摘要
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 under-reamed anchor.The pullout tests on the inflatable anchor are carried out to analyze its deformation and bearing mechanism.According to the volume-pressure relationship of the anchor,the deformation characteristic of rubber membrane is studied when being inflated with water.And the inflated shape of rubber membrane in soft soil is approximately cylindrical,which is mensurated by injected cement slurry.On such a basis,a series of scaled pullout tests are performed with various inflatable volume.The results show that the ultimate loads and displacements of inflatable anchor both increase with the increment of the volume.As for the large tensility and small tensile strength of rubber membrane to bear loads,two methods which are improved by wire or grouting are designed,and the results of pullout tests are analyzed comparatively.The results show that the inflatable anchors with wire transfer the loads from rubber membrane to wire,which enhances the bearing capacity of the anchor greatly.And the inflatable anchor with grouting has a small displacement.It combines the advantages of inflatable anchor and grouting anchor.These two improved methods are useful to the practical application of inflatable anchors.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2011年第9期1399-1404,共6页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(50878212)
关键词
充气锚杆
抗拔试验
力学特性
变形
极限承载力
位移
软土
inflatable anchor
pullout test
mechanical characteristic
deformation
ultimate load
displacement
soft clay
