IMHE OpenIR  > 山地灾害与地表过程重点实验室
无框架地锚体系加固边坡的受力机制及其稳定性分析
Alternative TitleLoaded Mechanism and Stability Analysis of Slopes Reinforced by Non-frame Anchor System
孙长宁
Subtype博士
Thesis Advisor苏立君
2018
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline岩土工程
Keyword边坡 无框架地锚 受力机制 稳定性 极限分析
Abstract随着我国经济建设的迅猛发展,建筑、公路、铁路、水电、矿山等基础设施大量修建,特别在丘陵和山区建设中,边坡问题尤为突出。传统的加固结构,如锚喷支护、框架预应力锚索结构、挡土墙、抗滑桩及桩锚支护结构等,在边坡工程中得到广泛应用。然而,许多边坡坡面植被(如树木)茂密,传统边坡加固结构施工困难,并且会造成植被破坏,与目前的环境保护焦点问题背道而驰。植被根系对边坡有一定的加固作用,但其加固深度有限。因此,如何在尽量保护边坡坡面现有植被的条件下,对工程边坡或自然边坡进行加固是一个亟待解决的问题。针对上述问题,论文介绍了一种无框架地锚结构体系,其特点是可以结合坡面植被(如树木)分布情况自由布置进行边坡加固,不破坏现有植被,并且不需要大型机械施工,施工方便简单。目前,在无框架地锚体系的相关文献中,已经进行了大量的物理模型试验,但其对应的设计分析理论仍存在不足之处。例如,锚杆的受力机制分析没有考虑锚杆与边坡岩土体的相互作用,并且不同工况或不同体系设计参数情况下的边坡稳定性分析仍需进一步研究。论文基于弹性地基梁理论、极限分析理论和数值分析技术等,并结合现有相关的物理模型试验,对无框架地锚体系加固边坡的受力机制及其稳定性进行深入研究,内容包括无框架地锚体系工作原理分析、剪切位移作用下体系中锚杆的受力机制分析、地震作用下加锚边坡稳定性分析以及无框架地锚体系设计参数对边坡稳定性和钢索内力的影响分析等,并取得如下成果和结论:(1)系统分析了无框架地锚体系的工作原理,如结构特点、结构形式和适用性,划分了三种无框架地锚体系加固边坡的破坏模式,并结合无框架地锚体系的特点,提出了一种新型路堑边坡复合支护结构。(2)考虑锚杆与边坡岩土体的相互作用,以及锚杆锚头处的约束情况,建立了剪切位移作用下无框架地锚体系中锚杆的力学模型。考虑锚杆周围介质的变形能力,将其分为弹性变形段和塑性变形段。基于Winkler假定和锚杆荷载传递机理,分别对边坡岩土体与锚杆横向和轴向的相互作用机制进行理论分析,并通过模型试验和数值模拟对该力学模型进行了验证。在此基础上,考虑锚杆周围岩土体的力学性质、锚杆材料特性和锚杆与滑面的夹角等影响因素,分析了锚杆在顺层岩质边坡中的受力机制。考虑到传统钢筋锚杆耐久性差的缺陷,引入GFRP锚杆,并讨论了GFRP锚杆加固顺层岩质边坡的适用性。(3)考虑地震作用和锚杆支护作用,基于极限分析上限法,结合岩土体服从相关联或非关联流动法则的不同情况,建立了适用于含任意形状滑面的边坡动力稳定性分析计算模型,从而进一步完善了地震工况下无框架地锚体系加固边坡的稳定性分析理论。考虑边坡沿折线型滑面滑动的破坏机制,将边坡滑体按照折线滑面离散为多个块体单元,根据位移协调条件,相邻块体单元移动不能发生重叠或分离,构建边坡滑体的速度场。在此基础上,计算滑体自重、地震作用所做的外力功率,以及滑体底部滑面、侧向接触面和锚杆作用产生的内能耗散,进而推导了边坡安全系数、屈服地震加速度和永久位移的表达式,并通过五个算例验证了不同流动法则下该计算模型的可行性。此外,还对岩土体服从不同流动法则时对边坡动力稳定性的影响进行了研究,并分析了非关联流动法则下剪胀角对加锚边坡动力稳定性的影响。结果表明:与相关联流动法则下的计算结果对比,非关联流动法则下计算得到的屈服地震速度偏小,相应的边坡永久位移偏大。在非关联流动法则下,随着岩土体剪胀角增大,边坡屈服地震加速度变大,永久位移减小。(4)考虑边坡坡脚局部开挖情况,采用无框架地锚结构体系加固边坡,利用有限差分软件FLAC3D分析了体系设计参数对边坡稳定性和结构体系中钢索内力的影响。其中,体系设计参数包括:体系平面布置形式、钢索预应力、锚杆倾角、锚杆有效长度、锚杆直径以及锚杆间距等。(5)根据本文研究结果,对无框架地锚结构体系的相关设计计算理论进行补充完善,并对体系设计参数的取值提出相应建议。此外,探讨了无框架地锚体系加固边坡的关键施工技术,如结构体系施工流程、关键部位施工、防腐和后期监测管理。 
Other AbstractWith the rapid development of China's economic construction, many infrastructures have been constructed, such as building, highway, railway, hydropower and mining, etc. Therefore, slope problem is particularly prominent in the construction of hills and mountains. Traditional reinforced structures, such as anchor bolts, frame structure with prestressed anchor cable, retaining wall and anti-slide pile, etc., were widely used in slope engineering. However, the vegetation in the slope surface may be thick in most cases. For traditional reinforcement structure, the construction is difficult and will cause the vegetation destruction, which disobeys the principle of environmental protection. Roots of vegetation have a certain reinforcement effect on slopes, but its reinforcement depth is limited. Therefore, how to reinforce the engineering slope or natural slope under the conditions of protecting the existing vegetations is a problem to be solved. For the above problems, this paper introduces a kind of non-frame anchor structure system. And it can be arranged combined with slope vegetation distribution without destruction of the existing vegetation and requirement of large mechanical construction. Besides, its construction is convenient and simple. In the existing literature about non-frame anchor system, a lot of physical model tests have been conducted. However, for the corresponding design analysis theory, there are still many disadvantages. For examples, the loaded mechanism analysis of the anchor bolt does not take into account the interaction between the anchor bolt and rock mass. And the slope stability analysis needs to be further studied considering the different case of the operating mode or system design parameters.In this paper, the loaded mechanism and stability analysis of slope reinforced by non-frame anchor system was studied based on the elastic beam theory, limit analysis theory and numerical analysis techniques, etc. The research contents include the working principle analysis of non-frame anchor system, mechanism analysis of the anchor bolt in the system under the action of shear displacement, slope stability analysis under the action of earthquake and sensitivity analysis of design parameters for non-frame anchor system, etc. And the research results and conclusions are shown as followed.