(中南大學(xué) 資源與安全工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 利用改進(jìn)的巖石動(dòng)靜組合加載SHPB試驗(yàn)系統(tǒng)，開(kāi)展矽卡巖在不同靜力軸壓水平上以不同卸載速率的卸載過(guò)程中受頻繁動(dòng)力擾動(dòng)作用的動(dòng)力學(xué)試驗(yàn)，研究矽卡巖在高靜應(yīng)力卸載過(guò)程中受頻繁動(dòng)力擾動(dòng)作用下的動(dòng)力學(xué)特性，重點(diǎn)討論靜力軸壓大小和卸載速率對(duì)巖石受頻繁動(dòng)力擾動(dòng)時(shí)的動(dòng)力學(xué)特性的影響。結(jié)果表明：當(dāng)卸載軸壓一定時(shí)，累計(jì)擾動(dòng)沖擊次數(shù)與卸載速率成線性正相關(guān)關(guān)系；而當(dāng)卸載速率一定時(shí)，累計(jì)擾動(dòng)沖擊次數(shù)與軸壓成線性負(fù)相關(guān)關(guān)系；隨著軸壓卸載速率的增大，當(dāng)卸載軸壓較小時(shí)，動(dòng)態(tài)變形模量先增大后減小；而當(dāng)軸壓較大時(shí)，動(dòng)態(tài)變形模量持續(xù)減小；巖石動(dòng)態(tài)峰值應(yīng)力與動(dòng)力擾動(dòng)次數(shù)呈二次函數(shù)關(guān)系，但隨卸載速率的增加，動(dòng)態(tài)峰值應(yīng)力與擾動(dòng)沖擊次數(shù)關(guān)系逐漸過(guò)度為線性負(fù)相關(guān)關(guān)系；最大動(dòng)態(tài)應(yīng)變與擾動(dòng)沖擊次數(shù)呈正相關(guān)關(guān)系。
關(guān)鍵字: 巖石力學(xué)；動(dòng)靜組合加載；高靜應(yīng)力；軸壓卸載速率；動(dòng)力學(xué)特性；頻繁動(dòng)力擾動(dòng)
（School of Resources and Safety Engineering, Central South University, Changsha 410083, China）
Abstract:Dynamic experiments on skarn were conducted with a modified one-dimensional coupled static and dynamic loads based on SHPB device, in which rock samples were frequently dynamically disturbed in the process of static unloading with different static unloading rates on different levels of high static axial compression, in order to research the dynamic properties of skarn in the process of high static stress unloading and frequent dynamic disturbance, and focus on the influence of level of axial compression and axial compression unloading rate on the dynamic properties. The results show that there is a positive correlation between accumulated number of dynamic disturbance and axial compression unloading rate when level of unloading axial compression is constant. But when axial compression unloading rate is constant, the accumulated number of dynamic disturbance is negatively related with unloading axial compression. When static axial compression is small, the dynamic deformation modulus firstly increases with the increase of axial compression unloading rate and then it decreases, and when static axial compression is large, the dynamic deformation modulus decreases steadily. The relationship between dynamic peak stress and the dynamic disturbance times is a quadratic function, but with the increase of axial compression unloading rate, it gradually becomes a linear negative correlation. And maximum dynamic strain is positive correlated with the dynamic disturbance times.
Key words: rock mechanics; coupled static and dynamic load; high static stress; axial compression unloading rate; frequent dynamic disturbance
