膏体充填开采胶结体的蠕变本构模型

为分析膏体充填开采胶结体的蠕变特性，进行了三轴蠕变试验。在试验基础上推导了考虑时间和应力2个变量的损伤演化方程，将损伤变量引入改进的西原模型中，建立了新的本构模型，推导了胶结体的三维蠕变本构方程。根据试验数据对该模型的蠕变参数进行拟合，将理论计算的蠕变曲线与试验得到的蠕变曲线进行了对比。研究结果表明：膏体充填开采胶结体属于黏弹塑性材料，具有明显的流变特性。在偏差应力值较小的应力水平下仅有衰减蠕变和稳态蠕变2个蠕变过程，在偏差应力较大时有加速蠕变阶段，蠕变值随偏差应力值的增加而增加，蠕变值增大速率随偏差应力值的增加而减弱。引入损伤的改进西原模型能较好地反映胶结体的蠕变规律。

Creep constitutive model of cemented body used in backfilling mining

In order to analyze the creep properties of cemented body used in backfilling mining，triaxial creep experiments were conducted.Based on these，the damage evolution equation considering time and stress was deduced，and damage variable was brought in modified Nishihara model，and the new constitutive model was established and the 3D creep equation of backfilling cemented body was deduced.The creep model parameters were integrated based on the experiment data，and the comparative analysis of creep curves in theory and on experiment was conducted.The findings show that backfilling cemented body is viscosity elastic plastic material and has obvious rheological characteristics，there are only decay creep and steady state creep when deviatoric stress is small，when it is big，there is accelerated creep.Creep amount increases with the increasing of stress，but increase rate is weakened.It shows that the modified Nishihara model considering damage can better reflect the creep law of backfilling cemented body.