复杂地基反力模式下高承台嵌岩灌注桩的屈曲稳定分析

Buckling analysis of cast-in-situ rock-socketed piles with highrise pile cap under complicated subgrade reaction modulus

为探讨桩侧地基土反力对高承台嵌岩灌注桩桩身屈曲稳定的影响,假定地基反力系数呈更为复杂的幂分布,基于弹性地基梁理论建立桩土体系总势能方程,采用最小势能原理,导出了桩身屈曲临界荷载与稳定计算长度的解析解,并据此获得了地基反力系数分布模式、桩身自重及桩侧摩阻力等对桩身屈曲稳定的影响规律。工程应用分析结果表明,考虑地基反力系数为一般幂分布时,桩身屈曲分析结果更趋合理。

To discuss the influence by the constraint of surrounding soil on the buckling stability of cast-in-situ rock-socketed piles with highrise pile cap, the most general exponential distribution of subgrade reaction modulus was assumed and the total potential energy equation of the pile-soil system was set up based on the simplified elastic beam model. Then, analytical solutions for the buckling length and buckling load of the pile shaft were deduced by applying the principle of minimum potential energy. And based on the obtained solutions, influencing rules by the distribution mode of subgrade reaction modulus, deadweight and side resistance along the pile shaft on the buckling behavior of cast-in-situ rock-socketed piles with highrise pile cap were discussed and obtained respectively in detail. Application of the present method to an engineering example shows that, more reasonable buckling analysis results of the pile shaft may be obtained when the distribution of subgrade reaction modulus is characterized by an exponential function.