基于节理面三维形貌的岩石节理抗剪强度计算模型

JRC-JCS模型在岩土工程领域被广泛应用,但也存在一定缺陷:其一,粗糙度系数(JRC)的二维性不能综合表征节理表面形貌的各向异性;其二,抗压强度系数(JCS)不能全面反映材料属性对节理剪切力学行为的影响。借助三维激光扫描和3D打印技术,浇筑具有自然节理形貌的人工节理试样,对其进行常法向应力下的剪切试验。将试验结果和理论推导相结合,建立了含有三维形貌参数和抗拉强度参数的抗剪强度模型。通过室内试验以及模型对比,分析了法向应力和三维形貌特征对岩石节理的抗剪强度以及剪胀角的影响。结果表明,节理剪切是以张拉为主导的破坏模式,而不是单纯的压缩破坏。不同的三维形貌特征会得到不同的初始剪胀角。随着法向应力的增大,峰值剪胀角减小,通过研究剪胀效应中峰值剪胀角的变化规律,可用于计算岩石节理的抗剪强度。     

能量原理在确定岩石节理抗剪强度方面的应用

为了确定剪胀节理的剪切强度，人们已开始运用能量原理研究岩体结构面（Ｌａｄａｎｙｉ和Ａｒｃｈａｍｂａｕｌｔ，１９７０）。本项工作基于分析规则的粗糙起伏面，并且假定其是不可变形的。自然条件下的复杂岩体结构面中，很难辩认出要测量的有代表性的起伏角。Ｌａｄａｎｙｉ和Ａｒｃｈａｍｂａｕｌｔ通过假定等价结构面的张开度和结构面的有效起伏将其成果推广到天然节理。显然，这种等量假设不是普遍适用的，而且可能导致结构面     

蒙特卡罗模拟在节理岩体抗剪强度研究中的应用

首先介绍了蒙特卡罗模拟的理论基础,然后,以具体工程为例分析了利用该方法模拟节理岩体抗剪强度的具体方法和步骤。将模拟结果与利用其他方法获强度的可行性与可靠性。     

含充填节理岩体加锚节理面力学特性研究

通过分析压剪，拉剪压力状态下加锚充填节理面的受力与变形特点，建立了锚杆应力与构元应力分量间的关系式，为合理计算锚杆对节理岩体的加固作用创造了条件。     

节理抗剪强度综合评价的试验研究

选取不同吻合度自然节理试样,进行干燥状态和饱和状态的JRC-JCS模型和JRC-JMS模型试验研究。结果表明,在节理粗糙度系数的定向统计测量和尺寸效应分析,以及剪切过程衰减折减的基础上,运用JRC-JCS模型综合评价节理抗剪强度可靠性较好,考虑吻合度系数的JRC-JMC模型比JRC-JCS模型具更好的预测能力。     

中缓倾角结构面分类及其抗剪强度的研究

西南某坝区中缓倾角结构面具有分别倾向上游和下游的空间分布规律。根据结构面接触情况,首先将结构面分为刚性结构面和软弱结构面两大类。其中,刚性结构面属于裂隙型;软弱结构面根据其物质组成和结构特征,可以细分为岩块岩屑型、岩屑夹泥型、泥夹岩屑型3个亚类。断层类结构面具有垂直于断层走向,由高高程到低高程,由泥夹岩屑型岩屑夹泥型岩屑砾型裂隙型逐渐过渡的发育规律。最后在分析抗剪试验资料和分类及发育规律的基础上,提出了抗剪强度指标的建议值。     

三峡库区岩体天然结构面抗剪性能试验研究

采用自制的试验装置对取自三峡库区的含天然结构面的岩块试件进行压剪试验,通过对4组试件进行不同正压力及不同含水量(天然状态与饱水状态)下的剪切试验,绘制出其相应的变形和强度曲线,并对这几组曲线进行了对比分析。试验结果表明：岩块中结构面的抗剪强度不仅与岩块所受法向应力的大小有关,而且与岩块含水量的大小有关,即结构面抗剪强度的大小随着法向应力的增大而增大,又随着含水量的增大而减小;最后,运用最小二乘法对该结构面的抗剪参数进行了求解,且与推荐值进行了比较,对比发现二者基本吻合,说明该试验装置与试验方法在实际工程应用中是可行、有效的。     

不规则柱状节理岩体力学特性模型试验研究

结合Voronoi图随机模拟和3D打印技术制备不规则柱状节理网络模型,采用白水泥浆类岩石相似模型材料浇筑模型并拆模,然后分别采用白乳胶和502胶水作为黏结剂黏结柱体得到两组不规则柱状节理岩体试件,通过对其进行室内单轴压缩试验研究不规则柱状节理岩体强度特性和破坏模式。试验结果表明:不规则柱状节理岩体试件单轴抗压强度随柱体倾角的变化曲线呈现近似"J"型,表现出显著各向异性特征;不规则柱状节理岩体试件典型破坏模式包括沿柱状节理面的劈裂破坏、沿柱状节理面的剪切破坏和沿柱体的压裂破坏等3种,其部分破坏形态有异于规则柱状节理岩体试件。同时,通过与采用净水泥浆作为黏结剂的柱状节理岩体试验结果进行比较,结果表明:采用白乳胶和502胶水作为黏结剂时柱体间黏结强度更低,能够较好反映柱状节理面的弱化效应,试件力学响应与真实柱状节理岩体更为一致。     

