Study On Construction Technology Of Bored Pile In Karst Area

With the further implementation of the strategy of developing western China and the rise of Central China,the investment in infrastructure in the central and western karst regions has been continuously increasing.Karst,as a typical adverse geological phenomenon in engineering construction,is extremely harmful to the project construction.Therefore,the quality of the pile foundation engineering quality and production during the factory production is very significant.In this paper,the actual engineering investigation and collection of documents on the karst bored pile construction technology and quality control in-depth study,the specific opening of the following aspects:In this paper,the construction process as the core,for the entire process of the construction of bored piles in karst areas,from the karst geological features,construction technology and quality control,construction accident handling three aspects of summary and research.(1)After the site investigation and data analysis,there are three main types of construction machinery suitable for bored piles in karst areas: impact drilling rig,rotary drilling rig and rotary drilling rig,and five main factors affecting the construction of pile foundation in karst areas Respectively,in the karst geological conditions of the capacity of the crossing technology,construction process improvement and construction points are summarized.(2)The causes,prevention and treatment measures of common accidents in the pile foundation construction in karst area from drilling to pile-forming are summarized.The common detection methods of bored piles and the application of joint detection methods in karst areas are introduced.(3)Analysis of common pile foundation quality defects in karst areas from the causes and preventive measures.Five methods to deal with the defects of pile foundation in karst area are summarized: pile-connecting method,high-pressure grouting method,stubbing method,re-staking method and area-increasing method,and corresponding concrete construction technology.(4)Combined with the actual project construction and quality control of bored piles in karst areas,the construction technology preparation,construction site preparation,follow-up construction of steel casing,through vertical control of cave and pile body,bearing stratum integrity control,quality control clearance hole,pouring concrete to control these nine areas summed up a quality control measures.