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充气锚杆是一种新型扩大头锚杆,模型试验有利于了解充气锚杆的变形与承载特性。根据充气压力与膨胀体积关系,分别采用清水与水泥浆作为膨胀介质,分析橡胶膜膨胀体在软土中的变形特性,得到充气锚杆膨胀体近似呈圆柱状。在此基础上通过改变膨胀体径向应变的大小进行一系列抗拔试验,得出充气锚杆极限承载力随膨胀体径向应变的增加而增大,但极限位移也增大。针对充气锚杆单以橡胶膜承担荷载时橡胶膜抗拉强度较小及位移过大的不足,分别设计钢丝加强及灌浆固结两种改进方法,并进行了抗拔试验对比分析,研究结果表明:钢丝加强型充气锚杆将承担在橡胶膜上的荷载转移到钢丝上,提高了充气锚杆极限承载力;灌浆固结型充气锚杆结合了充气锚杆与普通注浆锚杆的优点,显著减小了极限位移。该两种改进方法为充气锚杆的实际应用作了有益的探讨。
Inflatable anchor is a new type of expanded head anchor. The model test is helpful to understand the deformation and bearing characteristics of the inflated anchor. According to the relationship between inflation pressure and expansion volume, water and cement slurry were used as expansion medium respectively to analyze the deformation characteristics of rubber membrane expansion body in soft soil. The inflation bolt expansion body was approximately cylindrical. Based on this, a series of anti-pull tests were conducted by changing the radial strain of the expansion body. The results showed that the ultimate bearing capacity of the inflated anchor rod increases with the increase of the radial strain of the expansion body, but the ultimate displacement also increases. Aiming at the weakening of the tensile strength and excessive displacement of the rubber membrane under the load of the rubber membrane, two improved methods of strengthening the steel wire and grouting and consolidation were designed respectively. The results of the pullout test were compared : The steel reinforced aerated anchor will transfer the load on the rubber membrane to the steel wire to increase the ultimate bearing capacity of the aerated anchor. The grouted and consolidated aerated anchor combines the advantages of the aerated anchor and ordinary grouting anchor, Significantly reduce the limit displacement. The two improved methods for the practical application of inflatable anchor made a useful discussion.