ESTIMATING URBAN LOADS OF NITROGEN TO GROUNDWATER

Urban areas can impose significant loads of nitrogen, as ammonium or nitrate, onto the underlying groundwater. There are many sources of nitrogen pollution, including diffuse sources (parks and gardens), intense point sources (industrial chemical spills), and multi-point sources (leaking sewers). Data on the loadings associated with the various sources are scarce, although an estimate of the overall load is available for Nottingham. For other cities, a total load could be estimated by factoring the Nottingham result, or by considering each component of the load separately. Both approaches are described, and the integrated method is recommended for its simplicity.     

锚固质量的无损检测技术

基于锚固体系的锚杆动力学及应力波运动学理论,研究了锚固体系的振动特征和锚固体系中声频应力波传播的能量衰减规律,进而提出快速普查检测锚杆锚固状态的声频应力波法：介绍了依据拉拔曲线转折段两边割线的交点法确定锚杆锚固力的无损拉拔检测技术原理,并实际应用于潘集第一煤矿巷道锚杆支护施工质量的检测。     

真空预压降低地下水位机理探讨

根据真空渗流场理论,阐述了在真空预压中场地内不同区域地下水位的变化情况;并借鉴真空井点降水概念提出了降水“漏斗”的观点。还探讨了真空预压降低地下水位的几个相关问题,如真空预压中地下水位下降的影响因素、地下水位下降的极限深度、地下水位的现场量测问题和出水量与地下水位下降关系。     

地下水对地基基础设计的影响

地基基础设计主要包括地基承载力计算、地基变形计算和基础设计计算。承载力计算中要涉及到基底压力pk的确定和承载力深度的修正;变形计算要求基底附加压力p0;基础设计计算需要确定基础反力。当地基中存在地下水时,基底压力、基底附加压力、基础反力的计算,以及对地基承载力进行深度修正就变得比较复杂。通过讨论地下水对基底压力、基底附加压力、基础反力和承载力深度修正的影响,给出了上述设计参数的计算方法。     

节点剖分法在城区地下水计算中的应用研究

 城区渗流场中地下阻水结构物众多,由于结构物角点为奇异点,而且结构物的尺寸跟整个渗流场的尺寸相比起来非常小,这导致现有的计算方法难以对城区渗流场进行模拟分析。针对城区渗流场的这些特点,通过引进流体力学的复势、偶极子、绕流等理论,采用剖分节点并在节点上施加流量,从而形成等阻水效果的方法对结构物进行等效模拟。首先研究单个结构体元素绕流的模拟问题,然后研究渗流场的迭代计算问题。在这些理论的基础上,开发相应的有限元计算程序并通过算例进行验证。     

A REVIEW OF THE EFFECTS OF SEWER LEAKAGE ON GROUNDWATER QUALITY

Exfiltration (of sewage into the ground from faults in ageing sewerage networks) has been recognised for many years but has never been quantified. It was considered that this leakage did not pose a groundwater-contamination threat because it was assumed that pathogens in sewage would either die off or be attenuated before reaching the groundwater level.
This paper identifies why sewers have faults that could allow sewage exfiltration where the sewer is above a groundwater resource. Because of a lack of UK data on sewage exfiltration, research work in Germany is discussed and analogies are made between the sewerage networks of the two countries.
Until recently, it has not been possible to positively identify sewage contamination of groundwater because of other pollutants and potential sources within an urban environment. The development of sewage-fingerprinting techniques has overcome these difficulties and provides conclusive evidence of sewage contamination of shallow and deep groundwater resources in researched areas. Studies of groundwater recharge and total solute loadings allow quantification of sewage exfiltration reaching the groundwater within the Midlands conurbation. The paper concludes that urban aquifers are potentially more vulnerable to microbiological contamination from leaking sewers than has previously been assumed.     

EXPLORATION OF AQUIFER MANAGEMENT OPTIONS USING A GROUNDWATER MODEL

A methodology is described for harnessing the predictive capacity of a groundwater model to underpin aquifer management decisions for changing abstraction within a licensing regulatory framework. The use of a 'baseline predictive simulation' is advocated from both aquifer management and scientific perspectives, and an example of groundwater modelling predictive work on the Nottingham-Doncaster Sherwood Sandstone aquifer system is used to illustrate the methodology. Differences between the baseline predictive simulation and a predictive simulation are processed to extract quantitative information (spatially and temporally) on the response to changes in aquifer stresses. An explanation is given on the use of this information to aid aquifer management decisions for achieving environmental targets. The importance of the aquifer diffusivity with respect to a predictive simulation exercise is highlighted.     

