不同冷却速率下高温花岗岩微裂纹演化及力学性能仿真研究OA
Simulation Study on Microcrack Evolution and Mechanical Properties of High-Temperature Granite Under Different Cooling Rates
花岗岩作为典型干热岩储层岩体,在使用增强型地热系统(EGS)开采时常受到不同冷媒介质作用.研究结合室内试验与仿真模拟,建立考虑不同矿物组分的PFC-GBM仿真模型,深入分析了试样在空气、水和液氮冷却过程中微裂纹分布演化、数量规律及形成机制,并进一步探讨了不同冷却速率下高温花岗岩力学性能及破坏模式变化.结果表明:随着冷却速率的增大,微裂纹总数量显著增加,呈液氮冷却>水冷却>自然冷却的趋势,集中分布于矿物颗粒边界及石英晶粒内部;高温条件下晶界拉伸微裂纹占比超60%,石英晶内拉伸微裂纹占比约为20%,其微裂纹网络形成主要由3种矿物协同控制:石英体积变化主导网络形成,长石节理面控制扩展路径,云母结构调节应力;冷却速率显著影响高温花岗岩的力学性能及破坏模式,冷却速率越高,抗压强度和弹性模量降低幅度越大,峰后行为逐渐由脆性向延性转变,且塑性变形增强,破坏模式主要为复杂的多裂纹及块状结构.当温度低于450℃时,液氮冷却下花岗岩破坏模式及力学性能劣化更为明显;而在较高温度下,水冷却提供了一种更经济实用的替代方案.该研究结果为地热能源的有效开采提供一定参考.
Granite,as a typical rock mass of hot dry rock reservoirs,is often subjected to different refrigerant media during exploitation using Enhanced Geothermal System(EGS).In this study,a PFC-GBM simulation model was established by combining indoor experiments and simulation,and the evolution of microcracks distribution,number and formation mechanism of the specimens during the cooling process of air,water and liquid nitrogen were analyzed in depth.Furthermore,the changes in the mechanical properties and damage modes of high-temperature granite under different cooling rates were further explored.The results show that:with the increase of cooling rate,the total number of microcracks increased significantly,showing the trend of liquid nitrogen cooling>water cooling>natural cooling,concentrated in the boundary of the mineral particles and quartz grains;under high temperature conditions,intergranular tensile microcracks account for more than 60%,and intragranular tensile microcracks in quartz account for about 20%.The formation of microcrack network is mainly controlled by three minerals:quartz volume change dominates the network formation,feldspar nodal surface controls the expansion path,and mica structure regulates the stress.The cooling rate significantly affects the mechanical properties and damage mode of high-temperature granite.The higher the cooling rate,the greater the reduction range of compressive strength and modulus of elasticity,and the post-peak behavior is gradually shifted from brittleness to ductility,and the plastic deformation is enhanced,with the damage mode mainly characterized by complex multi-cracks and block-like structures.When the temperature is lower than 450℃,the damage mode and mechanical property degradation of granite under liquid nitrogen cooling are more obvious;while at higher temperatures,water cooling provides a more economical and practical alternative.The results of this study provide a reference for the effective exploitation of geothermal energy from dry-heat rocks.
苗箫雨;荣冠;邱钦焱;吕祖豪;全军松;王顺
武汉大学 水资源工程与调度全国重点试验室,湖北 武汉 430072||武汉大学 水工岩石力学教育部重点试验室,湖北 武汉 430072武汉大学 水资源工程与调度全国重点试验室,湖北 武汉 430072||武汉大学 水工岩石力学教育部重点试验室,湖北 武汉 430072武汉大学 水资源工程与调度全国重点试验室,湖北 武汉 430072||武汉大学 水工岩石力学教育部重点试验室,湖北 武汉 430072武汉大学 水资源工程与调度全国重点试验室,湖北 武汉 430072||武汉大学 水工岩石力学教育部重点试验室,湖北 武汉 430072武汉大学 水资源工程与调度全国重点试验室,湖北 武汉 430072||武汉大学 水工岩石力学教育部重点试验室,湖北 武汉 430072武汉大学 水资源工程与调度全国重点试验室,湖北 武汉 430072||武汉大学 水工岩石力学教育部重点试验室,湖北 武汉 430072
建筑与水利
高温花岗岩冷却速率PFC-GBM模型微裂纹力学性能
high-temperature granitecooling ratePFC-GBM modelmicro-cracksmechanical properties
《中国农村水利水电》 2026 (6)
214-221,8
国家自然科学基金面上项目(42472352、41772305).
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