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1.
超细尾砂已成为充填材料的主要来源。为了便于充填料浆配合比设计与强度预测,基于超细料浆微观结构,提出用固体填充率表征充填料浆结构密实程度。选用某矿山超细尾砂进行了63组配合比强度试验。研究结果表明：固体填充率和水灰比与充填体无侧限强度分别呈指数函数和负幂函数关系。采用Pearson理论对试验样本进行相关性分析,结果表明：固体填充率与水灰比相互独立。在此基础上,建立了超细尾砂胶结充填体双变量强度计算模型,模型计算值与试验值的误差在7%以内。进行了超细尾砂胶结体强度随养护时间增长的试验,基于试验数据拟合规律,提出了强度龄期数学模型,建立了三变量强度计算公式。模型能准确预测矿山充填体强度,且能有效指导矿山充填料浆设计。 相似文献
2.
尾砂胶结充填体损伤模型及与岩体的匹配分析 总被引：14，自引：0，他引：14
分别对灰砂配比为1:4,1:8,1:10和1:12的4种尾砂胶结充填体进行了力学试验,得出了其应力-应变曲线。分析了不同配比充填体变形与破坏特征,用损伤力学建立了4种不同配比充填体损伤本构方程。经验算对比,所建立的损伤本构方程与试验结果吻合。尾砂胶结充填体损伤研究表明,不同配比的充填体表现出不同的损伤特性,充填体配比越低,达到峰值应力时的损伤值越小;峰值应力后,损伤增长越快,破坏过程越突然。根据岩体开挖释放能量与充填体蓄积应变能相近的原则,探讨了充填体与岩体的合理匹配。充填体与岩体的匹配系数与原岩应力、岩体弹性模量、充填体弹性模量及充填体损伤参数相关。为了便于工程实际应用,对充填体力学试验结果进行了回归分析,得出了充填体强度设计公式,并研究了深部矿床不同开采深度所要求的充填体强度。 相似文献
3.
《岩土力学》2017,(1):101-108
采用MTS815岩石力学试验系统与自制的胶结充填体制作装置,对骨架颗粒满足Talbol级配理论的废石胶结充填体进行单轴抗压试验研究,分析了Talbol幂指数、初始孔隙度、胶结材料种类及含量对充填体强度及变形特性的影响规律。结果表明:充填体单轴抗压强度、弹性模量、变形模量均随Talbol指数n呈先增大、后减小的趋势;采用2次多项式拟合充填体单轴抗压强度与骨架颗粒Talbol指数的关系,得到了使充填体强度及变形特性达到最优的Talbol指数n=0.45。充填体单轴抗压强度基本上随其初始孔隙度的增大而减小,但当孔隙分布均匀性较差时,其试验结果具有一定差异。满足Talbol分布的充填体强度随其胶结材料胶结性能的提高而逐渐增大,其中水泥胶结充填体单轴抗压强度可以达到黏土胶结充填体的6倍以上。另外,胶结材料含量的提高同样可以增大充填体的强度,并能够相应地缩短其应力-应变曲线中的孔隙压密阶段。 相似文献
4.
5.
将全尾砂作为充填料进行充填法采矿,不仅可以降低采矿成本,而且还能够实现固体废弃物资源化利用,同时将固体废弃物充填地下保护环境,维护生态平衡。由于尾砂粒径较细,需要与棒磨砂、戈壁砂混合作为充填料应用于充填采矿,有必要开展混合充填骨料的配比优化研究。首先,分别测试了棒磨砂、戈壁砂和尾砂3种骨料的粒径级配和不均匀系数。然后进行了9组配比的胶结充填体强度试验,在该基础上对试验样本进行训练,建立了神经网络预测模型。最后采用该预测模型,进行混合充填骨料正交设计方案的充填体强度预测,并分别采用极差分析和回归分析,揭示了充填体强度与混合充填骨料特征值之间的关系。研究发现,混合骨料平均粒径和不均匀系数不同,充填体早期和后期强度存在显著差异;平均粒径较小的混合骨料早期强度较高,而平均粒径较大者则更利于提高充填体的后期强度。 相似文献
6.
