减压井灌淤机理的物理化学试验研究

本文以荆江大堤观音寺堤段减压井为研究对象，应用物理化学理论和试验方法，对减压井灌淤的物质来源，潜淤形成机理和防治进行了初步试验研究，试验结果表明：在一定水文地质环境中，化学灌淤是造成减井效能降低或失效主要原因，铁锰等的还原－络合－氧化－胶凝－沉淀－吸附－老化－堵塞是化学灌淤的物理化学过程。当在减压井两端外加一定电压而改变减压井周围氧化还原环境时，将有利于抑制和改善减压井灌淤的发生的发展。     

利用已建堤防减压井解决长江沿岸农村饮水问题初探

通过对荆南长江干堤李家花园堤段减压井基础砂矿化和井水水质进行分析,得出李家花园堤段减压井井水中含有较高的铁及铁化合物是导致减压井化学淤堵的主要原因。国际国内生活饮用水水质标准规定饮用水中铁含量不能超过0.3mg/L,降低减压井井水中铁含量是利用已建堤防减压井解决沿岸农村饮用水问题和减少减压井化学淤堵保障堤防安全的关键。针对减压井井水中铁含量过高的问题,在前人研究成果的基础上,提出了利用物理法、生物法等方法对李家花园堤段减压井井水进行净化处理。此研究对解决沿堤农村饮用水问题及保障堤防安全具有重要意义。     

长江干堤减压井淤堵的成因分析及防治措施的探讨

为了探讨防治减压井淤堵的措施，曾进行过室内现场的试验研究，本文首先论述了长江干堤减压井淤堵的生成原因，进而提出为防止减压井淤堵；（１）应制订正确的减压井运行制度；（２）应选择适应长江干堤这一特定条件的材料，尺寸等；（３）可采用电化学方法控制淤堵的发生，发展，为处理已淤堵的减压井，可采用化学一力学相结构的方法，即用化学分散剂将淤堵物分散，用力滨活塞式洗孔法进行清除。     

堤防工程减压井淤堵及其应对措施研究

 通过现场调查和试验以及室内多种模拟试验，揭示了机械、化学淤堵的形成条件与发展规律，以及生物淤堵成因及其对机械、化学淤堵的促进作用。在室内、外试验基础上根据工程经验提出了淤堵应对措施，包括根据淤堵溯源特性发明的过滤器可拆换式减压井，并通过工程应用证实了其有效性和可操作性。指出可以通过合理的设计、施工和运行管理使减压井尽可能避免淤堵，已淤堵者也可以通过一定措施恢复其功能，并建议推广应用过滤器可拆换式减压井。     

安庆市长江干堤减压井灌淤成因及处理措施探讨

通过现场查勘、测试、以及室内试验,对安庆市长江干堤减压井灌淤的成因进行了分析,对恢复减压井减压效能的措施进行了研究。研究结果表明,安庆长江堤段减压井的灌淤以化学淤堵为主;恢复减压效能的措施,以先用化学分散剂将淤堵物分散,然后用活塞式洗井法清除淤堵物最为有效。     

减压井超声波解堵试验初步研究

借鉴在石油工业中得到有效应用的超声波技术,自主研制了适用于砂土地基堤防减压井的超声波解堵系统。在室内大型渗透仪中模拟了减压井倒灌淤堵过程,采用自制超声波设备进行了解堵试验,并通过常水头渗透试验分析了超声波技术作用效果,研究了试验砂样装样密度和驱动水力比降对超声波解堵效果的影响。试验结果表明:倒灌悬浊液使得试样含水层发生了堵塞,井管排水能力减弱,承压水头增加;经超声波解堵后,减压井及其周边含水层综合渗透性得到提升,出水口流量增加,减压能力增强,超声波解堵效果明显,可使淤堵减压井恢复60%以上。减小装样密度使得砂样孔隙率增加,可提高淤堵前排水减压能力,但发生倒灌淤堵程度增加。装样密度对超声波解堵程度影响不显著,但在较小的装样密度下,超声波能在较短的时间内达到同等解堵效果。提高超声波解堵过程中驱动水力比降,更易于带动剥离的淤堵细颗粒从含水层孔隙中析出,能增加超声波解堵效果。     

