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对饱和哈尔滨黏土进行7次冻融循环后,在不同围压和应变速率下进行固结不排水三轴剪切试验,分析融化饱和黏土的有效偏应力及孔隙水压力随应变速率的发展规律。结果表明,融化饱和哈尔滨黏土在小于240 kPa的围压下表现出超固结特性,在240 kPa围压下表现为正常固结或者轻度超固结特性。随着应变速率的增大,融化哈尔滨黏土的强度变化规律以0.15 h~(-1)为节点分为2个阶段:当应变速率小于0.15 h~(-1)时,试件的强度随着速率的增大先增大后减小,当应变速率超过0.15 h~(-1)时,试件的强度随着速率的增大持续增大;孔隙水压力的发展趋势随着围压的增大由软化型转变为硬化型,但各围压下的应变速率效应对孔隙水压力的发展趋势影响不明确;利用广义双曲线模型对试验数据进行分析拟合,研究表明,该模型能够合理的描述融化哈尔滨黏土的应变速率效应。
After seven freeze-thaw cycles of saturated clay, the consolidated undrained triaxial shear tests were carried out at different confining pressures and strain rates, and the effective deviatoric stress and the law of pore water pressure with strain rate were analyzed. The results show that the thawed Harbin clay exhibits overconsolidation behavior at confining pressures less than 240 kPa and shows normal consolidation or mild overconsolidation at 240 kPa confining pressure. With the increase of strain rate, the variation of strength of Harbin clay melt is divided into two stages with 0.15 h ~ (-1) node as node. When the strain rate is less than 0.15 h ~ (-1) When the strain rate exceeds 0.15 h ~ (-1), the strength of the specimen increases with the increase of the velocity. The development trend of the pore water pressure increases with the increase of the confining pressure However, the effect of strain rate under confining pressure on the development trend of pore water pressure is not clear. By using generalized hyperbola model, the experimental data are analyzed and fitted. The results show that the model can be reasonable Describe the strain rate effect of melting Harbin clay.