隧洞地下水渗流场变化对衬砌受力影响的数值分析

为研究隧洞地下水渗流场变化对衬砌结构受力的影响,通过建立平面应变渗流耦合有限元模型,对隧洞开挖、设置排水管、进行固结灌浆等不同施工工况进行了数值模拟,动态地分析了不同施工措施时的地下水渗流场变化以及相应对衬结构受力的影响。     

加强工程试验检测在公路工程质量管理中的作用

如何解决道路工程质量问题、加强道路工程质量管理是一个亟待解决的现实问题,工程试验检测是解决上述问题行之有效的方法。通过运用文献研究和试验方法,论述了加强公路工程试验检测的必要性,构建了严格把好公路工程试验检测的5个控制环节,提出了加强试验检测工作、提高公路工程质量的5项措施。     

地下水位变化引起厂房地基沉降的研究

建造在滨海地区建筑物的桩基由于受到地下水头影响,其沉降在呈现周期性变化的同时不断增大,并且在相当长的时间内都无法稳定。本文给出了上海宝钢部分工业建筑桩基长期的沉降监测数据,采用现有数学模型进行回归分析,对已测得的数据拟合得到了较好的结果,但无法准确预测未来的沉降及稳定时间。于是在现有理论的基础上提出了由于周围土体在桩上产生的正负摩擦力反复变化而导致桩基沉降持续发展并且不收敛的机理,从而从原理上解释了桩基长期不收敛沉降产生的原因。     

GROUNDWATER IN A WATER-RICH ENVIRONMENT: WALES, A LAND OF PLENTY

Traditionally, Wales has relied on surface water, with only 8% of the total public supply currently derived from groundwater sources. There are various significant aquifers in Wales, including the Carboniferous Limestone in South and North-East Wales and the Triassic aquifer in the Vale of Clwyd, as well as superficial granular deposits that are of particular importance in West Wales. Groundwater quality is generally good and minimal treatment is required. Hydrogeological data in the public domain for Wales are scarce: the Carboniferous Limestone, for example, is particularly poorly documented. Despite this lack of information there are some notable groundwater schemes, but current legislative aspects now require a better overall understanding of the hydrogeology of Wales. A key recommendation is the preparation of public domain data-sets and a comprehensive report on the hydrogeology of Wales.     

基坑地下水渗流对邻近地铁结构影响的数值分析

以某邻近地铁结构的深基坑工程为例,采用等效刚度法将围护桩等效为地下连续墙建立有限元模型对基坑地下水渗流过程进行了三维数值分析,分析了基坑地下水渗流对邻近地铁结构影响,提出了优化改进措施以减小地下水渗流影响,对于指导工程实践有一定意义。     

地下水对泥板岩强度软化的损伤力学分析

针对18层泥板岩处于龙滩水电站坝址进水口高边坡中这一特殊情况,深入探讨水-岩相互作用使其劣化的损伤机理。采用RMT-150B型岩石刚性伺服试验机,进行18层泥板岩不同吸水率情形下的单轴压缩试验。结果表明,泥板岩抗压强度的软化不仅与吸水率密切相关,而且还是吸水时间的函数。运用损伤力学理论分析地下水对岩石强度与变形的影响,初步建立与应力状态密切相关的岩石遇水损伤演化方程。结果表明,该理论能较好地描述岩石遇水损伤演化特征,从而为岩质边坡细雨入渗滑坡现象提供理论依据。     

大力发展城市设计,提高城镇建设水平

中央城镇化工作会议的召开以及《国家新型城镇化规划》的出台为城市规划建设领域提出了新的探索方向和发展要求,而全面提升城镇建设水平更是成为了城镇化的核心任务之一.面对这样的形式,作为交叉学科的城市设计将会发挥更大作用,成为推动城镇建设水平提升的重要技术支撑.城市设计自身的技术特征决定了其在我国规划建设实践中的特殊价值和重大意义,而从我国的城市设计发展历程和近年趋势来看,城市设计的作用也愈发凸显,尤其是在重大事件推动、灾后重建援助以及城市建设日常管理等方面发挥了极为重要的作用.总的来看,我国城镇建设水平方面的不足很大程度源于观念、制度的滞后以及相应技术手段的缺失.因此,我们希望从城市设计的视角对如何提高城镇建设水平提出建议,进一步推动我国新型城镇化的健康发展.     

