新型防水产品--膨润土防水毯

介绍了膨润土防水毯的适用范围、主要技术性能指标和施工要点，阐述了其在防水防渗工程应用中的优越性和推广应用的可能性。     

浅谈膨润土防水毯施工

近年来,全国各大城市轨道交通迅猛发展,城市地铁以不可替代的优势,解决了城市交通拥堵的难题。地铁施工大部分为地下工程,而防水就是控制地铁施工质量的难点,膨润土防水毯以其独有的优势,在地铁施工中得到了大量的应用。     

膨润土防水毯在地下室防水工程中的应用

膨润土防水毯(以下简称防水毯)是一种新型的环保型防水材料?它是由经级配过的天然钠基膨润土颗粒和相应的外加剂混合均匀后，经特殊的工艺及设备将其均匀、牢固地固定在两层土工布之间制成的防水毯。该材料具有优异的防水防渗性能，施工中可根据工程的需要单独使用或与其他防水材料共同使用，是一种较好的地下防水防渗材料。     

膨润土防水毯施工及应用

本文对膨润土防水毯的分类、原理、特点、施工及应用做了较为详细的阐述。     

防水新材料—膨润土防水毯在地下室防水工程中的应用

膨润土防水毯提一种高新科技产品,应用于高等级防水的地下室工程中,具有显著的效果。     

膨润土防水毯在地下室防水工程中的使用

阐述膨润土防水毯的特点,结合工程实例对膨润土防水毯在地下室防水工程中的使用进行了的探讨。     

膨润土防水毯在水利工程中的应用

介绍了钠基膨润土防水毯的优点,通过水利工程中底部防渗处理对钠基膨润土防水毯应用的工程总结,提出了对水利工程中钠基膨润土防水毯施工的几点建议。     

新型材料——膨润土防水毯

膨润土防水技术最早在上世纪八十年代由国外的工程公司和设计师事务所引入国内，在九十年代开始有香港公司通过代理方式在国内推广，到了本世纪初，美国胶体环境技术公司在国内开设工厂，标志着这一国际领先的防水技术开始全面进入国内。近几年，经过设计院、工程公司和一些业主的不断努力，膨润土防水产品在许多领域已经开始使用，并逐渐展露出自己独特的优势。     

膨润土防水毯在地下防水工程中的应用

长春市商业银行大厦,建筑面积28000m^2,主楼28层,剪力墙结构,地下1层。地下室建筑面积约4000m^2,其底板、外墙防水材料为膨润土防水毯,总面积约5700m^2。     

膨润土防水毯的施工方法

1．工程概况 其游乐公园人工湖扩建工程,施工面积约为12680m^2。根据该工程防水要求的特殊性和重要性以及设计要求等情况。做到工程各部位防水达到优质防水效果。为此。人工湖防水全部采用天然钠基膨润土防水毯施工,投入使用以来取得令人满意的防水效果。     

Investigating the mechanism of downslope bentonite erosion in GCL liners using X-Ray CT

Exposed composite GMB-GCL liners are at risk of downslope bentonite erosion caused by the release of low ionic strength condensed water onto the top surface of the GCL following daily solar heating. This paper investigates the use of X-ray computed tomography (X-ray CT) to quantify the thinning of the bentonite layer and the application of X-ray diffraction techniques (XRD) to investigate the changes in clay chemistry (if any) of the bentonite from the virgin GCL to the eroded bentonite. The effect of specimen size and scanning orientation was investigated resulting in a revised testing procedure in which the CT scanning orientation was changed from horizontal to vertical to permit a longer test specimen which was also sealed at the bottom edge to minimise the edge boundary condition. The X-ray CT results provide highly visual evidence that a) bentonite thinning immediately under the upper cover geotextile is the initial location of erosion, and b) the bentonite core erodes at a significantly higher rate when not covered by a geotextile than when covered by a geotextile. These observations indicate that the upper geotextile of the GCL plays a significant role in controlling the rate of bentonite erosion. Finally, a comparison of the virgin and runoff bentonite properties was conducted to investigate potential changes in swell index, X-ray diffraction results, and concentration of Na and Ca cations. The runoff bentonite was observed to had a significantly higher swell index (40?ml/2?g) than the virgin bentonite (28?ml/2?g) and lower Na and Ca concentrations. This finding is consistent with the observation from XRD analyses of the runoff bentonite which illustrate that the clay fraction of the bentonite is preferentially eroded by the application of DI water.     

