土体冻融过程温度场与位移场耦合分析

Temperature-displacement field coupling analysis in freeze-thaw process of soil

通过ABAQUS软件进行了土体冻融过程温度场及位移场耦合分析,选取土体物理力学参数为温度场函数,模型边界条件与室内试验完全相同,提出了土体冻融过程的温度场、位移场耦合数值计算方法,即先进行土体冻融过程温度场模拟,然后将温度场作为场变量引入下一步的土体位移计算中,为保证同一时刻土体温度场和位移场相对应,在两步计算中调整时间步长应一致。计算结果表明:在土体室内冻融试验曲线中,土体在冻融开始阶段有历时不长的冻胀现象,之后进入持续融沉状态,而数值计算曲线中,对土体冻胀阶段反映不明显;由于冻胀量很小,土体总体变形主要表现为融沉变形,因此冻胀现象的差异并不影响土体最终沉降状况,可利用给出的计算方法进行冻土融沉数值模拟。

The temperature-displacement coupling simulation is carried out in freeze-thaw process of soil using ABAQUS software, the physical and mechanical parameters of soil is defined as function of temperature, the boundary conditions of simulation model is uniform to that of laboratory test mode, which is to carry out soil temperature field numerical simulation in freeze -thaw process firstly, and then, as field variable, the temperature field is introduced when displacement field is simulated. In order to ensure temperature field is correspond to displacement field at the same time, time step of calculation is identical in the two fields simulating. The simulation results show that in laboratory test the phenomenon of frost swelling occurs at earlier stage of freeze-thaw process and then at the thawing statement continually, the phenomenon of frost swelling does not happen in simulation curves. Since the frost swelling is tiny, it would not affect final soil settlement. So the presented numerical method is propitious to simulate frozen soil thawing. 1 tab, 7 figs, 10 refs.