疏浚淤泥流动固化处理与流动性试验研究

疏浚淤泥由于含水率高、强度低、渗透性低等特性,在工程上难以直接利用而往往作废弃处理,造成了资源的浪费和土地的占用。针对我国疏浚施工的特点,基于传统固化方法,提出了将高含水率疏浚淤泥进行流动固化处理,并进行了流动性试验研究。结果表明,固化淤泥拌合物的流动值与初始含水率及固化材料掺量之间均具有良好的线性关系,初始含水率2.5wL是能否进行流动固化处理的临界值。基于影响流动性的两个重要因素,即初始含水率和固化材料掺量,提出了广义水灰比的概念,建立了流动值的预测方法,并对预测公式进行了验证     

污水处理厂污泥处理处置方法

污泥是污水处理的伴生物,若不加以妥善处置,容易产生二次污染.污泥处理处置的目的是实现稳定化、无害化、减量化、资源化以及最终处置.本文主要介绍了污水处理厂污泥稳定化、无害化、减量化、资源化和最终处置的方法及利用途径.     

污泥屏障渗透性及重金属阻截效果试验研究

目前,废弃物处置场渗滤液中的重金属污染物只能依靠极低渗透性的水力屏障来控制,还不存在利用化学场专门拦截重金属污染物的反应型屏障。在有机结合生活污泥的低渗透性与丰富的有机质和厌氧微生物特性的基础上,提出“污泥屏障”的构想。研究利用柔性壁渗透仪测量不同有效应力作用下生活污泥试样的渗透系数,并对渗出液的化学性质进行了监测,验证污泥屏障的可行性。试验结果表明：随着有效应力的增大,污泥试样干密度提高,渗透系数的对数值随孔隙比的减小线性降低。试样内部微生物厌氧呼吸形成的生物膜和无机物沉淀以及黏土颗粒双电层厚度的增大,也是污泥渗透系数降低的原因,污泥渗透系数仅为 数量级。另外,污泥强烈吸附能力及厌氧微生物呼吸作用形成的中-弱碱性还原环境,对渗透液中的Zn和Cd都起到了很好的拦截作用。     

杭州西湖疏浚底泥工程性质试验研究

针对西湖疏浚底泥的沉积规律、颗粒分布、渗透特性、压缩特性等工程性质进行了室内试验,并分别对室内沉积土样和库区沉积土样的工程性质做了比较,得到了渗透系数、压缩系数等指标沿深度和距离上的变化规律。试验结果对进一步了解疏浚底泥的工程特性具有参考意义,也有利于指导蓄泥库疏浚底泥的后期处理措施的制定。     

提高石油化工污泥脱水性能试验研究

本研究通过污泥比阻试验及叶片吸滤试验，探讨化学调理前后污泥前后污泥的脱水性能，研制并开好改善石油化工污泥脱水性能的最佳药剂ＰｔＣ，并为石油化工污泥脱水提供了必要的运行参数。     

水泥-磷石膏双掺固化处理高含水率疏浚淤泥试验研究

在传统水泥固化处理方法的基础上,提出用水泥-磷石膏双掺固化处理高含水率疏浚淤泥的方法,以期达到以废治废,将废弃高含水率疏浚淤泥经济合理转化为良质土资源的目的。系列室内试验的结果表明,磷石膏对疏浚淤泥固化土的增强效果显著,并存在一最佳掺量,最佳掺量随淤泥初始含水率增大而增大,水泥-磷石膏双掺固化土的应力-应变曲线表明,其破坏应变一般在2%～3%左右,变形系数E50与抗压强度近似呈线性递增关系。     

