(1. 河南理工大學(xué) 能源科學(xué)與工程學(xué)院，焦作 454003；
2. 江西理工大學(xué) 資源與環(huán)境工程學(xué)院，贛州 341000；
3. 河南理工大學(xué) 煤炭安全生產(chǎn)與清潔高效利用省部共建協(xié)同創(chuàng)新中心，焦作 454003；
4. 中南大學(xué) 資源與安全工程學(xué)院，長沙 410083)
摘 要: 為探究熱處理后礦巖的動態(tài)力學(xué)特性及損傷破壞特征，以含銅矽卡巖為研究對象，開展“巖樣密度、熱處理溫度、沖擊氣壓”三因素影響下的動態(tài)沖擊試驗研究。研究結(jié)果表明：“三因素”對含銅矽卡巖本構(gòu)曲線變化趨勢的影響不明顯，都未改變動態(tài)壓縮應(yīng)力-應(yīng)變曲線先后經(jīng)歷的似直線段、非線性上凸段、類平臺段和峰后下降段；但含銅矽卡巖的動態(tài)峰值應(yīng)力、動態(tài)變形模量卻隨熱處理溫度的升高而減小，隨巖樣密度的增大而增大；基于生物種群理論定義了可反映熱損傷程度的損傷變量，并得出巖樣內(nèi)部損傷先后經(jīng)歷了緩慢增加-快速增加-減速增加-宏觀破壞四個階段；接著，通過捕捉?jīng)_擊過程中巖樣的損傷歷程、分析破碎塊度的形狀及分形維數(shù)特征，得出裂紋起裂于巖樣入射端，且分形維數(shù)的變化規(guī)律與破碎巖塊塊度隨熱處理溫度、巖樣密度、沖擊氣壓變化而變化的規(guī)律相呼應(yīng)；最后結(jié)合巖樣內(nèi)部破裂面形態(tài)及碎塊多呈長條狀、三棱錐狀和粉末狀，得出熱處理后含銅矽卡巖的破壞模式復(fù)雜多變，且以拉伸破壞和壓剪破壞為主，以混合型摩擦破壞為輔。基于研究結(jié)論，可推測熱處理溫度、動態(tài)擾動都對礦巖的動態(tài)強度劣化、損傷破碎程度起促進作用，而巖樣密度的增大有利于提升礦巖抗外界沖擊荷載的能力，其為深部資源開發(fā)利用及圍巖狀態(tài)控制方案的制定提供了理論參考。
關(guān)鍵字: 高溫處理；含銅矽卡巖；動態(tài)力學(xué)特性；損傷破碎特征；分形維數(shù)
（1. School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China;
2. School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China;
3. Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Henan Polytechnic University, Jiaozuo 454003, China;
4. School of Resources and Safety Engineering, Central South University, Changsha 410083, China）
Abstract:To explore the dynamic mechanical characteristics and damage failure behavior of the rock after heat treatment, a dynamic impact study was conducted on copper-bearing skarn under the influence of three factors: density, heat treatment temperature and impact pressure. The results show that the influences of the "three factors" on the trend of the constitutive curves of copper-bearing skarn were not obvious, and cannot change the approximate straight stage, nonlinear upward convex stage, plateau-like stage and post-peak stage of the dynamic compression stress-strain curves. However, the dynamic compressive strength and deformation modulus of copper-bearing skarn decrease with the increase of heat treatment temperature, but increase with the increase of sample density. Based on the biological population theory, the damage variables reflected the thermal damage degree is defined and it is found that the internal damage of rock samples have experienced four stages successively: slow increase-rapid increase-deceleration increase-macroscopic failure. Then, by capturing the damage history of rock sample during the impact process and analyzing the shapes and fractal dimension behaviors of rock fragments, it is found that the cracks initiate from the incident end of rock sample, and the changed rules of fractal dimension corresponded to the variation of the fragmentation with the change of heat treatment temperature, density and impact pressure. Finally, combined with the internal fracture surfaces of rock and the fragments which are mostly shown as long strip, triangular pyramid and powder shape, it could be obtained that the failure modes of copper-bearing skarn after heat treatment are complex and variable, which are mainly tensile and compression-shear failure and supplemented by mixed friction failure. Based on the conclusions, it could be speculated that the heat treatment temperature and dynamic disturbance promote the dynamic strength degradation and damage failure degree of deep ore rocks, and the increase of sample density is beneficial to improve the ability to resist external impact loads, which could provide theoretical references for the exploitation and utilization of deep resources and the formulation of surrounding rock state control scheme.
Key words: high temperature treatment; copper-bearing skarn; dynamic mechanical characteristic; damage-fracture behavior; fractal dimension
