充气锚杆抗拔承载力特性研究

Study on uplift bearing capacity characteristics of aerated bolt

为了研究特定条件下充气锚杆抗拔界面变形特性及其对承载力的影响,采用三维有限差分软件FLAC 3D建立充气锚杆数值计算模型,在此基础上,改变锚杆充气压力、埋设深度和橡胶膜长度,得到相应的荷载-位移曲线,分析充气锚杆的承载特性与位移变化。研究结果表明:从锚固机理理论分析,锚固段膨胀体可有效提升锚杆抗拔承载力。从数值模型计算分析,改变充气压力、橡胶膜长度和埋设深度均可提高锚杆抗拔承载力,分别较初始条件提高了1.93%、1.66%和13.2%,极限位移变化量分别为0.05 mm、0.17 mm和0.15 mm。改变埋设深度是最有效提高锚杆承载力的方式,增加锚杆气压在有效提高承载力的同时,又可较好的控制位移的变化。

In order to study the deformation characteristics of the pull-out interface of inflatable bolts under specific conditions and their influence on bearing capacity.The three-dimensional finite difference software FLAC 3Dis used to establish the numerical calculation model of inflatable bolt,on this basis,the inflatable pressure,buried depth and rubber membrane length of the bolt are changed to obtain the corresponding load-displacement curve,and the bearing characteristics and displacement changes of the inflatable bolt are analyzed.The results show that from the theoretical analysis of anchoring mechanism,the expansion body of the anchor section can effectively improve the pull-out bearing capacity of the anchor.From the numerical model calculation and analysis,changing the inflation pressure,rubber membrane length and burial depth can improve the pull-out bearing capacity of the bolt,which is increased by 1.93%,1.66%and 13.2%compared with the initial conditions,and the limit displacement changes are 0.05mm,0.17mm and 0.15mm,respectively.Changing the buried depth is the most effective way to improve the bearing capacity of the bolt,and increasing the air pressure of the bolt can effectively improve the bearing capacity while better controlling the change of displacement.