模糊集合在等强度胶结充填材料优化中的应用

采用模糊集合论方法，通过计算机模拟和试验，合理选择尾砂浓度和胶结剂用量。在等强度和一定料浆浓度的前提下，尾砂浆浓度较大，胶结剂用量则较小，且相对成本较低。尾砂浓度和胶结剂用量两集合交集中的元素，即是矿山可选择的在等强度下较合适的尾砂浓度和胶结剂用量。模糊集合论用于胶结充填材料质量决策系统是可行的。     

界河金矿下向胶结充填采矿法试验研究

界河金矿4号矿体属于矿岩很破碎、极易冒落、金属品位高的难采矿体。以往矿山用上向水平分层废石充填法开采时,在安全、资源回收上存在较大问题。因而改用下向胶结充填法。首先进行试验回采,完善回采工艺后再全面推广应用。试验中采用了预埋钢筒形成充填小井的新方法,首创工艺简单实用的充填接顶指示装置。由于使用下向胶结充填法,提高了回采安全性及资源回收率,使损失率降至8％,贫化率降至5％。     

高浓度水泥-尾砂充填料浆沉降性能试验研究

对不同配比的高浓度水泥金级配尾砂充填料浆进行自然沉降试验，分析相关因素对沉降特性的影响。结果表明。水泥含量对充填料浆沉降性能的影响较大。在特定范围内，质量浓度对沉降速度的影响小于水泥含量的影响。于料中水泥含量从0%增加到20%（即灰砂配比0～1：4）。对应试件的沉降速度逐步减小。充填料浆沉降速度越快。沉降水在总用水中所占的比率随浓度和水泥含量的增加而减小，沉降水与料浆体积比也随浓度和水泥含量的增加而减小。对于具体采场来说，若采用合理有效的脱排水设施将泌出的沉降水及时排出，则能够对料浆凝结硬化起到帮助作用。     

直埋电缆回填土导热系数测试

为了测定直埋电缆回填土的导热系数并探究导热系数随水质量分数的变化规律,采集浙江省境内掩深为0.7~1.2 m的5种土壤,分别配制了水质量分数为0%、5%、10%、15%、20%和25%的充分压实的试样,利用热探针法测试了各试样在(20±1) °C时的导热系数. 结果表明：不同土壤的导热系数随水质量分数递增最快的区间不同,如粗骨土为10%~15%,潮土为15%~20%,红壤为20%~25%;水质量分数超过20%后,水稻土、红壤和黄壤的导热系数随着水质量分数递增,粗骨土和潮土的导热系数减小;不同土壤的导热系数差别较大,如粗骨土的导热系数是相同条件下黄壤的2倍左右.     

Effects of water content,water type and temperature on the rheological behaviour of slag-cement and fly ash-cement paste backfill

The pumping ability and placement performance of fresh cemented paste backfill(CPB) in underground mined cavities depend on its rheological properties. Hence, it is crucial to understand the rheology of fresh CPB slurry, which is related to CPB mixture design and the temperature underground. This paper presented an experimental study investigating the effects of binder type, content, water chemical properties and content, and temperature, on the rheological properties of CPB material prepared using the tailings of a copper mine in South Australia. Portland cement(PC), a newly released commercially manufactured cement called Minecem(MC) and fly ash(FA) were used as the binders added to the mine tailing materials. Various amounts of two different water types were added to the mixtures in the preparation of backfill material slurry. Six different temperatures ranging from 5 to 60 °C were to investigate the effect of temperature on CPB rheology. Overall, the increasing water content and decreasing temperature lead to lower yield stress. Based on the results obtained from the rheological properties of CPB slurry, it was found that at room temperature(25 °C), with regards to the unconfined compressive strength(UCS) performance, the replacement of 4% PC mixed CPB(28 days UCS 425 k Pa) to 3% MC mixed CPB(28 days UCS 519 k Pa), reduced the slurry yield stress from 210.7 to 178.5 Pa. The results also showed that the chemical composition of water affects the yield stress of CPB slurry and that MC mitigates the negative effect of mine-processed water(MW) and thus lead to improve the rheological properties of the slurry. However, the results suggested that the rheological properties of a mixture using MC is very sensitive to the water volume and temperature change. Therefore, using MC in backfill requires better quality control in slump mixing.     

运用强夯法处理港口开山碎石土回填地基的应用实践

对开山碎石土回填的地基,采用强夯法进行加固处理,可以改变地基结构排列、使其致密,从而提高地基承载力。强夯能起到深层地基加固、减少地基沉降量、提高地基承载力的作用,是一种经济有效的地基处理方法。     

复杂基础综合施工技术的研究与应用

萧山机场二期工程中,航站楼及穿主楼隧道基础部分施工存在标高种类多、当地土质粘聚性差等难点。工程应用复合土钉墙支护技术,在保证了特定土质下成孔的稳定性同时加快了施工速度;通过将连系梁底垫层混凝土变更为整体浇筑的方式,改善了基础防水层的薄弱点;拆撑阶段合理选用、安排机械,并利用专业计算软件对施工工序进行合理变更,提高了施工进度;采用创新的泥浆回填技术,合理利用当地资源解决了护坡桩间距过窄的问题。     

海水条件下矿山充填应用粉煤灰的可行性研究

三山岛金矿充填用水中Cl-、SO2-4和Mg2+等离子浓度较高,影响充填体的强度。根据海水和粉煤灰的化学成分检测结果,分析研究海水中氯盐、硫酸盐、镁盐对充填体的破坏机理以及在尾砂胶结充填中粉煤灰在活性效应、粉末效应和形态效应3个方面的作用机理。分析认为,海水成分中的硫酸盐、氯盐和海水的弱碱性成分对化学激发粉煤灰活性发挥重要作用。因此,为了提高海水条件下充填体的强度,添加粉煤灰不仅可以减少海水中相关离子对充填体强度的影响,而且海水中的部分化学成分对粉煤灰活性的激发作用可以进一步提高粉煤灰的胶凝作用。     

矿山胶结充填体中胶凝材料含量检测方法试验研究

针对矿山充填体质量评价过程中胶凝材料含量的检测问题,基于元素守恒原理,发明了一种操作简单的充填体中物料组分检测方法——元素检测法,并通过试验验证了该方法的可靠性及准确性。该方法的检测精度满足充填生产实际需求,对充填配比试验、矿山充填设计及质量检测具有重要意义。     

Pressure dependence of morphology and phase composition of SiC films deposited by microwave plasma chemical vapor deposition on cemented carbide substrates

SiC films were deposited on cemented carbide substrates by employing microwave plasma chemical vapor deposition method using tetramethylsilane (Si(CH₃)₄) diluted in H₂ as the precursor. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and scratching technique were used to characterize morphology, composition, phases present and adhesion of the films. Experimental results show that the deposition pressure has great influence on morphologies and phase composition of the films. In sequence, SiC films with a cauliflower-like microstructure, granular films with terrace-featured SiC particles coexisting with Co₂Si compound and clusters of nanometer SiC nanoplatelets appear as a function of the deposition pressure. In terms of plasma density and substrate temperature, this sequential appearance of microstructures of SiC films was explained. Adhesion tests showed that among the three types of films studied, the films with the terrace-featured SiC particles have relatively higher adhesion. Such knowledge will be of importance when the SiC films are used as interlayer between diamond films and cemented carbide substrates.