强震论文强震条件下岩质路堑边坡与预应力锚索结构的动力相互作用机制研究.doc

强震论文：强震条件下岩质路堑边坡与预应力锚索结构的动力相互作用机制研究【中文摘要】根据对四川省内的由2008年5.12汶川8.0级地震造成的路堑边坡震害进行的调查,归纳分析了锚固边坡的震害情况。在通过室内直剪试验获得锚固体与岩体界面的抗剪强度参数的基础上,结合锚固边坡震害调查结果,对预应力锚索结构与边坡岩土体的动力相互作用机制进行了计算分析。本文的主要工作内容与结果如下：1)通过对岩质路堑边坡的震害情况的调查分析,发现采用锚固结构加固的边坡具有较好的抗震性能。2)通过直剪试验模拟了砂浆和岩石粘结面的剪切破坏过程；分析了峰值强度的影响因素及砂灰比对砂浆岩石粘结强度的影响规律,得到残余内摩擦角和残余粘聚力分别在砂灰比为0.75、0.50时取得较大值；得到砂浆与三种常见岩石的粘结强度参数。3)用拟静力法推导了平面滑动和圆弧滑动模式的边坡在水平地震作用下的预应力锚索内力的计算公式形如T=Af(kei)+B,得到随着水平地震影响系数的增加,锚索的锚拉力呈线性增长的变化特征。利用弹性理论推导了锚索锚固段剪应力分布公式及最大剪应力出现的位置与其影响因素,得到岩体越软,剪应力分布范围越大峰值越小；地震过程中锚固段未破坏时,最大剪应力位置保持不变(zmax=(?)1/b,b为与锚固体直径及变形参数有关的计算参数)；岩体泊松比越小、岩体与锚固体弹性模量比值越大,锚固段剪应力峰值位置越浅。4)利用理论分析和数值模拟方法讨论了锚固结构动力作用机制与特征,得到在地震条件下关于锚固结构和边坡的动力响应规律如下：锚固结构内力会增加,平均增加幅度约为60%,在地震过程中会加大对边坡的锚固作用；对降低坡脚处的剪应变、限制坡面位移、维护边坡稳定发挥了重要作用；锚固结构可与坡体发生很好地变形协调,改善边坡岩土体的应力状态,提高边坡中潜在滑动面或软弱结构面的抗剪强度,有利于坡体稳定。锚固结构受竖向地震作用的影响较小。就整体而言,随着岩质边坡高程的增加,水平加速度、速度、位移有垂直放大的规律；但沿坡面向上PGA放大系数呈先增大后减小规律；竖向地震作用会增大坡顶、坡脚处的剪应变,降低坡体的安全系数,但对坡体主应力、放大系数、锚固结构内力影响不大。本文在锚固边坡的震害调查、锚固结构与岩体界面抗剪强度参数、预应力锚索结构与边坡的动力相互作用分析方法及作用机制方面的研究工作,有助于进一步认识在强震条件下边坡锚固结构的力学作用特征,可为实际工程提供理论参考。【英文摘要】Based on the investigation of cutting slope damage caused by the Wenchuan 8.0 earthquake in Sichuan Province, the author mainly summarizes the anchored cutting slope earthquake damage. On the basis of getting the shear strength parameters of interface between mortar and rock through direct shear tests, and in conjunction with the results of anchored cutting slope earthquake damage investigation, dynamic interaction mechanism of cutting rock slope with prestressed anchor cable structure is calculated and analyzed. The main work content and results are as follows:1) The analysis of the cutting slope earthquake damage investigation shows that slope reinforced by anchor structure has better seismic performance.2) Through direct shear tests, simulation of the shear failure process of bonding interface between mortar and rock is carried out. Analysis of influencing factors of the peak strength and the influencing rule of sand cement ratio on shear bond strength of mortar to rock is carried out. The residual angle and the residual cohesion are greater while in the sand cement ratio of 0.75 and 0.50 respectively. Shear strength parameters of mortar to three types of rocks are obtained.3) In situations of considering the horizontal earthquake in plane and arc sliding destruction, the cable axial force formula is derived such as T=Af(kcl)+B by pseudo-static method which shows that cable axial increases linearly with the increase of horizontal seismic effect coefficient.With elastic theory, the paper deduces the anchoring section grout shear stress distribution formula and the location and influencing factors of maximum shear stress appears.The formula shows that the softer the rock is, the greater the shear stress distribution is and the smaller the peak shear stress is. The conclusion is obtained that under the earthquake anchoring section shear stress peak position remains unchanged while plasticfailure does not occur(zrmax=(?)V1/b, b is a parameter related to diameter, elastic