将全尾砂作为充填料进行充填法采矿,不仅可以降低采矿成本,而且还能够实现固体废弃物资源化利用,同时将固体废弃物充填地下保护环境,维护生态平衡。由于尾砂粒径较细,需要与棒磨砂、戈壁砂混合作为充填料应用于充填采矿,有必要开展混合充填骨料的配比优化研究。首先,分别测试了棒磨砂、戈壁砂和尾砂3种骨料的粒径级配和不均匀系数。然后进行了9组配比的胶结充填体强度试验,在该基础上对试验样本进行训练,建立了神经网络预测模型。最后采用该预测模型,进行混合充填骨料正交设计方案的充填体强度预测,并分别采用极差分析和回归分析,揭示了充填体强度与混合充填骨料特征值之间的关系。研究发现,混合骨料平均粒径和不均匀系数不同,充填体早期和后期强度存在显著差异;平均粒径较小的混合骨料早期强度较高,而平均粒径较大者则更利于提高充填体的后期强度。 相似文献
7.
为研究石膏激发的水泥-矿渣-粉煤灰固化淤泥的力学强度与水分转化过程的演变规律,从本质上揭示水泥-矿渣-粉煤灰对淤泥的固化机理,通过无侧限抗压强度、抗剪强度试验探究水泥/矿渣/粉煤灰配比、固化剂掺量、养护龄期对固化淤泥土强度的影响,结合核磁共振弛豫分析(NMR)、矿物成分分析(XRD)、微观结构分析(SEM)探究结合水量、水化物种类、微观形貌随养护龄期的变化规律,并建立无侧限抗压强度qu、抗剪强度参数c、tan φ与结合水量Cw的函数关系。结果表明：14 d龄期内较高水泥配比(20%)的固化土强度显著高于低水泥配比(5%)固化土,其早强效应归功于水化物的大量生成,结合水量大幅提高,14 d龄期后5%水泥配比固化土强度增长迅速并超过20%水泥配比固化土强度。从宏观力学强度看,较高水泥配比(20%)固化土qu、c、tan φ均与龄期对数lg t呈线性增长关系,低水泥配比(5%)固化土则呈幂型函数关系;从微观水分转化角度分析,高低水泥配比固化土的结合水量与抗压强度、抗剪强度参数的函数关系相同,即qu-C 相似文献
8.
矿山充填开采正逐步向寒区甚至永久冻土区发展，这些区域含盐地下水分布非常广泛。同时，极端寒冷条件下往往需要向充填材料中加入一些防冻盐以防止料浆在输送过程中发生冻结。通过室内测试分析了?6 ℃环境下不同盐分（NaCl）膏体充填体力学特性（强度和初始弹性模型）随时间演化特征。利用单轴压力机测得了龄期为7、28、90 d膏体充填体的强度和初始弹性模量，结果表明NaCl的加入会降低冻结充填体的强度，其影响程度取决于胶结料类型。试样的强度随着养护时间的增加而增大。此外，不论盐分浓度、养护时间和胶结料类型，试样的强度与初始弹性模量之间存在显著的线性关系。该研究结果可以为寒区含盐膏体充填技术的开展提供一些依据。 相似文献
9.
为探究黄原胶及瓜尔胶对尾矿砂的改良效果及加固机理,通过无侧限抗压强度、扫描电镜及工业CT扫描试验研究不同含量的水溶性植物胶对尾矿砂的强度提升及其作用机理。试验结果表明：与未处理的尾矿砂相比,黄原胶与瓜尔胶的最优配比均为1%,抗压强度随养护龄期的增长而增长,28 d时黄原胶及瓜尔胶改良土的强度分别提升了266.84%和262.33%。微观试验表明：随着养护龄期的增长,土体中胶体演变发展形态为“小粒状-胶结状-包裹状”,内部裂缝及孔隙逐渐减少,尾矿砂的孔隙率为14.55%,而28 d黄原胶及瓜尔胶孔隙率分别为3.08%和3.26%。分析得到胶体聚合物的最优配合比、养护龄期对土体抗压强度、微观表面结构及内部裂缝孔隙的影响关系。 相似文献
10.
