Bond Mechanical Properties of Glass Fiber Reinforced Polymer Anti-Floating Anchor in Concrete Baseplate

Combined with fiber Bragg grating(FBG)sensing technology,four glass fiber reinforced polymer(GFRP)anti-floating anchors and four steel anti-floating anchors were tested for on-site destructive failure to investigate the anchoring performance and the bonding characteristics between GFRP anti-floating anchor and concrete floor.The test results show that bending GFRP anchor will be broken at the common boundary between vertical anchorage section and bending section during the pullout process,and the spring-back load provided by the rupture contributes to a decrease of bearing capacity and an inflection point on the load-slip curve.The loaddisplacement curve of the straight anchor GFRP anti-floating anchor is smoother and has better predictability than the same type of steel anchor.Additionally,different forms of GFRP anti-floating bolt have different bondslip constitutive relations.By introducing the sliding-slip correction factor of bending bolt,constitutive models describing the rising-section of sliding-slip relation of bending and straight-anchored GFRP anti-floating bolt are established respectively.The model can fit the test results rightly.

基于数值模拟隧道仰拱开挖对初期支护的影响分析

在山岭隧道施工过程中,施作仰拱虽能很好地控制洞室位移,抑制底鼓现象发生,但隧道仰拱的开挖一般都在初期支护基本稳定之后,其开挖会使上部支护结构底角短暂悬空,底角应力释放,从而引起开挖段洞周位移的急剧增加。通过对阎家庄隧道开挖过程的实时监测,分析仰拱开挖前后拱顶下沉和净空收敛的变形量和变形速度,结合ANSYS有限元软件,分析隧道开挖前后初期支护内力的变化。仰拱的施作能使围岩内力分布更加均匀,避免应力集中,但隧道仰拱开挖引起的洞室围岩的变形约占总变形量的25%,需引起施工注意。

某项目抗浮锚杆工程设计

针对项目具体抗浮要求,充分考虑场地水文地质、工程地质条件,根据相关规范确定了抗浮锚杆设计轴向拉力值、钢筋截面面积、锚杆长度,并选取地层情况最差点对单根抗浮锚杆的抗拔力进行了验算,合理布置了抗浮锚杆,为类似的工程设计提供参考数据和积极的借鉴经验。

超高层钢结构预埋锚栓施工技术探究

以预埋锚栓为切入点,结合和谐天下一、二区项目工程实际情况,从施工流程、施工方法、预埋锚栓安装质量检查三方面,探讨了超高层钢结构预埋锚栓施工技术,以期对同类工程提供参考。