A METHOD FOR INVESTIGATING THE POTENTIAL IMPACTS OF CLIMATE-CHANGE SCENARIOS ON ANNUAL MINIMUM GROUNDWATER LEVELS

Previous approaches to assessing the impact of climate-change scenarios on groundwater levels and groundwater droughts have focused on modelling specific recharge processes or phenomena. However, statistical methods, based on correlations between historic groundwater level and rainfall time-series, provide an alternative and robust approach to predicting minimum groundwater levels and droughts. For the purposes of this study, groundwater droughts are defined in terms of the return period of a given groundwater level. A multiple linear regression model (regression of monthly rainfall totals for a given period against values of minimum annual groundwater levels for the same period), when used with synthetic rainfall data based on climate-change scenarios, enables changes in future annual groundwater-level minima to be modelled. The method is illustrated at three sites on the Chalk, Permo-Triassic sandstone and Jurassic limestone aquifers.     

高地下水位下的深基坑综合支护技术

聊城市东昌湖畔某高层住宅基坑开挖深度7.2m,地下水位距地表2.0m,周边环境复杂,基坑支护综合采用了深层搅拌桩、钻孔灌注桩、锚杆和土钉墙等多种支护措施,取得了良好的加固效果。     

顶进施工法用大口径排水管质量检测

应用无损检测技术对顶进施工法用大口径钢筋混凝土排水管进行施工质量检测,检测钢筋混凝土排水管的尺寸偏差、混凝土抗压强度及纵向、环向钢筋数量及保护层厚度,并对检测数据进行系统分析和精确计算,全面评价排水管的施工质量,为实际工程提供数据参考。     

某高速公路修建对地下水的影响防治

高速公路建设在对地区经济发展起到促进作用的同时,对地下水环境的影响也日益显著。鉴于滇东北特殊的地形地貌,群山环绕,山川交错,桥隧长度占据着路线施工比例的很大部分,然而在线路施工和运营期对沿线地下水的破坏尤为突出。本文以滇东北富兴高速公路为例,对沿线水文地质条件现状进行评价,分析沿线主要地下水类型及工程对沿线地下水环境的影响,重点针对有敏感点的隧道施工对地下水水位、水质、生态环境造成的影响进行评价,提出地下水环境保护措施。     

岩溶裂隙水与不良地质情况超前预报研究

在岩溶地区隧道施工过程中,经常遇到突水、突泥等无法预料的地质灾害,给施工安全带来了重大灾难和无法估计的经济损失。为了保证岩溶隧道施工安全,对岩溶裂隙水与不良地质体的发育情况进行准确及时的超前预报,是当前岩溶地区隧道设计与施工中亟待研究与解决的关键问题。首先,对隧道建设过程中岩溶裂隙水与不良地质情况超前预报和综合预报体系的研究现状进行详细的介绍,指出岩溶裂隙水与不良地质情况超前预报中存在的主要问题,总结隧道建设过程中地质缺陷超前勘探方法和高压大流量岩溶裂隙水超前预报方法;然后,重点介绍TSP超前地质预报系统探测溶洞、陆地声纳法探测断层、地质雷达探测地下水和红外探水法探测岩溶裂隙水等工程实例。最后,总结预报各种不同地质体的有效方法和将要开展的研究热点和难点,并对下一步所要开展的工作进行深入探讨,对我国在岩溶裂隙水和不良地质体探查的理论和技术创新方面给予一定的帮助和指导。     

基坑地下水渗流对周边环境影响分析

为了研究基坑开挖引起的地下水渗流对周边环境的影响,通过平面应变渗流耦合有限元法结合基坑支护形式和地下水控制措施对竖向位移、水平位移影响范围进行了分析。数值模型对实际施工工况进行了模拟,动态地分析了施工过程中地下水渗流对周边环境的影响。