滑移线法计算环形基础竖向承载力  

Calculating Vertical Bearing Capacity for Ring Footings with Slip Line Method

作　　者：赵岚 

机构地区：[1]上海应用技术大学轨道交通学院,上海201418

出　　处：《应用技术学报》2017年第3期262-266,共5页Journal of Technology

基　　金：上海应用技术大学引用人才基金项目(YJ2013-57)资助

摘　　要：用滑移线法计算了环形基础竖向承载力.假设:①环形基础为刚性且被置于非黏性(c=0)土上,土体遵循线性Mohr-Coulomb(c,φ)屈服准则和太沙基破坏机理.②基础正下方有一刚性三角形土楔,其与基础底面角度为φ,与竖向对称轴角度为(π/4-φ/2),土楔随基础一起向下移动;有一个对数螺线剪切区和一个与基础底面角度为φ的被动朗肯三角形土楔.③基础底面与其下土体之间的摩擦用摩擦系数t和接触面摩擦角δ表示,t、δ和土体内摩擦角φ满足tanδ=t tanφ.计算发现,随着环形基础内外半径比的增大,承载力系数N_γ明显减小,随着接触面摩擦角δ的增大和土体内摩擦角φ的增加,承载力系数N_γ显著增大.该方法的另一优点是可避免对滑移面的形状作任意性假设.最后比较发现计算结果和已有文献结果基本一致.The vertical bearing capacity for a ring footing is studied with slip line method. The following assumptions are considered in the computation： the ring footing stands on the non-adhesive soil mass which obeys the linear Mohr-Coulomb （c,φ） yield criterion and Terzaghits failure mechanism; there is a rigid triangular wedge with base angle φ which moves downwards along with the footing, and a log spiral shear zone and a passive Rankine＇s triangular wedge with base angle π/4-φ/2; the roughness between the footing base and underlying soil mass is expressed by roughness factor t and interface friction angle δ, and t, δ and the inner friction angle φ satisfy the following relationship formula： tan δ =t tan φ It is found that the value of bearing capacity Nγ, significantly decreases with the increasing ratio of inner radius to outer radius, and significantly increases with the increasing interface angle 8 between base and soil mass and the increasing inner friction angle φ of the soil mass. This method can avoid the assumption of arbitrary slip surfaces and the results are compared with those published in the literatures and consistent with them well.

关 键 词：承载力 滑移线法 屈服 环形基础 轴对称 

分 类 号：TU470[建筑科学—结构工程]