Post Pressure Grouting Technology Of Bored Pile Applied In Wuhan Area

The post grouting technology of bored pile is a new type of pile technology,which not only retains the original advantages of bored piles,but also improves its defects.By selecting the appropriate grouting device and designing of the reasonable grouting parameters,it can be found that many problems of construction in recent years,like no enough carrying capacity in large buildings and the excessive settlement and so on,can be solved via the post grouting technology of bored pile because the grout and the soil around the pile can achieve the better reaction with each other.Due to its advantages,the post grouting technology of bored pile is worthy of being extended to constructing of a variety of large buildings.Based on Wuhan DSM project,the research of grouting device at home and abroad is reviewed,and the devices and their effect used in the similar areas are compared in this thesis.Considering the geological characteristics of the engineering site,the project adopts the open pile-end grouting device with the "double control of pressure & amount” grouting mode.The results show that the grouting device can reach the optimum interaction of the grout and soil in Wuhan.What’s more,8 piles were tested by static load test in this project,and the results indicate that the vertical bearing capacity of the pile is increased by 172%-200%,and the settling amount is reduced by 42%-64%.After unloaded,the pile with post grouting technology of bored pile can rebounds 25%-35%,while 0-10% without the technology.Through the above datum it can be found that the application of post grouting technology of bored pile can improve the bearing capacity of pile body as well as the tensile and pullout performance,and reduce the total settlement.In addition,this thesis makes not only a comparison among the methods of determining parameters of post grouting technology of bored pile,but also a further exposition of how to overcome the common problems of the traditional driven cast-in-place pile technique.The detail datum for the post-grouting technology of bored pile in present engineering can be used as a reference for the similar projects in Wuhan,and the present works establishes foundation to study the further mechanism and the equipments of the post-grouting technology of bored pile.