Coupling effect of pond ash and polypropylene fiber on strength and durability of expansive soil subgrades:An integrated experimental and machine learning approach

This study explores the coupling effect of pond ash(PA)and polypropylene(PP)fiber to control the strength and durability of expansive soil.The PA is used to chemically treat the expansive soil and PP fiber is adopted as reinforcement against tensile cracking.The sustainable use of PA and PP fiber are demonstrated by performing mechanical(i.e.unconfined compressive strength,split tensile strength and ultrasonic pulse velocity),chemical(pH value,electrical conductivity and calcite content),and microstructural analyses before and after 2nd,4th,6th,8th and 10th freezing-thawing(F-T)cycles.Three curing methods with 7 d,14 d and 28 d curing periods are considered to reinforce the 5%,10%,15%and 20%PA-stabilized expansive soil with 0.25%,0.5%and 1%PP fiber.In order to develop predictive models for mechanical and durability parameters,the experimental data are processed utilizing artificial neural network(ANN),in association with the leave-one-out cross-validation(LOOCV)as a resampling method and three different activation functions.The mechanical and durability properties of the PA-stabilized expansive soil subgrades are increased with PP fiber reinforcement.The results of ANN modeling predict the mechanical properties perfectly,and the correlation coefficient(R)approaches up to 0.96.

Performance evaluation of cement-stabilized pond ash-rice husk ashclay mixture as a highway construction material

This paper reports the results of an investigation carried out on clay soil stabilized with pond ash(PA),rice husk ash(RHA) and cement. Modified Proctor compaction tests were performed in order to investigate the compaction behavior of clay, and California bearing ratio(CBR) tests were performed to determine the strength characteristics of clay. For evaluation purpose, the specimens containing different amounts of admixtures were prepared. Clay was replaced with PA and RHA at a dosage of 30%e45% and5%e20%, respectively. The influence of stabilizer types and dosages on mechanical properties of clay was evaluated. In order to study the surface morphology and crystallization characteristics of the soil samples, scanning electron microscopy(SEM) and X-ray diffraction(XRD) analyses were carried out,respectively. The results obtained indicated a decrease in the maximum dry density(MDD) and a simultaneous increase in the optimum moisture content(OMC) with the addition of PA and RHA.Multiple linear regression analysis(MLRA) showed that the predicted values of CBR tests are in good agreement with the experimental values. Developed stabilized soil mixtures showed satisfactory strength and can be used for construction of embankments and stabilization of sub-grade soil. The use of locally available soils, PA, RHA, and cement in the production of stabilized soils for such applications can provide sustainability for the local construction industry.

Application of polymeric flocculant for enhancing settling of the pond ash particles and water drainage from hydraulically stowed pond ash

Delayed settling of the ash particles and poor drainage of water from the pond ash are the major problems faced during the hydraulic stowing of pond ash. In this study the effect of polymeric flocculant on settling of the ash particles and drainage of water during pond ash stowing are investigated. In addition, the parameters, viz. drainage and absorption of water during pond ash stowing are quantified by stowing a mine goaf model with pond ash slurries of five different concentrations added with and without flocculant. The study revealed that addition of only 5 10 6 of Sodium Carboxymethyl Cellulose (Na-CMC) flocculant with the pond ash slurries during stowing offers best result in terms of quicker settling of the ash particles and enhanced water drainage from the hydraulically stowed pond ash. Besides, it resulted in drainage of more than 85% of the total water used in the initial 45 min of stowing. The improvement in drainage is caused due to coagulation and flocculation of the pond ash particles because of charge neutralization and particle-particle bridging. This study may provide a basis for estimating the drainage and absorption of water during the real pond ash stowing operation in underground mines.

Bearing ratio and leachate analysis of pond ash stabilized with lime and lime sludge

Recycling of industrial waste is one of the effective ways to overcome their disposal problem. Ash produced by thermal power plants and lime sludge produced by paper mills require huge disposal land and may create environmental problems such as dusting and leaching of harmful heavy metals. Stabilization of the ash can improve its engineering properties and address the environmental problems. This paper reports the laboratory test results of a Class F pond ash stabilized with lime(2%, 4%, 6% and 8% by weight)alone and in combination with lime sludge(5%, 10% and 15% by weight). The X-ray diffraction(XRD) and scanning electron micrograph(SEM) tests were also performed to identify the possible formation of crystalline phases after stabilization. The effects of lime sludge on the unsoaked and soaked bearing ratios of pond ash with different lime contents, after 7 d, 28 d and 45 d of curing, were observed. Test results indicated that the bearing ratio increased considerably up to a 4% lime content which can be taken as the optimum lime content. Further increase in lime content increased bearing ratio gradually but at a slower rate. The effect of lime sludge was more pronounced at the optimum lime content,particularly at a low curing period. Lime sludge improved the bearing ratio in soaked condition significantly. Leachate analysis of stabilized ash was performed using toxicity characteristic leaching procedure(TCLP-1311) method. The concentrations of toxic elements Zn, Cu, Cd, Ni and Cr in the stabilized mixes were lower than those in the unstabilized waste. The results indicated that the pond ash-lime-lime sludge mixes have potential application as road subbase material.

