高级检索

    激光作用下砂岩表面热响应分区特征与温度时空演化规律

    Thermal-response zonation and spatiotemporal evolution of surface temperature in sandstone under laser irradiation

    • 摘要: 浅部易开采矿产资源正逐渐枯竭,矿山开发向深部延伸已成为必然趋势。传统机械破岩技术在深部高围压硬岩条件下往往面临着钻进效率降低、钻头磨损加剧和环境污染等问题。激光破岩技术凭借其高能量密度、高作用效率以及可实现远距离无接触破岩等显著优势,在深部破岩中具有广阔的应用前景。以我国西部深埋典型硬质砂岩为研究对象,采用自主研发激光致裂弱化硬岩实验装置联合有限元数值分析方法,系统讨论了激光作用下砂岩表面热响应的分区特征与温度场时空演化规律。研究结果表明:激光作用下砂岩上表面温度场呈现出典型高斯分布特征,砂岩表面温度会随激光照射时间的增加而呈整体上升且逐渐均匀趋势;激光功率是影响岩石热响应的重要因素,激光功率的提升会导致岩石温升速率和温度梯度的不断上升;光斑直径的增大则会导致激光束能量均布化,热影响范围变大,但中心区域能量聚集效应减弱;岩石热导率的增加扩大了激光热影响区范围,但使得温度水平整体呈下降趋势;比热容的增加和吸光率的减少使激光热影响区范围减小且温度水平呈下降趋势。研究成果系统揭示了激光作用下砂岩热响应分区特征以及温度场的演化规律,为深部硬岩激光破碎机制的定量化认识提供了可靠依据,也为深地激光破岩理论研究与激光破岩实际工程的参数选择提供参考。

       

      Abstract: As shallow, easily accessible mineral resources are progressively depleted, the extension of mining operations into deep rock masses has become an inevitable trend. Traditional mechanical rock breaking techniques often encounter challenges under deep-seated, high confining pressure, and hard rock conditions, such as reduced drilling efficiency, accelerated drill bit wear, and environmental impacts. Laser rock breaking technology, leveraging significant advantages such as high energy density, high interaction efficiency, and the capability for remote, contactless fragmentation, holds broad application prospects in deep rock engineering. Taking typical deep-buried hard sandstone from Western China as the research object, this study utilizes a self-developed laser-induced fracturing and weakening test apparatus combined with Finite Element Method (FEM) numerical analysis. It systematically investigates the zonal characteristics of the thermal response and the spatiotemporal evolution of the temperature field on the sandstone surface under laser irradiation. The results indicate that the temperature field on the sandstone's upper surface exhibits a typical Gaussian distribution. With increasing laser irradiation time, the overall surface temperature rises and shows a trend towards gradual homogenization. Laser power is a crucial factor influencing the rock's thermal response; an increase in laser power leads to a continuous rise in both the heating rate and the temperature gradient. An increase in spot diameter results in a more uniform distribution of the laser beam energy, leading to an expanded Heat-Affected Zone (HAZ), but weakens the energy concentration effect in the central region. Increased rock thermal conductivity enlarges the laser HAZ but causes an overall decrease in the temperature level. Conversely, an increase in specific heat capacity and a decrease in absorptivity reduce the laser HAZ and lower the overall temperature level. The research findings systematically reveal the zonal characteristics of the thermal response and the evolutionary laws of the temperature field in sandstone under laser irradiation. This provides a reliable basis for the quantitative understanding of the laser fragmentation mechanism in deep hard rock, and offers a reference for theoretical research on deep-rock laser rock breaking and for parameter selection in practical laser rock breaking engineering.

       

    /

    返回文章
    返回