极限荷载作用下临近基坑c-土地基的破坏模式

与地面水平时地基土体的对称破坏模式不同,临近基坑（边坡）地基土体的破坏模式呈现明显的非对称性.利用FLAC-3D数值模拟技术,研究了在竖向极限荷载作用下临近基坑c-ψ土地基不同工况时的破坏模式,得出了与J.Graham所假设的边坡附近无黏性土地基破坏模式相一致的结论.最后将数值模拟结果与大尺寸模型试验数据以及J.Graham的基于应力特征线法的非对称滑动破坏模式的地基承载力理论解进行了分析对比.结果表明,采用叠加计算方法得到的承载力系数Nγq偏于安全.

Analysis of c-φ soils failure zone of footings near excavations under ultimate load

In contrast with the symmetry that is seen beneath footings on level ground, results from theoretical analyses and physical models near an excavation or on slope show that the failure zones are asymmetric. This paper studies on the failure zones of c-φ soils near excavations under vertical ultimate load, and the numerical simulating results obtained by using FLAC-3D approximate to J.Graham's failure zones using the method of stress characteristics in cohesionless slope. Finally, Nγq from numerical simulating technique are compared with large-scale experimental and theoretical values of Nγq in cohesionless slope under various construction conditions; and a brief assessment using numerical simulating method of superposition assumption indicated that the assumption is conservative.