加锚岩体力学性能的数值模拟
发布时间：2018-08-30 17:45
【摘要】：岩体中节理的存在,导致其宏观力学性能大大降低,给支护工程的设计提出了很大的挑战。锚杆锚固技术由于其安全可靠、经济实用的特点,备受工程师的青睐。该技术经过一个多世纪的发展,但是对锚杆加固的机理的系统的研究仍然缺乏。拉拔试验是加锚岩体力学试验中的基本试验,可以为今后调整锚杆的结构参数、改进锚杆的制作工艺提供参考,而剪切试验对于认识锚杆对弱面抗剪能力的加固特性,具有重要的意义。因此,本文以全长粘结式锚杆为研究对象,系统的研究加锚岩体的力学特性。本次论文采用RFPA系列软件,既考虑到了细观的破坏特点,也能模拟宏观破坏行为,同时考虑了岩体、粘结材料、锚杆三者之间的相互作用和整体联系。分别模拟加锚岩体的拉拔试验和加锚节理岩体的剪切试验,获取加锚岩体的破坏特征、极限荷载与变形参数,旨在研究不同因素水平对加锚岩体力学性能的影响,确定锚杆的极限承载能力,揭示锚杆内力传递规律与加固机制。本文首先开展锚杆的拉拔试验,与经典的Phillips理论进行结合,并与其他学者的物理实验进行验证对比,验证数值模型的可行性,然后根据已有的全长粘接式锚杆的拉拔物理试验,设计了相应的数值正交试验,对数值模拟结果进行整体性的数理统计分析,并与物理试验结果进行比对,研究了抗拔力与岩石弹模、锚杆埋深的关系,总结了锚固岩体的破坏形式和特点。在单根锚杆的拉伸试验基础上,进一步模拟了锚杆间距间的影响和群锚效应对破坏效果的影响,系统研究了群锚结构在拉拔和剪切作用下的力学性能,揭示出其与单锚结构的不同特点。在剪切试验中,本文主要验证加锚节理岩体抗剪性能的增强机制,探讨加锚注浆节理面的抗剪性能,揭示锚杆倾角对加锚注浆节理岩体抗剪性能的影响规律,总结锚杆倾角与加锚起伏节理面抗剪性能的关系。研究结果表明：节理岩体的抗剪强度可以通过锚固的方式得以加强；较小的锚杆倾角具有较大的抗剪能力,而这种提高是牺牲锚杆抗拔能力获得的,具有一定局限性；当起伏角为17°的起伏节理面时,锚杆倾角α=45°时试样的抗剪效果最好；为了提高岩体的综合抗剪能力,可以采用增加节理单位面积内的锚杆数或者在节理面注入水泥砂浆的方法。本文的研究结果,不仅有助于了解加锚岩体的力学性能,也可以为设计可靠有效的岩体锚固方案,提供有力的试验数据和理论基础。
[Abstract]:Because of the existence of joints in rock mass, the macroscopic mechanical properties of rock mass are greatly reduced, which poses a great challenge to the design of supporting engineering. Anchorage technology is favored by engineers because of its safe, reliable, economical and practical characteristics. The technology has been developed for more than a century, but the systematic research on the mechanism of anchor reinforcement is still lacking. Drawing test is the basic test in mechanical test of bolted rock mass, which can provide a reference for adjusting the structural parameters of anchor rod and improving the manufacture technology of anchor rod in the future. It is of great significance. Therefore, the mechanical properties of bolted rock mass are systematically studied in this paper. In this paper, RFPA series software is used, which not only takes into account the characteristics of mesoscopic failure, but also simulates the macroscopic failure behavior. At the same time, the interaction and the whole relation among rock mass, bond material and anchor rod are considered. The tensile test of anchored rock mass and shear test of anchored jointed rock mass are simulated respectively to obtain the failure characteristics, ultimate load and deformation parameters of anchored rock mass. The purpose of this paper is to study the influence of different factor levels on mechanical properties of anchored rock mass. Determine the ultimate bearing capacity of anchor, reveal the law of internal force transfer and reinforcement mechanism. In this paper, the drawing test of anchor rod is first carried out, combined with the classical Phillips theory, and compared with the physical experiments of other scholars to verify the feasibility of the numerical model, and then according to the physical test of the full-length adhesive anchor rod, The corresponding numerical orthogonal test is designed, and the numerical simulation results are analyzed and compared with the physical test results. The relationship between the pull-out force and the elastic modulus of rock and the buried depth of the anchor rod is studied. The failure forms and characteristics of anchoring rock mass are summarized. Based on the tensile test of single anchor rod, the influence of the spacing between anchors and the effect of group anchor effect on the failure effect is further simulated, and the mechanical properties of the group anchor structure under the action of drawing and shearing are systematically studied. The difference between the structure and the single anchor structure is revealed. In the shear test, this paper mainly verifies the strengthening mechanism of the shear resistance of the anchored jointed rock mass, discusses the shear behavior of the bolted grouting joint plane, and reveals the influence law of the anchor inclination angle on the shear property of the bolted grouting jointed rock mass. The relationship between Anchorage angle and shear resistance of Anchorage undulating joint is summarized. The results show that the shear strength of jointed rock mass can be strengthened by the way of anchoring, and that the small inclination angle of anchor rod has larger shear resistance ability, and this increase is obtained by sacrificing the pulling ability of anchor rod, and has some limitations, and the results show that the shear strength of jointed rock mass can be strengthened by means of anchoring. When the fluctuation angle is 17 掳, the shear effect of the specimen is the best when the Anchorage angle is 45 掳. In order to improve the comprehensive shear resistance of rock mass, the method of increasing the number of anchors in the joint unit area or injecting cement mortar into the joint surface can be adopted. The results of this paper not only help to understand the mechanical properties of anchored rock mass, but also provide a strong experimental data and theoretical basis for the design of reliable and effective rock mass anchoring scheme.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45
