开挖深度对抗拔桩极限承载力的影响

EFFECT OF EXCAVATION DEPTH ON ULTIMATE BEARING CAPACITY OF UPLIFT PILES

基坑开挖会改变地基应力场,进而对抗拔桩产生不利影响。采用弹塑性有限元法,借助ABAQUS软件建立有限元分析模型,分析抗拔桩承载机理和开挖深度对抗拔桩极限承载力的影响规律。分析结果表明:在开挖宽度不变的条件下,随着开挖深度增加,抗拔桩极限承载力降低,极限状态下的桩顶位移减小;当开挖深度为0.5倍有效桩长和1倍有效桩长时,抗拔桩极限承载力较开挖前分别下降16.59%和35.46%。

Bearing capacity of uplift piles would be influenced by the change of the ground stress under deep excavation. The elastic - plastic finite element method is adopted to build a finite element a- nalysis model by using ABAQUS software, and the influence of excavation depth is analyzed. Finally, the bearing mechanism of uplift piles and the influence law of excavation depth are obtained. The analy- zing results show that： under the condition of constant excavation width, as the excavation depth increa- ses, ultimate bearing capacity and the corresponding displacement of the top of pile decrease; the ulti- mate bearing capacity falls by 16. 59% and 35.46% respectively, when the excavation depth is half and one times length of the effective pile.