高烈度地震区锚索抗滑桩加固边坡的应用与优化研究

发布时间：2018-04-04 05:49

本文选题：抗滑桩　切入点：地震　出处：《兰州交通大学》2017年硕士论文

【摘要】：我国是一个多丘陵、多山地、地形地貌复杂多样、山脉起伏较大的国家,山地丘陵约占全国土地总面积的43%。同时,它又是大陆地震最集中,活动性最高的国家之一。因而,研究地震作用下支挡结构的抗震性能具有重要意义。预应力锚索抗滑桩作为一种新型组合支挡结构,由于其良好的受力模式和抗滑特性,在工程中到了广泛的应用。但是,目前相对于其工程应用,理论研究,尤其对于单锚索抗滑桩的动力特性以及锚索抗滑桩抗震性能优化方面的研究报道明显滞后。为此,本文开展大型振动台对比试验,采用混合加载方式,初步研究了在地震作用下单锚点与多锚点锚索抗滑桩的动力特性及加固边坡的变形破坏模式。通过数值模拟,研究了不同向加载时,同一动峰值作用下锚索抗滑桩加固边坡的位移变形特点。最后,为解决实际过程中的锚头失效现象和提高锚索抗滑桩的抗震性能,结合我国抗震设计相关规范,以及结构抗震方面的参考文献、工程实例,对锚索抗滑桩抗震性能提出优化,提出了抗震型锚索抗滑桩,并开震振动台对比试验,研究了其优化效果研究内容和成果:(1)试验1试验现象表明,振动作用下滑体并不一定沿软弱滑面破坏;坡体坡面的破坏形式为张拉和剪切的复合破坏。且多锚点锚索抗滑桩加固的边坡位移较小,有利于控制坡体的进一步变形。(2)从震后桩头水平倾角和水平位移来看,多锚点锚索抗滑桩震后桩头水平倾角和水平位移较小;(3)输入的EI-Centro波动峰值加速度越大,锚索抗滑桩的动土压力峰值越大。从动土压力分布曲线来看,多锚点锚索抗滑桩在滑面处动土压力值较小。(4)数值模拟结果表明,锚索抗滑桩加固边坡在加载方式上具有以下特征:Z向加载,坡体后缘位移较大,具有明显的高程效应;X向加载,滑面处及以部位下位移较大。双向加载时,坡体的变形比单向加载要大。随着动峰值加速度的增大,Z向振动效应不断增强,且在坡体变形破坏中发挥的作用越加显著。(5)振动台试验2的震后桩头水平倾角表明,在锚索抗滑桩锚头与桩间设置柔性缓冲层可在一定程度上缓解锚头失效问题。(6)试验结果表明:桩后设置EPS材料可以减小受力侧动土压力,且其缓冲消能效果跟输入的动峰值加速度相关,输入的动峰值加速度越大,缓冲消能效果减弱。当输入的动峰值加速度小于0.6g时优化后的锚索抗滑桩抗震性能更好,动土压力峰值明显减小,降幅约为50%。(7)通过试验现象及实测结果分析得出,上述优化措施是行之有效的,可以为高烈度地震区锚索抗滑桩设计提供参考。但由于EPS材料刚度较小,实际工程应用中有待进一步研究。
[Abstract]:China is a hilly and mountainous country with complicated landforms and undulating mountains. The hilly areas account for about 43% of the total land area in China.At the same time, it is one of the most concentrated and active countries in the continent.Therefore, it is of great significance to study the seismic behavior of retaining structures under earthquake.As a new type of composite retaining structure, prestressed anchor cable anti-slide pile has been widely used in engineering because of its good stress mode and anti-slide characteristics.However, compared with its engineering application, the theoretical research, especially the research on the dynamic characteristics of single anchor cable anti-slide pile and the seismic performance optimization of anchor cable anti-slide pile, is obviously lagging behind.In this paper, a comparative test of large shaking table is carried out, and the dynamic characteristics and deformation failure mode of anti-slide pile with order anchor point and multi-anchor cable under earthquake action are preliminarily studied by using mixed loading method.Through numerical simulation, the displacement and deformation characteristics of the slope strengthened by anchor cable anti-slide pile under the same dynamic peak load are studied.Finally, in order to solve the failure phenomenon of anchor head in the actual process and improve the seismic performance of anchor cable anti-slide pile, combined with the relevant codes for seismic design of our country, as well as the reference of seismic structure, engineering examples,The aseismic performance of anchor cable anti-slide pile is optimized, the anti-slide pile with anti-seismic cable is put forward, and the contrast test of shaking table is carried out. The research contents and results of the research on optimization effect and the result of test 1 show that,The failure of sliding body under vibration is not necessarily along the weak slip surface, but the failure form of slope surface is the composite failure of tensioning and shearing.And the slope displacement strengthened by multi-anchor anchor cable anti-slide pile is smaller, which is helpful to control the further deformation of slope body.) from the angle of horizontal inclination and horizontal displacement of pile head after earthquake,The larger the peak acceleration of EI-Centro wave wave input from the horizontal dip angle and horizontal displacement of pile head after earthquake, the greater the dynamic earth pressure of anchor cable anti-slide pile.From the point of view of the dynamic earth pressure distribution curve, the numerical simulation results show that the slope strengthened by anchor cable anti-slide pile has the following characteristics: Z direction loading, large displacement of the back edge of the slope, and small dynamic earth pressure value of the multi-anchor cable anti-slide pile on the sliding surface.There is obvious height effect in X direction loading, and the displacement is larger at the slip surface and under the position.Under bidirectional loading, the deformation of slope is larger than that of unidirectional loading.With the increase of the dynamic peak acceleration, the effect of Z direction vibration is increasing, and the effect on the deformation and failure of slope body is more and more significant. The horizontal inclination angle of post earthquake pile head in shaking table test 2 shows that,The test results show that the installation of flexible buffer layer between anchor head and pile can alleviate the failure problem of anchor head to some extent. The test results show that the dynamic earth pressure on the side of the pile can be reduced by setting EPS material behind the pile.The effect of buffering energy dissipation is related to the dynamic peak acceleration of input. The larger the dynamic peak acceleration of input is, the weaker the effect of buffer energy dissipation is.When the input dynamic peak acceleration is less than 0.6 g, the seismic performance of the optimized anchor cable anti-slide pile is better, and the peak value of the dynamic earth pressure is obviously reduced, the drop is about 50. 7) through the analysis of the experimental phenomena and the measured results, it is concluded that the above optimization measures are effective.It can provide reference for the design of anchor cable anti-slide pile in high intensity seismic area.However, due to the small stiffness of EPS materials, further research is needed in practical engineering applications.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU472

【参考文献】