冻结泥炭质土分数阶蠕变模型参数确定及验证

Determination and Verification of Fractional Creep Model Parameters of Frozen Peat Soil

人工冻结法是在泥炭质土地层中施工的一种有效方法。为了更加准确地预测冻结泥炭质土的蠕变规律,以昆明地区泥炭质土为研究对象,配制了3种含水率的重塑试样,进行低温条件下的单轴抗压和单轴蠕变试验。在得到土体强度与冻结温度、含水量间的关系的基础上,引入分数阶微积分算子构建了人工冻结泥炭质土分数阶蠕变模型,并通过联立方程组的方法求得各项模型参数。研究结果表明,该模型可以较好地描述冻结泥炭质土在低应力水平下蠕变随温度、含水率的变化规律,计算结果与试验数据之间拟合度好;所建模型参数较少、易于确定且物理意义明确。该模型为淤泥质土层人工冻结壁变形计算提供一种有效方法。

Artificial freezing method is an effective method for construction in peat soil layer.In order to predict the creep law of frozen peat soil more accurately,three remolded samples with water content were prepared to carry out uniaxial compression and uniaxial creep tests at low temperature,taking peaty soil in Kunming area as the research object.Based on the relationship between soil strength,freezing temperature and water content,fractional order creep model of artificially frozen peat soil was established by introducing fractional order calculus operator,and the model parameters were obtained by simultaneous equations.The results show that the model can well describe the creep of frozen peaty soil with temperature and water content at low stress level,and the calculated results have a good fit with the experimental data.The model has few parameters,easy to determine and clear physical meaning,which can provide a reliable basis for the design and construction of artificial frozen wall in silty soil layer.