CAJ | 학술논문

吹填地基真空加固过程中,吹填土由液体泥浆变为固态土体,其孔隙降低非常大.由于土体的渗透性和压缩性是孔隙比的函数,因此,吹填土在固结过程中固结系数变化很大,而现行设计方法中固结系数取为常数,这导致预测结果和实际结果差异较大.为考虑固结过程中孔隙变化对固结过程的影响,推导了真空荷载作用下土体固结系数与有效应力的关系,并将该关系应用于巴隆固结理论,从而建立吹填土地基真空固结分析模型.通过室内模型试验,验证了该模型的合理性.计算结果表明,考虑孔隙变化的影响时,吹填土地基前期固结速度快,而在后期逐渐变慢.由于排水面附近土体渗透系数迅速降低,阻碍了周围土体中孔隙水向排水面排出,因此,与现行固结设计方法计算结果相比,吹填土地基后期固结速度慢,总体固结时间长.
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Dredger fill changes from fluid to soil and its void reduces markedly during the consolidation of reclaimed ground under vacuum loading. Because both permeability and compressibility are functions of void ratio, the consolidation coefficient of dredger fill changes greatly. The prediction by current design method is much different from engineering practice because the consolidation coefficient in this method is taken as a constant. In order to account for the effect of varying void on consolidation, the relation between consolidation coefficient and effective stress is derived;and a consolidation model for dredger fill is built by applying this relation to Barron’s consolidation theory. The model is proved by comparing the result of this model with that of model test. The analysis result shows that the consolidation coefficient of dredger fill decreases with the void during the consolidation. Therefore, the consolidation of reclaimed ground is rapid in the initial stage and slow later. The quick decrease of the permeability of soil near the drainage board area will hinder the consolidation of soils in the farther area. Therefore, compared with the result of current design model, the consolidation of reclaimed ground is slower in the later stage and the whole period of consolidation is longer.