高含水率疏浚淤泥新型复合固化材料试验研究

基于传统水泥固化处理方法,提出了水泥-生石灰-高分子添加剂新型复合固化材料处理高含水率疏浚淤泥的新方法,以期快速降低淤泥含水率并提高固化淤泥的无侧限抗压强度,拓展水泥固化淤泥的含水率范围,达到高效廉价固化处理高含水率疏浚淤泥的目的。通过系列室内试验,探讨了该方法处理后高含水率淤泥的无侧限抗压强度变化规律以及各材料掺入比对强度的影响规律。研究结果表明,水泥掺入比低于7%的新型固化材料处理初始含水率2倍液限的高液限淤泥,早期强度大于0.5 MPa,28 d强度大于1 MPa;固化淤泥强度随龄期、水泥和生石灰掺入比的增大而增大;给出了考虑多因素多水平的无侧限抗压强度预测公式,预测值与实测值基本一致     

疏浚淤泥的土工材料化处理技术的试验与探讨

疏浚淤泥的弃埋会产生环境问题,如何进行处理是国内外十分关注的问题。采用固化及轻量化处理技术开发再生土工材料,具有广阔的应用前景。根据室内试验,研究了不同配比的淤泥固化土和轻量化土的无侧限抗压强度和密度,并分析了固化和轻量化的强度形成机理。疏浚淤泥土工材料化处理在技术上是可行的,且具有废物利用和保护环境的优点,可带来良好的环境效益和社会效益。     

Mobility of heavy metals in harbour sediments: an environmental aspect for the reuse of contaminated dredged sediments

Different methods to determine the source strength of two harbour sediment fractions were applied and are discussed with a focus on As, Cd, Cr, Co, Cu, Mo, Ni, Pb, and Zn. Four different batch experiments were performed with both the sandy and the silty fractions of harbour sediments sampled at the disposal site for dredged material in Bremen Seehausen, north Germany. In addition to the batch experiments a modified centrifugation tube was used in order to obtain pore water from the unsaturated silty fraction. Column experiments were run with the sandy fraction of the material under saturated and unsaturated conditions, irrigated with artificial acid rain water. The results show that the legal threshold value applying to Mo and Pb is not exceeded in any of the methods applied to the sandy or the silty fractions. As for the sandy fraction, Cr and Co were also below this limit. Cd, Ni, Cu and Zn exceeded the threshold values in some of the batch experiments applied to both fractions, depending on the pH value and the elution agent used in the experiment. All results obtained from saturated column leaching were below the respective threshold values; however, it should be noted that the pH was between 7 and 8 throughout the entire experiment. This pH also applied to the unsaturated column, with the exception of the first flush. This first sample had a pH value of 3.8, which was due to sulphide oxidation at the beginning of the experiment and led to strong leaching of all the elements under study. As a consequence, arsenic, Cu and Ni values exceeded their respective threshold values.     

初始含水率对水泥固化淤泥效果的影响

通过室内调配不同初始含水率的淤泥,研究了初始含水率对水泥固化效果的影响。研究发现,固化淤泥的无侧限抗压强度随淤泥含水率的增加呈乘幂关系下降,随着初始含水率的增加,固化淤泥的塑性增加,破坏应变增加,而黏聚力降低。随着初始含水率的增加,水分过多导致水化产物在单位体积中的数量较少,难以形成整体强度。在实际工程中,应在满足固化搅拌的施工要求下,尽量降低淤泥的初始含水率以取得较好的经济效益.     

固化淤泥压缩特性的试验研究

淤泥固化技术在国内已经进入到工程应用阶段,明确固化淤泥的压缩特性对于指导淤泥固化工程的设计具有重要意义。通过单因素试验方案对不同初始含水率、不同水泥添加量、不同养护龄期的固化淤泥的压缩特性进行了研究。结果发现,固化淤泥压缩特性的最大特点是存在固结屈服应力,当荷载小于固结屈服应力时固化淤泥的压缩性非常小,而固化淤泥屈服之后的压缩性是屈服前压缩性的20倍以上,并且远大于未处理淤泥的压缩特性。淤泥本身是高压缩性的土,固化处理以后变为中等压缩性和低压缩性的土体。固化淤泥的固结屈服应力随水泥量增加线性增大,龄期越长、含水率越低固结屈服应力越大。固化淤泥的这种在固结屈服应力处发生突变的压缩特性和天然沉积结构性土类似,可以用双对数压缩模式来表示固化淤泥的这种压缩特性。     

