土工合成材料与土界面作用特性的研究

土工合成材料加筋土工程中 ,土工合成材料与填料的界面作用特性是最关键的技术指标 ,因此利用直剪试验和拉拔试验研究土工合成材料与填料的界面作用特性是非常必要的。本文以 5种不同种类的国产土工合成材料为加筋材料 ,以砂和石灰粉煤灰为填料 ,通过直剪试验和拉拔试验比较各种国产土工合成材料与填料的界面作用特性 ,得到一些有益的结论 ,可指导土工合成材料的优选和研究加筋机理。     

土工合成材料加筋的试验研究

以 6种不同种类的国产土工合成材料为加筋材料 ,即针刺无纺土工织物、涤纶纤维经编土工格栅、玻璃纤维土工格栅、单向塑料拉伸土工格栅、双向塑料拉伸土工格栅和土工网 ,进行三轴试验比较各种土工合成材料对砂的加筋效果 ;进行直剪试验和拉拔试验比较各种土工合成材料与填料 (砂和石灰粉煤灰 )的界面作用特性 ,得到一些有益的结论 ,可指导土工合成材料的优选和研究土工合成材料的加筋机理。     

土工合成材料加筋作用室内试验及机理分析

通过土工合成材料加筋作用的室内试验,研究了土工合成材料对路基顶面塑性变形和应力消散的影响等作用机理,针对试验结果进行了分析,并得出相关结论,以期促进土工合成材料加筋技术应用的理论研究。     

土工合成材料加筋非饱和土界面作用特性研究

通过室内拉拔、摩擦试验研究绵阳非饱和土与不同土工合成材料间的界面相互作用特性及加筋效果试验,得出了三种土工合成材料在各级荷载作用下的应力-应变关系曲线;分析了曲线特征及土工合成材料与土体界面的相互作用特性,其结论为今后土工合成材料在绵阳地区的工程应用提供了理论参考依据。     

土工合成材料在公路工程中的应用

介绍了土工合成材料的种类、土工合成材料在公路工程中的应用现状、土工合成材料与土相互作用的加筋机理,包括准粘聚力原理和摩擦加筋原理及工程应用实例。     

土工合成材料在高填方路堤路段的加筋应用

结合在高等级公路的施工技术经验,探讨了土工合成材料在高填方路段的加筋应用,分析了加筋土作用机理,有利于土工合成材料在高填方路堤路段的加筋应用推广,为此类高填方路堤路段的结构设计与施工积累了经验。     

土工合成材料加筋砂土三轴试验研究

本文以 5种国产土工合成材料为加筋材料 ,它们分别是针刺无纺土工织物、涤纶纤维经编土工格栅、玻璃纤维土工格栅、聚丙烯双向土工格栅和聚乙烯土工网 ,用三轴试验比较各种土工合成材料对砂土的加筋效果 ,得到一些有益的结论 ,可指导土工合成材料的优选和研究加筋机理 ,同时指出部分国产土工合成材料产品的不足。     

土工合成材料在高速公路软基处理中的应用研究

分析论述了土工合成材料的特性、用途、作用机理、应用设计等内容。结合土工合成材料在连霍高速公路三门峡～灵宝段软基中的应用，总结了土工合成材料在解决软弱地基上修筑高速公路引起的地基承载力不足、沉降量过大、沉降不均匀等严重影响路堤路基稳定性的岩土工程问题的经验。土工合成材料在公路工程软基处理中，可起加筋加固、排水、隔离等多重作用。     

土工合成材料施工损伤问题的探讨

土工合成材料加筋砂、石垫层是在基础下有效深度范围土体内铺设土工合成材料，通过土工格栅、土工织物等加筋材料与砂、石间的相互作用，可提高地基承载力和稳定性，这种地基处理方法因具有施工简便、无污染、造价低、工期短等优点而广泛应用。     

土工合成材料与风积砂的摩擦特性研究

以拉拔试验测定土工合成材料与风积砂的界面摩擦特性。根据试验结果分析风积砂与土工合成材料在接触面上粘聚力和内摩擦角的变化，得出不同种类的土工合成材料对填料产生的影响。     

