边坡框架锚杆锚固系统力学行为及特性研究

发布时间：2018-06-14 08:14

本文选题：锚杆锚固系统 + 坡面框架格梁　；参考：《兰州大学》2014年博士论文

【摘要】：历次地震震害调查表明,边坡框架锚杆支护技术具有良好的抗震性能,然而,目前边坡框架锚杆锚固系统力学行为及特性研究,尤其是其动力领域极不成熟,严重滞后于工程应用,开展此项研究,对边坡锚固工程科学设计与安全评价均具有重要理论和工程实践意义。鉴于此,本文采用理论分析、数值模拟与工程资料对比验证等技术手段,在弄清边坡锚固系统锚杆静载拉拔受力机制的基础上,着重研究边坡锚固系统锚杆自由振动、锚杆共振效应、锚杆受迫振动、锚杆动力固坡效应以及坡面框架格梁受迫振动特性等。通过系统分析,得到以下几点认识：根据界面二阶段黏滑本构模型假定,推导了锚杆拉拔临界松动荷载理论公式、锚杆拉拔荷载与松动长度内在关系表达式；依据界面抗剪强度与残余强度之间大小关系,将锚杆拉拔松动破坏类型划分为渐进式和突发式两种类型,并给出了破坏类型定量判别标准及其所对应的锚杆拉拔极限荷载理论解；同时,以此为基础,给出了层状地层锚杆、缺陷锚杆锚固迭代计算方法与求解步骤,并开展此两种复杂情形下锚杆拉拔力学行为及特性分析。基于一定假定,建立了边坡锚固系统锚杆自由振动力学模型,给出了锚固系统自由振动控制方程及其边界条件；分别推导了无阻尼和有阻尼情形下有关系统固有频率或特征参数、振型理论计算公式；结合锚固工程抗震设防要求,给出了确定场地锚固工程危险区域与共振锚杆设计图谱的计算方法；同时,通过参数灵敏度分析,进一步揭示了影响锚固系统无阻尼固有频率和有阻尼特征参数的主要因素及其内在规律。基于锚杆微段动力受力分析,给出了锚固系统锚杆受迫振动动力平衡方程；分别推导了无阻尼和有阻尼情形锚杆简谐受迫振动力学响应理论解,同时还建立了锚杆受迫振动响应具体的有限差分格式,并结合MATLAB编程技术使其程序化,通过算例,相互验证方法的可行性与正确性,并指出了各方法的优劣及锚固系统锚杆受迫振动力学响应分析计算方法的选取原则；通过算例分析,揭示了在水平地震荷载作用下锚杆动力响应规律。通过FLAC数值模拟,在重新审视地震边坡岩土体变形破坏机制的基础上,通过不同工况下地震边坡位移场、应力场及典型单元应力状态的对比分析,进行了地震边坡加锚效应分析；同时,通过锚杆动力固坡效应参数影响分析,提出了一些指导边坡锚固工程抗震设计的参考建议。基于一定假定,建立了坡面框架格梁支护结构动力力学模型,推导了框架竖梁受迫振动动力平衡控制方程；获得了锚固系统无阻尼和有阻尼情形竖梁简谐受迫振动动力力学响应理论解析解；同时,根据有限差分原理,建立了框架竖梁受迫振动响应具体的有限差分格式及其计算流程,并采用MATLAB编程技术使其程序化；通过算例相互验证方法的可行性与正确性,并指出了各方法的计算特点；通过算例分析,揭示了在水平地震荷载作用下竖梁动力响应规律。
[Abstract]:The seismic damage investigation shows that the slope frame anchor bolt support technology has good seismic performance , however , the mechanical behavior and characteristics of the anchor rod anchoring system in the present slope frame , especially its power field , is extremely immature , which lags behind the engineering application seriously , and carries out the research , and has important theoretical and practical significance for the scientific design and safety evaluation of the slope anchoring engineering .

Based on the theory analysis , numerical simulation and comparative validation of engineering data , this paper focuses on the study of free vibration of anchor rod of slope anchoring system , the resonance effect of anchor rod , the forced vibration of anchor rod , the dynamic slope effect of anchor rod and the forced vibration characteristics of slope surface frame lattice beam .

Based on the assumption of the interface two - phase slip constitutive model , the theoretical formula of the critical loose load of the anchor rod is deduced , and the relationship expression between the pull - out load and the loose length of the anchor rod is deduced .
According to the relationship between shear strength and residual strength of the interface , the types of fracture types are divided into progressive and burst types , and the criterion of damage type and the theoretical solution of the ultimate load of anchor rod are given .
At the same time , on the basis of this , the iterative calculation method and the solution procedure of the anchor bolt and the anchor of the defective anchor rod are given , and the mechanical behavior and characteristic analysis of the anchor bolt are carried out under the two complex situations .

Based on the assumption , the mechanical model of free vibration of anchor rod of slope anchoring system is established , and the control equation of free vibration of anchorage system and its boundary conditions are given .
The natural frequency or characteristic parameters of the system under the condition of undamped and damping are derived respectively , and the formula of vibration mode is calculated .
Combined with the seismic fortification requirements of anchorage engineering , a calculation method for determining the dangerous area of site anchoring project and the design map of resonance anchor rod is given .
At the same time , through the analysis of the sensitivity of the parameters , the main factors and the inherent law of the undamped natural frequency and damping characteristic parameters of the anchorage system are further revealed .

Based on the analysis of dynamic force of anchor bolt micro - section , the dynamic equilibrium equation of anchor system anchor rod is given .
In this paper , the mechanical response theory of undamped and damped bolt is deduced , and the specific finite difference scheme is also established . The feasibility and validity of the method are verified by using MATLAB programming technique , and the selection principles of the method are pointed out .
By means of an example analysis , the dynamic response law of the anchor rod under the action of horizontal seismic load is revealed .

Based on the simulation of FLAC numerical simulation , based on the re - examination of the deformation and failure mechanism of the rock and soil body of the seismic slope , the seismic slope and anchor effect analysis is carried out by comparing the displacement field , the stress field and the stress state of the typical unit under different working conditions .
At the same time , some reference suggestions to guide the anti - seismic design of slope anchoring engineering are put forward by analyzing the influence of the dynamic slope effect parameters of the anchor rod .

Based on the assumption , the dynamic mechanical model of grid beam supporting structure is established , and the dynamic balance control equation of the frame vertical beam is deduced .
The analytical solution of the dynamic mechanical response of the vertical beam with no damping and damping in the anchorage system is obtained .
At the same time , according to the finite difference principle , the finite difference scheme of the frame vertical beam forced vibration response and its calculation flow are established , and the program is programmed by MATLAB programming technique .
The feasibility and validity of the mutual verification method are verified , and the calculation characteristics of each method are pointed out .
Through an example analysis , the dynamic response law of the vertical beam under the action of horizontal seismic load is revealed .
【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU476

【参考文献】