含水率对重塑淤泥不排水强度性质的影响

通过室内调配不同含水率的重塑淤泥,利用研制的室内微型高精度十字板剪切仪,研究了含水率对重塑淤泥重塑不排水强度的影响。该仪器的剪切强度分辨率为1 Pa,经试验验证,仪器测量结果的稳定性较好,但对强度越低的重塑淤泥试样其测量值的相对平均偏差越大。淤泥含水率对淤泥的不排水强度有显著影响,不排水强度均随含水率/液限的增大而减小,含水率/液限越大,不排水强度下降趋势越小。相同的含水率/液限时,不同种类的重塑淤泥的不排水强度比较接近。在双对数坐标中,不排水强度均随含水率/液限的增大而线性减小。由试验数据得出了不同种类重塑淤泥的不排水强度与含水率/液限之间的关系式,利用该关系式可以求得每一种重塑淤泥任意含水率下的不排水强度。文中的试验值大于洪振舜提出的关系式的计算值。当IL >2时,试验值与Locat和Leroueil提出的关系式的计算值基本吻合,当IL <2时,试验值大于Locat和Leroueil提出的关系式的计算值。     

固化淤泥三轴试验研究

对不同水泥掺加量固化淤泥进行了固结不排水(CU)三轴剪切试验,对固化淤泥的破坏模式和抗剪强度参数进行了分析。试验结果表明：应力-应变曲线随着水泥量增加由理想弹塑性向应变软化型转变;当水泥量为50 kg/m3时,随固结压力的增加应力-应变曲线有理想弹塑性、应变软化和应变硬化三种类型;当水泥量高于100 kg/m3时,试样都呈脆性破坏模式。淤泥经水泥改良后成为一种结构性土,固结压力在小于试样结构屈服应力时对抗压强度影响不大。有效粘聚力随水泥量的增加呈较大的增长趋势,而有效内摩擦角分布在32o~42o,表明水泥固化淤泥的作用主要是提高土颗粒间的胶结,而填充孔隙的作用较弱。     

基于碳化-固化技术的武汉东湖淤泥耐久性演变微观机制

引入活性MgO-粉煤灰固化材料,采用碳化-固化联合技术处理武汉东湖疏浚淤泥,通过无侧限抗压强度、X射线衍射、扫描电镜和压汞试验,研究持续浸水、干湿循环和冻融循环等复杂环境下碳化-固化淤泥力学性质和微观结构演变。结果表明:活性MgO-粉煤灰固化淤泥经碳化处理后具备更优异的水稳性,浸水破坏后碳化淤泥试样整体抗压强度高于固化试样,提升幅度约为29%;碳化试样强度随干湿循环次数增加呈缓慢增加趋势,而固化试样则表现为先上升后下降;随着冻融循环次数增加,碳化前后试样抗压强度变化一致,即快速达到峰值后缓慢减小至保持不变。微观分析表明:起骨架支撑作用的棱柱形碳酸镁石、起填充与黏结作用的花骨状和片状的水碳镁石和球碳镁石为主要碳化产物,骨架-填充-黏结协同作用使碳化试样强度高,水稳定性好,抗干湿冻融能力强;持续浸水促使球碳镁石和水碳镁石向碳酸镁石转化,大孔隙增多;干湿循环促使碳酸镁石向球碳镁石和水碳镁石转化;冻融作用下试样碳化产物之间无明显转化。     

