高密集片理结构千枚岩边坡变形特性研究

以某露天采场边坡为例,结合现场勘察,对高密集片理结构千枚岩边坡的变形特性进行了分析,揭示了该类边坡岩体的失稳模式,并综合分析了该边坡的变形破坏机制及发展趋势.研究结果表明,该类边坡岩体具有多种失稳方式,其中以局部的弯曲折断破坏为主,并在一定条件下,可能朝着蠕滑—拉裂的破坏方式发展.     

高海拔寒区岩质边坡变形破坏机制研究现状及趋势

高海拔寒区矿山岩质边坡变形破坏机制研究已取得一定的研究成果,但基于现行理论与技术还难以全面解决未来高寒边坡失稳机理和灾害防控的所有问题,至今尚未建立起完善的高寒边坡开采研究体系和边坡稳定性判别标准. 本文对高寒岩质边坡变形破坏的室内岩石力学试验、边坡物理相似模拟、多场多相耦合数值模拟、变形破坏原位监测、高海拔寒区岩质边坡失稳机理五个方面开展了大量的文献调研,总结高寒岩体变形破坏有关的研究成果,继而对存在的问题进行探讨并分析当前研究的不足,总结出高寒岩质边坡变形破坏研究领域亟待解决的关键问题:一是开采扰动条件下高海拔寒区矿山边坡岩体结构损伤劣化机制,二是冻融循环条件下流?固?气多相多场耦合边坡失稳时效特征与评价方法;并就未来高寒边坡变形和破坏研究方向及发展趋势予以分析,指出开展不同应力路径冻融循环耦合作用下岩体结构损伤劣化机理研究,开展爆破采动条件下高海拔寒区岩质边坡结构面致溃机制及边坡失稳破坏研究,开展地震荷载作用下高海拔寒区节理岩质边坡地震动力响应及致灾规律研究,研究多场多相耦合条件下节理岩体损伤劣化机理,开展高海拔寒区矿山边坡抗寒多参量实时安全监测及失稳预警技术研究五个方面是未来研究的趋势.      

底摩擦模型模拟露天转地下开挖采空区影响下边坡变形破裂响应特征及其稳定性

以云南磷化集团晋宁磷矿6号坑口东采区深部缓倾斜中厚磷矿层露天转地下开采为工程背景,利用底摩擦模型实验仪,进行了不同露天坑境界顶柱厚度边坡高度下的底摩擦模拟模型实验.结果表明:边坡的变形破坏响应特征可分为边坡岩体小范围微破裂和松动→边坡岩体局部范围失稳破坏→边坡岩体整体向采空区滑落失稳破坏三个阶段,边坡岩体变形破坏模式主要是采动边坡岩体向采空的拉裂、破断和滑移破坏.在边坡高度一定情况下,随着露天境界顶柱的厚度由30 m逐渐减小到20 m和10m,边坡的稳定性与境界顶柱的厚度呈正比关系,20~30m是露天境界顶柱比较合理的厚度.在境界顶柱的厚度一定情况下,边坡高度由60 m增大到108 m,边坡的稳定性与坡高的厚度呈反比关系,108 m边坡转入地下开采后是不稳定的.      

大新锰矿露天转地下开采边坡稳定性分析

在露天转地下开采过程中,为了研究大新锰矿边坡岩体稳定性及其对地下开采的影响,分析了该矿的边坡稳定性因素,探讨围岩移动变形、应力分布特征和破坏机理。以大新锰矿典型的中部矿体的回采为工程背景,采用FLAC3D程序创建数值模型,对处在回采的矿房上覆边坡岩体进行失稳分析,给出了再开采过程中容易产生失稳破坏的部位及失稳破坏机理,对今后矿山地下开采提供合理的采矿参数和支护方法。     

