Research And Application Of A Kind Of Rectifying And Strengthening Technology For High-rise Building With Pile Foundation

With the development of era,more and more high-rise buildings with pile foundation have been tilted or even collapsed.Based on the uneven settlement accident of a high-rise building with pile foundation,the paper expounded and analyzed the causation of inclination of buildings and a method of rectification and reinforcement for high rise building with pile foundation put forward in this paper.The specific studies are as follows:1.Summarized the main reasons for the uneven settlement of the building,damage and inclined building’s treatment methods and its technical characteristics.Also,introduced the settlement control theory and calculation method of pile foundation.Finally,distribution ideas and distribution methods of load for settlement calculation in pile foundation reinforcement are briefly expounded.2.Aiming at a differential settlement of certain pile foundation of high-rise buildings.Through consulting a lot of data and combining with the building structure form,geological condition,surrounding environment and pile foundation detection,this paper comprehensively analyzed the cause of uneven settlement accident of building.And combined with the characteristics of the building,a theory of rectification and reinforcement based on the principle of counterforce center of pile foundation is put forward.According to the offset degree of the pile foundation counterforce center and the mass center of the superstructure,the force of the pile foundation is redistributed on the basis of considering the eccentric bending moment.Then strengthen the piles according to the force situation of the piles after distribution.At the same time,in the process of strengthening the original pile foundation,it relies on the self-weight of the building to rectify it.With the technology of supplement raft & broaden the external raft & the static bolt pile,the pile foundation will be changed into raft-pile composite foundation,which can improve the intensity and the bearing capacity of foundation.And utilizing the static bolt pile’s locations,quantity and construction order to create the conditions of building return back and to attain the aims of the mass center of the building and the back force of the pile foundation coincidence and rectification of the building.3.Combined with the building,the principle,design calculation method and construction steps of the scheme are introduced,and the matters needing attention in construction are summarized in detail.Practice has proved that the technology of supplement raft & broaden the external raft & the static bolt pile worked well and serving as a reference for similar engineering.4.Established a numerical model by using ABAQUS software,this paper firstly made a comparison of settlement and stress of adding and non-adding piles on the basis of supplementing the raft.Then also studied the influence of the thickness of the raft,the length of the pile and the diameter of the pile on the control of the settlement of the foundation.Through calculation,it is found that the supplement raft and adding pile can effectively improve the bearing capacity of the foundation,reduce the maximum foundation settlement and differential settlement.When the thickness of the raft is at 0.6m-1m,the effect of settlement control is better.When the length of the pile is 2 times higher than that of the original pile,the settlement control effect is not obvious,and increasing the diameter of the adding pile was of little affection on the settlement of building.