考虑横向约束作用的锚杆锚固参数优化

Optimization of Anchor Parameters Considering Lateral Restraint

为了探究锚杆不同锚固参数对顺层岩质边坡稳定性的影响,基于综合考虑锚杆轴向作用力和横向作用力的锚杆数值模型,嵌入离散元软件UDEC(universal distinct element code)中的局部加固单元LOCAL REINFORCE单元,针对某顺层岩质边坡,分析了锚杆长度、锚固角、锚杆间距和布设方式对边坡稳定性的影响,并基于正交试验提出了锚固优化方案。结果表明:锚杆存在有效长度,在有效长度内,锚杆长度和边坡安全系数存在线性关系;锚杆存在最优锚固角,且锚杆长度越大,最优锚固角越小;锚杆间距越大,边坡安全系数越小,且安全系数下降速率随间距的增大逐步减小;以边坡安全系数和锚杆用量为评价指标,通过正交试验对等长支护锚固参数进行了优化设计,得出了较佳的两个锚固试验方案;各锚固参数对边坡稳定性影响由大到小分别为:锚杆间距、锚杆长度、锚固角;锚杆布设方式对边坡稳定性的提升由大到小分别为:由长到短型、等长布置型、由短到长型。在考虑锚杆布设方式时,应使锚杆穿越的岩层与边坡位移情况相匹配。

In order to explore the influence of different anchoring parameters of anchor on the stability of bedding rock slope,based on the numerical model of anchor rod considering the axial force and lateral force,the local force element of universal distinct element code(UDEC)is embedded.For a bedding rock slope,the influence of anchor length,anchor angle,bolt spacing and layout on slope stability was analyzed.Based on the orthogonal test,the optimal anchoring scheme was proposed.The results show as follows.There is an effective length of anchor rod,and within the effective length.There is a linear relationship between the length of anchor and the safety factor of slope.There is an optimal anchor angle of anchor rod,and the larger the length of anchor rod,the smaller the optimal anchoring angle.The larger the distance between bolts,the smaller the safety factor of slope,and the decreasing rate of safety factor gradually decreases with the increase of spacing.The slope safety factor and bolt amount are used as evaluation indexes:through orthogonal test,the optimization design of anchor parameters of equal length support is carried out,and two better anchorage test schemes are obtained.The influence of anchoring parameters on slope stability from large to small are:bolt spacing,anchor length,anchor angle;the improvement of slope stability by anchor arrangement is from long to short,equal length,from short to long.When considering the layout of anchor bolts,the strata that the anchor bolts cross should be matched with the displacement of the slope.