堆场疏浚淤泥含水率分布规律调查研究

堆场淤泥的沉积、固结过程直接影响到后续淤泥的处理方法和经济成本。通过在南水北调东线白马湖现场使用绞吸式挖泥船疏挖白马湖底泥,吹淤进入堆场,研究了堆场内淤泥含水率随时间、沿程和堆场深度上的变化规律。结果表明,堆场内疏浚淤泥含水率随时间逐渐降低,随沿程逐渐升高,130 d后吹淤口处含水率降低到20%～50%之间;160 d后,距离吹淤口100 m距离吹淤口200 m处和处含水率维持在100%～150%和100%～170%之间;随深度逐渐降低,到40 cm深时,含水率降低减缓,维持在140%左右;疏浚泥中黏粒含量随着距离吹淤口距离的增大而增多,随着深度的加深而减小,疏浚泥的渗透系数随着距离吹淤口距离的增大而减小,随深度的加深而增大。     

Zn, Pb, Cu and As distribution patterns in overbank and medium-order stream sediment samples: their use in exploration and environmental geochemistry

Overbank and medium-order stream sediment samples were collected in Belgium and Luxembourg from 66 sampling locations (area of about 33,000 km²) and analysed for major and trace elements among which Zn, Pb, Cu and As. At each sampling location large bulk samples were taken, namely in the lower (normally at ≥1.5 m depth, over an interval of about 20–40 cm) and upper (normally upper 5–25 cm) parts of the overbank profiles and from the stream sediments. Furthermore, at a number of these sites, a detailed geochemical analysis of vertical overbank sediment profiles (sampling intervals of 10–20 cm) was subsequently carried out to unravel element variations through time and to help in the overall evaluation. For most sampled sections evidences such as ¹⁴C-dating and the absence of anthropogenic particles point towards a pre-industrial and often pristine origin of the lower overbank sediment samples. From the latter bulk samples, mean background concentrations were deduced. They reveal the existence of significant differences between the northern and southern part of Belgium (incl. Luxembourg) which relate to the difference in geological substrate. In the north dominantly non-lithified Quaternary and Tertiary sands, marls and clays occur while in the south Palaeozoic sandstones, shales and carbonate rocks outcrop. Consequently separate mean background values were calculated for the two areas. In the southern study area, some anomalous metal concentrations have been recorded in pre-industrial sediments. They are derived from mineralised Palaeozoic rocks, a feature which could be of interest for base metal exploration. In the upper overbank and stream sediments, in general, higher heavy metal and As contents were recorded with highest values in areas with metal mining, metal melting and cokes treatment industries. By comparing the trace element concentrations of the upper overbank or stream sediment samples with the concentrations detected in the lower overbank samples at each of the sampling locations, and by evaluating the vertical distribution patterns where available, the degree of pollution of the alluvial plain and the present-day stream sediments can be assessed. From this exercise, it is clear that highest pollution occurs in the northern part of Belgium, which relates to its high population density and industrial development.     

淤泥堆场人工硬壳层地基极限承载力室内模拟研究

针对淤泥堆场利用淤泥固化技术制作的人工硬壳层（MMC）地基的极限承载力问题,利用模型试验研究了人工硬壳层的无侧限抗压强度、厚度以及淤泥的不排水强度对这种人工硬壳层地基极限承载力的影响规律。结果表明,淤泥上覆人工硬壳层地基的极限承载力随人工硬壳层的无侧限抗压强度的增加呈指数增加的趋势,随硬壳层厚度的增加呈现出线性增加的趋势。     

中国北方某湖泊底泥污染分析及重金属潜在生态风险评价

以中国北方某湖泊(以下称A湖)为例,开展了底泥中氮磷污染及重金属生态风险评价研究,探讨多种评价方法的相关性,并分析底泥中氮磷元素向上覆水迁移造成水体富营养化的风险.选取A湖中心区域的10个底泥监测点位数据,对其总氮、总磷及重金属(Pb、Cr、As、Cd、Ni)含量进行分析,并采用有机污染指数法评价总氮污染,单因子指数法...