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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。
During the process of vacuum filling of the foundation, the dredger filled soil is changed from liquid mud into solid soil, and its porosity is greatly reduced. Because the permeability and compressibility of soil are a function of void ratio, the consolidation coefficient of dredged soil varies greatly during the consolidation process, while the consolidation coefficient of current design method is taken as a constant, which leads to the prediction result and the actual The result is quite different. In order to consider the influence of pore change on the consolidation process during the consolidation process, the relationship between consolidation coefficient and effective stress under vacuum load was deduced. The relationship was applied to Baron consolidation theory to establish the foundation Vacuum consolidation analysis model. Through the indoor model test, the rationality of the model is verified. The calculation results show that, considering the influence of pore change, the pre-consolidation consolidation speed of the dredger-filled soil is fast, but gradually slows down in the later period. Due to the rapid decrease of permeability coefficient of soil near the drainage surface, the pore water in the surrounding soil is impeded from being discharged to the drainage surface. Therefore, compared with the calculation results of the existing consolidation design method, the post-consolidation consolidation speed of the dredged soil foundation is slow and the overall consolidation long time.