Study On Impacted Soil Around The Squeezed Pile In The Squeezing Process

As a type of new pile, the squeezed pile with expanded branches orplates is developed on top of the traditional cast-in-place pile. In thisapproach, the hard soil layers around different parts of the pile areutilized to form branches or plates to turn a friction pile into amulti-fulcrum, end bearing one. By changing the mechanism of bearing ofthe pile, the capability of bearing is improved significantly while thesettlement of the pile decreases dramatically. This paper focuses on our study of the squeezing process as well asthe suffering area of the soil surrounding the pile in the process ofsqueezing. Considereding the non-linearity of soil, we supposed that thepressure on the squeezing arms obey the law of two-times-paraboladistributing;Considering the flexibility of soil, we gave the formula ofthe contact length,namely (x=l[(90－α)/90]1/2).Based on two assumptionsabove, we built the mechanic model for the squeezing equipment and derivedthe mechanic parameter expressions . We then applied the Columnar HoleExpansion Theory to the squeezing process to analyze the influence on soilaround the branches or plates in two different squeezing processes,one-side and two-side squeezing. For both cases, we plotted the plasticarea as a function of the expanding angle. Finally, we came to thefollowing conclusions: 1. One-side squeezing process can significantlyimprove the vertical load because the soil under the plates has been fullysqueezed; 2. Two-side squeezing process can significantly improve thelateral load because the soil about the plates has been well squeezed. Finally, we simulated the squeezing process using the software of FLAC.According to the date derived from squeezing effect experiment, we builtthe numerical calculating model for the squeezing equipment,and got thesuffering area after squeezing process..For one-side squeezing,theimpact area reaches 1.8m in the level direction and,especially, the soilwithin 0.9m is well squeezed; In the vertical direction, the inpact areareaches 1.4m under the plate and 0.7m on top of it.For two-sidesqueezing,the impact area reaches 2.5m in the level direction and the soilwithin 1.3m is fully squeezed;In the vertical direction,the impact areareaches 1.1m. The experimental result of the squeezing effect matches well with theconclusions drawn from the theoretical analysis thus it verified that ourmechanical models are correct and it is a good beginning for deep researchin the future.