Changes in concentration–discharge regression parameters due to coal mining and reclamation activities / Changements dans les paramètres de régression entre concentration et débit,causés par l’exploitation minière de charbon et des activités de reconversion

Abstract

Abstract Assessment of the impacts of mining and reclamation, and design of management practices to reduce chemical loads in stream channels, require knowledge of changing hydrological conditions and of changing sources and rates of release of chemicals into stream waters. One simple method for evaluating these impacts is to combine flow duration curves with regression relations between surface-water chemical concentrations (C) and instantaneous discharge (Q). However, little is known regarding the drainage basin-scale effects of mining and reclaiming drainage basins on regression relations. These effects were assessed on three small experimental drainage basins in Ohio subjected to surface mining for coal. Comparisons were made between regression parameter changes for natural/undisturbed conditions, land disturbances caused by mining and reclamation, incomplete reclamation, and the final condition of the reclaimed drainage basins. Regression analysis used a total of 5047 laboratory analyses of 36 constituents. Of 429 regressions, 153 (36%) were statistically significant. Knowledge of changes in regression parameters is important because regressions supply information on the rate of release and supply of chemical constituents in mined and reclaimed drainage basins. Duration curves of concentration and loads can be constructed using these regressions with flow–duration curves to give estimates of the percentage of time that concentrations and loads are exceeded during different phases of disturbance. This study assessed the changes in regression relations due to mining coal seams and reclamation activities for 36 chemical constituents, two mining methods, three reclamation practices and three distinct geologic settings.     

Development of a simplistic vegetative filter strip model for sediment and nutrient retention at the field scale

Vegetative filter strips (VFSs) are a commonly used conservation measure to remove pollutants from agricultural runoff. The effectiveness of VFSs has been widely studied at the plot scale, yet researchers generally agree that field scale implementations are far less effective. The purpose of this research was to develop a field scale VFS submodel for the Soil and Water Assessment Tool (SWAT). A model for the retention of sediments and nutrients in VFSs was developed from experimental observations derived from 22 publications. A runoff retention model was developed from Vegetative Filter Strip MODel (VFSMOD) simulations. This model was adapted to operate at the field scale by considering the effects of flow concentration generally absent from plot scale experiments. Flow concentration through 10 hypothetical VFSs was evaluated using high resolution (2 m) topographical data and multipath flow accumulation. Significant flow concentration was predicted at all sites, on average 10% of the VFS received half of the field runoff. As implemented in SWAT, the VFS model contains two sections, a large section receiving relatively modest flow densities and a smaller section treating more concentrated flow. This field scale model was incorporated into SWAT and verified for proper function. This model enhances the ability of SWAT to evaluate the effectiveness of VFSs at the watershed scale. Published in 2009 by John Wiley & Sons, Ltd.     

带状数字线划图（DLG）坐标转换方法研究

带状地形图狭长,带状数字线划图坐标转换涉及坐标转换参数和接边问题。本文采用多项式拟合法和分区块重叠带,确定区块坐标转换参数,实现了带状数字线划图坐标转换,解决了分区图形坐标转换的接边问题。并采用实测带状数字线划图数据进行坐标转换实验,转换精度高,能够满足大比例尺带状数字线划图坐标转换要求。     

机载LiDAR点云航带平差方法研究

以航带平差作为系统误差消除的关键技术,提出了基于无控制三维表面匹配的方法,并用最小高程差(LZD)和最小法向距离(LND)两种算法加以实现。实验表明,LND和LZD算法的平差结果均可满足工程精度的需求;LZD较LND算法的整体计算效率偏低,但其精度较高;与商业软件TMatch的结果相比,LZD的精度和其相当,且两种方式在TMatch软件平差失败时也能成功地完成航带平差任务。     

利用空间投影分带方法研究卫星图像的连续制图

试图在遥感图像的连续制图方面做一些理论上的探讨，首次提出利用空间投影方法研究卫星遥感影像的连续制图问题。该方法的宗旨是利用空间投影坐标系来表示遥感图像坐标．利用邻带坐标的相互换算法来实现相邻轨道的图像坐标的统一，从而解决遥感图像的连续制图问题。文中同时研究了空间投影的分带投影方法，讨论了分带规定和邻带坐标换算等问题。     

Seismic uplift capacity of strip anchors in soil

Uplift capacity of horizontal strip anchors in soil embedded under an inclined ground surface has been obtained under seismic conditions. Limit equilibrium approach with logspiral failure surface together with pseudo-static seismic forces has been adopted. The results have been presented in the form of seismic uplift capacity factors as functions of ground inclination, embedment ratio, angle of internal friction of the soil and seismic acceleration coefficients. The uplift capacity factors have been worked out separately for cohesion, surcharge and density components. Effect of the vertical seismic acceleration coefficient has been found to always reduce the uplift capacity whereas the effect of horizontal seismic acceleration coefficient has been found to reduce the uplift capacity in most of the cases. The obtained results of seismic uplift capacity factors are found to be the minimum when compared with the results available in literature on the basis of planar failure surface. This revised version was published online in July 2006 with corrections to the Cover Date.     

坚硬顶板薄煤层条带开采技术在杨庄煤矿中的应用

杨庄煤矿村庄下压煤具有典型的坚硬顶板薄煤层特点，具有控制地面沉降，保护地面设施的有利条件，在矿井地质与水文地质条件较为复杂的情况下，对村庄下压煤选择了条带开采技术，成功地解决了村庄下大量压煤和村庄下不搬迁开采问题，为该村庄下压煤开采积累了经验。     

Interference effect of two closely-spaced shallow strip foundations on geogrid-reinforced sand

Summary Geotextiles and geogrids are now being used extensively in many civil engineering construction works. This study presents some laboratory model test results for the ultimate bearing capacity of an isolated, and two closely-spaced, strip foundations resting on unreinforced sand, and sand reinforced with layers of geogrid. Based on the model test results, the variation of the group efficiency with the centre-to-centre spacing of the foundation has been determined.     

基于总体最小二乘匹配的机载LiDAR点云航带平差方法

机载LiDAR技术在快速获取空间三维地理信息及其应用方面具有不可估量的前景,然而,机载LiDAR系统获得的相邻航带点云数据在重叠区存在"漂移"问题,需要采用航带平差的方法实现不同航带点云数据之间的"无缝"拼接。针对最小二乘航带平差方法中存在的某些不足,结合总体最小二乘与航带平差方法,将总体最小二乘应用于点云的平面拟合,从而提高了相邻航带匹配的精确性。采用实际飞行数据,设计实验方案对航带平差效果进行比较分析。     

数码相机莫尔效应位移测量算法的改进

针对正弦函数拟合两期相机效应莫尔条纹图像同名行像素的两条灰度曲线时没有考虑曲线之间的相关性问题,提出改进方法,即:两期数据联合平差,并附加两曲线角频率相等这一约束条件。采用附有约束条件的联合平差法计算的结果与y轴的选取位置无关,精度得到改善,特别是在两期相片曝光量相差较大时,目标位移量的计算精度显著提高。实验结果表明:改进算法计算的位移量和精度不随y坐标轴位置的变化而变化,在两期图像曝光量不等时,计算精度提高明显。