高陡层状土质边坡风蚀失稳过程及机理研究

吐鲁番交河故城台地高陡层状土质边坡的失稳过程受风蚀控制和影响非常典型;在土层组合特征和抗风蚀能力差异以及当地终年多大风的气候特征的共同作用下,坡体土层形成风蚀空腔并在空腔的控制下发生变形破坏.以工程地质定性分析、风洞实验、物理模拟为主要手段,结合数值模拟,分析了该边坡在自然风蚀改造过程中表现出具有特殊性、多样性和阶段性特征的失稳过程,验证了边坡风蚀空腔形成与发展的存在性,揭示了边坡在风蚀失稳过程中的客观存在的差异风蚀和外挑块体变形破坏机理,为防治和监测此类边坡的变形破坏提供了有益的参考.     

基于PEM-JFEM方法的节理岩质边坡稳定性评价

以赞比亚一露天铜矿南帮边坡(矿体下盘)为研究对象,将Rosenbluth点估计方法与节理有限元方法相结合应用于该节理发育的岩质边坡稳定性评价中.建立以边坡岩体材料强度参数(内摩擦角和黏聚力)为输入变量,安全系数为输出变量的概率模型,点估计状态函数的求解过程引入节理有限元方法.通过现场节理及结构面调查,建立边坡节理有限元模型求解边坡安全系数,得到基于安全系数的边坡变形破坏概率统计指标,对边坡稳定性进行了概率分析,分析结果与现场失稳情况一致.该方法既考虑了岩体材料参数在赋值过程中实际存在的不确定性,同时也考虑了节理岩质边坡的节理属性,充分体现了岩层接触作用的非线性关系,使得对节理岩质边坡的稳定性评价更加合理.      

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。     

折腰山铜矿露天转地下开采边坡岩体结构稳定性浅析

本文以岩体结构为中心,剖析了边坡岩体的稳定性,概述了地下开采与边坡岩体稳定的相互关系,及其对边坡稳定的影响和变形破坏形式。     

不同倾角顺层岩质边坡失稳机制的相似模型试验

露天矿山采场边坡的稳定性决定矿山的安全生产,边坡开挖引起的变形及应力调整规律是边坡稳定性的重要依据。应用相似模型试验的方法研究倾角对顺层岩质边坡失稳机制的影响,模型的物理力学参数参考云南某露天矿采场的岩体参数,进行配比试验并选出最优配比,按照30°,35°,45°,50°倾角分别进行试验,对每组试验进行观测,作位移变形图和位移矢量图,对每组的试验的变形情况进行分析,最后对比各试验的变形情况,发现模型出现顺层岩质边坡典型的上部"下陷"、下部"鼓胀"的变形特征,并得到30°和35°倾角边坡表现为拉裂破坏,45°和50°倾角边坡表现为滑移-压裂破坏。     

德兴铜矿露采矿区岩体结构特征对边坡稳定性的影响

从边坡的破坏现象入手,找出影响岩体强度和变形的内在因素,进行边坡岩体结构特性的研究,探讨边坡岩体结构的成因,并预测它们在工程条件下的变化趋势,是边坡工程中一项重要工作。     

银山矿露天边坡稳定性分析

露天边坡稳定性受岩性、岩体结构、水文地质、边坡形态和爆破等多种因素影响。露天矿常见的边坡失稳,滑坡等地质灾害直接威胁露天采场的正常生产。为研究银山矿现有边坡的稳定性,建立了Dimine软件三维模型,采用工程地质分区、极限平衡法分析边坡各种破坏模式下的受力状态,以边坡滑体上的抗滑力和下滑力之间的关系评价边坡的稳定性,分析结果表面银山矿总体边坡较稳定,南部后续开采过程中需加强现场巡视与边坡监测,及时消除安全隐患。     

