基于动力非线性的隧道式锚碇力学响应分析

发布时间：2018-04-13 06:09

本文选题：隧道式锚碇 + 非线性　；参考：《重庆交通大学》2014年硕士论文

【摘要】：随着国内经济快速发展，生产方式逐渐向环境友好型转变，可持续发展成为土木工程建设领域重要思想理念。隧道式锚碇作为悬索桥受力结构的重要部分，以其开挖量低，对环境扰动少等优点成为理想的锚碇形式。本文基于弹塑性力学和动力学非线性基础理论，运用有限元软件，以普立特大桥隧道式锚碇为原型建立三维模型，，以分析计算该结构体系的受力特征和地震动力响应，并提出抗减震措施。 1利用Ansys有限元软件的Drucker-Prager强度准则对锚区岩体进行材料定义；采用等效荷载法模拟对结构预应力；运用三维粘弹性边界理论模拟锚区半无限介质岩体边界条件，以及结合Matlab软件对输入地震波进行快速Fourier变换和滤波处理等，为仿真分析奠定了基础。 2计算普立特大桥隧道式锚碇模型静载效应，验算其常规设计荷载作用下的承载能力；分析了锚区岩体的初始应力场、锚塞体和围岩间的初始穿透、锚塞体预应力张拉以及主缆设计张拉荷载作用下锚区岩体和锚塞体的静力响应。 3对普立特大桥隧道式锚碇的地震动力响应进行分析。考虑锚区岩体在地震地面运动波作用下产生的大变形和主缆随机变化动张拉荷载下锚塞体的响应。分析锚区岩体对水平地面运动波的响应，按照目标选取6个监测点，对比分析应力时程响应，得到结果：锚区岩体的地震动力响应具有“辫梢”效应；坡顶质点的振幅大于坡底质点的振幅；锚区岩体的地震动力响应具有临空面效应等。 4地震时，从锚塞体及洞口边坡对主缆动张拉力荷载的响应方面考虑。以锚塞体底面4个角点及锚塞体前后锚面两个顶点为监测点，通过计算出来的应力及应力幅值分析，得到锚塞体前锚面质点的响应比锚塞体后锚面质点响应更强烈；洞口区域质点响应比远离洞口质点响应强烈；在约0s~4.4s及6.35s~10.65s时间段内锚塞体监测点振动强烈，锚塞体和围岩的紧密接触导致接触围岩质点塑性应变积累加剧等。 5通过锚区岩体对地震地面水平运动波的响应以及锚塞体、洞门边坡对主缆动张拉力的响应分析结果，分析锚区岩体及隧道式锚碇的稳定性，并针对研究结果对隧道式锚碇的抗减震措施进行了探讨。
[Abstract]:With the rapid development of the domestic economy, the mode of production has gradually changed to the environment-friendly type, and sustainable development has become an important ideological concept in the field of civil engineering construction.As an important part of the structure of suspension bridge, tunnel Anchorage is an ideal Anchorage form because of its low excavation quantity and less disturbance to the environment.Based on the nonlinear theory of elasto-plastic mechanics and dynamics, a three-dimensional model is established by using finite element software, which is based on the tunnel Anchorage of Puli Bridge, to analyze and calculate the mechanical characteristics and seismic dynamic response of the structure system.The anti-vibration measures are also put forward.The main contents are as follows: 1. The Drucker-Prager strength criterion of Ansys finite element software is used to define the material of rock mass in anchor area; the equivalent load method is used to simulate the prestress of structure; the boundary condition of semi-infinite medium rock mass in anchor area is simulated by using three-dimensional viscoelastic boundary theory.The fast Fourier transform and filter processing of the input seismic wave are combined with the Matlab software, which lays a foundation for the simulation analysis.(2) the static load effect of tunnel Anchorage model of Puli super bridge is calculated, and the load-carrying capacity under conventional design load is checked, and the initial stress field of rock mass in anchor area and the initial penetration between anchor plug and surrounding rock are analyzed.The static responses of the rock mass and the anchor plug in the Anchorage zone under the action of the prestressed tension of the anchor plug and the design of the main cable.The seismic dynamic response of tunnel Anchorage of Puli Bridge is analyzed.The large deformation of rock mass in anchoring area under earthquake ground motion wave and the response of anchor plug under dynamic tension load with random variation of main cable are considered.The response of rock mass in Anchorage area to horizontal ground motion wave is analyzed. Six monitoring points are selected according to the target, and the stress time history response is compared and analyzed. The results are as follows: the seismic dynamic response of rock mass in anchor area has "braided" effect;The amplitude of the mass at the top of the slope is larger than the amplitude of the particle at the bottom of the slope, and the seismic dynamic response of the rock mass in the anchor area has the effect of face to face.The response of the anchor plug and the slope of the hole to the dynamic tension load of the main cable is considered during the earthquake.Taking the four corners of the bottom surface of the anchor plug and the two vertices of the front and rear anchor face of the anchor plug as monitoring points, through the analysis of the stress and stress amplitude, it is concluded that the response of the front anchor particle of the anchor plug is stronger than the response of the anchor surface particle behind the anchor plug.The response of particle is stronger than that of far away from the hole, and the vibration of the monitoring point of anchor plug is strong in the period of 0s~4.4s and 6.35s~10.65s, and the close contact between anchor plug and surrounding rock leads to the accumulation of plastic strain in contact with surrounding rock.(5) the stability of rock mass and tunnel Anchorage in Anchorage area is analyzed through the response of rock mass in anchor area to the horizontal motion wave of earthquake ground and the response of anchor plug and portal slope to the dynamic tension of main cable, and the stability of rock mass in anchor area and tunnel Anchorage is analyzed.The anti-vibration measures of tunnel Anchorage are also discussed.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.25

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