锚固参数对地震作用下岩质边坡锚固界面剪切作用影响的数值分析

基于FLAC~(3D)建立锚固岩质边坡数值分析模型,并用优化的cable单元建模分别模拟分析锚杆-砂浆界面上和砂浆-岩体界面上的剪切作用,通过改变全长黏结锚杆的锚固参数(锚固角、锚固段长度、锚杆竖向间距、锚杆直径、锚孔直径),对地震作用下锚固岩质边坡锚固界面上的剪应力及动力响应规律进行研究。研究发现:在地震作用下,随着锚固角的增大,锚固界面上的峰值剪应力减小,边坡永久位移增大;当锚杆在结构面两侧的长度相等时锚杆界面的锚固作用最大化;当锚杆竖向间距减小,峰值剪应力和边坡永久位移均减小;随锚杆和锚孔直径的增大,峰值剪应力和边坡永久位移总体呈减小的趋势。在考虑安全性、经济性的前提下,建议适当减小锚固角和锚杆竖向间距,保持锚杆拉拔段与锚固段长度相等,锚杆和锚孔直径保持合理的比值。该研究可为相关理论、试验研究和锚固边坡抗震设计提供参考。

Numeral analysis of anchoring parameters for bolt in rock slope anchored interface shear action under earthquake

Based on FLAC3D,building an anchored rock slope numerical model.The shear interaction on cable grout interface and grout rock interface were simulated separately by modified cable element,to study the regularities of wholly grouted anchor bar anchored interface shear stress in anchored slope and slope dynamic response under different support parameters (anchorage angle,anchoring section length,bolt spacing,diameter of anchor bar and anchor drill hole).The results of the study include the following:With the increase of anchorage angle,the anchored interface peak shear stress value decreases while the permanent displacement of slope increase.The effect of interface anchoring was optimized with the same length of bolt between both side of structural surface.With the decrease of bolt vertical spacing,the peak shear stress value and peak displacement decrease,and they decrease with the addition of diameter of anchor bar and anchor drill hole.On the premise of safety and economy,the authors suggest to decrease anchorage angle and bolt vertical spacing properly,keep the same length between drawing section and anchoring section of bolt,maintain a proper ratio between the diameter of anchor bar and anchor drill hole.The study can provide references for theoretical and experimental study on relevant aspects,and earthquake resistant design of anchored slope.