%A Lianxiang LI,Hongxia XING,Jinliang LI,Hengli HUANG,Lei WANG %T Optimal structure of pressure cast-situ-pile with spray-expanded frustum %0 Journal Article %D 2020 %J Journal of Shandong University(Engineering Science) %R 10.6040/j.issn.1672-3961.0.2020.090 %P 82-91 %V 50 %N 6 %U {http://gxbwk.njournal.sdu.edu.cn/CN/abstract/article_1993.shtml} %8 2020-12-20 %X

According to the field test results of pressure cast-situ-pile with spray-expanded frustum, with the help of Abaqus to establish the numerical model of the experiment, the influence rule of expanded body with frustum (hereinafter referred to as frustum) on surrounding soil under vertical load was obtained. It was clarified that the soil mass had squeezing effect within the 2D~3D range (D is frustum's diameter) and it reached the limit at 0.5 m under the frustum. Stress relaxation occured in the upper soil of frustum, which reached the limit value at the top of the frustum, and of which the vertical influence range was extended by 1.25D and the horizontal influence range was 1.5D~2.5D. Revealed that the optimal spray angle for frustum expanding was 50°~55°, the optimum expanding ratio was 2~2.75, the optimal position was in the D~2D range of upper part of pile, and it was optimal when the fixed spray wing was 7~8 m below the pile top. The optimal construction model could increase the bearing capacity by 19%, therefore it was suggested to adopt the optimal structural pile type to further improve efficiency and promote application of the pile.