Basic Research on Temperature- and Time-Depending Constitutive Equations for Cohesive Soils

通过变温度下的竖向恒压固结试验和恒应变率固结试验，研究了粘性土在一维压缩条件下的温度和时间效应，试验中考虑了土颗粒的热膨胀效应。从密度-温度关系确定热膨胀。该方法的有效性通过从两种试验中确定金属的热膨胀系数来评估：来测量长度的变化并利用密度温度关系。温度升高会导致孔隙比减小，二次压缩也会导致孔隙比减小。温度变化与二次压缩持续时间之间的理论关系，两者都会导致相同的孔隙比减小。比率推导出来。提出了一种粘性土的计算公式， ...更多信息 热膨胀的作用。由于CRS固结试验的基本理论和确定本构关系的方法中存在一定的假设，因此CRS固结试验不能确定土的本构特性。因此，为了研究压缩率对本构性质的影响，我们必须以某些方式估计真实性质。首先，建立基于CRS固结试验的时间本构模型，并利用该模型对CRS固结过程进行数值模拟;然后，将数值模拟结果与真实的固结试验结果进行比较，并在差异超过一定范围时对模型进行修正。采用有限变形有限元法进行了数值模拟。该过程可以评估压缩率对本构模型中参数的影响。少

Temperature- and time-depending behavior of cohesive soils in one-dimensional compression conditions was studied vertical-pressure-constant consolidation tests under varying temperature and constant-rate-of-strain (CRS) consolidation tests.The effects of thermal expansion of soil particles were considered in results from tests conducted with varying temperature from 20 to 80℃. The thermal expansion was determined from density-temperature relationships. The validity of the method was evaluated by determining thermal expansion coefficients of a metal from two kinds of tests : to measure the change in length and to use the density-temperature relationships.Raising temperature causes the decrease in void ratio and secondary compression also causes it. A theoretical relationship between the change in temperature and the secondary compression duration both of which will cause an identical decrease in void ratio was derived. The relationship for a cohesive soil was presented with the consider … More ation of the thermal expansion. The account of thermal expansion resulted in a higher degree of thermally promoted consolidation.Constitutive properties of a soil can not be determined from the CRS consolidation test because of assumptions included in the basic theory and the method for determining constitutive relationships. Therefore, in order to examine the effects of compression rate upon the constitutive properties, we have to estimate true properties in certain ways. The following procedures were employed : at first, to make a temporal constitutive model based on the CRS consolidation test and to numerically simulate the behavior in the CRS consolidation with the model ; second, to compare the behavior of numerical simulation with that of the real consolidation test and to modify the model if the difference is observed beyond a certain limit. The numerical simulation was done by the finite-deformation finite-element method. This process could assess the effects of compression rate on the parameters in the constitutive model. Less