细粒尾矿堆坝加筋加固模型试验研究

采用龙都尾矿库内的细粒尾矿作为试验材料,以该尾矿库的设计尾矿坝为原形堆积尾矿坝体模型,进行细粒尾矿堆坝加筋加固模型试验。通过模型试验,检验了细粒尾矿堆积的尾矿堆坝加筋加固的作用效果,获得了加筋尾矿坝体与不加筋尾矿坝体的不同破坏模式,在细粒尾矿堆坝的稳定性研究以及将加筋材料应用于尾矿坝的加固方面作了一些新的探索。     

粒径大小对非饱和尾矿抗剪强度的影响研究

尾矿库是金属矿山最大的危险源之一。而尾矿坝是尾矿库的主要构筑物,尾矿坝的稳定性与尾矿库的安危息息相关。尾矿坝主要由尾矿堆积而成。尾矿材料的抗剪强度决定了尾矿堆积坝的稳定程度。本文利用改造的土工试验仪器,在非饱和状态下,针对颗粒大小对尾矿抗剪强度的影响进行了试验分析,结果显示,非饱和尾矿的中值粒径与抗剪强度参数的粘结力呈指数函数关系,与内摩擦角呈指数函数关系;且随着中值粒径的增大,非饱和尾矿的内聚力(c)会降低,而内摩擦角(φ)却会增大。     

铁尾矿砂混凝土耐久性能的试验研究

通过6组不同尾矿砂替代率制备试件,开展尾矿砂混凝土抗冻融、抗渗性能和氯盐腐蚀后强度变化及尾矿砂混凝土水化产物的电子显微镜微观扫描分析,探究尾矿砂对混凝土耐久性能影响的规律。试验结果表明:尾矿砂混凝土的冻融循环后的质量损失和相对弹性模量随尾矿砂替代率的增加而降低;尾矿砂替代率不大于20%时,尾矿砂混凝土的抗渗性能随替代率的增加而增加,替代率大于20%时,抗渗性能随替代率的增加而减少,尾矿砂混凝土的抗渗系数为1.78×10^-5~5.96×10^-6cm/h;界面黏结特征显示尾矿砂与水泥水化物黏结表面结构致密,随着尾砂掺量的增加,微孔结构逐渐粗化;建议工程采用替代率40%~60%尾矿砂制备混凝土,以实现工业废料的循环利用。     

A case study on utilizing geotextile tubes for tailings dams construction in China

This research presents a successful case, in which geotextile tubes have been used to construct a tailings dam for fine tailings disposal since 2008. Up to the end of 2016, the tailings dam raise has reached 9?m in height. The total height of the dam including the starter dike was 61?m. In order to ensure that the tailings reservoir is safe in its current condition and during future construction, the comprehensive geotechnical investigation and stability analyses of the tailings embankment are conducted in this study. The results show that the application of geotextile tubes in the construction of tailings dam is a good alternative for fine tailings disposal.     

Three-Dimensional Modeling of Tailings Beach Shape

Abstract: Tailings (mining waste) disposal is a significant consideration for the mining industry, with the majority of the ore processed in most mining operations ending up as tailings. This creates large volumes of tailings, which must be handled and stored responsibly to avoid potential environmental catastrophes. The most common form of tailings storage facility is the impoundment, where tailings are contained within a basin, with beaches forming around the perimeter of the impoundment and a pond standing in the middle. A relatively new method of tailings storage is to create a “stack,” whereby the tailings solids form a large heap, with the discharge of tailings slurry from the apex of the heap. This method of tailings storage is finding greater popularity as the industry seeks to reduce the amount of water discharged with the tailings, and usually features the discharge of non‐segregating tailings slurry that flows turbulently in its own self‐formed channel down the tailings beach. It is of significant interest for mine operators and tailings engineers to be able to predict the shape of the beach that forms in either of these disposal scenarios. The key to being able to do this relies on a method of prediction of the beach slope. In this article two new beach shape models are presented for the three‐dimensional (3‐D) geometric modeling of the beach surface of a tailings stack that has been formed through the variable discharge of a non‐segregating slurry that periodically changes in its composition, whereby the overall discharge output is defined as a sequence of smaller finite periods of steady uniform discharge, each having its own resulting beach slope. A beach slope model previously presented by the authors has been used here to predict the applicable beach slope for each finite discharge regime. The shape models presented here present two different methods for the compounding of the individual tailings deposits that are generated by each of these finite discharge regimes. Historic tailings discharge data is run through both models, and the shapes predicted by the models are compared with aerial survey data of real tailings stacks. This work not only presents a method of tailings stack shape prediction, but also a plausible theory for explaining the concavity of tailings beaches. The models also have the potential to be developed further for the 3‐D modeling of tailings beaches formed in other types of storage facilities, such as impoundments or valleys.     