利用膨润土的膨胀和稠度特性对GCL渗透系数进行预测的试验研究

以土工合成粘土衬垫(Geosynthetic Clay Liner,GCL)在尾矿库防渗层中的应用为背景,研究不同浓度重金属离子(Cu和Zn)作用下,膨润土的自由膨胀量、液限及GCL渗透系数的变化规律,并分析它们之间的对应关系。试验结果显示,当重金属离子浓度在0.01mol/L到0.1mol/L之间递增时,膨润土的自由膨胀量和液限会随着重金属离子浓度的增大而大幅度减小,但当重金属离子浓度从0.1mol/L增加到0.5mol/L时,膨润土的自由膨胀量和液限则只有微小变化。在渗透试验中,当渗透溶液中重金属离子浓度小于0.01mol/L时,GCL的渗透系数能够保持稳定;但当重金属离子浓度大于0.02mol/L后,GCL的渗透系数会随着渗透溶液中重金属离子的浓度增加而不断升高。研究结果表明,当尾矿库渗滤液中重金属离子浓度大于0.02mol/L时,GCL的渗透系数与膨润土的自由膨胀量和液限之间具有良好的数学对应关系,可以利用自由膨胀量和液限对渗透系数进行预测。     

Field observation of GCL shrinkage at a site in Melbourne Australia

The findings from an investigation of GCL overlap for a GCL constructed as part of a 55 m long (3H:1V) composite side liner for a landfill cell after 18 months exposure in Melbourne Australia are reported. It is concluded that the nominated minimum overlap of 300 mm was appropriate to achieve the design intent for the particular GCL examined. It is also concluded that for the exposure to which the GCL was subjected, the particular GCL experienced 50–80 mm of shrinkage during 18 months of exposure when the geomembrane was covered by a 5 mm thick off-white geotextile protection layer.     

膨润土防水毯在渗滤液环境下防渗性能的测试应用研究

膨润土防水毯作为一种优异的防渗材料,国内暂无其在渗滤液环境下的渗透性能报道。本文拟配置性能组分稳定的代表性合成渗滤液作为实际渗滤液的替代试验介质,研究合成渗沥液对膨润土原料膨胀性能和滤失性能的影响,测试在合成渗滤液环境中,不同压力和温度条件下膨润土防水毯的渗透系数,以此为垃圾填埋工程和其他固废填埋工程使用膨润土防水毯作为防渗衬垫提供指导。     

我国四类衬垫系统防污性能的比较分析

对我国填埋场采用的四类衬垫进行了防污性能的比较分析。评价参数包括渗漏率、污染物击穿时间及衬垫系统底部浓度值。除了2m压实黏土衬垫(CCL)外,其余3种均为包含土工膜(GM)的复合衬垫。分析模型采用了污染物通过有缺陷膜复合衬垫的一维运移解析解。以镉离子(Cd2+)为渗滤液中重金属离子的代表;以苯为其中挥发性有机污染物的代表。研究表明土工复合膨润土垫(GCL)复合衬垫的渗漏率最小,2m黏土最大,两者的差别可在3～5个数量级。GCL复合衬垫对重金属离子具有较好的防污性能,尤其是在高水头及复合衬垫接触较差的情形。厚度较大的2m黏土对挥发性有机污染物的防污性能较好,其击穿时间要比GCL复合衬垫大2～3个数量级。随着水头的增大,CCL复合衬垫的防污性能逐渐地优于2m黏土。在10m水头作用下,CCL复合衬垫底部的100年浓度可比2m黏土小近一个量级。单层膜衬垫的防污性能较差,不适合作为填埋场的衬垫系统。控制填埋场复合衬垫的施工质量和渗滤液水头尤为重要。     

Assessment of consolidation-induced VOC transport for a GML/GCL/CCL composite liner system