可拆换过滤器减压井的应用研究

减压井作为一种渗流控制措施,在长江堤防中常用于降低承压含水层的水压力。然而,由于它在长江复杂的水文地质条件下间歇运行的特点,因此淤堵问题是一个普遍现象。对工程师来说,如何解决淤堵或延长减压井的使用寿命,是一个重要话题。根据以前对淤堵机理研究的经验,提出了一种新型可拆换过滤器减压井,其滤体在受到淤堵后可以进行更换,通过一系列的室内试验和现场试验对其进行了验证。结果表明,主要是粉细砂、粘粒、化学矿物质及细菌等沉积于多孔泡沫塑料滤体内,通过对滤体进行更换或清洗,延长了减压井的使用寿命。     

北江大堤减压井效果分析及改进方法研究

 减压井是堤坝防渗工程的主要手段之一,其机械淤堵和化学淤堵是关系减压井减压效果的重要因素。广东省北江大堤已实施383口减压井,分布于石角、大塘、黄塘、西南等堤段。其中石角堤段建有147口减压井,建设年代由1966至2001年,成孔工艺有回旋钻泥浆护壁和钢套管振动沉管法,反滤方式有开孔缠丝和开槽法,汛期减压井出水量各不相同,减压效果也存在较大差异。根据汛期减压井实测流量和测压管数据、现场抽水试验和现场试验井的研究、数值模拟分析,得出北江大堤减压井以机械淤堵为主的结论。汛期70%减压井出水满足设计要求的莲藕塘段,减压效果明显;而只有20%减压井满足要求的横基段,减压效果差,存在安全隐患;应根据地层特性研究并选择合适的成井工艺,保证减压井的成活率,确保大堤安全。     

北江大堤石角堤段减压井试验分析

简要介绍北江大堤石角堤段减压井的实际情况以及试验检测的内容,分析了本次减压井试验所取得的成果.试验结果分析表明,影响石角堤段减压井减压效果的主要因素是成井工艺和反滤方式而不是化学淤堵.因此,只要在成井工艺和反滤方式上加以改进和提高,在北江大堤石角堤段采用减压井进行减压防渗保护堤防是可行的.     

排水暗管化学淤堵及其防治

为治理农田渍害，土壤长期处于还原状况，地下埋设暗管后存在着化学淤堵倾向。本文介绍国外有关暗管排水化学淤堵的资料，分析农田排水暗管中化学淤堵发生的原因和影响因素，阐述化学淤堵形成的过程及防治方法，指出在暗管周围应避免使用丙纶丝等化纤制品作为外包料     

Continuous biological ferrous iron oxidation in a submerged membrane bioreactor.

Microbial oxidation of ferrous iron may be available alternative method of producing ferric iron, which is a reagent used for removal of H2S from biogas. In this study, a submerged membrane bioreactor (MBR) system was employed to oxidize ferrous iron to ferric iron. In the submerged MBR system, we could keep high concentration of iron-oxidizing bacteria and high oxidation rate of ferrous iron. There was membrane fouling caused by chemical precipitates such as K-jarosite and ferric phosphate. However, a strong acidity (pH 1.75) of solution and low ferrous iron concentration (below 3000 mg/I) significantly reduced the fouling of membrane module during the bioreactor operation. A fouled membrane module could be easily regenerated with a 1 M of sulfuric acid solution. In conclusion, the submerged MBR could be used for high-density culture of iron-oxidizing bacteria and for continuous ferrous iron oxidation. As far as our knowledge concerns, this is the first study on the application of a submerged MBR to high acidic conditions (below pH 2).     