Dynamic Behaviour of Pond Ash Mixed with Coir and Crumb Rubber

An experimental program was conducted to determine the dynamic properties of pond ash(PA)and pond ash mixed with admixtures like crumb rubber(CR)and coir fiber(CF)which are wastes of different industries.Additives CR and CF were mixed separately with pond ash in a percentage ranging from 0%–20%at an interval of 5%and 0%–2%at an interval of 0.5%by weight of pond ash,respectively.Dynamic properties(Shear modulus,Number of cycles to initiate liquefaction,Degradation index and Damping ratio)for pond ash mixes were determined using strain-controlled cyclic tri-axial apparatus.The shear strain was kept constant at 1.2%and the frequency varied from 0.4 to 1 Hz.Liquefaction resistance improves when crumb rubber is added to pond ash,however adding Coir fiber to pond ash has essentially no effect on the number of cycles required to initiate liquefaction.The dynamic shear modulus decreases when crumb rubber was mixed in pond ash whereas when coir fiber is added to pond ash,the dynamic shear modulus increases significantly.A mix of PA,CR,and CF was also tried to balance the number of cycles required to initiate liquefaction and shear modulus.The mixed sample in the proportion of PA(84%)+CR(15)+CF(1%)can be termed a balanced mix as the number of cycles to initiate liquefaction was more than all PA-CF mixes and also the shear modulus was more than all PA-CR mixes.Damping ratio increases with increasing frequency of loading(0.4 to 1 Hz).

贮灰场灰水渗漏特性及防渗措施的研究

以中砂、细砂、粉砂、砂质粉土和粉质粘土为贮灰场底部包气带的主要代表土层，试验研究了贮灰场灰水在包气带土层中的渗漏特性。防渗试验表明，压实后的粘性土层和上工膜具有良好的防渗性能，且简便易行、无污染。结合各土层的具体情况，提出了相应的防渗措施。

燃煤电厂灰场排水除氟研究

本文研究了采用天然斜发沸石—硫酸铝钾体系对燃煤电厂灰场排水中氟的吸附效果及影响因素,并对吸附与再生过程的机理进行了探讨。研究结果表明,天然斜发沸石—硫酸铝钾体系除氟效果良好,运行成本也比较低。

燃煤电厂灰水pH值变化规律及其CO_2调整理论分析

讨论了燃煤电厂水力除灰系统灰浆pH值变化规律.灰浆初始pH值受除尘器类型影响,干式除尘器远大于湿式除尘器；灰浆在输往灰场过程中,灰中游离氧化钙的溶出会使灰浆pH值不断上升；在灰场入口,灰浆pH值达到最高;水与灰在灰场中分离,并吸收空气中CO2,使水pH值下降,最后排出灰场.针对灰浆pH值变化规律和除灰系统的结构特点,从理论上论证了CO2投入点的选择依据及投加量的估算方法.

拟建窑河洼电厂灰场对地下水环境的影响评价

在对淮南市窑河洼区环境水文地质调研基础上,对拟建窑河洼灰场及邻区的浅层地下水环境质量现状进行了模糊数学评价;基于地下水水质模型,以F-作为模拟因子,对地下水F-浓度变化进行了数值模拟,对其5a后的污染范围和程度进行了预测评价。结果表明,模型较为可靠、合理,灰场建成后对场区及邻区地下水环境质量的短期影响不大,这为灰场选址决策及灰场建设后可能引起地下水污染的范围和程度预测提供了科学依据。

海水池塘混合施肥养殖台湾红罗非鱼的鱼产力和负荷力

于１９９５年７—９月，在烟台市黄海水产集团公司第二养虾场，采用围隔实验法研究了海水池塘混合施肥养殖台湾红罗非鱼的鱼产力、负荷力和最适放养量。实验中每个围隔面积为 ５ｍ×５ｍ，各设 １台 ９０Ｗ的搅水机（４ ８００ｒ／ ｈ）。每日施肥基准为：鸡粪干物质， ２５ｋｇ／ｈａ：氮肥， Ｎ０．１５× １０－６；磷肥，Ｐ０．０１５× １０－６。结果表明，静水海水池塘混合施肥的鱼产力为０．７９ｇ／（ｍ２·ｄ），池塘对台湾红罗非鱼的负荷力为１７９６．０ｋｇ／ｈａ，鱼（体重７０ｇ／ｉｎｄ）的最适放养量约为８０００ｉｎｄ／ｈａ。