为实现岛礁公路建设资源集约化,提出采用水泥固化稳定珊瑚礁岩、砂作为路面基层材料。通过无侧限抗压强度、劈裂强度、回弹模量、水稳性、干缩和温缩试验,探究水泥固化稳定珊瑚礁岩、砂吹填材料强度、刚度、水稳性和收缩性等路用性能,为后续岛礁工程建设提供理论依据和数据支持。结果表明:在标养条件下,相同龄期的试样抗压强度和劈裂强度随水泥用量增加而提高,水泥用量相同的试样随龄期增长而提高;抗压强度增长基本符合线性规律。回弹模量随水泥用量增加而提高,但增幅逐渐减小。相同龄期下,试件饱和抗压强度相对于低于标准抗压强度;水泥用量和龄期越大,强度损失率越小,抗软化能力越强,如水泥用量6%试样28 d强度损失率与软化系数是水泥用量3%的93%和101%。试样失水率与干缩应变随龄期与水泥用量增加而增长,如水泥用量6%试样180 d失水率和干缩应变是水泥用量3%的1.35倍和1.27倍。温缩试验表明:温缩应变和温缩系数随水泥用量增加而增大,而随温度降低先增大后减小,处于30~45℃温度区间是岛礁公路建设最不利的状态,应尽量避免高温施工。 相似文献
11.
尾矿充填主要包括3种类型：尾矿砂浆充填、尾矿糊状充填（paste fill）和废矿石充填（rock fill）,其中前面两种充填属于水力充填,第3种属于干式充填。3种充填方法在加拿大的矿山都有应用。压缩强度和渗透性是水力充填材料的关键力学特性,直接影响井下充填的效果。一方面,为了使充填材料具有一定的强度,必须在尾矿砂浆（slurry backfill）材料中添加水泥,其用量非常大,水泥在充填成本中占有很大的比例。另一方面,尾矿砂浆水力充填是利用水力旋流器来分级固体颗粒,颗粒较细的部分将通过溢流派到废矿池中,颗粒较粗的部分回收利用作为井下充填的材料使用,有时充填的尾矿数量不够,需要另外购置砂子混合作为充填材料。如何减少水泥的使用量和从水力旋流器底流增加尾矿砂的细颗粒的固体部分产量,以达到节约充填成本的目的,一直是矿山企业所面临的重要课题。为此,专门研究絮凝药剂对尾矿砂浆充填材料的单轴抗压强度的影响。研究结果表明,絮凝药剂能够大幅度地提高尾矿砂浆充填材料的强度,而且絮凝药剂使用量有一个最优值,使强度达到最大。当过量使用絮凝药剂,尾矿砂浆充填材料的强度则有所降低。 相似文献
12.
Martin Fahey Matthew Helinski Andy Fourie 《Geotechnical and Geological Engineering》2011,29(5):709-723
Paste backfill used to provide ground support in underground mining is generated from full-stream tailings and is almost always
placed underground with cement. For the backfill, both the rate of strength development and the final strength are important
considerations for design, particularly when the backfill is subsequently exposed in the stope-mining sequence. There is strong
evidence that strengths measured on specimens obtained from coring the in situ cemented backfill are much greater than laboratory-cured
specimens with the same cement content. The paper reviews some of the experimental evidence showing that one of the major
reasons for the different strength is the difference in effective stress acting on the backfill during curing. Laboratory
specimens are (almost) always cured under zero total stress, so no effective stress develops. In contrast, backfill in a stope
may cure under high effective stress, which develops due to either “conventional” consolidation in free-draining backfills,
or to the so-called “self-desiccation” mechanism in fine-grained fills. Evidence is presented showing how the final strength
is affected by applying stress to specimens at different stages of curing and at different rates. It is shown that a fully-coupled
analysis of the filling behaviour is required to determine the appropriate effective stress regime to apply in curing laboratory
specimens, where “fully-coupled” in this context means taking account of the interaction of consolidation/drainage rate, filling
rate and cement hydration rate. Curing protocols for laboratory specimens are proposed, which would ensure that the strengths
obtained are representative of in situ conditions. 相似文献
13.