module, and Possion ratio of anchorage section).The smaller the rock Poissons ratio is and the greater the ratio of rocks and anchoring sections elastic modulus is, the more shallow the anchoring section peak shear stress position is.4) By using the theoretical calculation and the numerical analysis method to analyze the dynamic mechanism and characteristics of anchor structure, the paper gets the dynamic responses of anchor structure and slop which are as follows:The internal force of anchor structure will increase, it increases by 60% or so in this paper example. The anchor structure plays an important role in reducing the shear strain increment at the toe of slope, limiting slope surface displacement, maintaining the stability of slope. The structure can well coordinate deformation with slope in the earthquake process, fully mobilize their own strength and steady ability of slope masses, and improve the slope masses stress state, which can be helpful to increase shear strength of potential sliding surface and weak structure plane in an earthquake. Compared to the horizontal seismic wave, corresponding vertical wave has little effect on the anchor structure.On the whole, with the increase of elevation, the amplification factor of horizontal acceleration, velocity, displacement increases. But the PGA amplification coefficient first increases, then decreases upwards along the slope surface.The vertical earthquakes will increase the shear strain at top of slope and toe of slope, reduce the safety factor of slope, but have little effect on the principal stress, amplification factor and internal force of anchor structure.In this paper, the research contains anchored slope earthquake damage investigation, shear strength parameters of bond interface between anchor structure and rock, dynamic mechanism of interaction between cutting rock slope with prestressed anchor cable structure during strong earthquakes. The research results are helpful to further understanding of the mechanical mechanism of slope with anchor structure during strong earthquakes, and can provide theoretical references for practical projects.【关键词】强震 岩质路堑边坡 预应力锚索结构 动力相互作用 放大效应 锚固段剪应力 砂浆岩石界面【英文关键词】strong earthquakes cutting rock slope prestressed anchor cable structure dynamic interaction between prestressed anchor cable and rock slope amplification effect shear stress in anchoring section interface between mortar and rock【目录】强震条件下岩质路堑边坡与预应力锚索结构的动力相互作用机制研究摘要6-7Abstract7-8第1章 绪论11-191.1 研究意义111.2 国内外研究现状11-151.2.1 地震作用下岩质边坡的动力分析11-141.2.2 竖向地震作用141.2.3 锚固边坡及锚固结构动力反应14-151.3 主要研究内容15-161.4 技术路线16-171.5 主要创新点17-19第2章 汶川地震锚固边坡动力响应特征调查19-352.1 概述19-202.2 汶川地震锚固边坡变形特征调查20-262.2.1 锚杆加固、挂网喷混凝土支护边坡变形特征20-212.2.2 锚固结构加固边坡的变形特征21-252.2.3 预应力锚索抗滑桩加固边坡变形特征25-262.3 汶川地震锚固边坡破坏特征调查26-332.3.1 锚杆加固、挂网喷混凝土支护边坡破坏特征26-292.3.2 锚固结构加固边坡的动力破坏特征29-312.3.3 采用和未采用支护的边坡的破坏特征对比31-332.4 本章小结33-35第3章 锚固体与岩体界面的参数试验35-503.1 概述353.2 试验设计35-363.2.1 试验目的353.2.2 试验内容353.2.3 试验方案35-363.3 试验过程36-413.3.1 材料准备363.3.2 试样制作36-393.3.3 试验过程及数据采集39-413.4 试验结果及分析41-473.4.1 典型的剪应力水平剪切位移曲线及分