不同截面抗滑桩的土拱效应对比研究

Comparative Study on Soil Arching Effect of Anti‑slide Piles with Different Sections

土拱效应是桩土作用理论研究的重要依据,但由于对不同截面形式抗滑桩的土拱效应作用机理研究较少,在抗滑桩设计中大多采用传统截面形式,考虑到传统矩形抗滑桩在形成土拱效应方面的不足,提出梯形截面优化抗滑桩截面形式。基于材料力学理论,利用轴向受压杆件的斜截面应力计算模型推导出梯形桩桩侧土拱拱脚受压区应力状态,并结合摩尔—库伦强度准则得出梯形桩桩侧极限承载力,通过算例对比分析梯形与矩形桩桩侧土拱极限承载力,结合数值模拟分析验证理论与计算结果。研究结果表明:梯形截面桩桩侧极限承载力相较于矩形截面有较为明显的提升,最大约为矩形桩的2.5倍;相同条件下梯形截面桩桩间土位移与剪应变增量更小,应力集中现象更明显,梯形截面桩对土拱效应的形成与发展更有利。

Soil arching effect is an important basis for theoretical research of pile-soil interaction.But due to less research on the soil arching effect mechanism of anti-slide piles with different cross-sec‐tions,the traditional cross-section is mostly used in the design of anti-slide piles.Considering the shortcomings of traditional rectangular anti-slide piles in forming soil arching effect,the trapezoidal cross-section was proposed to optimize the design of the anti-slide piles.Based on the theory of materi‐al mechanics,the stress state in the compression zone at the foot of the soil arch on the side of the trap‐ezoidal piles was deduced by using the oblique section stress calculation model of the axial compres‐sion bar,and the ultimate bearing capacity of the trapezoidal piles was obtained by combining the Mohr-Coulomb strength criterion.The ultimate bearing capacity of the soil arch on the side of the trap‐ezoidal and rectangular piles was analyzed by a numerical example,and the theory and calculation re‐sults were verified by a numerical simulation analysis.The results show that the ultimate bearing capacity of the trapezoidal piles is significantly improved compared with that of the rectangular piles,and the maximum bearing capacity is about 2.5 times that of the rectangular piles;Under the same condi‐tions,the increment of soil displacement and shear strain between trapezoidal piles is smaller,while the stress concentration is more obvious.The trapezoidal sectional pile is more favorable to the forma‐tion and development of soil arching effect.