A coupled chemo‐viscoplastic cap model for simulating the behavior of hydrating cemented tailings backfill under blast loading 
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下载免费PDF全文 Although the use of blasting has become a routine in contemporary mine operations, there is a lack of knowledge on the response of cement tailings backfills subjected to sudden dynamic loading. To rationally describe such a phenomenon, a new coupled chemo‐viscoplastic cap model is proposed in the present study to describe the behavior of hydrating cemented tailings backfill under blast loading. A modified Perzyna type of visco‐plasticity model is adopted to represent the rate‐dependent behavior of the cemented tailings backfill under blast loading. A modified smooth surface cap model is consequently developed to characterize the yield of the material, which also facilitates hysteresis and full compaction as well as dilation control. Then, the viscoplastic formulation is further augmented with a variable bulk modulus derived from a Mie–Gruneisen equation of state, in order to capture the nonlinear hydrostatic response of cemented backfills subjected to high pressure. Subsequently, the material properties required in the viscoplastic cap model are coupled with a chemical model, which captures and quantifies the degree of cement hydration. Thus, the behavior of hydrating cemented backfills under the impact of blast loading can be evaluated under any curing time of interest. The validation results of the developed model show a good agreement between the experimental and the predicted results. The authors believe that the proposed model will contribute to a better understanding of the performance of cemented backfills under mine blasting and contribute to evaluating and managing the risk of failure of backfill structures under such a dynamic condition. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
14.
Unsaturated hydraulic properties of cemented tailings backfill that contains sodium silicate 总被引：2，自引：0，他引：2
Recycling the mine waste (tailings) into cemented tailings backfill has economical and environmental advantages for the mining industry. One of the most recent types of cemented tailings backfill is gelfill (GF), a backfill that contains sodium silicate as chemical additive. GF is typically made of tailings, water, binder and chemical additives (sodium silicate gel). It is a promising mine tailings backfill technology. From a design point of view, the environmental performance or durability of GF structures is considered as a key factor. Due to the fact that GF structures are cementitious tailings, their durability and environmental performance depend on their ability to resist the flow of aggressive elements (water and oxygen). Thus, understanding the unsaturated hydraulic properties of GF is essential for a cost-effective, environmentally friendly and durable design of GF structures. However, there is a lack of information with regards to unsaturated hydraulic properties of GF, the factors that affect them and their evolution with time. Hence, the unsaturated hydraulic properties (water retention curve (WRC) or water characteristic curve, air entry value (AEV), residual water content, unsaturated hydraulic conductivity) of GF are investigated in this paper. GF samples of various compositions and cured in room temperature for different times (3, 7, 28, and 90 days) are considered. Saturated hydraulic conductivity and microstructural tests have been conducted; WRCs are measured by using a WP4-T dewpoint potentiameter and the saline solution method. Unsaturated hydraulic conductivity is predicted using the van Genuchten (1980) equation. The water retention curve (WRC) is determined as the relationship between volumetric water content and suction for each GF mix and curing time. The van Genuchten (1980) equation is used to simulate the WRC to best-fit the experimental data. AEV and residual water content are also computed for each mix and curing time. Furthermore, functions are developed to predict the evolution of AEVs, residual water content and fitting parameters of the van Genuchten model with degree of hydration. Important outcomes have been achieved with regards to unsaturated hydraulic properties. The unsaturated hydraulic conductivity of GF was calculated to decrease when the suction, binder content, and degree of hydration increase. The effects of binder content and degree of hydration are more obvious at low suction ranges. The obtained results would contribute to a better design and assessment of the durability and environmental performance of GF structures. 相似文献
15.
Understanding the shear behaviour of the interface between cemented tailings backfill and retaining wall structures (barricades,
bulkheads) is important for the optimal design of barricades or bulkheads, and for mine operators to balance strength and
safety against cost. However, our understanding of the shear behaviour of the aforementioned interface is limited. This paper
is aimed at investigating the interfacial behaviour and properties of cemented tailings backfill-retaining wall structures,
including stress–strain behaviour, cohesion, friction angle and shear stiffness through direct shear tests. Two different
types of barricade or bulkhead materials (brick and concrete) are used in this study. Interface shear tests are performed
at various curing times of the cemented backfill. Valuable results are obtained with regards to the interface shear behaviour
of backfill-retaining structures. Based on these results, interfacial properties between cemented tailings backfill and barricades
or bulkheads show a significant time-dependent variation. 相似文献
16.
