干燥及饱水充填体的动载破坏特性研究

Research on dynamic load failure characteristics of dry and saturated backfill

为了研究不同料浆质量分数的饱水与干燥状态下的充填体在动载冲击下的力学特性,采用分离式霍普金森杆(SHPB)装置对其进行冲击加载,得出两种状态下的应力-应变曲线,并从损伤力学的角度利用Lemaitre应变等价原理与Mazars模型对试验数据进行分析。试验结果表明:料浆质量分数相同时,饱水状态下充填体的极限应力均小于干燥状态下的充填体,说明孔隙水压的存在使充填体更加容易破坏,同时饱水充填体料浆质量分数越大,其刚度越高,达到破坏应力时的变形量越小。在弹性变形阶段,干燥状态充填体更易损伤,在变形破坏阶段饱水状态充填体损伤程度要高于干燥状态,同时得出其损伤本构模型与损伤演化方程。

The stress-strain curve of two states is developed u- sing SHPB to make the dynamic load impact test for researching the mechanical properties of saturated water at different concen- tration and dry backfill under the dynamic load impact and the test data are analyzed in the Lemaitre equivalent strain principle and adopting Mazars model from the perspective of damage me- chanics. The test results show that with the same concentration, the saturated backfill is smaller than dry backfill in limiting stress ,which indicates that the existence of pore water pressure makes the backfill be more easy to break and the higher t the concentra- tion of saturated backfill, the higher its stiffness and the smaller the deformation in failure stress. In the elastic deformation stage, the dry backfill is more likely to damage and in the deformation failure stage, the damage degree for saturated backfill is greater than dry backfill. The damage constitutive model and damage evo- lution equation are developed.