甘肃北山地质处置库围岩节理抗剪强度经验估算

节理抗剪强度参数是地质处置库预选地段工程地质对比和围岩稳定性分析的重要指标。本文在旧井地段英云闪长岩节理分组的基础上,运用定向统计测量方法估测节理粗糙度系数,通过评价节理粗糙度系数的尺寸效应,确定节理抗剪强度经验估算有效长度,由JRC-JCS模型求得各组节理4个方向的抗剪强度参数,并评价了地质处置库围岩节理抗剪强度的各向异性特征。     

不同充填度岩石分形节理抗剪强度的数值模拟

在对岩石节理进行分形模拟的基础上,建立了岩石分形充填节理直剪试验数值分析模型,采用数值模拟方法,研究了充填度与岩石分形充填节理抗剪强度之间的关系。结果表明,随着充填度的增大,分形节理抗剪强度总体上呈非线性减小。当充填度小于1时,随着充填度的增大,分形节理抗剪强度迅速减小,节理抗剪强度受节理表面形态、充填物力学性质以及壁岩力学性质的共同影响;当充填度大于1时,节理抗剪强度主要受充填物力学性质的控制,强度参数接近于节理充填物的强度参数。     

Experimental Study of Mechanical Behaviour of Rock Joints Under Cyclic Loading

Summary Evaluation of the effects of small repetitive earthquakes on the strength parameters of rock joints in active seismic zones is of interest of the designers of underground constructions. In order to evaluate these effects, it is necessary to study the behaviour of rock joints under dynamic and cyclic loadings. This paper presents the results of a systematic study on the behaviour of artificial rock joints subjected to cyclic shearing. More than 30 identical replicas have been tested using triaxial compression devices under different conditions of monotonic and cyclic loading. At the first stage a few samples have been tested in monotonic loading modes under various confining pressures and rate of displacement. In the second series of tests, small cyclic loads were applied on the samples for increasing number of cycles, frequency levels and stress amplitudes. These were then followed by monotonic loading again. The variations of maximum and residual shear strengths for each test have been studied. The results show increase of shear strength as a result of the increase in confining pressure and they display decrease of shear strength due to the increase of rate of loading, number of cycles, frequency levels and stress amplitudes.     

岩体中节理面、软弱夹层等的力学性质和模拟分析方法(一)

岩体中的软弱结构面、特别是软弱夹层和软弱的节理面以及基岩和建筑物的结合面或称界面(以下对这些面简称为弱面)对于水工建筑物的抗滑稳定,天然或人工岩石边坡和地下洞库的稳定性常常起控制作用.     

The Mechanical. Behaviors and Analog Analytical Method of Joints and Weak Intercalations in Rock Mass

In this paper, the mechanical behaviors of rock joints and internationals etc. are described. According to the filed results of the shear tests, several basic types of shear displacement are discussed and classified。 based on the nonlinear properties of these weak plants ,the analytical models and methods suggested in this paper, the influence of normal stress on the shear deformation may be considered .It also can be applied to the complicated conditions of loading-unloading-reloadings. The non-linear and the problems of the weak plane’s reclosing after opening can be handled simultaneously. The same analytical method is also acceptable to the shear deformation properties of various types only by choosing different parameters. Wish this analytical method, analogic calculations for the in-situ weak-plane shear tests are made and results are well checked by curves .This method has been used in some practical engineering problems .     

The Mechanical. Behaviors and Analog Analytical Method of Joints and Weak Intercalations in Rock Mass (Continued)

In this paper, the mechanical behaviors of rock joints and internationals etc. are described. According to the filed results of the shear tests, several basic types of shear displacement are discussed and classified。 based on the nonlinear properties of these weak plants ,the analytical models and methods suggested in this paper, the influence of normal stress on the shear deformation may be considered .It also can be applied to the complicated conditions of loading-unloading-reloadings. The non-linear and the problems of the weak plane’s reclosing after opening can be handled simultaneously. The same analytical method is also acceptable to the shear deformation properties of various types only by choosing different parameters. Wish this analytical method, analogic calculations for the in-situ weak-plane shear tests are made and results are well checked by curves .This method has been used in some practical engineering problems .     

岩体中节理面、软弱夹层等的力学性质和模拟分析方法(续)

六、滑移条件的实验依据和节理单元的塑性变形问题采用关联流动理论来推导节理单元的弹塑性物性矩阵可以明显看出它将使处于继续加载状态的单元的新应力点将落在残余强度线上,也就是说是满足“滑移条件”的,但这与实验结果是否接近呢? 现在我们列举一九七○年在某矿区所作的野外剪切“单点法”试验结果以资说明.     

岩石节理面形态与水力特性研究

通过节理面粗糙度测量、张开度模拟、节理渗流试验及有限元数值分析,探讨了岩石节理复杂的水力特性。研究表明,节理渗流具有明显的不均匀性、各向异性及与变形耦合等性质,节理的渗透系数与法向应力之间呈负指数关系。     

Experimental Study on the Rheological Shear Mechanical Behavior of Bolted Joints

Geotechnical and Geological Engineering - Landslides, which are predominantly caused by the rheological behavior of preexisting joints, occur frequently around the world and are among the most...