露天边坡对地下采场覆岩稳定性影响的数值模拟研究

以某矿山露天转房柱法地下开采为研究背景,根据现场调研获得的岩土力学参数,利用FLAC3D等软件进行三维建模[1],对倾角为40°时边坡高度为90m的地下采场上覆岩层位移与应力响应特征进行数值模拟分析。研究结果表明:在露天终了边坡高度为90m倾角为40°时,地下开采完后采场上覆岩层受到开挖的扰动,稳定性降低,塑性区面积已经发育至坡面,整个岩体处于临界破坏状态,不利于矿山的安全稳定,因此建议该矿山露天终了边坡高度不超过90m。     

Influence of Osmotic Suction on the Soil-Water Characteristic Curves of Compacted Expansive Clay

Unsaturated clays are subject to osmotic suction gradients in geoenvironmental engineering applications and it therefore becomes important to understand the effect of these chemical concentration gradients on soil-water characteristic curves (SWCCs). This paper brings out the influence of induced osmotic suction gradient on the wetting SWCCs of compacted clay specimens inundated with sodium chloride solutions/distilled water at vertical stress of 6.25 kPa in oedometer cells. The experimental results illustrate that variations in initial osmotic suction difference induce different magnitudes of osmotic induced consolidation and osmotic consolidation strains thereby impacting the wetting SWCCs and equilibrium water contents of identically compacted clay specimens. Osmotic suction induced by chemical concentration gradients between reservoir salt solution and soil-water can be treated as an equivalent net stress component, (pπ) that decreases the swelling strains of unsaturated specimens from reduction in microstructural and macrostructural swelling components. The direction of osmotic flow affects the matric SWCCs. Unsaturated specimens experiencing osmotic induced consolidation and osmotic consolidation develop lower equilibrium water content than specimens experiencing osmotic swelling during the wetting path. The findings of the study illustrate the need to incorporate the influence of osmotic suction in determination of the matric SWCCs.     

露天矿山边坡稳定性影响因素及分析方法研究

对露天矿山边坡稳定性影响因素从内外因两个方面进行分析,总结了极限平衡法、基于FLAC3D强度折减的有限差分法和基于强度折减的有限元法等3种常用的边坡稳定性分析方法,提出了加强地质勘查、做好安全监测、合理确定台阶要素和选择爆破方法、削坡减压和减重压脚、加强边坡检查与管理等治理边坡滑动灾害的控制措施。研究结果对露天矿山的安全生产及预防和控制边坡失稳具有一定的指导意义。     

新钢分宜矿边坡稳定性分析

为了评价新钢分宜露天矿边坡的稳定性,应用有限差分强度折减法,对该矿山人工边坡的稳定性进行了计算分析,并和现场实际情况进行了对比.结果表明,由于有限差分强度折减法能够实际模拟边坡计算模型,客观的分析边坡的稳定状态,求得的边坡安全系数较为合理.     

Influence of State of Stress on Dynamic Recrystallization in a Titanium-Modified Austenitic Stainless Steel

The influence of the state of stress on the microstructure and dynamic recrystallization (DRX) in a titanium-modified austenitic stainless steel is assessed by performing plane-strain and uniaxial hot compression studies. Although the state of stress does not alter the mechanisms of DRX nucleation, the kinetics of DRX is hindered during plane-strain deformation vis-à-vis uniaxial deformation.     

Numerical Analysis of Rainfall Effects on Slope Stability

The finite element analysis of transient water flow through unsaturated–saturated soils was used to investigate effects of hydraulic characteristics, initial relative degree of saturation, methods to consider boundary condition, and rainfall intensity and duration on water pressure in slopes. The finite element method with shear strength reduction technique was used to evaluate the stability of slopes under rainfall. The results of the finite element analysis indicated that the hydraulic characteristics, initial relative degree of saturation, methods to consider boundary condition, and rainfall intensity and duration had significant influence on the water pressure in slopes, and thus on the stability of slopes under rainfall. The good comparisons of the numerical results with statistical and observational results showed the ability of the finite element analysis to evaluate the stability of slopes under rainfall.     

