共查询到17条相似文献,搜索用时 853 毫秒
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《应用力学学报》2016,(1)
节理岩质边坡的稳定性很大程度上取决于节理的抗剪强度及节理分布形式,多组节理控制下的岩质边坡稳定性分析存在参数选取和计算方法方面的问题。本文以某公路的节理岩质边坡为研究对象,采用节理抗剪强度折减的有限元方法研究了两组节理控制下的岩质边坡滑动机理,通过节理室内剪切试验和边坡稳定性反分析相结合的方法给出了合理的节理抗剪强度参数:节理1的强度参数是内聚力30k Pa、内摩擦角40°;节理2的强度参数是内聚力5k Pa、内摩擦角5°。在此基础上,考虑爆破施工对边坡岩体节理抗剪强度的弱化作用,对边坡稳定性进行了评价,分析结果得到了边坡的潜在滑动模式为节理控制下的浅层滑动。针对该边坡实际情况建议了以预应力锚索地梁为主的防控措施,即坡面中部采用三排1000k N级预应力锚索,间距3m,钢筋混凝土地梁水平间距5m。 相似文献
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柱状节理玄武岩体抗剪强度参数尺寸效应研究 总被引:4,自引:0,他引:4
结合柱状节理玄武岩块室内直剪试验和现场大尺度直剪试验所取得不同尺度岩块的抗剪参数试验成果,进行异计拟合回归分析得到柱状节理玄武岩体抗剪强度参数内聚力c和内摩擦系数f的尺寸效应经验表达式,认为抗剪强度参数与试样尺寸间近似呈幂函数形式。抗剪强度参数的表征单元体积研究表明,内聚力对试样的尺寸更为敏感。 相似文献
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光弹模拟岩石分形节理的抗剪强度 总被引:3,自引:0,他引:3
本文用分形维数人为地制成具有分形曲线的节理面以模拟岩石节理粗糙度特征,利用光弹技术测定了分形节理最大剪应力随维数变化的过程.研究表明,岩石分形节理的抗剪强度不会随分维的增加而无限制地增大 相似文献
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边坡工程中,结构面抗剪强度是非常重要的力学参数,合理地选择确定抗剪强度的方法,常常要分析c、φ值在边坡稳定中的作用。根据极限平衡原理,对10~30m高的平面滑动型边坡不同抗剪强度的控稳结构面c、φ值在边坡稳定中的作用进行了定量分析。研究表明c值对稳定系数的影响随坡高增大逐渐减弱,φ值对稳定系数的影响随坡高增大逐渐增强。得到了不同坡高下c、φ值边坡稳定作用等值曲线,该曲线很容易确定抗剪强度参数c、φ值在边坡稳定中的作用。 相似文献
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岩体结构面粗糙度系数定量表征研究进展 总被引:7,自引:0,他引:7
1978年,Barton提出的节理粗糙度系数(joint roughness coefficient,JRC)被国际岩石力学学会作为评估节理粗糙度的标准方法.然而该方法存在人为估值的主观性缺陷.就此,国内外学者围绕岩体结构面粗糙度定量化表征开展了大量的研究工作.首先,从二维节理轮廓线到三维岩体结构面,系统地阐述了其粗糙度定量化表征方法研究进展,并总结了各方法参数与JRC的关系;评价了各表征参数的本质特性及其适用性;指出了各方法参数获取过程中存在的问题,主要有:采样间隔的影响,三角形单元划分的影响,如何确定综合参数法中各参数的权重;针对这些问题,给出了笔者的一些想法、建议.与此同时,对结构面粗糙度表征的两个热点问题,即各向异性和尺寸效应的研究也进行了详细总结分析.最后,笔者认为:(1)分形维数因是描述自然界复杂几何体的一种简洁有力的工具,其仍是结构面粗糙度定量描述的有效方法;(2)3D打印技术的应用,有望在开展结构面各向异性、尺寸效应研究方面取得突破性进展. 相似文献
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The particle flow code 2D (PFC2D) is used to establish a coplanar, non-persistent joint model. Three joint distribution types, namely, both-side (type a), scattered (type b), and central (type c), are set according to their position. Numerical simulations of the direct shear test are conducted to investigate the effect of non-persistent joint distribution and connectivity on shear mechanical behavior. Simulation results are in good agreement with the analytical solutions to Jennings' criterion, and show: (1) type-c and type-b joints have high strength, whereas type-a joints have low strength. Shear strength and modulus increase with a decrease in joint persistency, and the shear displacement that correspond to shear strength increases with a decrease in persistency. (2) The brittle failure characteristics of the sample are evident when the intact rock bridge area is large. Reinforcement at both ends of the joint limits shear deformation, and shear strength can be effectively improved when joint persistency is large. The small-area dispersed reinforcement joint method cannot effectively improve shear strength. (3) The comprehensive shear strength parameters and the shear strength of the non-persistent joints can be predicted well using Jennings' criterion. Cohesion is the dominant factor that controls shear strength. 相似文献
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岩体结构面粗糙度系数JRC的定向统计研究 总被引:4,自引:1,他引:4
本文回顾了岩体结构面粗糙度系数JRC的研究成果,分析了各种JRC研究方法的应用范围。在野外实际结构面形态的详细调查和深入研究的基础上,发展了Barton直边法,并提出按岩性定向统计研究结构面粗糙度系数JRC的科学思想。 相似文献
