Analytical solution for consolidation of soils with vertical drain considering time-and depth-dependent well resistance under vacuum and multi-stage surcharge preloading
SHI Lantian，LI Chuanxun
(Faculty of Civil Engineering and Mechanics，Jiangsu University，Zhenjiang，Jiangsu 212013，China)
Abstract：Considering the well resistance varies with time and depth during consolidation of soils with vertical drain，a consolidation model of soils with vertical drain under vacuum combined surcharge preloading was developed based on the equal strain assumption，aiming at the situation of multi-stage surcharge preloading and single stage application of vacuum preloading and incorporating the different decay modes of horizontal coefficient in smear zone. The analytical solution of the consolidation model is obtained by using the homogeneous boundary conditions and solving ordinary differential equations. Analytical solutions are verified for validity by comparing them to the existing analytical solution and the field data，and the consolidation behavior is investigated by the parametric analysis. The results indicate that the variable well resistance theory can theoretically support the assumption that the final negative pressure reduces linearly with the increase of depth. The degree of vacuum attenuating with depth at a specific time will grow as the attenuation coefficient of drainage capacity increases and the final drainage capacity of the vertical drain decreases. The larger the attenuation coefficient of drainage capacity is，the slower the consolidation rate of the vertical drain is. The larger the final drainage capacity is，the faster the consolidation rate of the vertical drain is. Based on the consolidation model in this paper，an appropriate vacuum loading value is selected before construction to carry out vacuum combined surcharge preloading，which can simultaneously take soil consolidation rate and economic benefit into account.
史蓝天，李传勋. 真空联合多级堆载下考虑井阻时空变化的竖井地基固结解析解[J]. 岩石力学与工程学报, 2023, 42(S1): 3755-3766.
SHI Lantian，LI Chuanxun. Analytical solution for consolidation of soils with vertical drain considering time-and depth-dependent well resistance under vacuum and multi-stage surcharge preloading. , 2023, 42(S1): 3755-3766.
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2023, Vol. 42 
