基于颗粒流GBM模型的花岗岩热力损伤特性研究  

Study on Study on thermal damage characteristics of granite based on GBM modeling method of particle flow thermal damage characteristics of granite based on GBM modeling method of particle

作　　者：闫程锦 郤保平[2] YAN Chengjin;XI Baoping(Department of Architectural Engineering,Shanxi Engineering Vocational College,Taiyuan030000,Shanxi,China;College of Mining Engineering,Taiyuan University of Technology,Taiyuan030024,Shanxi,China)

机构地区：[1]山西工程职业学院建筑工程系,山西太原030000 [2]太原理工大学矿业工程学院,山西太原030024

出　　处：《水利水电技术（中英文）》2024年第5期170-180,共11页Water Resources and Hydropower Engineering

基　　金：国家自然科学基金项目(51874207)。

摘　　要：【目的】为了研究花岗岩在热力耦合作用下的裂纹扩展规律及损伤特征,揭示岩石细观结构演化对其力学行为的影响,【方法】基于颗粒流GBM算法,建立了非均质花岗岩热力耦合数值模型,研究20℃及高温(200℃、400℃、600℃和800℃)处理后花岗岩细观裂纹演化规律及力学行为。【结果】结果显示,热致裂纹数量随热处理温度升高显著增加,且所有热处理温度下,花岗岩模型中热致裂纹均以矿物晶界的拉伸裂纹为主;当热处理温度超过400℃后,石英和长石矿物内部开始萌生大量晶内拉伸与晶内剪切裂纹。【结论】结果表明:热致裂纹的萌生、扩展和贯通导致花岗岩的力学性质劣化,随着热处理温度升高,花岗岩峰值强度和弹性模量减小,而峰值应变增加;当温度大于600℃时,热致裂纹开始主导花岗岩试件的最终破坏模式,同时应力-应变曲线峰后阶段开始由脆性向延性转变;热致裂纹随热处理温度的升高而显著增加,导致花岗岩在单轴加载的早期阶段产生了更多的声发射事件。此外,轴向应力引起花岗岩试件内部的应力重分布,应力集中区域产生更多应力诱导裂纹,并最终引起失稳破坏。[Objective]It is great significance to study the crack propagation law and damage characteristics of granite under thermal-mechanical coupling,and to reveal the influence of rock microstructure evolution on its mechanical behavior.[Methods]Based on the GBM modeling method of particle flow code,a thermal-mechanical coupling numerical model representing the heterogeneous microstructure of granite is established.The evolution law and mechanical behavior of micro-cracks in granite at 20℃and treated under high temperatures(200℃,400℃,600℃and 800℃)are studied.[Results]The numerical results show that the number of thermal-induced cracks increases significantly with the increase of heat treatment temperature,and the thermal-induced cracks in granite model are mainly tensile cracks at mineral grain boundaries.When the heat treatment temperature exceeds 400 ℃, a large number of intragranular tensile and shear cracks begin to initiate in quartz and feldspar minerals. [Conclusion]The initiation, propagation and coalescence of thermally induced cracks lead to the deterioration of mechanical properties of granite. With the increase of heat treatment temperature, the peak strength and elastic modulus of granite decrease, while the peak strain increases. When the temperature rises to 600 ℃, thermal-induced cracks begin to dominate the final failure mode of granite, and the post-peak stage of stress-strain curve change from brittleness to ductility. Due to the obvious increase of thermal-induced cracks with the increase of heat treatment temperature, granite produce more acoustic emission events in the ear-ly stage of uniaxial loading. In addition, axial stress causes stress redistribution in granite, and more stress-induced cracks are produced in stress concentration areas, which eventually leads to instability and failure.

关 键 词：花岗岩 GBM模型 热致裂纹演化 声发射特征 力学行为 力学性能 

分 类 号：TU45[建筑科学—岩土工程]