In municipal solid waste landfills, a triple-layer composite liner consisting of a geomembrane liner (GML), a geosynthetic clay liner (GCL) and a compacted clay liner (CCL) is commonly used at the landfill bottom to isolate the leachates from surrounding environment. This paper presents a numerical investigation of the effect of liner consolidation on the transport of a volatile organic compound (VOC), trichloroethylene (TCE), through the GML/GCL/CCL composite liner system. The numerical simulations were performed using the model CST3, which is a piecewise linear numerical model for coupled consolidation and solute transport in multi-layered soil media and has been extensively validated using analytical solutions, numerical solutions and experimental results. The performed numerical simulations considered coupled consolidation and contaminant transport with representative geometry, material properties, and applied stress conditions for a GML/GCL/CCL liner system. The simulation results indicate that, depending on conditions, consolidation of the GCL and CCL can have significant impact on the transport results of TCE (i.e., TCE mass flux, cumulative TCE mass outflow, and distribution of TCE concentration within the GCL and CCL), both during the consolidation process and long after the completion of consolidation. The traditional approach for the assessment of liner performance neglects consolidation of the GCL and CCL and fails to consider the consolidation-induced transient advection and concurrent changes in material properties and, therefore, can lead to significantly different results. These differences for with and without the consolidation effects can range over several orders of magnitude. The process of consolidation-induced contaminant transport is complex and involves many variables, and therefore case-specific analysis is necessary to assess the significance of liner consolidation on VOC transport through a GML/GCL/CCL composite liner system.     

氨氮在土工合成黏土衬垫中的扩散行为研究

氨氮是垃圾渗滤液中最具代表性的污染物之一,但其在土工合成黏土衬垫(GCL)中的扩散行为至今尚未得到重视。开展批式吸附试验和扩散试样浸提试验测定氨氮在GCL中的吸附分配系数;进行扩散试验测定氨氮在GCL中的扩散系数;基于试验得到的吸附分配系数和扩散系数,使用数值软件POLLUTE v7.0对氨氮在GCL中的运移行为进行模拟。试验结果表明,氨氮在膨润土上的吸附分配系数为0.017L/g,在GCL中的扩散系数约为9.0×10^-11m²/s。POLLUTE v7.0的模拟结果显示,当考虑扩散存在时,氨氮将提前30 a击穿GCL。     

膨润土防水毯在基础底板防水工程中的应用

膨润土防水毯可广泛应用于市政、公路、水利及民用建筑中,通过首都机场三号航站楼滑行桥下基础底板防水工程,详细介绍了膨润土防水毯的施工工艺,尤其对各特殊节点部位施工进行了详述,保证了工程质量。     

Effect of geosynthetic component characteristics on the potential for GCL internal erosion

Experiments quantifying GCL permittivity and the ultimate water head the GCLs can sustain before the initiation of internal erosion when underlain by a 50 mm angular to subangular gravel subgrade are conducted. The influence of different geotextiles over the subgrade, water heads, hydration periods before testing, masses per unit area of bentonite within the GCL, and ionic strengths of the solution (cation exchange) are considered. Test results show that GCL with the scrim-reinforced nonwoven geotextile over the subgrade has the best hydraulic performance against internal erosion, followed by the woven geotextile coated with a 110 g/m² polypropylene film. A woven or nonwoven is the least useful for preventing internal erosion, with the corresponding threshold water head initiating internal erosion >39 m for scrim-reinforced nonwoven, 21 m for lightly coated woven, 4–5 m for woven and nonwoven alone, respectively. Cation exchange, length of hydration, and mass per unit area of bentonite do not notably affect the threshold water head for the subgrade examined. Once internal erosion occurs, there is a 3-order of magnitude increase in permittivity. The practical implications are discussed.     

福州海西动漫园人工搿防渗工程施工技术

摘要：介绍了LAKEMAT膨润土防水毯应用于福州海西动漫园人工湖的施工技术,对基面处理、材料性能、施工工艺、细部节点处理等重要环节进行了详细阐述,指出LAKEMAT膨润土防水毯是一种特别适用于人工湖等水工建筑的防水材料。