Experiments Research Of The Drilling Pile Compressive Bearing Permormance In Haikou Coastal Soft Foundation Area

With the rapid development of economy in coastal region,the shape and height of the building continues to increase,while the super high-rise building needs larger bearing capacities to be supported.For now,bored piles is the preferred method to increase bearing capacities.Because of high cost of bored piles,how to obtain the largest bearing capacities with least money is what the profession of construction field emphasize.Through practices at home and aboard,it proves that the post-pressure technique,as a new grouting technology,can greatly improve load capacity of piles.The coastal region is located within land and sea,the soft soil layer is thick,ground water table change great,and waves crash form fluid pressure,the series factors will seriously weakened the capacity and quality stability of bored pile.Related literature express,the post-pressure technique can improve the capacity and increase quality assurance rate of the pile,but the use of post-grouting on soft ground reported less,the existing articles are about project experience,so theory research is still backwardness.Therefor,clear the post-grouting pile bearing characteristics in the coastal region soft ground is a key to design the post-grouting pile.In this paper,based on a Haikou-meilisha project,according to the field experiment of 13 test piles and the actual conditions of the construction site,the post-grouting pile bearing characteristics in the coastal region soft ground is carried on systematic research.The research expect acquire the reliable formulas of pressure grouting pile bearing capacity in the coastal region soft ground,which can provide a clearly thinking for the designer.The specific steps are as follows:First,analyze the mechanism that the post-grouting reinforce the soft soil,increase side friction and tip resistance from the theory angle.The result offers a theoretical criterion for design and bearing characteristics of grouting pile.Then use the theory to guide design of post-grouting pile in the coastal region soft ground and apply the design project to practice.At the same time,Serious experiments about the foundation pile in the actual engineering was done,included static loading test,internal force test,small strain test and ultra sonic test.Using test result to analyze high efficiency of post-grouting pile on bearing capacity and bearing characteristics on the process of loading,and sum up of typically bearing characteristics in the coastal region soft ground and consolidate test data to derive calculation formula of capacity.At least,based on the construction and actual test experience,sum up of causes of common engineering accidents and handing practices.