Large-scale model test on installation characteristics of open-ended pipe pile

The open pipe pile is widely used because of its high bearing capacity, reliable quality, and convenient construction.The formation of the soil plug makes the total resistance of the open pipe pile different from that of the closed pipe pile. The bearing capacity of the open pipe pile includes three parts: the external friction of the pile, the pile end resistance, and the pile inside the friction. According to the stress characteristics of open pipe piles during installation, a self-developed large-scale laboratory test apparatus was used to test the penetration of open pipe piles under different forms of pile boots, and based on the results, the open pipe pile was compared with closed pipe pile. The results show that the open pipe pile tends to be occluded with the increase of pile depth. The resistance of pile increases linearly with the pile sinking process, while the frictional resistance inside and outside the pile has "lateral degeneration effect. "The influence range of surface displacement decreases with the increase of radial distance. The uplift rate gradually reduced with the increasing depth of pile sinking. The influence range of soil around pile is about 5 to 7 times of pile diameter. The pile shoe affects the height of the soil plug, pile resistance distribution, internal and external frictional resistance, and the effect ofpushing against soil. The pile of 30° inside pile boots has the largest height of soil plug formation, as well as the maximum friction resistance and the maximum proportion of total pile resistance. The amount of surface soil uplift around the pile is the smallest. The outer 30° pile boot is opposite to the inner 30° pile boot, while the right-angle pile boot is centered. The resistance, lateral friction, and soil compaction of closed-end pipe pile are greater than those of the open pipe pile.