本文编号：2213809
[Abstract]:Because of the existence of joints in rock mass, the macroscopic mechanical properties of rock mass are greatly reduced, which poses a great challenge to the design of supporting engineering. Anchorage technology is favored by engineers because of its safe, reliable, economical and practical characteristics. The technology has been developed for more than a century, but the systematic research on the mechanism of anchor reinforcement is still lacking. Drawing test is the basic test in mechanical test of bolted rock mass, which can provide a reference for adjusting the structural parameters of anchor rod and improving the manufacture technology of anchor rod in the future. It is of great significance. Therefore, the mechanical properties of bolted rock mass are systematically studied in this paper. In this paper, RFPA series software is used, which not only takes into account the characteristics of mesoscopic failure, but also simulates the macroscopic failure behavior. At the same time, the interaction and the whole relation among rock mass, bond material and anchor rod are considered. The tensile test of anchored rock mass and shear test of anchored jointed rock mass are simulated respectively to obtain the failure characteristics, ultimate load and deformation parameters of anchored rock mass. The purpose of this paper is to study the influence of different factor levels on mechanical properties of anchored rock mass. Determine the ultimate bearing capacity of anchor, reveal the law of internal force transfer and reinforcement mechanism. In this paper, the drawing test of anchor rod is first carried out, combined with the classical Phillips theory, and compared with the physical experiments of other scholars to verify the feasibility of the numerical model, and then according to the physical test of the full-length adhesive anchor rod, The corresponding numerical orthogonal test is designed, and the numerical simulation results are analyzed and compared with the physical test results. The relationship between the pull-out force and the elastic modulus of rock and the buried depth of the anchor rod is studied. The failure forms and characteristics of anchoring rock mass are summarized. Based on the tensile test of single anchor rod, the influence of the spacing between anchors and the effect of group anchor effect on the failure effect is further simulated, and the mechanical properties of the group anchor structure under the action of drawing and shearing are systematically studied. The difference between the structure and the single anchor structure is revealed. In the shear test, this paper mainly verifies the strengthening mechanism of the shear resistance of the anchored jointed rock mass, discusses the shear behavior of the bolted grouting joint plane, and reveals the influence law of the anchor inclination angle on the shear property of the bolted grouting jointed rock mass. The relationship between Anchorage angle and shear resistance of Anchorage undulating joint is summarized. The results show that the shear strength of jointed rock mass can be strengthened by the way of anchoring, and that the small inclination angle of anchor rod has larger shear resistance ability, and this increase is obtained by sacrificing the pulling ability of anchor rod, and has some limitations, and the results show that the shear strength of jointed rock mass can be strengthened by means of anchoring. When the fluctuation angle is 17 掳, the shear effect of the specimen is the best when the Anchorage angle is 45 掳. In order to improve the comprehensive shear resistance of rock mass, the method of increasing the number of anchors in the joint unit area or injecting cement mortar into the joint surface can be adopted. The results of this paper not only help to understand the mechanical properties of anchored rock mass, but also provide a strong experimental data and theoretical basis for the design of reliable and effective rock mass anchoring scheme.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45
【参考文献】
相关期刊论文 前2条
1 唐春安,赵文;岩石破裂全过程分析软件系统RFPA~(2D)[J];岩石力学与工程学报;1997年05期
2 杨松林,朱焕春,刘祖德;加锚层状岩体的本构模型[J];岩土工程学报;2001年04期
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