P. K. Kolay M. R. Aminur S. N. L. Taib M. I. S. Mohd Zain 《Geotechnical and Geological Engineering》2011,29(6):1135-1141
This paper describes a study on tropical peat soil stabilization to improve its physical properties by using different stabilizing
agents. The samples were collected from six different locations of Sarawak, Malaysia, to evaluate their physical or index
properties. Out of them, sample having the highest percentage of organic content has been selected for stabilization purposes.
In this study, ordinary portland cement (OPC), quick lime (QL), and class F fly ash (FA) were used as stabilizer. The amount
of OPC, QL, and FA added to the peat soil sample, as percentage of dry soil mass, were in the range of 5–20%; 5–20% and 2–8%,
respectively for the curing periods of 7, 14, and 28 days. The Unconfined Compressive Strength (UCS) test was carried out
on treated/stabilized samples with the above mentioned percentages of the stabilizer and the result shows that the UCS value
increases significantly with the increase of all stabilizing agent used and also with curing periods. However, in case of
FA and QL, the UCS value increases up to 15 and 6%, respectively with a curing period of 28 days but decreases rather steady
beyond this percentage. Some UCS tests have been conducted with a mixture of FA and QL to study the combined effect of the
stabilizer. In addition, Scanning Electron Microscope (SEM) study was carried out on original peat soil and FA, as well as
some treated samples in order to study their microstructures. 相似文献
17.
Stabilization of arsenic-contaminated mine tailings using natural and calcined oyster shells 总被引：1，自引：0，他引：1
Deok Hyun Moon Kyoung-Woong Kim In-Ho Yoon Dennis G. Grubb Dae-Yewn Shin Kyung Hoon Cheong Hyung-Il Choi Yong Sik Ok Jeong-Hun Park 《Environmental Earth Sciences》2011,64(3):597-605
Natural oyster shells (NOS) and calcined oyster shells (COS) were used to immobilize arsenic (As) from contaminated mine tailings.
In addition, a blend of Portland cement (PC)/cement kiln dust (CKD) was used as a stabilizing agent. The Korean Standard Test
(KST) method (1 N HCl extraction) was used to evaluate the effectiveness of the treatment. The experimental results showed
that COS effectively immobilized As in treated mine tailings. Specifically, an As concentration less than 1 mg L−1 was obtained following COS treatment at 25 and 30 wt%. However, all the samples subjected to NOS treatments failed the Korean
warning standard of 1.2 mg L−1 after 28 days of curing. All of the COS-PC treatments were successful meeting the Korean warning standard after 7 days of
curing. However, the PC-only treatment failed to meet the Korean warning standard. Similarly, the CKD-only treatment was failed
to meet the Korean warning standard after 7 days of curing. However, the COS-CKD treatment showed that when the COS content
was greater than 20 wt%, less than 1 mg L−1 of As leachability was obtained. Scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDX) showed needle-like
and torpedo-like Ca–As phases in the COS-treated samples suggesting that As was strongly associated with Ca and O. X-ray absorption
near edge structure (XANES) analyses confirmed that As(V) was prevalent in the tailings and that there were no changes in
As speciation following NOS or COS treatment. 相似文献
18.
为了验证固化剂GX08加固杭州海湖相软土的效果及考察有机质对水泥固化的不利影响,对固化土的强度特性进行了试验研究。结果表明,有机质的添加会显著阻碍固化土强度的增长,而固化剂GX08能有效增强固化土的强度;固化土强度与有机质含量存在二次函数关系,与水泥掺量呈线性关系,与固化剂GX08掺量和龄期都以对数函数的形式相关;将总灰水比C/W用于固化土强度模型的建立,通过对试验数据的分析与整理,建立了同时考虑固化土中有机质含量、水泥掺量、固化剂掺量和龄期影响的固化土综合强度预测模型。最后对模型进行了推广使用,验证了模型的适用性。 相似文献