边坡稳定性及其防治措施的研究

针对我国矿山边坡研究情况,分析边坡产生变形破坏的原因,对影响边坡失稳提出了治理措施,以确保整体边坡的稳定。     

Seismic Stability of Soil Retaining Walls Situated on Slope

Many soil retaining walls, which were used to stabilize highway embankments constructed on hillside, were severely damaged during the major earthquake (Chi-Chi earthquake, ML = 7.3) on September 21, 1999 in Taiwan. We investigated two typical cases of soil retaining wall damage using survey, soil borings and soil tests. To this end we developed a new pseudo-static method to evaluate the seismic stability of retaining walls situated on slope. Sliding failure along the wall base and bearing capacity failure in the foundation slope were considered in the new pseudo-static method. Results of the analysis showed that seismic stability of the wall against bearing capacity failure may be greatly overestimated when the inertia of soil mass is not taken into account. The analytical results also showed that sliding failure along the wall base occurs prior to the bearing capacity failure of the wall situated on a gentle slope at Site 1. The opposite is true for the wall situated on a steep slope at Site 2. For soil retaining walls constructed on slope, sliding failure of the wall may occur under small input horizontal ground acceleration when the passive resistance in front of the wall is not effectively mobilized. This highlights the importance of improving the strength of backfilled soils in the passive zone when constructing soil retaining walls on slope. The results obtained in the present study also suggest a modification of the current design considerations for soil retaining walls situated on slope.     

基于动态权重的边坡稳定性评价方法

为了保证露天矿边坡的稳定性,提高开采的安全性,减少人身财产损失,针对边坡稳定性存在的模糊不确定性和层次性的特点,采用模糊数学方法,建立边坡稳定性模糊综合评价模型。通过实地走访结合文献总结,选用5个影响因素及其对应的18个影响因子,集成误差传递原理、相似性和差异性分析以及区间数矩阵相对优势度分析建立动态权重。研究结果表明：该模型得到的结果能较准确地反映边坡的稳定程度,评价结果与实际结果相吻合,为边坡稳定性评价提供了一种可行的方法。     

Effect of Stress State on Fracture Features

Present article comprehensively explores the influence of specimen thickness on the quantitative estimates of different ductile fractographic features in two dimensions, correlating tensile properties of a reactor pressure vessel steel tested under ambient temperature where the initial crystallographic texture, inclusion content, and their distribution are kept unaltered. It has been investigated that the changes in tensile fracture morphology of these steels are directly attributable to the resulting stress–state history under tension for given specimen dimensions.     

分段崩落法回采顺序对进路受力状态影响分析

某金矿主要开采 7-2# 矿脉,矿体及围岩节理裂隙发育,且矿体赋存深度超过 500m,在较大地应力条件下围岩受采动影响极易冒落。该矿浅部资源采用干式嗣后充填采矿法时岩层不易控制,且留设矿柱造成高品位矿石损失率较高,冒落的围岩混入矿石中使贫化率居高不下。为解决上述问题,在开采深部资源时变更为进路式无底柱分段崩落法开采,而不同进路的回采顺序对与之相邻的回采进路受力状态影响较大,为提高进路内凿岩、出矿作业的安全性,需深入分析回采顺序与进路稳定性之间的关系。结合实际,本文提出了 5 种进路回采顺序,并通过 FLAC3D 数值模拟对各回采顺序条件下进路的受力进行了分析,结果表明采用双翼阶梯式回采方式,进路周边围岩应力分布较为均匀,回采进路一定时期内能够保持稳定,可大幅提高进路内作业安全性。     

岩体边坡开挖卸荷稳定性分析

笔者应用弹塑性力学及断裂力学的相关理论，分析讨论了裂纹的分形特性及裂隙面的压剪起裂破坏机理；分析了静载、动载和不同类型裂隙的相互作用对边坡稳定性的影响规律。结合工程实际问题，研究了边坡开挖前后其应力应变的分布规律，提出了由于开挖卸荷而引起裂纹扩展的作用机理。     

穆利亚希南露天边坡稳定性分析

露天边坡角的大小对矿山边坡稳定及开采成本有着重要影响,合理的边坡角是保证露天采场安全、经济回采的重要因素。本文以卢安夏铜矿穆利亚希南矿区为背景,应用 Geo-Slope 软件在考虑地震影响因素下使用极限平衡法中的 Ordinary 法、Bishop 法、Janbu 法及 Morgenstern-Price 法对穆利亚希南矿区一区和二区不同角度的露天边坡稳定性进行分析,结果表明 ：当一分区的边坡角为 40°,二分区的边坡角为 39°时,边坡最为稳定,能保证工作平台安全生产。研究成果可为卢安夏其它露天矿边坡稳定性分析提供借鉴。     

露天边坡稳定性分析及防治措施探讨

论述了凉山矿业股份有限公司露天矿在陡帮开采工艺条件下,通过认清露天边坡的特点及找准影响边坡稳定性因素的基础上,采用减震爆破技术,是确保露天边坡稳定的重要手段之一。     

