Testing Study On Removable Anchor

With the economy developing rapidly in our country,ground anchorage,as an advanced technique for various geotechnical engineering reinforcement,is being used more and more widely.But in all of the anchors used in domestic projects,most of which are tension anchors,for this anchor type,there exist some defects as follows:1.When applying the load,the bond stress is concentrated over the proximal length of the fixed anchor and the distal component of the fixed anchor can not operate effectively.2.The stress concentrations over the proximal length of the fixed anchor can result in cracking in the grout,which will affect the long term behavior of anchors.3.When used in urban excavations as temporary anchors,the anchor tendons can not be removed after usage,then resulting in the"contamination"of adjacent ground and making it difficult for the later developments.4.In the city temporary underground engineering cinstruction,the anchors usuly oversteping the bounds of"red line".But this situation will be limited gradually.With the exaltation of people's legal consciousness,the constructions oversteping the bounds of"red line"will be limited gradually,for the sake of adapting to the demand of projects development in our country,it is imperative to perform the testing study of removable anchor.Through testing research,two types of removable anchors are developed,lt is proved in the on-site test that the removable anchors developed have such specialties as good working behavior,high load holding capacity,fine performance of corrosion protection and easy to be removed.When used in urban excavations,it allows removal of the tensile steel member from the borehole over both free and fixed length.Moreover,because of the special makeups,the removable anchor developed can also beused for permanent anchors and their anchorage performance will be superior to the tension anchor used widely at present.