某金矿尾矿库土壤污染现状调查及发展趋势分析

对某金属矿尾矿库流域内的土壤、植物等进行调查取样,确定尾矿库对周边环境的污染范围和污染趋势,对尾矿库所在流域的污染程度、污染特征等进行评价与分析,探明尾矿库是否对周边及下游植物造成严重污染。研究结果表明,该尾矿库的土壤砷元素含量超标严重,总氰化物、锑、镉、汞、锌元素含量也略有超标,尾矿库流域的污染区以尾矿库为中心,向周边由近及远污染程度递减;尾矿库的周边植物样品中各检测元素含量均未超标,可以推测尾矿库尚未对周边及下游植物造成严重污染。这些分析可以为其它尾矿库污染方面的研究提供依据。     

再筑坝过程中上部荷载对原有尾矿坝体的影响

尾矿坝稳定与否是尾矿库能否安全的关键所在,尾矿坝又是随着生产过程而不断加高的特殊岩土工程体,各种因素处于动态变化过程中,这使得尾矿坝工程的不确定性尤为明显,工程难度较其他类型的边坡工程有增无减.运用FLAC模拟某尾矿坝的筑坝施工过程,分析了再筑坝过程中,逐级加载时上部荷载对原有尾矿坝体安全性能的影响,考虑了由下至上逐步...     

利用铁尾矿制备全利废烧结制品的研究

铁尾矿是铁矿石经选取有用组分后剩余的固体废弃物,可用于制备烧结制品,但在利用其为主要原料制备烧结砖时存在塑性较差、利用率低的问题,为解决以上问题,通过以尾矿、尾矿泥、围岩三种尾矿废料为主要原料制备烧结制品,研究不同尾矿掺量对塑性指数、烧成收缩率、吸水率、显气孔率与体积密度、抗压强度等指标或产品性能的影响规律,在此基础上,通过XRD、SEM微观手段测试了产品的微观结构.结果表明,通过合理的工艺参数优化,可100%利用铁尾矿废弃物作为原料制备烧结制品,范围为:尾矿(尾矿泥)30% ~ 70%,围岩30% ~ 70%,研究结果对减少铁尾矿的环境污染、节约土地等具有重要的意义.     

Experimental study of the shrinkage behavior of cemented paste backfill

Cemented paste backfill(CPB) is largely used in underground mine stopes worldwide.When a CPB is placed in a stope,an important task is to estimate the settlement associated with the shrinkage and selfweight consolidation of the CPB.This is closely related to the volume management to ensure the stability of barricades and tight contacts between the backfill and stope roof.Over the years,shrinkage studies were mostly performed on fine-grained soils(silts and clays),with only a few publications on the shrinkage behavior of uncemented tailings.No study has been published on the shrinkage behavior of CPB.To fill this gap,a series of shrinkage tests has been conducted on CPB with different cement contents,including zero cement content(uncemented paste backfill,uCPB).The results show that the shrinkage response of CPB is very different from that of uCPB.At a given initial water content,CPB exhibits a shorter normal shrinkage stage than uCPB.The unsaturation onset water content and void ratio,shrinkage limit and final void ratio of CPB are generally higher than those of uCPB.At a given cement content,the shrinkage behaviors of CPB and uCPB are significantly influenced by the initial water content.     

铁尾矿砂改良膨胀土基本工程性质试验研究

研究利用工业废料铁尾矿砂作为添加剂改良膨胀土的可行性与改良效果。通过室内试验,对尾矿砂改良土的基本物理性质指标、膨胀性指标、强度指标以及微观结构进行了研究。试验结果表明,随着掺砂率的增大,试验土样的界限含水率及塑性指数都减小;自由膨胀率、有荷膨胀率和膨胀力等膨胀特性指标随掺砂率的增大均降低。无侧限抗压强度和黏聚力随着掺砂率的增加先增大后减小,在掺砂率为30%时达到最大;内摩擦角随着掺砂率增大而增大。通过观察SEM试验结果,发现在掺砂率为30%时,改良土结构处于最稳定状态,说明掺铁尾矿砂改良膨胀土具有显著效果,为膨胀土改良提供了一种新方法。综合考虑各项指标,认为铁尾矿砂改良膨胀土的最佳掺入比应为30%。