鉴于目前半对数模型难以较好地描述大应变软土的非线性压缩和渗透关系的现状,引入适用于软土大应变的双对数压缩渗透模型,建立了考虑非达西渗流的饱和软土地基一维大应变固结方程,并给出了有限差分数值解,通过与室内试验和解析解对比,验证了解答的可靠性。在此基础上,分析了渗流参数、双对数压缩和渗流非线性关系参数和外荷载对固结性状的影响。结果表明:压缩指数Ic一定时,渗透参数越大,土层固结越慢;渗透参数一定时,压缩指数Ic越大,土层固结越慢; 外荷载qu越大,土层的沉降量就越大,超静孔隙水压力消散越快,土层的固结速率也越快;最后,对大、小应变固结理论下差分解对比分析,发现土体发生较大应变时,小应变固结理论将不再适用,此时应采用大应变固结理论开展计算。
Abstract
Given the limitations of semi-logarithmic model in describing the nonlinear compression and permeability relationship of large-strain soft soil, we present a bilogarithmic compression and permeability model specifically designed for such conditions. Furthermore, we established a one-dimensional large-strain consolidation equation for saturated soft soil foundation, taking into account non-Darcy flow, and provided a finite difference numerical solution. Through a comparison with indoor testing and analytical solutions, we verified the reliability of this solution. On this basis, we analyzed the effects of seepage parameters, bilogarithmic compression and nonlinear seepage parameters as well as external loads on consolidation behavior. Results indicate that, when the compression index (Ic) remains constant, greater permeability parameters lead to slower soil consolidation. Similarly, when the permeability parameter is constant, a larger compression index results in slower soil consolidation. Additionally, higher external loads (qu) correspond to greater settlement of the soil layer, faster dissipation of excess pore water pressure, and accelerated consolidation rate. To conclude, a differential analysis of large-strain consolidation theory versus small-strain consolidation theory reveals the inapplicability of the latter in the presence of significant soil strain. Instead, the large-strain consolidation theory should be employed for accurate calculations.
关键词
软土 /
双对数模型 /
大应变固结 /
非达西渗流 /
有限差分法
Key words
soft soil /
bilogarithmic model /
large-strain consolidation /
Non-Darcy flow /
finite difference method
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基金
国家自然科学基金项目(51879104);湖南省研究生科研创新项目(CX20220408)
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