摘要
为研究强冲击倾向性煤在多级循环加载条件下的能量耗散特征及损伤演化过程,在实验室开展了陕西某矿煤样的多级循环加载试验,试验研究结果表明:在多级应力循环下煤样的耗散能先迅速降低,后缓慢增加,当循环上限应力达到63%破坏载荷时,耗散能开始急剧增加;而能量耗散率先迅速降低,后逐渐稳定;煤样加卸载阶段弹性模量均有增大趋势,加载阶段弹性模量先迅速增大,后缓慢增加,而卸载阶段弹性模量变化较为平稳。采用累积耗散能定义循环加载中试件的损伤变量,并建立煤样损伤演化方程,通过试验和数值计算测定各个参数。理论和试验研究表明,基于能量耗散分析建立的冲击倾向性煤损伤演化方程能够较好反映煤样的损伤演化过程。
In order to study the energy dissipation features and damage evolution process of the bump proneness coal under the condition of the multi cyclic loadings,a multi cyclic loading experiment was conducted in a lab on the coal samples from a coal mine in Shaanxi.The experiment study showed that under the multi grade stress cycle,the dissipated energy of coal sample would be rapidly decreased firstly and then would be slowly increased.When the cycle upper stress reached at the 63% failure load,the dissipated energy would start the serious increased.But the energy dissipation rate would be firstly and rapidly decreased and then would be steadily stabilized.The elastic modulus of coal sample at the unloading and loading stage would be all in an increasing tendency.At the loading stage,the elastic modulus would be firstly increased rapidly and then would be slowly increased.But the variation of elastic modulus would be stable at the unloading stage.The damage variation of sample in a circulated loading with an accumulated dissipated energy definition was applied to establish the damage evolution equation of coal sample and each parameter was measured with the experiment and numerical calculation.The theoretical and experiment study showed that the damage evolution equation of the bump proneness coal established based on the energy dissipation analysis could well reflect the damage evolution process of coal sample.
出处
《煤炭科学技术》
CAS
北大核心
2017年第2期59-64,共6页
Coal Science and Technology
基金
国家自然科学基金资助项目(51574150)
关键词
强冲击倾向煤
多级循环加载
能量耗散
损伤变量
损伤演化
strong bump proneness coal
multi cyclic loadings
energy dissipation
damage variation
damage evolution
