液氮半溶浸煤裂隙扩展试验研究

发布时间：2018-06-16 03:16

本文选题：饱水度 + 液氮　；参考：《煤炭工程》2017年03期

【摘要】：为分析液氮半溶浸作用下不同饱水度煤裂隙扩展特征,取山西无烟煤原煤煤样,利用自制的液氮半溶浸试验装置对不同饱水度煤样开展了半溶浸试验研究,测试了液氮作用前后煤样波速变化和表面微裂隙宽度扩展情况,结果表明:煤样的饱水度对液氮冷冻煤作用效果影响很大,饱和煤样波速改变率和裂隙宽度扩展率最大,半饱和煤样次之,干燥煤样最小;越靠近液氮作用面,煤样温度变化越大,液氮作用效果越显著,液氮溶浸煤样的波速变化率和裂隙宽度扩展率都最大;饱和、半饱和煤样微裂隙扩展的主要原因是水相变为冰引起的冻胀力,干燥煤样微裂隙扩展的主要原因是温度梯度引起的温度应力。
[Abstract]:In order to analyze the crack propagation characteristics of coal with different saturation degree under the action of liquid nitrogen semi-solution leaching, the semi-solution leaching test of coal samples with different saturated degrees was carried out by using the self-made liquid nitrogen semi-solution leaching test device, taking Shanxi anthracite raw coal sample. The variation of wave velocity and the propagation of surface microfracture width before and after the action of liquid nitrogen were measured. The results show that the saturation degree of coal sample has a great influence on the effect of liquid nitrogen freezing coal, and the change rate of wave velocity and the propagation rate of crack width of saturated coal sample are the greatest. The temperature change of coal sample is bigger, the effect of liquid nitrogen action is more significant, the rate of wave velocity change and crack width expansion of liquid nitrogen solution leaching coal sample are the biggest; saturation, the temperature of coal sample is near to the surface of liquid nitrogen, and the effect of liquid nitrogen action is more significant, the wave velocity change rate and crack width expansion rate of liquid nitrogen leaching coal sample are the largest. The main reason of micro-crack propagation in semi-saturated coal sample is the frost heaving force caused by the change of water phase into ice, and the temperature stress caused by temperature gradient is the main reason for the expansion of micro-crack in dry coal sample.
【作者单位】：石家庄市市政建设总公司;河北科技大学建筑工程学院;
【基金】：国家自然科学基金项目(51274079,51574139) 河北省自然科学基金项目(E2015208089)
【分类号】：TD712;TQ531

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