高温作用对3种砂岩物理参数特征的影响分析

Research on Physical Parameters of Three Kinds of Sandstone after High Temperature

基于3种煤层顶底板砂岩经历400~1 000℃高温前、后进行了X射线衍射和物理参数测试,分析高温作用对3种砂岩试样矿物成分及物理参数的影响。试验结果表明:高温后3种砂岩矿物晶体发生了相变,矿物成分发生较大变化;经历400℃高温对3种砂岩试样物理参数的影响甚微,超过400℃高温后试样视密度、波速与温度呈负相关,体膨胀率和烧失率与温度呈正相关。高温后3种砂岩试样视密度与纵波波速呈正相关,烧失率、体膨胀率与纵波波速呈负相关,高温后3种砂岩的物理参数之间具有一定关联性,岩石物理参数是对岩性特征宏观表述。研究结果可为局部区域煤层自燃对隧道围岩稳定性、安全性评价以及支护设计提供一定的参考。

To analyze the influence of high temperature on mineral components and physical parameters of sandstone,X-ray diffraction and physical tests were conducted on three kinds of sandstone which were sampled from roof and floor of coal seam and processed by high temperature ranging from 400 ℃ ~ 1 000 ℃. The results show that phase transformation occurred in the three kinds of sandstone samples after high temperatures,mineral components had a lager change. Within 400 ℃,The influence of high temperature on mineral components is very little; above600 ℃,The relationship between apparent density,wave velocity and temperature is a negative linear correlation,The relationship between expansion rate,wave velocity and ignition loss is a positive linear correlation. After high temperature wave velocity of three kinds of sandstone samples has a positive linear relationship with apparent density,which has a negative linear correlation with expansion rate and ignition loss. Physical parameters of sandstone sample after high temperature have a certain correlation,which is a macroscopical description of rock characteristics. The results can provide a reference for the stability,safety evaluation and support design of tunneling surrounding rock after spontaneous combustion of coal seam.