非对称破坏模式下临坡地基的Meyerhof承载力新解

New solutions of Meyerhof’s bearing capacity for foundations near slopes under asymmetric failure modes

利用统一强度理论的平面应变强度方程,综合考虑中间主应力、基础至坡肩的水平距离、边坡高度和基底粗糙情况等因素,提出临坡地基坡面非对称破坏模式和坡底非对称破坏模式,继而建立条形基础下临坡地基新的Meyerhof承载力解答,给出具体应用步骤并开展理论退化分析与对比验证。研究表明:考虑坡后土体强度贡献所提出的非对称破坏模式更符合临坡地基的实际破坏形态;所得临坡地基Meyerhof承载力解答与文献模型试验和数值模拟均吻合良好;中间主应力可明显提高临坡地基的承载力;临坡地基承载力随边坡高度增加先减小后恒定。研究结果合理反映了土体强度的中间主应力效应、破坏模式的非对称性以及基础旁侧土体强度等工程实际情况,对临坡地基优化设计具有一定的理论指导意义。

The asymmetric failure modes involving the slope face failure and the below-toe failure are proposed,and then new solutions of Meyerhof’s bearing capacity for strip foundations near slopes are presented by adopting the shear strength equation of unified strength theory under plane strain conditions.The combined effects of the intermediate principal stress,the horizontal distance of foundation from the slope shoulder,the slope height and the base roughness are taken into account.The specific application steps of the obtained solutions are provided,and theoretical degradation analysis and comparison verifications are conducted.It is found herein that the proposed asymmetrical failure mode considering the contribution of soil strength behind the slope is more consistent with the actual failure behavior of foundations near slopes.The obtained solutions of Meyerhof’s bearing capacity for foundations near slopes are in good agreement with those of the model tests and numerical simulations in the literature.The intermediate principal stress has a marked improvement effect on the bearing capacity of foundations near slopes.The bearing capacity of foundations near slopes first decreases and then remains unchanged with the increase of the slope height.This study accounts for practical engineering conditions,such as the intermediate principal stress effect of soil strength,the asymmetry of failure modes and soil strength at foundation lateral side,which is of theoretical guiding significance to the optimal design of foundations near slopes.