Slope Reliability Analysis Considering Site-Specific Performance Information

The performance of a slope, such as surviving a certain groundwater condition, can be viewed as the outcome of a full-scale test performed directly on the slope and may provide valuable information for safety assessment, upgrading analysis, and repair design of the slope. Performance information can be divided into two types: (1)?the slope survived a certain state, and (2)?the slope failed at a certain state. This paper illustrates two methods for slope reliability analysis considering site-specific performance information, i.e., an indirect method based on back-analysis of the performance information, and a direct method, in which the back-analysis procedure is bypassed. The two methods are theoretically the same but different in implementation details. As examples, an existing slope for safety assessment and a failed slope to be repaired are studied in this paper. Considering the past survival information increases the reliability of the slope. The increase in reliability is larger if the slope survives a more critical state. Thus, ignoring the survival information may result in uneconomical decisions. In contrast, ignoring the failure information may either underestimate or overestimate the reliability of a slope. As a result, neglecting the past failure information may lead to unsafe or uneconomical decisions.     

基于分级分析法评价结构面对岩质 高边坡稳定性的影响

以云南省普洱市大平掌铜矿东部边坡为工程实例,研究结构面对岩质高边坡稳定性的影响.通过大型露天矿山边坡岩体工程稳定性分级分析方法,按照岩体结构面与矿山边坡规模的匹配性,依次对矿山边坡的总体边坡、组合台阶边坡、台阶边坡进行分层次的岩体稳定性分析并找出控制边坡稳定的关键性结构面及其组合.经过现场与实验分析对比,得到结构面对台阶边坡和整体东部边坡的影响很大,对组合台阶坡影响甚小.同时台阶边坡相对于整体东部边坡而言规模较小,故台阶边坡的结构面对整体东部边坡影响较小.最后,运用Midas-GTS建立考虑结构面及不考虑结构面的东部边坡三维有限元模型,进行稳定性计算分析及对比.      

持续暴雨作用下排土场层状碎石土边坡稳定性

为了研究排土场层状碎石土边坡在持续暴雨条件下的入渗过程及稳定性,推导了土体天然含水率、天然重度与天然体积含水量的换算公式,作为快速确定边坡土体初始基质吸力分布的依据.建立算例排土场有限元分析模型,进行降雨条件下饱和-非饱和渗流、孔压-应力耦合以及边坡稳定分析.结果表明:持续暴雨作用下排土场会在透水性最强的边坡浅层形成集中渗流通道,当坡底存在弱透水性土层时会切断渗流通道,导致雨水从坡脚涌出;排土场边坡位移在降雨期间不断增长,但增长速度越来越慢,雨后边坡位移立即开始减小;降雨初期边坡稳定性系数下降较快,边坡浅层渗流稳定后基本保持不变,雨后缓慢增大.排土场层状碎石土边坡在持续暴雨作用下容易在降雨中后期失稳.      

Slope Stability Analysis with Nonlinear Failure Criterion

A linear failure criterion is widely used in slope stability analyses. However, the strength envelope of almost all geomaterials has the nature of nonlinearity. This paper computes rigorous upper bounds on slope stability factors under the condition of plane strain with a nonlinear yield criterion by employing the upper bound theorem of plasticity. A stability factor (or a limit load) computed using a linear Mohr-Coulomb (MC) failure criterion which circumscribes the actual nonlinear failure criterion is an upper bound value of the actual stability factor (or limit load). In this paper, an improved method using a “generalized tangential” technique to approximate a nonlinear failure criterion is proposed to estimate the stability factor of a slope on the basis of the upper bound theorem of plasticity. Using the “generalized tangential” technique, the curve of the nonlinear failure criterion is simplified as a set of straight lines according to the linear MC failure criterion. The straight line is tangential to the curve of the nonlinear failure criterion. The set of straight lines of the linear MC failure criterion is employed to formulate the slope stability problem as a classical optimization problem. The objective function formulated in this way is minimized with respect to the location of sliding body center and the location of tangency point. Two typical slope stability problems (a homogeneous soil slope with two slope angles and a vertical cut slope with a tension crack) are analyzed using the proposed method. For the soil slope with two slope angles, the computed results are compared with published solutions by others. The comparison shows that the proposed method gives reasonable and consistent values of the stability factor of the slope. For the vertical cut slope with a tension crack, a statically admissible stress field is constructed for the slope. The stress field does not violate the nonlinear failure criterion. Lower bound solutions are obtained by satisfying stress equilibrium conditions. The upper bound solutions obtained from the proposed method are equal to the lower bound solutions for the vertical cut slope. The agreement further supports the validation of the proposed approach. The influences of the strength parameters in the nonlinear criterion on the stability of slopes are also studied and discussed in this paper.     

