共查询到20条相似文献,搜索用时 31 毫秒
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Sheng-hong Chen Yong-ming Li Wei-ming Wang Isam Shahrour 《Canadian Metallurgical Quarterly》2004,130(7):759-763
In this Technical Note, the adaptive block element method of rock masses is formulated, in which the elastoplastic characteristics of both rock blocks and discontinuities are taken into account. The concept of an overlay element is illustrated first; then the displacement fields of rock blocks are expressed as functions of so-called general degree of freedoms using the shape functions of the hierarchical finite element method; the governing equations of the rock block system are deduced on the basis of the virtual work principle; and the p-version adaptive algorithm based on the energy norm error estimation of each block element is proposed. The method is applied to the deformation and stability study of a gravity dam, and the parallel laboratory physical test is used to check the validity and ability of the method. 相似文献
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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. 相似文献
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Evaluation of Seismic Performance for Tunnel Retrofit Project 总被引:1,自引:0,他引:1
A seismic retrofit program at Yerba Buena Island Tunnel is presented as a case history. The studies include evaluations of portal stability under earthquake excitation and performance of the tunnel liner as a result of seismic induced deformation. Due to different potential failure modes at the two portal areas, two separate evaluation techniques were utilized. Key block theory in conjunction with a Newmark type analysis was used to assess movements of a potential failure wedge at the west portal slope, while discontinuous deformation analysis was utilized at the east portal slope to evaluate a rotational mode of failure. To assess the performance of the liner subjected to design earthquakes, a two-step analysis procedure was adopted. The first step was to compute seismic induced deformations of the tunnel subjected to seismic wave propagation through the island rock without the presence of the liner. The second step, not reported in this paper, involved imposing the deformations of the tunnel onto the structural liner through spring elements that accounted for interaction between the liner and the surrounding rock. From the studies, performance of the existing tunnel supports was found to be acceptable. 相似文献
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Seismic Displacement of Slopes Reinforced with Piles 总被引:1,自引:0,他引:1
The seismic stability of slopes reinforced with a row of piles is analyzed using the kinematic theorem of limit analysis within the framework of the pseudostatic approach. An existing method which is based on the theory of plasticity is used to determine the lateral forces provided by the piles. Expressions for calculating the yield acceleration coefficient are derived. Then, based on Newmark’s sliding block concept, the permanent displacement induced by an earthquake shocking can be calculated by the integrals of seismic records. An example is investigated to illustrate the validity of this method and the effects of piles on a restraining slope’s dynamic deformation. 相似文献
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Sheng-hong Chen Ming-yi Xu Isam Shahrour Peter Egger 《Canadian Metallurgical Quarterly》2003,129(11):977-986
This paper presents the use of the trial load method and the block element method with elastoviscoplastic discontinuities for analysis of arch dams. The arch dam is considered as an arch-cantilever system and the foundation as a block element system. With the displacement compatibility condition at the contact surface of the dam and the foundation (including abutment), the governing equations of the arch dam and foundation are established. These methods are used for the analysis of the double curvature arch dam with complex geology conditions of the Xiaowan Hydroelectric Project in China. The deformation and stress states in both the dam body and the foundation are determined. Furthermore, the stability safety factors of the foundation and the abutment are calculated at the same time, which allows for an optimal design of the arch dam considering the strength, the deformation and the stability of the dam and foundation. 相似文献
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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. 相似文献
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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。 相似文献
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为了给深部资源开采和大型地下空间工程中围岩体的变形机理及稳定性控制提供理论基础,通过查阅大量关于表征岩石裂纹扩展的裂纹扩展模型、应力强度因子和断裂韧性的国内外文献,总结了前人的研究成果。依据现有研究,提出了动荷载作用下岩石裂纹扩展的几点建议:(1)综合考虑弹性力学、断裂力学和损伤力学建立岩石材料从微观断裂到宏观破坏这一演变过程的理论模型,使理论模型更加适应岩石材料的非线性特征;(2)采用分形、自组织和混沌等非线性理论表征动荷载作用下岩石内部以及表面裂纹的扩展演化特征;(3)采用颗粒离散元和有限差分模拟岩石材料裂纹扩展演化特征。 相似文献
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本文根据非洲如瓦西矿西南边坡为案例,分别采用运动学分析方法和极限平衡法,对边坡稳定性进行分析研究。研究结果表明:西南边坡发生平面滑坡和楔形体滑坡的概率较小,但由于边坡部分岩体较破碎,结构面较发育,不排除小规模楔形体滑坡的可能。极限平衡法计算的最小安全系数均高于规范要求值,其边坡为稳定边坡。 相似文献
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结合有限元滑面应力法和Hermite随机响应面法建立了金鸡岭岩质边坡稳定可靠度非侵入式分析模型,在此基础上研究了均匀设计抽样、LHS抽样、改进LHS抽样和分层抽样4种抽样配点方法对随机响应面的拟合精度、边坡失效概率及安全系数统计特征的影响。结果表明:(1)金鸡岭岩质边坡未支护状态下的失效概率约为18.4%,失稳风险较大,需采取支护加固措施;(2)改进LHS抽样和LHS抽样所构造的随机响应面具有较好的拟合精度,抽样配点效果优于分层抽样和均匀设计抽样;(3)建议边坡可靠度非侵入式随机分析采用改进LHS抽样或LHS抽样进行随机响应面的抽样配点计算,并尽可能多地选取样本点以外的验算点对随机响应面拟合精度进行校验。 相似文献
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边坡是各类工程中一类常见的工程结构。地质条件多种多样导致影响边坡的稳定性的因素也多种多样。本文分析了某工程含煤岩质高边坡内存在煤洞采空区时对边坡的稳定性影响。并对此高边坡进行了数值分析,对其稳定性作出了一定的评价。 相似文献
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结合露天矿边坡实际情况,利用FLAC3D数值模拟软件对露天矿边坡进行三维数值模拟分析,运用有限元强度折减法计算边坡稳定安全系数。为研究各因素对边坡稳定性的影响,选取6个典型边坡影响因素(内摩擦角、黏聚力、抗拉强度、重度、弹性模量和泊松比)设计正交试验,采用FLAC3D数值软件对正交实验方案进行模拟运算,运用多因素灰色关联分析法分析计算结果,并与单因素分析进行对比。结果表明:根据计算不收敛这一判据,求解安全系数流程简单,在满足精度要求的情况下,求得边坡安全系数为1.96;2种分析方法计算得出的各因素敏感性大小基本一致,内摩擦角对边坡稳定性的影响最大,其次是黏聚力,泊松比的影响最小。其中,多因素分析过程中正交实验灰色理论耦合分析考虑各因素之间的交互作用,通过计算各影响因素之间的关联度,得出各影响因素的敏感性大小,所得结果更加可靠。 相似文献
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地质模型的精确性是露天矿边坡稳定性数值分析可靠性的决定因素。针对地质体间相互交叉、穿切的复杂性和无规律性,研究了基于非均匀有理B样条NURBS(Non-Uniform Rational B-Spline)的自由曲面生成技术。以矿山普遍采用的二维地质勘探剖面图为基础数据,通过对其进行矢量化处理提取出岩土体边界离散点信息,建立起NURBS三维地质体分界曲面,据此以MIDAS软件为平台制定了边坡工程复杂地质结构三维可视化及数值模型构建方案,并选取江西城门山露天矿边坡工程进行了应用实践。结果表明,运用该技术构建复杂边坡地质体模型,方法简单可靠,可极大提高模型的精度和建模效率,不仅使复杂地质体得以形象再现,同时可为边坡稳定性分析提供可靠的有限元数值计算模型。 相似文献