质调查相应内容的分析,从而为建筑工程的顺利建设及提升建筑工程质量提供支持。     

Hydraulic head interpolation using anfis—model selection and sensitivity analysis

The aim of this study is to investigate the efficiency of anfis (adaptive neuro fuzzy inference system) for interpolating hydraulic head in a 40-km² agricultural watershed of the Seine basin (France). Inputs of anfis are Cartesian coordinates and the elevation of the ground. Hydraulic head was measured at 73 locations during a snapshot campaign on September 2009, which characterizes low-water-flow regime in the aquifer unit. The dataset was then split into three subsets using a square-based selection method: a calibration one (55%), a training one (27%), and a test one (18%).First, a method is proposed to select the best anfis model, which corresponds to a sensitivity analysis of anfis to the type and number of membership functions (MF). Triangular, Gaussian, general bell, and spline-based MF are used with 2, 3, 4, and 5 MF per input node. Performance criteria on the test subset are used to select the 5 best anfis models among 16. Then each is used to interpolate the hydraulic head distribution on a (50×50)-m grid, which is compared to the soil elevation. The cells where the hydraulic head is higher than the soil elevation are counted as “error cells.” The anfis model that exhibits the less “error cells” is selected as the best anfis model. The best model selection reveals that anfis models are very sensitive to the type and number of MF. Finally, a sensibility analysis of the best anfis model with four triangular MF is performed on the interpolation grid, which shows that anfis remains stable to error propagation with a higher sensitivity to soil elevation.     

水文地质评价中的灰色系统理论

本文重点阐述了灰色预测理论的基本内容、水文地质系统的灰色特性及其在水文地质评价中的可能应用。并运用灰色预测模型举例进行了计算与分析。