针对复合地基固结问题,建立了考虑真空-堆载联合预压和初始孔压均布的复合地基计算模型,推导出真空-堆载联合预压复合地基固结一般解,讨论了复合地基孔压和固结度的变化规律。研究表明:桩径比n、扰动区大小s、加压方式和时间因子T_h对复合地基孔压和固结度有重要影响。n值和s值越大,孔压越大,固结越慢;荷载越大,孔压越大;深度增加,孔压增大,在地基浅部孔压随深度增大明显,而在深部孔压随深度增加较为缓慢;真空荷载和堆载荷载引起的孔压和固结效果是可以叠加的;T_h值变化对地基中孔压分布规律有重要影响,在地基浅部,孔压呈线性分布,当深度超过一定值时孔压呈非线性分布,T_h值越大孔压非线性分布越明显。研究结果对于真空-堆载联合预压理论和复合地基研究有一定促进意义。

Aiming at the consolidation problem of composite ground with granular columns, the calculation model for the consolidation of composite foundation in consideration of vacuum-surcharge preloading and uniform distribution of initial excess pore water pressure is established. The general analytical solution for the consolidation of composite ground under vacuum-surcharge preloading is given, and the variation regularity of excess pore pressure and consolidation degree is discussed. Research findings demonstrate that the excess pore pressure and consolidation degree of composite ground are much more affected by pile diameter ratio (n), disturbance area (s), loading method and time factor (T_h). The greater the values of n and s are, the greater the excess pore pressure is, and the slower the consolidation is; the greater the load is, the greater the excess pore pressure is. Excess pore pressure rises as depth increases, and such increase is more apparent in the shallow part of the foundation, while attenuates in the deep. The effects of vacuum loading and surcharge loading can be superimposed. In addition, the changes of time factor (T_h) have important influence on the distribution law of excess pore water pressure: excess pore pressure distributes linearly in the shallow part of the foundation, but distributes nonlinearly when depth exceeds a certain value, and such nonlinearity gets more evident when the value of T_h is larger.