锚杆支护边坡动力响应规律及锚固参数影响

Dynamic Response of Anchored Slopes and Influence of Anchoring Parameters

现场调查表明,锚杆支护能有效提高边坡在地震作用下的动力稳定性。通过采用拟静力法对汶川震区内锚杆支护边坡的地震稳定性进行验算后得知,边坡的动力安全系数随锚杆长度的增加而增大。利用FLAC3D分析了地震作用下锚杆支护边坡的动力响应规律以及锚固参数对边坡动力特性的影响。结果表明,锚固措施能有效抑制坡表加速度的放大作用,地震后锚杆支护边坡水平位移的最大值出现在坡顶,且锚杆的轴力较地震前也有一定程度的增大;坡面峰值加速度放大系数和最大位移随锚杆长度的增大而减小,随锚杆间距的减小而增大,锚杆倾角对边坡PGA放大系数的影响规律并不明显;根据锚杆轴力的分布特征,提出了锚杆支护边坡在地震作用下潜在滑裂面位置的确定方法。

By means of field investigation,it is shown that slope supported with anchor has good effect on resisting earthquake.The pseudo-static method was used to analyze the stability of anchored slopes in Wenchuan earthquake region,the result shows that the dynamic safety factor of slope increases with the increase of anchor length.Based on FLAC3D program,the dynamic response regularity and the influence of anchoring parameters on dynamic characteristics of anchored slope were analyzed.It is shown that（1） anchoring structures can restraining amplification of surficial acceleration,the maximum horizontal displacement occurs at the crest and anchor axial force increases after earthquake;（2） the peak displacement and the coefficient of amplification of PGA along the slope surface decrease with the increase of anchor length,while increase with increase of anchor space,but the amplification coefficient is less affected by the anchor angle;（3） according to the characters of anchor axial force,a convenient approach was presented to determine the potential sliding surface of anchored slopes under earthquake.