Study On Bearing Behavior Of Disk Pile With Different Shape Of Disk Combination

The squeezed branch pile is a new type of bored concrete piles with variable cross-sections. The pile has high bearing behavior under vertical loads, uplift loads and horizontal loads. Compared with the pile with constant section, the pile has well stability, better economy and wider application range. However, the theoretical study on the disk pile is incomplete, especially the study on the effect of different shapes on bearing behavior. Based on lots of literatures home and abroad, the bearing behavior of double-disk squeezed branch piles with different angles in the complex soil was studied through indoor model test and finite element simulation. During this research, the top and bottom disk of this squeezed branch pile were located in different soil layers, changed disk dip and formed different type of piles. The main research contents are as follows:(1) Bearing behavior characteristics of equal-diameter piles and double-disk piles was studied through indoor model test. The result showed that the squeezed branch pile has similar load transfer path in depth and wider diffusion span compared with common piles.(2) Sixteen model piles with different disk shapes was divided into four groups in the indoor model test. The disk shapes refers to the bottom angle of the disk, and the disk shapes were 20°, 30°, 45° and 60°, respectively. Fixed the dip of footwall and changed the dip of hangingwall. Analyzed the results after every test, such as pile top settlement, axial force of pile shaft and pile lateral earth pressure, and drawn the effect on the bearing performance of the double disk pile in different soil layer under different disk shapes i.e. the bottom dip of each disk.(3) Finite element simulation of the squeezed branch pile with different footwall dip is studied. In this paper, the variation of bearing behavior is analyzed systematically, and find out the optimal combination of the disk bottom dip(30°-45°).(4)The effect of footwall shapes under different soil properties is studied through changing soil parameter.(5)The effect of the difference of dip on mechanical behavior was studied as well. The result showed that the greater difference between the other disk dip and the optimal dip, the smaller in percentage of disk sharing.