The objective of this study is to discuss the plugging effects of open-ended pipe pile. According to the formation process and mechanism of soil plug,the forced state of soil plug is analyzed, and the balance equation of unit plug is established. The expression of the total vertical load is also obtained. Moreover, the plug is regarded as a ＂pile in the pile＂,and then the formula of bearing capacity limit for pile end is reduced, based on the ultimate bearing capacity model theory that was put forward by Terzaghi K. Accordingly, the expression of the soil critical height in the process of driving is derived. Finally, the conclusion is drawn that these expressions are appropriate by comparing and analyzing the results of theoretical calculation and engineering examples, and the influence of the factors such as radius-thickness ratio, cohesion of soil and roughness of the surface between piles and soil are also discussed. It is concluded that the height of the soil increases with the increase of the radius-thickness ratio, and decreases with the increase of the surface roughness between piles and soil, but the cohesion of the soil has little effect on the height of the soil. The rationality of the formula has a certain reference value to predict the height of soil plug of open-ended pipe pile during jacking into soil.
Journal of Hunan University（Naturnal Science）