变截面桩水平承载规律研究

基于变截面桩水平承载计算理论,考虑不同异化深度、有效截面面积等因素,对变截面空心方桩、变截面管桩和变截面加翼管桩这3种类型变截面桩在淤泥质土中的承载性状进行了规律性研究,结果表明:变截面桩桩顶位移均随异化深度的增大而非线性减小,减小速率先增大后趋缓;桩身最大弯矩随异化深度的增大均呈先减小后增大的趋势,当异化深度为(3~4)d时桩身最大弯矩值最小;变截面桩的水平承载力均随异化深度增大而非线性增大,异化深度小于7d时变截面加翼管桩的承载力较其他2种变截面桩有明显优势,异化深度大于7d后则开始情况相反;异化深度相同时,变截面空心方桩承载力较变截面管桩有优势。综合考虑承载力及桩身弯矩随异化深度的变化后,建议变截面桩异化深度(3~4)d为宜。

Research on Horizontal Bearing Characters of Variable Cross-Sectional Pile

Based on calculation theory of variable cross-section bearing pile, factors of alienation depth and effective cross-sectional area were considered to study the horizontal bearing characters of 3 variable cross-sectional piles such as hollow square pile, pipe pile and pile with wing plate in silt soil condition. The result shows that, the displacement of pile head nonlinearly decreases with the increase of alienation depth, and the decrease rate is increasing at first and then slowing down. The maximum bending moment of pile presents a trend of first decreased and then increased with the increase of alienation depth, the smallest of maximum bending moment appears when the alienation depth is between 3d to 4d. The bearing capacity of abnormal section pile nonlinearly increases with the increase of alienation depth, and the bearing capacity of pile with wing plate has obvious advantage compared with other two kind piles when the alienation depth is less than 7d, and the situation is just opposite after 7d. The bearing capacity of hollow square pile is superior to that of the pipe pile with the same alienation depth. After comprehensive consideration of the variation of bearing capacity and maximum bending moment, 3d to 4d of alienation depth is suggested to the variable cross-section pile.