复合地基复合模量的理论修正

复合模量是计算复合地基沉降的关键指标,目前主要采用面积加权公式计算复合模量,实践证明沉降计算值与实测值有较大误差·在考虑桩长、桩端土性质对复合模量的影响后,利用复合地基桩体的承载机理对复合模量面积比公式进行修正·通过与实际工程进行对比,利用修正后的公式计算的沉降值比利用面积比公式计算更接近实测值·分析表明复合模量随着桩长的增加呈线性增长,桩土模量比越小,变化幅度越大·同样,随着桩端土刚性的增长复合模量也逐渐增大,但桩土模量比越大,变化幅度越大·因此应把桩土模量比作为复合地基类别的判据·

Theoretical Analysis on the Modulus of Construction Composite Foundation

Composite modulus is a key parameter of composite foundation, which is calculated in present by virtue of area ratio formula. Practically there is a big error between calculated value and measured value. Taking account of the pile length and the nature of pile-end soil, the bearing mechanics of composite foundation pile were used to correct the area ratio formula. Comparatively, the value calculated by the corrected formula is more accurate than by area ratio formula. With the increase of pile length, composite modulus increases linearly. The smaller the ratio of pile-soil modulus, the bigger the change. Similarly, with the increase of stiffness of pile-end soil, composite modulus increases. However, the bigger the ratio of pile-soil modulus, the bigger the change. So, the ratio of pile-soil modulus should be regarded as a criterion to differentiate the type of composite foundation.