圆形深基础下砂土地基破坏模式分析-工程科学与技术.DOC

考虑砂土地基轴对称压密变形的 圆形深基础承载力研究 刘贯飞，雷胜友 (长安大学公路学院，陕西 西安 710064) 摘要：地基土相对密度通过分析地基土的颗粒移动、土体压密和土体剪切三者之间的关系，I、剪切区II和压密区III三个区；压密区III以上的基础周围土体外侧面上作用有向上的负摩阻力，与Berezantzev的结论相似；同时考虑基础埋深地基土相对密度的影响I、剪切区II和压密区III的范围；结合地基的轴对称变形特性建立了适用于H/b）2≤H/b≤5时的圆形深基础下砂土地基破坏模式。根据的静力平衡条件，推导了圆形深基础下砂土地基极限承载力。通过圆形深基础地基极限承载力系数NγqH/b、地基土内摩擦角（φ）之间的变化关系，并与常用的Berezantzev解、Terzaghi解和Durgunoglu解进行对比。发现，当考虑到基础相对埋深和地基轴对称变形特性等因素对地基破坏模式的综合影响时，所得Nγq值在不同的φ条件下均小于 Nγq值H/b的增加而减小，所得圆形深基础下砂土地基承载力值更接近于规范值。 关键字：砂土轴对称压密 中图分类号：TU43 文献标识码：A Study on the Bearing Capacity of Deep Circular Foundation Considering the Axisymmetric Compaction Deformation of Sand Ground LIU Guan-fei, LEI Sheng-you (School of Highway, Chang’an University Xi’an 710064, China) Abstract: The failure model proposed by Berezantzev for calculating the ultimate bearing capacity of deep circular foundation in sand had considered the properties of axisymmetric deformation of the ground, but neglected the influences of buried depth of the foundation and sand density on the model, thus, the calculation results were relatively large usually. A new model of ground failure was developed to calculate the ultimate bearing capacity of sand under the deep circular foundation by considering the properties of axisymmetric deformation of the ground, which the relative buried depth (H/b) is small (2≤H/b≤5). In this model, the suggested shear failure pattern consists of three zones: a highly compressed zone I, a radial shear zone II, and a slightly compressed zone III. A resistance shearing force existence in an upward direction on the soil annulus above the zone III, which is similar to Berezantzev. The failure process of sand ground was researched by analyzing the relationships among the movement of soil particles, soil compaction and shearing broken of the subsoil. The extent of zone I, II, III was determined by considering the effects together of buried depth, sand relative density and the?roughness?of base on the model. According to the static equilibrium o