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加锚节理岩体有着复杂的细部结构和力学行为,常规的数值模型很难满足模拟这种力学行为的要求。进一步发展了笔者建立的加锚岩体的复合单元法,提出加锚节理岩体的复合单元法研究。在不考虑锚杆、节理等细部结构的情况下划分网格,分别定义了加锚岩体复合单元、不连续岩体复合单元和加锚节理岩体复合单元,并建立了其数值模型。同时,在复合单元中还定义了不同材料介质的子单元用来模拟加锚节理岩体内复杂的细部构造。对加锚节理复合单元法进行了理论推导和算例研究,通过与常规有限单元法计算结果的比较,表明了加锚节理岩体复合单元法的合理性,同时也突出体现了其前处理简便的优势。 相似文献
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节理岩体中富含结构面等不连续体,其中很多结构面之间具有一定黏结强度,在冲击荷载作用下会发生脱结（debond）行为,从而消耗岩体应变能。在该结构面之间的黏结性质在很大程度上决定着岩体的破坏行为,发生脱结后,结构面之间不再具有黏结强度,岩体的力学性能发生弱化。为了对该类结构面进行模拟,在改进的Xu-Needleman势函数基础上推导出结构面单元,并将其嵌入到单元劈裂法中,模拟结构面的开裂过程,当结构面完全脱结后结构面单元就转化为一般节理单元。相应地,在数值实现过程中只是将结构面单元替换为一般节理单元即可。该结构面单元与单元劈裂法相结合,能够有效地模拟节理岩体的破坏过程。 相似文献
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复合单元法动力分析初步研究 总被引：1，自引：0，他引：1
复合单元法是一种适用于不连续介质结构分析的数值计算方法,优点是建立网格时不用考虑结构中不连续面,计算时能离散模拟不连续面。在复合单元法静力计算模型的基础上,提出了复合单元的动力分析方法。给出了复合单元动力分析的质量矩阵和阻尼矩阵的具体表达式,通过质量矩阵、刚度矩阵和阻尼矩阵将分布于复合单元内部的惯性力和阻尼力分别转移到复合单元的广义节点上。建立了惯性力、阻尼力、动力荷载及弹性力作用下的复合单元动力系统的控制方程组。以一个基岩内含有两条断层的混凝土重力坝模型地震为例,采用复合单元法动力分析程序进行计算,其结果与有限单元法解吻合得较好,说明所提出方法的正确性和有效性。 相似文献
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不连续面在双重介质热-水-力三维耦合分析中的有限元数值实现 总被引：1，自引：0，他引：1
在建立双重介质热-水-力耦合微分控制方程的基础上,提出了裂隙岩体热-水-力耦合的三维力学模型,对不同介质分别建立以节点位移、水压力和温度为求解量的三维有限元格式,开发了双重介质热-水-力耦合分析的的三维有限元计算程序,在有限元数值分析中不连续面应力计算采用等厚度空间8节点节理单元进行离散,而不连续面渗流和热能计算时采用平面4节点等参单元进行离散,这样保证了不同介质之间的水量、热量交换和两类模型接触处节点水头、温度和位移相等。通过高温岩体地热开发算例,揭示了在热-水-力耦合作用下不连续面处于低应力区,其张开度随运行时间的延长呈非线性增加,非稳定渗流阶段不连续面显著地控制着渗流场的整体分布,它的水头远高于拟连续岩体介质的水头,而进入稳定渗流阶段不连续面的控渗作用不明显,由于高温岩体地热开发系统中存在大规模的热量补给,不连续面对岩体温度场分布的影响并不显著。 相似文献
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简述了复合单元法的基本原理和算法,该方法的主要优点在于可以明显地减少前处理的工作量和难度,且可以与有限单元很好地耦合在一个系统中。介绍了宝珠寺重力坝的物理模型超载试验。分别采用三维弹黏塑性复合单元法和三维弹黏塑性有限单元法对宝珠寺重力坝的超载工况进行了数值试验,并与物理试验进行比较。结果表明,三种方法得到的特征点位移吻合得较好,两种数值试验方法的整体位移和应力也基本一致。研究验证了复合单元法的正确性,也说明了该算法的主要优点：前处理简单,计算精度与有限单元法相当,同时还证实了复合单元单元法可以较好地解决复杂岩基上重力坝的变形与破坏问题。 相似文献
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三维复杂域非结构化六面体网格全自动生成方法 总被引：3，自引：0，他引：3
使用自适应有限单元法在三维复杂域内求解水工及岩土工程问题,讨论了应用行波法在多介质三维复杂块体内六面体单元网格的自动生成过程。其特点是对不规则区域具有较强的适应性,并考虑了节理单元的自动生成。 相似文献
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In this paper a coupled finite and boundary element formulation is developed for the analysis of excavation in jointed rock. The presence of joints in the rock mass has been included implicitly by treating it as an appropriate anisotropic elastic continuum. The boundary element formulation for an anisotropic medium is briefly discussed. Good agreement has been found between numerical and analytical solutions for several example problems, demonstrating the accuracy of the present formulation. Numerical solutions are also presented for the problems of a deep circular tunnel and a basement excavated in a variety of jointed rock masses. 相似文献
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利用复合单元技术,建立节理岩体喷锚支护的弹性模型。该模型可先不考虑节理、锚杆、喷层等细部结构,生成常规有限元网格,然后根据节理、锚杆、喷层的相关信息,形成复合单元网格信息。该模型可重点考虑锚杆和喷层在节理面上的局部化非线性变形与相互作用关系。算例研究验证了模型的合理性。该复合单元算法同时包含等效模拟和离散模拟的优点,有着较好的应用前景 相似文献
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Modeling strategy for jointed rock masses reinforced by rock bolts in tunneling practice 总被引：2，自引：1，他引：1
Shunsuke Sakurai 《Acta Geotechnica》2010,5(2):121-126
This paper deals with the modeling of jointed rock masses reinforced by rock bolts. It is well known that rock bolts are extremely
effective in reinforcing jointed rocks. However, if a continuum approach is adopted for modeling jointed rock masses, it is
often misleading to evaluate the effectiveness of the rock bolts by numerical analyses such as the finite element method.