基于极限平衡法和强度折减法的边坡稳定性分析

考虑传统的极限平衡法和FLAC二维非线性数值分析方法的优缺点,将边坡稳定性分析的Slide极限平衡法和FLAC2D强度折减法相结合,以某排土场为工程实际,进行了边坡在天然、天然地震、降雨和降雨地震四种不同工况下的稳定性验算比较;鉴于影响边坡稳定因素的不确定性,采用基于Spencer法的Mont-Carlo法进行了边坡可靠度指标的计算,并对强度参数C、（φ）和容重γ对边坡稳定的影响进行了分析,得出边坡稳定对内摩擦角（φ）的敏感性高于内聚力C的敏感性,而容重γ的影响较C、（φ）可忽略不计.该方法通过两者的相互校核,不仅给出边坡非线性应力-应变关系和安全系数来共同评价边坡的稳定性,而且结合排土场边坡安全系数的概率分析提供边坡潜在的失效概率使边坡稳定性评价更加科学、精确.     

排土场边坡堆排设计及稳定性分析

排土场作为露天采场剥离废石的堆放场地。其稳定性设计和分析至关重要,也是边坡工程的核心问题,是露天矿组织生产不可缺少的一项永久性工程。以某铁矿排土场为例,根据工程地质情况,对该排土场进行了堆排设计,然后对该堆排设计进行了边坡稳定性数值模拟分析。模拟结果表明：在浸水状态下,排土场边坡处于稳定状态,说明该排土场堆排设计方案具有一定的可行性和合理性,为露天采场的废石堆排提供了一定的指导依据。     

城门山铜矿边坡稳定性分析与治理研究

城门山铜矿采场南部边坡为典型的倾斜沉积地层,在开采过程中,受到暴雨、爆破等影响,易发生整体失稳,威胁采矿活动的安全开展。采用工程类比法、理论分析法和数值模拟法,在此边坡建立三维模型进行稳定性评估并制定边坡治理优化方案。结果表明,南部边坡岩土体风化程度较高,下部发育F1断层走向与边坡走向平行、倾向相反,岩土体受到结构面切割、整体强度较低,这是南部边坡发生失稳的主要原因。通过Midas/GTS数值软件分析计算,南部边坡破坏以楔形体和圆弧形破坏为主,目前处于基本稳定状态。根据现场实施条件,提出三个治理方案,结果分析认为方案二（上部削坡减载、下部堆载反压,形成5级台阶）既能降低工程费用、平衡挖填方量,又能为后续生产预留运输和养护通道,还能减少-82 m平台的侵占,利于边坡的长期稳定。     

Stress History Effects on Graded Bed Stability

This paper presents the first detailed examination of the dependence of graded bed stability on antecedent flow conditions (stress history). Thirty-three experiments, including repetitions, were undertaken where a bimodal sediment bed (D50 = 4.8?mm, σg = 2.1) was conditioned for between 30 and 5,760?min. The antecedent shear stress ranged from 53 to 91% of the critical shear stress for the D50 of the sediment bed. Data indicate that higher antecedent shear stresses reduce bed stability due to selective entrainment of the fine matrix; conversely, extending the duration of the antecedent conditioning phase increases bed stability due to local particle rearrangement. Analysis of the competitive effects indicates that particle rearrangement may be of greater relative importance than compositional change. Overall, the paper demonstrates the significance of antecedent flow conditions for hydraulic engineering and research, including the modeling of bed-load transport during flood events and the need for standardizing the flume-based experimental procedure.     

索尔库都克铜矿渗水边坡稳定性初步分析

新疆索尔库都克铜矿含水层位于矿床顶底板风化带裂隙内,造成部分区域露天边坡常年处于淋水状态。根据加拿大C.O.Brawner教授的研究结论,从假设地下水压可降低边坡稳定20%和假设地下水压相当于使边坡角增加5°两个角度,分别对地下水对边坡稳定性影响进行了模拟分析,得出了矿山边坡仍处于稳定状态的初步结论。实际生产中,建设了基本覆盖露天采场边坡各主要渗水点的监测系统,采用喷浆支护的方式封闭了裂隙水渗流通道,边坡渗水情况明显减弱,露天边坡处于稳定状态,有效保障了矿山安全生产。     

基于BP神经网络的边坡稳定性分析

阐述了BP神经网络的基本思想、学习算法的步骤,以构建的学习样本为基础,建立边坡稳定性分析的BP神经网络模型,对学习样本进行归一化和训练,建立输入向量与输出向量的非线性关系,把训练好的网络运用于某露天矿边坡,结果表明：BP神经网训练结果与现场实际情况相符,说明该方法对工程实际有指导意义.