高含水率疏浚泥在外加荷载作用下通常产生大应变固结变形,不适用于传统的Barron轴对称小应变固结理论。为此,基于Gibson一维大应变固结理论和Hansbo径向固结理论,摒弃小应变假定,考虑高含水率疏浚泥的材料和几何非线性、径竖向渗流等因素,建立了等应变条件下以孔隙比为变量的轴对称大应变固结模型ALSC,Gibson、Hansbo、Kjellman等建立的固结方程是该模型的特例。基于有限差分法,编制了计算程序,进行了ALSC模型与小应变模型的数值模拟,验证了ALSC的有效性。研究结果表明:土体变形较小时,ALSC模型与Barron模型计算的固结度和超静孔压数值基本吻合;土体变形较大时,ALSC模型与"Barron+Terzaghi"理论计算的最终沉降量和固结速率取决于土体的固结参数;当C_c/C_k=1时,ALSC模型的最终沉降量小于"Barron+Terzaghi"理论,但二者固结速率相当;当压缩系数av保持不变,ALSC模型(C_k=1)与"Barron+Terzaghi"相比,最终沉降量大,固结速率慢。
Large strain generally occurs in dredged clay with high water content under external loading. The traditional axisymmetric small-strain consolidation theory developed by Barron is no longer applicable. Based on the Gibson large-strain consolidation theory and the Hansbo equal-strain consolidation theory, the axisymmetric large strain consolidation(ALSC) model is established under equal strain. ALSC accounts for radial and vertical flows and variation of compressibility and permeability of dredged clay with high water content. The equations established by Gibson, Hansbo and Kjellman are the special cases of ALSC. Based on the finite difference method, the calculation program for ALSC is compiled. The ALSC model and the small-strain model are simulated, and the validity of ALSC is verified. The results show that when the soil deformation is small, the predicted consolidation degree and the excess pore water pressure results of ALSC model are in good agreement with the Barron ones. When the soil deformation is large, the final settlement and consolidation rate of ALSC model and "Barron+Terzaghi" model depend on soil parameters. When C_c/C_k=1, the final settlement of ALSC model is less than that of "Barron+Terzaghi" model, but the consolidation rate is relatively the same. If the compression coefficient av remains unchanged during consolidation process, the final settlement is larger but the consolidation rate is slower for ALSC model(C_k=1) than the ones for "Barron+ Terzaghi" model.