添加GYH高抗渗混凝土的结构特性研究

 通过测定氯离子扩散系数、孔结构、水抗渗系数和SEM观察，研究了减水剂、引气剂、微细集料复合添加剂对水泥净浆、砂浆和混凝土结构特性的影响。结果表明：添加GYH①可通过减水、引气和化学反应的协同作用，减小开口孔体积、阻断毛细孔、增加C S H凝胶和改善过渡区结构，从而大幅度提高材料的抗渗性能，有利于材料强度的提高     

海绵城市入渗设施淤堵研究进展及长期性能改进方案探讨

针对海绵城市渗井、渗透管和渗透塘等典型入渗设施,阐述了淤堵机理和性能改进研究的意义。将淤堵影响因素分为淤堵物源性质、水动力条件和滤层特性3个方面,分别围绕这3个方面概述了淤堵研究进展。将我国海绵城市入渗设施淤堵问题研究的不足和需要加强研究的方面归纳为:淤堵物源特征仍然不够明确,水流条件研究不够全面,间歇运行的影响研究不够,实际组合滤层结构缺乏研究,时间效应研究不够,主要作用机制认识存在分歧,结构形式和运行维护方案研究不够,缺乏原型试验和实际工程研究。针对我国海绵城市建设,提出急需针对典型城市区域监测实际雨洪,尤其是久未下雨后暴雨中的第1波雨洪,研究入渗设施的淤堵物源性质。基于类似问题的研究工作,分析了入渗设施滤层性能改进的途径,认为可更换滤层方案可以突破入渗设施淤堵问题,促进入渗设施的更广泛运用,从而保障海绵城市建设的长期效果。     

Potential Clogging and Dissolution Effects During Artificial Recharge of Groundwater Using Potable Water

To avoid the water quality deterioration that are caused by artificial recharge (AR) of groundwater, potable drinking water has been used as one of the source water for AR to control the side effects caused by the over-exploitation of groundwater. Chemical clogging problems can still be caused by certain chemical components, especially Fe and Al, and a lower concentration of these elements can cause a notable decrease in hydraulic conductivity at the top layer of the infiltration medium. Some components in AR source water can be obstructed by the clogging layer, leading to a change in water quality. The accumulation of total suspended solids (TSS) at the clogging layer can cause physical clogging and worsen the degree of chemical clogging. Although clogging and the related change in water quality were the dominant issues that affect the infiltration rate and health risks during the AR process, the dissolution of the aquifer matrix should also be taken into account. This dissolution contributed to not only the hydraulic conductivity of the infiltration medium but also the potential change in water quality during the aquifer recharge, storage and recovery processes.     

泰莱盆地地下水蓄水构造特征及勘查定井研究

针对基岩山区勘查定井问题,以旱区找水定井为目标,在地形地貌、地质和水文地质等实测资料的基础上,对泰安市地下水蓄水构造进行了分类,并阐述其特征。针对不同蓄水构造类型,基于构成地下水蓄水构造"三个基本要素"原理,并结合水文地质钻孔、高密度电阻率法、可控源音频大地电磁测深法等方法,对典型蓄水构造区构造特征及勘查定井进行了研究。结果表明:山东泰安市蓄水构造可分为水平岩层蓄水构造、断裂蓄水构造和基岩风化壳蓄水构造3种类型;水平岩层蓄水构造的含水层为古河道沉积砂层,隔水层为下伏古近系的泥岩和页岩,该区定井井位应布设在砂层上,井深宜在200 m左右,且应揭露砂层;断裂蓄水构造的含水层为奥陶系和寒武系白云岩和灰岩,隔水层为下伏的基岩岩层,导水通道为张性断裂带,在该区定井主要寻找奥陶系和寒武系地层,并尽量在断裂处或断裂交汇处定井;基岩风化壳蓄水构造的含水层为基岩风化壳,隔水层为下伏的基岩岩层,导水通道主要为张性断裂带,在该区定井主要是寻找基岩风化壳地层。     

