充填体单轴加载速率效应的模拟分析

在矿山开采中充填体发生的卸荷破坏与室内的不同加载速率下的加载破坏过程十分相似。为探究充填体的力学特性与加载速率的关系,采用PFC2D数值模拟建立充填体模型,施加5种不同的加载速率试验。结果表明:1)充填体抗压强度随着加载速率的增大而呈多项式关系增长。峰值应变呈S状曲线增大,弹性模量先增后减。2)裂纹演化与损伤能耗的演变规律相似,速率越小,曲线拐点到来越早。3)模型的主要破坏形式为张拉破坏,速率增大,由单调破坏向多种破坏发展,裂纹分布更密集。4)不同加载速率下充填体的破坏形式统一,但速率的不同使得能耗增长速率和所需总能耗量存在差异。

Analysis of uniaxial loading rate effect of backfill based on particle flow simulation

The load unloading failure process in mining engineering is very similar to the loading failure process at different loading rates in the room. In order to explore the relationship between the mechanical properties of the backfill and the loading rate, the PFC2D numerical simulation method was used to establish the backfill, and five different loading rate tests were applied. The results show that: 1) The compressive strength of the backfill body increases linearly with the increase of the loading rate. The peak strain increases in an S-shaped curve, and the modulus of elasticity increases first and then decreases. 2) The evolution of cracks is similar to the evolution of damage energy consumption, the smaller the rate, the earlier the curve inflection point arrives. 3) The main form of destruction of the model is tensile failure, the rate increases, from monotonous destruction to multiple failures, and the crack distribution is more dense. 4) The destruction form of the backfill body under different loading rates is uniform, but the difference in the rate makes the energy consumption growth rate and the total energy consumption required differently.