燃煤电厂贮灰场防尘固化剂的研究

针对我国燃煤电厂贮灰场普遍存在的灰尘二次飞扬问题，进行了灰场表面固化防尘试验研究，筛选出固化剂配方，并在数家电厂贮灰场进行了工程应用。结果表明：该技术具有防尘效果好，治理见效快，成本低廉，施工工艺简单灵活等突出优点，适宜在电厂贮灰场推广应用。

山谷灰场土坝坝体及坝肩渗流分析

通过对阳坡灰场工程设计,分级加筑子坝增加库容,针对灰场工程地质条件,采取恰当的地基处理和防渗措施;重点对山谷灰场进行了渗流分析计算,评价了坝体和坝肩的渗透稳定性,制定了多项坝体及坝肩相应的防、排渗工程措施,确保整个灰场安全运行。

火电厂外排废水CODcr超标的原因分析与应对措施

针对缺少废水集中处理设施的钢铁行业自备电厂,就其外排废水CODcr频繁超标的原因进行了分析,并提出降低电厂外排废水CODcr的应对办法。

火电厂灰场溃坝事故与渗流

近年来，火电厂灰场溃坝、泄漏、污染的事故屡有发生。针对火电厂发生的灰场溃坝事故的具体事例，分析造成这些事故的主要因素，提出渗流是造成灰场溃坝事故的主要原因，并提出防止渗流的技术措施。

某电厂灰渣库整体稳定性探讨

从物理力学参数的选取方面对某电厂灰渣库一期工程1号副坝的整体稳定性进行探讨,从中发现原有研究结果的偏差,并对坝体的整体稳定性作出了比较客观的结论,同时也通过对比总应力强度与有效应力强度指标的不同适用范围,提出了在灰渣坝(尾矿坝)的稳定性分析中应对其区别对待,以免出现不必要的错误,从而有效地指导灰渣库(尾矿库)的安全管理工作。

浓缩池溢流灰水回用技术

与常规技术相比，浓缩池溢流灰水处理新技术。可以节省３～４个处理水池。该技术用于输送溢流灰水的管道改造为管式混合反应器，有机高聚合物就加在距分离池一定距离的位置，省去常见的沉淀池而代之予多功能、高效率的分离池，所加药剂在其中絮凝，从而分离悬浮物，且可以一池多用。该技术已正常运行３年，处理后的水质良好且稳定，回用系统中未出现结垢和磨损现象。

渣池系统零排放改造措施

锅炉灰水从渣池溢流口直排,污染环境,堵塞下水道。分析锅炉渣池系统不能正常投用的原因,对锅炉渣池系统进行改造,减少生活水补充水量,消除渣池灰水溢流,解决下水道堵塞,实现渣池零排放。

基于非饱和渗流的干灰场边坡稳定分析

干灰场运行条件和水灰场有很大差别,规范规定的灰场边坡计算方法和计算工况是根据水灰场运行条件规定的,对干灰场不合适。通过干灰场运行条件分析,推荐了合理的干灰场边坡稳定计算算法,并基于非饱和渗流理论,分析了粉煤灰的水土特征曲线、渗透系数—孔隙水压力曲线、降雨入渗条件,得出了干灰场边坡稳定计算的主要结论。

山谷型干灰场边坡稳定敏感性分析和对策

为研究山谷型干灰场边坡稳定的影响因素,在分析其他学者的研究成果的基础上,选择粉煤灰的物理力学指标(容重、内摩擦角和内聚力)和灰场内地下水位为主要影响因素。通过敏感性计算分析发现,在影响边坡稳定的各因素中,地下水位最敏感,其余依次是粉煤灰内摩擦角、内聚力和容重。结合目前国内灰场边坡设计施工现状分析认为,在诸多对边坡稳定有影响的因素中,灰场内地下水位是最危险的影响因素。针对这个问题提出了对策,建议在防渗膜下设置地下水导排设施,并增加防渗土工膜厚度,以降低灰场内地下水位,降低灰场边坡失稳风险,提高灰场边坡稳定性。

某发电厂沉渣池上浮纠偏与加固施工

某发电厂沉渣池由于设计时没有考虑抗浮措施,施工完成后,池体在地下水浮力的作用下上浮倾斜,严重影响池的正常使用。本文通过分析,并采取纠偏及加固措施,使沉渣池恢复正常的使用。