Stability Analyses of Rainfall Induced Landslides

The slope stability issues concerning rainfall induced slope failures are investigated and presented. Specifically, the effect of both negative and positive pore water pressures on the stability of initially unsaturated slopes are carefully explained and coupled with infinite slope analysis methods in order to present a predictive formulation of slope failures that occur as a result of rainfall events. The formulation serves as a baseline analysis method for evaluating potentially unstable soil slopes that are subject to surface infiltration and explains the various triggering mechanisms that may occur based on individual combinations of the slope geometry, soil strength, and infiltration parameters. A procedural method is outlined for utilizing the analytical formulation to predict the change in the factor of safety for a slope subject to infiltration and a detailed analysis of a case study is presented to verify the method. Quantitative statements are made concerning the time and depth of failure in relationship to the soil, slope, and rainfall parameters.     

基于MSR300雷达监测的凹山采场降雨条件下的边坡变形及滑坡

降雨是诱发滑坡的主要因素之一,尤其在暴雨条件下,更易激发滑坡.随着南帮边坡开采高陡化,滑坡发生频繁.为研究降雨条件下南山矿凹山采场南帮边坡稳定性特征,采用MSR300型雷达对边坡进行了连续4 a的实时稳定性监测,基于采集到的采场降雨数据和边坡滑移数据,分析了降雨量和降雨强度与边坡变形规律,对凹山采场滑坡各阶段进行了划分,建立了凹山采场边坡失稳模型和预警阈值.结果表明:凹山采场变形与降雨量呈正相关,服从幂函数规律;边坡变形速度曲线与降雨强度有良好的一致性,滑坡一般发生在最大降雨强度之后;滑坡阶段主要包括初始变形阶段,稳定变形阶段和加速变形阶段;报警阈值分别为:6 h时序内,位移阈值为20 mm,速度阈值1.5 mm·h-1;12 h时序内,位移阈值为30 mm,速度阈值为2.5 mm·h-1.凹山采场滑坡曲线与岩土体非稳定蠕变曲线具有较高的相似性,位移曲线出现了"阶跃"现象,速度曲线出现了"尖凸"现象,这种情况易引起滑坡事故,其中在位移曲线的"拐点"处和相应速度曲线的"凸点"处发生滑坡的可能性最大.研究成果为类似矿山边坡稳定性监测和破坏机制提供了科学依据和参考.      

双利铁矿2号露天采场扩帮后西半帮边坡稳定性分析

保持边坡稳定是露天矿生产经营的一项重要内容。为确定双利铁矿2号露天采场扩帮后的最终边坡角,通过运用FLAC3D软件建模分析边坡的应力分布、位移移动趋势、弹塑性区分布以及有限元强度折减法计算边坡的安全系数,从而确定合理的边坡角,并为后期边坡的监测提供参考依据。     

安岳县拱桥乡初级中学崩塌特征、成因机制及稳定性分析

拱桥乡初级中学崩塌位于资阳市安岳县拱桥乡,由公路内侧切坡形成的边坡发展而来,公路开挖致使内侧形成约8米高边坡,边坡高度高、坡度大.边坡物质成分主要为中等风化泥岩夹砂岩,自身稳定性较差,在长年风化剥蚀过程中,软硬岩之间差异风化形成了凹腔.特别是雨季,雨水入渗,增大岩土体容重、减小内部结合力,致使边坡受冲刷而进一步变形失稳...