摘要
为研究强震作用下边坡锚固系统的抗震作用及破坏特征,采用振动台模型试验,分别输入汶川波、EL-Centro波、正弦波作为地震激励,监测坡体加速度、锚杆和格构梁的应变,研究加固滑坡在强震作用下的动力响应差异以及不同位置锚杆和格构梁在地震作用下的受力特征。结果表明:强震作用下,坡脚剪切松弛区的形成导致坡脚首先进入塑性区,坡脚锚杆的承载能力受到影响,坡脚处的横梁出现拉弯变形;由于潜在滑面的存在,坡体上部土体易发生张拉破坏,坡顶首层锚杆受拉作用增强,中上部的格构梁和锚杆存在明显的不协调性,坡顶的首层横向格构梁发生拉弯变形;与横梁相比,竖梁的弯应变较小,各层的应变差值不大,与锚杆的协调性较好;建议在拟静力法设计的基础上,在锚固滑坡坡脚密集地打入短锚杆或土钉以平衡坡脚滑面处出现的不协调往复运动;加长设计坡顶的第1层锚杆,以抑制坡顶滑面处的拉张裂缝;同时在坡体顶面垂直地打入短锚杆、微型桩或种植根系发达的植物护坡,且在格构梁设计时应多考虑横梁的拉弯变形。
To investigate the seismic behavior and failure characteristics of slope anchorage system under strong earthquake, Wenchuan wave, EL-Centro wave and sinusoidal wave were regarded as the seismic excitation in the shaking table model test. The dynamic response difference of landslide under strong earthquake and mechanical behavior of anchor and lattice beam at different locations were investigated. The results show that under strong earthquake, the form of shear relaxation zone gives rise to slope toe first entering into the plastic zone. At the same time, the bearing capacity of anchors at slope toe is affected and horizontal beams at the slop toe become bended and deformed. Because of a potential sliding surface on the slope, the upper part of the slope is prone to form tensile failure area and the tension of anchors in the first column at the top of slope increases. Thus the discordance of upper lattice beams and anchors is obvious and bending deformation occurs in horizontal beams at the top of slope. The bending strains of vertical beams are lower than those of horizontal beams and the differences of bending strains in each vertical beam are not notable, in good coordination with anchors. On the basis of pseudostatic method design, it is advised that short anchors or soil nails are driven into slope toe to balance the uncoordinated reciprocating motion at sliding surface near slope toe. In order to prevent tension crack near the sliding surface, top anchors should be lengthen in design. Short anchors and micro piles are vertically driven into top surface of slope or plants with roots flourishing are cultivated to protect the slope. The stretch bending deformation of horizontal beams should be emphatically considered in design.
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2017年第5期20-27,37,共9页
China Journal of Highway and Transport
基金
国家自然科学基金项目(41440021
41102177)
中央高校基本科研业务费专项资金项目(310826175029)
关键词
道路工程
边坡锚固系统
振动台试验
压力型锚杆
抗震作用
road engineering
slope anchoring system
shaking table test
pressure-type anchor
seismic behavior
