抗浮锚杆极限荷载现场试验及抗拔承载力预测

Field test on the ultimate load of anti-floating anchor and the prediction of its pull-out bearing capacity

基于青岛某工程抗浮锚杆的极限承载力现场拉拔试验,对抗浮锚杆荷载-位移规律进行分析,明确“一锚多筋”型抗浮锚杆破坏形式、破坏机理,同时,采用三次多项式函数预测极限上拔位移下抗浮锚杆的抗拔承载力。研究表明:锚杆的荷载-位移曲线呈“缓变-陡升”型;锚-岩界面黏结强度较小,抗浮锚杆主要产生锚固体拔出破坏;规范公式预测值存在较大偏差。通过三次多项式函数的回归分析,杆体位移的误差控制在10%以内,且锚杆杆体位移小于20 mm时,预测精度最高可达97.4%。研究结果对该地层抗浮锚杆的设计与工程应用具有一定的参考价值。

Based on the field pull-out test on the ultimate bearing capacity of anti-floating anchor of a project in Qingdao,the load-displacement law of anti-floating anchor was analyzed,and the failure form and mechanism of anti-floating anchor of“one anchor and multi-reinforcement”type were defined.At the same time,cubic polynomial function was used to predict the uplift bearing capacity of anti-floating anchor under ultimate uplift displacement.The research showed that the load-displacement curve of anchor presents a“slow change-steep rise”pattern,the interfacial bond strength between anchor and rock was small,and the anti-floating anchor mainly produced pull-out failure of anchor solids.There were large deviations from the predicted values of the standard formulas.Through regression analysis of cubic polynomial function,the error of anchor displacement was controlled within 10%,and when the anchor position displacement was less than 20 mm,the forecast accuracy could reach 97.4%.The research results have a certain reference value for the design and engineering application of the anti-floating anchor in this formation.