Study On Pull-out Test And Numerical Simulation Of Newly Recoverable Anchor

Accompanying the maturity of the techniques to reinforce anchors, anchors come into wider and wider applications in the constructions of foundation pit and slope protection. The intensive use of anchor contributes a lot to the development of national economy. However, as the further development of reconstructions, many fields previously buried with anchors will face the problem of secondary development. The once essential anchors unfortunately become the obstruction of secondary development, thus leading to the great difficulties in development and increasing cost in constructions. On the other hand, in some temporary reinforcement projects, if the anchor can be recovered, not only the materials will be saved, but also the construction cost will be reduced, which will lead to very nice economic effects.As a result, according to the development of construction, Prof. Hanlong Liu in Geotechnical Research Institute of Hohai University developed a new kind of recoverable anchor technology based on his abundant experiences on constructions. Since this new pattern hasn't be widely applied, its support ability and working mechanism haven't be well appreciated. This paper will focus on introducing this new technique. The paper will cover the following several parts,1. The detailed introduction to the technical principles, basic technical parameters, key points of construction, technical specialty and the application area.2. Conducting field pull-out tests on recoverable anchor at some specific experimental period in Nanjing Yanziji middle school slope protection projects. Through the analysis of p-s curve under pressure and the stress distribution along the anchor, the distortion mechanism of anchor and the rule of stress distribution along the anchor under different pressure and different length of anchor will be investigated.3. Applying the software ANSYS to investigate the rule of stress distribution along the anchor under increasing pressure, and to simulate the various situations under different length of anchorage body, different anchor radius, different soil, etc. We have come to the following conclusions: (l)The internal pressure distribution is not uniform. The pressure in the directed touched end between cement mortar and load is much larger than the average value and pressure goes small along the direction of cement mortar. (2)The longer the anchorage is, the lower the shear stress and the smoother the curves of shear stress are. However it is helpless to elongate anchorage unlimitedly. (3)Compared to small diameter anchorage under the same load, larger diameter anchorage promises better uniformity distributing of shear stress and bearing character. (4)It makes peak value of shear stress larger, when uniformity distributing...