关键词: 钙质砂, 挤土桩, 颗粒破碎, 离散元法, 细观分析

Abstract: Based on two-dimensional discrete element method, this paper simulates the calcareous sand particle of easily-crushed feature as a cluster cell. It uses the clump cells with the same shape and deformation characteristics to simulate the particles without crushing. The jacking processes for different types of pipe piles are simulated with the model to analyze the meso-mechanical behaviors and breakages of the calcareous sands. The results show that the particle breakage can cause the gradation readjustment, resulting in a better contact between the particle and the pile. The driving speed in calcareous sands is relatively fast. There is a smaller disturbance to the foundation soil. The stress field around the pile has the same tendency. The stresses near the pile tip increase dramatically and result in the formation of the stress nucleus. Under the same surrounding conditions, the horizontal and vertical stresses of crushable calcareous sands are obviously greater than those of the unbroken soil.

Key words: calcareous sands, soil compaction pile, grain breakage, discrete element method (DEM), meso-scopic analysis