基于Terzaghi极限承载力理论的加筋地基承载力研究

RESEACH ON ULTIMATE BEARING CAPACITY OF REINFORCED FOUNDATION BASED ON TERZAGHI THEORY ON ULTIMATE BEARING CAPACITY OF FOUNDATION

为研究筋带对地基承载力的影响,基于Terzaghi极限承载力理论,采用极限平衡法和条分法计算了无黏性土加筋地基的极限承载力。首先,将地基滑裂土体分为主动区、过渡区和被动区。其中,主动区侧面与水平面的夹角δ_1不再为固定值,而应满足地基破坏时承载力最小的原则。其次,过渡区滑面为对数螺旋线,计算时采用折线代替从而将过渡区划分为若干三角条块。最后,将筋带等效为作用在三角条块上的拉力,利用极限平衡理论计算被动区、过渡区、主动区各条块的受力,求出不同δ_1对应的地基极限承载力,进而可得到最小地基承载力。同时,分析了筋带层数、埋深和间距、长度及内摩擦角对地基承载力的影响。通过与试验数据对比,验证了本文方法的可行性。

In order to study the effect of reinforcement on the bearing capacity of foundation,the limit equilibrium method and slice method were adopted for calculating the ultimate bearing capacity of reinforced foundation in non-cohensive soil based on Terzaghi ultimate bearing capacity theory.The slip blocks of foundation were divided into the active zone,transition zone and passive zone,in which the angleδ1 between the side of the active zone and horizontal plane was not a fixed value but could meet the minimum prinicple of the bearing capacity of the foundation at failure.The sliding surface of the transition zone assumed to be a logarithmic spiral was divided into many triangular slices in calculation.The reinforcement was equivalent to tensile forces acting on the blocks.Based on the limit equilibrium theory,the force equilibrum formulas on the passive zone,active zone and transition zone were established,which could calculate the angles ofδ1 corresponding to the ultimate bearing capacity of foundation.By optimizingδ1,the minimum bearing capacity of foundation could be calculated.The effects of the layers of being reinforced,embedment,spacing,length and internal friction angles on the bearing capacity of foundation were also analyzed.By comparison with experimental data,the feasibility of the method was verified.