地下厂房岩锚梁接触面非线性有限元模拟方法

发布时间：2018-11-14 11:53

【摘要】：地下厂房岩锚梁接触面是岩锚梁整体结构薄弱环节,建立合理的接触面模拟方法是岩锚梁有限元数值分析的重要内容。针对地下厂房岩锚梁与围岩接触问题,分别构建模拟岩锚梁与围岩接触面非线性特征的有限元数学模型和力学模型。在Desai薄层单元基础上,推导岩锚梁接触面单元有限元数学模型,该数学模型形式简单,便于有限元计算;结合非线性弹性理论和弹塑性理论,提出岩锚梁接触面3维非线性力学模型,该力学模型能够模拟岩锚梁接触面弹性阶段的非线性现象和塑性阶段的损伤软化现象。针对岩锚梁接触面闭合、张开、剪切滑动等变形特征,提出考虑接触面黏结、开裂、滑移现象的分段式抗滑安全系数。详细论述了所提模型的有限元实现方法,并据此编写了有限元程序。将本文模型应用于某地下厂房岩锚梁有限元分析计算中,与接触面等效连续模型相比,所提模型计算得到的岩锚梁梁体应力稍小,荷载更多的是由长锚杆承担,梁体的整体变形量增加了2~3 mm,说明接触面的存在使得岩锚梁整体稳定性降低,岩锚梁接触面处的安全系数也稍小,局部出现拉裂损伤,与实际工程岩锚梁接触面开裂现象相吻合,说明所提模型能够合理反映岩锚梁接触面非线性接触特征。为地下厂房岩锚梁稳定分析提供了一种有效的有限元分析方法。
[Abstract]:The contact surface of rock anchor beam in underground powerhouse is a weak link in the whole structure of rock anchor beam. It is an important content of finite element numerical analysis of rock anchor beam to establish a reasonable contact surface simulation method. Aiming at the problem of contact between rock anchor beam and surrounding rock in underground powerhouse, the finite element mathematical model and mechanical model are constructed to simulate the nonlinear characteristics of rock anchor beam and surrounding rock contact. On the basis of Desai thin layer element, the finite element mathematical model of contact surface element of rock anchor beam is derived. The mathematical model is simple and convenient for finite element calculation. Combined with nonlinear elastic theory and elastic-plastic theory, a three-dimensional nonlinear mechanical model of rock anchor beam interface is proposed. The model can simulate the nonlinear phenomena in the elastic stage and the damage softening phenomenon in the plastic stage of the rock anchor beam interface. In view of the deformation characteristics of rock anchor beam such as closing, opening and shearing sliding, a segmental safety factor of anti-slip is put forward considering the phenomena of joint bonding, cracking and sliding. The finite element method of the proposed model is discussed in detail, and the finite element program is compiled accordingly. The model is applied to the finite element analysis of rock anchor beam in an underground powerhouse. Compared with the equivalent continuous model of contact surface, the stress of rock anchor beam calculated by the proposed model is slightly smaller, and the load is more borne by long anchor rod. The total deformation of the beam is increased by 2 ~ 3 mm, which indicates that the existence of the contact surface reduces the overall stability of the rock anchor beam, and the safety factor at the contact surface of the rock anchor beam is also slightly smaller, and the local tensile damage occurs. It is consistent with the cracking phenomenon of rock anchor beam contact surface in actual engineering, which shows that the proposed model can reasonably reflect the nonlinear contact characteristics of rock anchor beam contact surface. An effective finite element analysis method is provided for the stability analysis of rock anchor beam in underground powerhouse.
【作者单位】：武汉大学水资源与水电工程科学国家重点实验室;武汉大学水工岩石力学教育部重点实验室;中国电建成都勘测设计研究院有限公司;
【基金】：国家重点基础研究发展计划资助项目(2015CB057904) 国家自然科学基金资助项目(91215301;51279136) 教育部博士点基金资助项目(20130141110015)
【分类号】：TV223;TV731.6

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