滴灌系统灌水器堵塞机理与控制方法研究进展

滴灌系统灌水器堵塞问题直接影响灌水均匀度、系统运行效益和使用寿命,是滴灌领域的国际难题之一,而地下滴灌系统中负压吸泥作用与根系入侵效应使得灌水器堵塞机理更为复杂。尤其是水资源短缺与水污染并重的现状迫使滴灌水源多元化、滴灌系统由单一灌溉功能逐步向灌溉施肥等多功能转变以及滴灌技术在高附加值的多年生作物上的应用等因素,对灌水器抗堵塞能力提出了更高的要求。本文通过回顾滴灌系统灌水器堵塞问题研究历程,系统总结了灌水器堵塞类型、测试与评价方法以及发生特征与预报方法,通过建立堵塞物质提取与精细测试方法,分别从堵塞物质形成与生长过程、水源中多物质运移过程两个角度,揭示了灌水器堵塞耦合诱发机制与持续增长机理,通过综合控制堵塞物质来源(前控)、提升自身抗堵塞能力(中排)和有效清除堵塞物质(后清)等多角度建立了灌水器堵塞控制方法,最终提出该领域急需进一步研究的问题和方向。本文旨在为解决滴灌系统灌水器堵塞问题及推动滴灌技术规模化应用与推广提供理论支撑。     

Unclogging improvement based on interdate and interreach comparison of water release monitoring (Durance,France)

Large‐scale flow release experiments are becoming common for improving aquatic habitat quality downstream of dams. Because of the naturally high fine sediment load in the Durance River, France due to inputs from torrential tributaries draining badlands, unpredictable high flow events with dam overspill are not always sufficient to prevent clogging, which can lead to habitat degradation (especially spawning habitats) in bypassed reaches. Therefore, large‐scale flow experiments were conducted on four reaches to test the efficacy of clear‐water releases to improve aquatic habitat conditions. Continuous measurements of water depth, suspended sediment concentrations, and turbidity were conducted during twelve releases and compared on nine. Before and after each release, superficial clogging was measured. The study shows that there is a link between the volume of suspended sediments carried by water releases and the initial clogging. The volumes carried were low compared with the river's annual transport. The effect on clogging can vary significantly from one release to another. In particular, the hydrological context surrounding the releases has a significant influence on clogging. Comparisons of monitoring showed that releases are more effective on reaches that are more severely regulated (high hydrological control) than on those that are less well‐controlled. The areas with the highest initial clogging tend to unclog more than those with lower initial clogging; however, the latter zones are most impacted by ineffective releases. Performing a release on environments with low initial clogging can therefore be environmentally damaging. To ensure that releases are successful and that intervention is warranted, initial clogging should be measured in the field and releases should only be performed if the clogging is judged to be unfavourable.     

Coagulation mechanisms--nano- and microprocesses.

Possible coagulation mechanisms were studied in relatively high alkalinity model systems and surface waters. On the basis of available information, original laboratory experiments and simple calculation were performed in order to show that the adsorption of Al3+ and Fe3+ ions is not the dominant process in decreasing the stability of suspended particles. The ions of the feeding coagulants hydrolyse within short time and form positively charged water soluble aluminium- or ferric hydroxides. Adsorption of these water soluble hydroxides onto the surface of colloids and quasi-colloid particles are restricted because of the quick completion of the hydrolysis process in relatively high alkalinity (>1.2 mmol/L) water. The result of complete hydrolysis of Al3+ or Fe3+ ions are slightly positively charged poorly water soluble aluminium or ferric hydroxide sols. The positively charged hydroxides and the associated water molecules are connected to each other by hydrogen bonds, providing a stabile structure. The hydrogen bonds provide the aggregation of slightly positively charged sol aggregation into flocs. Considering the repulsing forces among the sols, high numbers of individual sol particles (having nm sizes) are able adsorb onto the surface of suspended particles, changing their electrical charge and decreasing the stability of the colloids and quasi-colloid particles. This process is dominant in the destabilisation of suspended particles.