湖相沉积泥炭质土蠕变特性

    Creep characteristics of lacustrine sedimentary peaty soil

    • 摘要: 利用SLB-1型应力应变控制式三轴剪切渗透试验仪,对湖相沉积泥炭质土进行三轴固结不排水蠕变试验,研究泥炭质土在不同围压及偏应力条件下的蠕变过程,并通过“陈氏法”得到分级加载下蠕变曲线。三轴蠕变试验研究表明:原状样在围压为50,100 kPa时,应变时间关系呈现明显的衰减蠕变特征,而当围压为200 kPa,偏应力为129 kPa时表现为明显的非衰减蠕变特征;重塑较原状样能承受的加荷等级少;“陈氏法”较Boltzmann线性叠加法更加适用于处理蠕变数据。以围压100 kPa下的蠕变试验曲线为例,结合最小二乘法的拟合分析,建立了广义kelvin模型与改进分数阶Maxwell蠕变模型,得到的蠕变模型具有参数少、适用性较强的特点。

       

      Abstract: By using the SLB-1 stress-strain controlled triaxial shear permeability tester, the triaxial consolidation undrained creep tests on lacustrine sedimentary peaty soil are carried out to study its creep process under different confining pressures and partial stresses, and the creep curve under graded loading is obtained by the Chen's method. The results of the triaxial creep tests show that the strain-time relationship of the undisturbed samples exhibits obvious attenuation creep characteristics when the confining pressure is 50 and 100 kPa, while it exhibits obvious non attenuation creep characteristics when the confining pressure is 200 kPa and the deviating stress is 129 kPa. The remolded sample can bear less loads than the original one. The Chen's method is more suitable for processing the creep data than the Boltzmann's linear superposition method. Taking the creep tests under the confining pressure of 100 kPa as an example, by combining with the fitting analysis of the least square method, the generalized Kelvin model and the improved fractional Maxwell creep model are established. The obtained creep model has the characteristics of few parameters and strong applicability.

       

    /

    返回文章
    返回