Impact Performance Test Of Prestressed High Strength Concrete Pipe Pile

With the development of China’s civil engineering construction, prestressed high-strength concrete pipe pile (hereinafter referred to as PHC pipe pile) in China was developed rapidly. Compared with other building foundation, PHC pipe piles have not only showed the fast construction speed, low cost, and suitable for different geological conditions, but also have superior dynamic performance, and high bearing capacity.However, PHC pipe piles have showed the serious energy consumption, pollution and other disadvantages in the production process. The high temperature and high pressure steam curing make great heat of steam emissions and fuel combustion, which can not meet the national energy-saving emission reduction policies. In order to save energy, many enterprises develop their own non autoclave pipe pile (hereinafter referred to as non autoclave pipe pile) production process, after a short period of the natural curing, the non autoclave pipe piles can reach the national standard. At present, there are some reports about that the PHC pipe piles were easily to be damaged by the hammer in the construction process, PHC pipe piles, as an important type of building foundation, are related with the safety and stability of the building, so it is necessary to study the impact performance of the PHC pipe piles. In this paper, the autoclave pipe pile and non autoclave pipe pile were tested by the drop-weight test system to test the dynamic mechanical properties of the two kinds of pipe piles under different impact energy. The main work in this study is as follows.(1) Two types of pipe piles were prepared in factory with dimension of 300mm in diameter and 1000mm in length. The production process and the difference between the autoclave pipe pile and non autoclave pipe pile were introduced in detail.(2) In order to obtain the hammer impact energy, the trigger data were recorded and the impact energy was calculated in detail so that to get the accurate test results.(3) The quality of hammer is 600kg. By adjusting the hammer drop height, hammer will have the high energy impact and the low energy impact were obtained. The impact force time history curves, the curves of the circumferential and the axial strain time history curves were obtained. And then the impact force-impact energy curve, strain-impact energy curve, strain impact force curve were analyzed.The test results show that with the increase of impact energy and impact force, the increase of circumferential strain of non autoclave pipe pile was larger than that of the autoclave pipe pile, however there were not many differences on the axial strains for the two types of pipe piles.