(1) The working principles of non-frame anchor system, such as structure characteristics, structure form and applicability, etc., were analyzed systematically. The failure mode of slope reinforced by non-frame anchor system is divided into three kinds of cases. Combining with the characteristics of non-frame anchor system, a new type of cutting slope composite supporting structure is put forward. (2) Considering the interaction between anchor bolt and surrounding medium and the constraint condition of anchor head, the mechanics model of anchor bolt under the action of shear displacement is established. According to the deformation ability of material around the anchor bolt, it can be divided into elastic deformation and plastic deformation. Based on the Winkler assumption and load transfer mechanism of anchor bolt, the interaction mechanism between rock mass and anchor bolt is analyzed. The mechanics model is verified through the existing model test and numerical simulation. On this basis, considering the influencing factors, such as mechanics properties of rock mass around the anchor bolt, materials characteristics of anchor bolt and the angle between the anchor bolt and slip surface, etc., the loaded mechanism of the anchor bolt reinforcing the bedding rock slope is analyzed. Besides, considering the poor durability of steel anchor bolt, the GFRP anchor bolt was introduced. And the applicability of the GFRP anchor bolt reinforcing the bedding rock slope is also discussed.(3) A computational model for the seismic stability analysis of slope is presented based on the upper bound limit analysis method considering the effect of anchor bolts. The model is suitable for arbitrary shape of slip surface and discusses two cases, which is that the soil or rock is deemed to follow the associated flow rule or non-associated flow rule. The slope is divided into multiple block elements along the broken-line slip surface. On the basis of the displacement compatibility, a kinematic velocity field of slope can be obtained computationally. The proposed model allows not only calculation of the rate of external work owing to the combined effect of self-weight and seismic loading, but also analysis of the energy dissipation rate caused by slip surface, interfaces of block elements and anchorage effect of the anchors. Considering a direct relationship between the rate of external work and the energy dissipation rate, the factor of safe, yield acceleration and permanent displacement of the anchored slope can be calculated. Finally, the validity of this proposed model is illustrated by investigating five typical slopes. Besides, the influence of obeying different flow rule for rock and soil mass on the slope dynamic stability are studied, and the effect of the different dilatancy angle on the of dynamic stability of the anchored slope was analyzed under non-associated flow rule. It is concluded that compared with the results under the associated flow rule, the yield acceleration based on the proposed model is smaller and the corresponding permanent displacement is larger. As the increasing dilatancy angle under non-associated flow rule, the yield acceleration become bigger and permanent displacement is smaller.(4) Considering the partial excavation situation in the slope foot, the slope is reinforced by non-frame anchor system. On this basis, the effect of the different system design parameters on the slope stability and cable force in the structural system is analyzed by using the finite difference software FLAC3D. The system design parameters include layout form of system, prestress of wire, anchor angle, anchor length, anchor diameter and space of anchor bolts, etc.(5) According to the research results, some suggestions on the design analysis of non-frame anchor system are put forward. And the key technology of construction of non-frame anchor system is discussed, such as the process of structure construction, the construction of key parts, corrosion protection and monitoring management. 
Pages144
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24774
Collection山地灾害与地表过程重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
孙长宁. 无框架地锚体系加固边坡的受力机制及其稳定性分析[D]. 北京. 中国科学院大学,2018.
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