悬索桥重力式锚碇结构-地基联合承载机制

发布时间：2018-04-03 22:14

  本文选题：悬索桥　切入点：重力式锚碇　出处：《交通运输工程学报》2017年02期

【摘要】：基于普宣高速公路宣威岸重力式锚碇工程,设计了不回填无预应力、不回填有预应力和回填有预应力3种计算工况,利用数值仿真试验分析了重力式锚碇和地基的力学机制和破坏模式。承载机制表明:8倍设计荷载之前没有塑性变形,为弹性工作状态,最大变形在锚岩界面,摩擦效应居主导,基底拉应力区可控,锚碇结构抗滑移和抗倾覆性均处于稳定可控状态;12倍设计荷载之后塑性区逐步扩展,达到20倍设计荷载时全部贯通,基底塑性变形明显,锚碇结构变形显著,基底夹持岩体剪切破坏,夹持效应居主导,基底拉应力区不可控,锚碇结构抗滑移和抗倾覆性均处于不可控状态;锚碇施加的预应力只在结构-岩基协调变形之前起作用,之后影响不大;回填可以极大地改善基底应力状态与结构扭转变形、抗滑移和抗倾覆稳定性,可在容许变形范围内适当考虑增强效应。可见,重力式锚碇结构-地基协调变形与联合承载机制,表现为摩擦效应、夹持效应和回填效应的综合作用。监测结果显示:通过基底拉应力和压应力监控结构与地基接触面安全性,监测值小于地基容许承载力3MPa;通过基底变位和地基深部水平位移监控结构抗滑移稳定性,实际工程监测值小于1mm;通过角点不均匀沉降监控锚碇抗倾覆稳定性,倾斜值小于0.006;通过大体积混凝土温控监测可知,内部最高温度小于60℃,进出水温差小于15℃,内表温差小于20℃,峰后降温速率小于3℃·d~(-1);锚束锁固荷载监测变化幅值不超过设计值的5%。
[Abstract]:Based on the gravity Anchorage project of Xuanwei Bank of Puxuan Expressway, three calculation conditions are designed: no backfilling without prestress, no backfilling with prestress and backfilling with prestress.The mechanical mechanism and failure mode of gravity Anchorage and foundation are analyzed by numerical simulation test.The load-bearing mechanism shows that there is no plastic deformation before the design load of: 8 times, which is an elastic working state. The maximum deformation is at the interface of the anchor rock, the friction effect is dominant, and the tensile stress zone of the basement is controllable.After 12 times of design load, the plastic zone of Anchorage structure is gradually expanded after 12 times of design load in stable and controllable state. When the load reaches 20 times of design load, the plastic deformation of the base is obvious, the deformation of the Anchorage structure is obvious, and the deformation of the Anchorage structure is obvious.The shear failure of the basement clamped rock mass, the dominant clamping effect, the uncontrollable tensile stress zone of the basement, the uncontrollable anti-slip and anti-overturning properties of the Anchorage structure, and the prestress exerted by the Anchorage only act before the structure-rock foundation coordinated deformation.The backfill can greatly improve the stress state of the base and the torsional deformation of the structure, and the stability of anti-slip and anti-overturning. The reinforcement effect can be considered properly within the allowable deformation range.It can be seen that the coordinated deformation and combined bearing mechanism of gravity Anchorage structure and foundation are the combined effects of friction effect, clamping effect and backfill effect.The monitoring results show that the monitoring value is less than 3 MPa of the allowable bearing capacity of the foundation through the monitoring of the safety of the interface between the structure and the foundation by the tensile stress and compressive stress of the foundation, and the stability of the structure against sliding is monitored by the displacement of the base and the horizontal displacement of the deep foundation.The actual engineering monitoring value is less than 1mm; the anti-overturning stability of Anchorage is monitored by uneven settlement of corner point, the inclination value is less than 0.006; through the temperature control monitoring of mass concrete, the maximum internal temperature is less than 60 鈩，

本文编号：1707103