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Most problems faced by the practicing rock mass engineering involve the evaluation of rock mass dynamic strength and deformability. As part of a rock mass, the mesoscopic flaws such as the microcracks and the macroscopic ones such as the joints both inherently affect the rock mass dynamic strength and deformational behavior. Nearly none of the existing models can handle the co-effect of these two kinds of flaws on the rock mass dynamic mechanical behavior. This study focusses on the rock mass with multi-sets of non-persistent joints and establishes a mathematical model accounting for the anisotropy in dynamic strength and deformability induced by the joints. Accordingly, an approach incorporating the existing models or methods to enable perfect simulation of the dynamic stress-strain relationship of a rock mass is proposed, in which the joint geometrical parameters such as the joint length and dip angle, the strength ones such as the joint internal friction and the deformational ones such as the joint normal and shear stiffness can all be taken into account. In order to investigate the validity of the proposed model, a series of calculation examples have been made and the results fits very well with the theoretical ones. 相似文献
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《Comptes Rendus Mecanique》2019,347(8):561-575
The scale effect of rock joint shearing is of great significance in rock engineering. Most existing shear constitutive models could describe the pre- and post-peak deformation of rock joints, but only in one particular scale, that is, those existing models will fail to depict the rock joint shearing in different length scales. Therefore, this study aims to establish a constitutive relationship for rock joints with considering the scale effect. Based on the assumption of a random statistical distribution of rock material strength and statistical mesoscopic damage theory, damage variables are defined as the ratio of the number of damaged elements to the total number in the shear process. Together with the nonlinear relationship between the microelement failure and the joint scale, an empirical statistical constitutive relationship for joint is established. And then, the determination method of constitutive relationship parameters and the variation laws with the scale are discussed. Results show that the predicted results of the proposed empirical relationship not only agree well with the experimental results but also fully describe nonlinear deformation, pre-peak softening, post-peak softening, residual stage, and other mechanical properties of the shear deformation of joint with different dimensions, thereby demonstrating the rationality of the constitutive relationship. The physical meaning of the constitutive relationship parameters is clear, and the expressions of the constitutive relationship parameters can be deduced from the experimental results. In addition, the influence of scale effect on the shear deformation of rock joints can be quantified using parameters, which help accurately describe the action form of scale effect. 相似文献
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岩石分形节理粗糙性对应力场影响的光弹模拟研究 总被引:2,自引:0,他引:2
节理的粗糙性是影响岩体力学特性的重要因素。现有的众多的研究结果表明:不规则的节理面具有很好的自相似特征,可以用分形几何去描述,节理面的分形维数是表征节理面粗糙度(JRC)恰当的统计量。基于以上观点,为了能够精确地控制节理面的粗糙性,本文以Mandelbrotweierstrass函数生成不同分维的分形曲线来模拟实际的粗糙节理面,制成光弹实验试样进行多组的单压和压剪实验,通过光弹条纹和接触点的变化来研究不规则的节理对于岩体变形,应力场的影响,得出了一些有益的结论. 相似文献
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断续节理将对工程岩体的强度及变形等力学特性产生显著影响,损伤力学中视节理为岩体的一种宏观损伤,因而采用损伤张量来刻画其对岩体的影响。目前学术界提出了用节理的几何、强度及变形等3类参数来描述节理的物理力学性质,而目前的岩体损伤张量计算方法都只涉及前2类参数,均没有涉及其变形参数即法向及切向刚度。为此,在前人研究的基础上,基于断裂及损伤理论提出了考虑节理法向及切向刚度的单轴压缩下单条断续节理引起的损伤张量计算公式,进而通过考虑节理间相互作用给出了单组单排或多排节理岩体损伤张量计算公式。其次,以岩石细观动态损伤模型为基础,结合宏细观损伤耦合观点提出了一个能够同时考虑节理几何、强度及变形参数的断续节理岩体动态损伤本构模型。最后,利用该模型讨论了节理参数及载荷应变率等对岩体动态力学特性的影响,认为节理长度减小及摩擦角增大将导致岩体动态峰值强度及弹性模量增大;岩体动态峰值强度及弹性模量则随着节理法向及切向刚度的增大分别减小或增大;而当节理法向及切向刚度按照同一比例增大时,岩体动态峰值强度及弹性模量则是增大的。岩体动态峰值强度与载荷应变率呈正相关。 相似文献