This may be due to the fact that since no more joints exist in the continuum, the effectiveness of the rock bolts in constraining
the relative displacements along the joints cannot be evaluated properly. In order to investigate the reinforcement effect
of rock bolts, physical model tests were performed in the laboratory. The test results revealed that jointed rock masses should
be modeled as an equivalent continuum after the installation of rock bolts and that the mechanical parameters of the equivalent
continuum should be evaluated by considering the reinforcement effect of the rock bolts. Therefore, the values of the mechanical
parameters differ from place to place in accordance with the relation between joint orientation and rock bolt direction, even
though joint systems are homogeneous. In conclusion, in the continuum approach for modeling jointed rock masses, it should
be emphasized that rock bolts and jointed rock masses should not be modeled separately but should be modeled simultaneously
by considering the reinforcement effect of the rock bolts in constraining joint movement. The modeling of shotcrete reinforced
by steel ribs is also discussed in comparison to the modeling by rock bolts. 相似文献
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The general purpose finite element code DYNA2D is used to calculate the response of an unlined tunnel in jointed rock, with sliding interfaces used to represent the joints. The model problem selected for analysis closely follows a calculation using the discrete element code UDEC. Results for two cases [(1) jointed rock with lubricated joints (no joint friction) and (2) jointed rock with frictional resistance to joint motion] are presented and compared with each other and the UDEC results. 相似文献
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将非线性有限元分析和极限分析相结合形成强度参数折减有限元法,可以灵活地分析强度不均匀顺层路堑边坡支护结构稳定性问题。将岩体力学理论、非线性有限元分析技术和强度折减系数法相结合,对顺层岩体路堑边坡稳定性进行分析。在对密集假设节理有限元模拟中,假设节理在岩体内连续分布,采用连续介质力学方法建立密集分布节理岩体材料模型。采用强度折减系数法计算岩体结构安全系数,建议采用给定的岩体强度参数计算节理岩质边坡开挖、支护完毕后的内力,再逐渐降低岩体强度参数进行岩体边坡非线性有限元分析,直至岩体边坡达到极限状态,从而求出岩质边坡安全系数。采用该方法对渝怀铁路梅江河右岸DK409+989.4～DK410+020段顺层路堑边坡土钉墙支护结构稳定性进行分析,分析结果表明：采用土钉墙支护后的节理边坡塑安全系数为2.3,支护后的岩质边坡处于稳定状态;土钉墙潜在破裂面为岩体弹性区和塑性区的交界面,与测试得到的各排土钉拉力最大值位置一致。 相似文献
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Composite Element Model of the Fully Grouted Rock Bolt 总被引：12，自引：1，他引：12
Summary The three dimensional elasto-viscoplastic composite element method is formulated in this paper for rock masses reinforced by a fully-grouted bolt. If a bolt segment penetrates a finite element representing the rock mass, then a composite element is formed including five sub-elements corresponding to the rock material, the grout material, the bolt material, the rock-grout interface and the bolt-grout interface. The displacements in each sub-element are interpolated from the corresponding nodal displacements of the composite element. By the virtual work principle the governing equation for the solution of the nodal displacements can be formulated. The elasto-viscoplastic characteristics of the materials are considered in the formulation. The new model can be incorporated into the conventional finite element analysis grid, in which several composite elements have fully grouted bolts embedded. In this way the mesh generation of large scale bolted rock structures becomes convenient and feasible. The model has been implemented in a FEM program, and a comparative study between the numerical analysis and a pull out field test has been carried out, from which the validity and the robustness of the new model are justified. 相似文献
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节理岩体等效损伤流变模型初步研究 总被引：1，自引：0，他引：1
对节理岩体等效损伤流变模型进行了初步研究,假设岩石为各向同性体各向同性损伤,节理面的法向和切向损伤不同,分别建立了岩石和节理面流变损伤演变函数。假设材料无损,计算应力采用有效应力,推导了节理岩体等效损伤流变模型有限元计算公式,编制了相应的有限元程序。算例分析表明,采用的节理岩体等效损伤流变模型是可行的,可较好地反映节理岩体的损伤演变过程。 相似文献
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节理岩体三维偶应力弹性理论 总被引：7，自引：3，他引：7
节理的存在使得岩体的力学特性十分复杂。偶应力理论考虑了介质内颗粒尺度的影响，它以具有一定尺度的微元体为研究对象，引进了偶应力及弯曲曲率的概念，从而考虑了弯曲效应对介质变形特性的影响，可以用来解决岩土工程中的地下洞室底鼓、顶板开裂及反倾向层状岩体的弯曲倾倒等弯曲变形及弯曲破坏问题。本文考虑了节理间距的影响，对节理岩体的空间间题提出了弹性偶应力理论并建立了有限元计算模式，最后通过算例说明用偶应力理论解决上述问题的有效性。 相似文献