循环升温-水冷作用下花岗岩的力学特征与破坏模式  

Mechanical Properties and Failure Modes of Granite under the Condition of Cyclic Heating and Water-cooling

作　　者：杨敏 杨磊[1] 李玮枢 梅洁[1] 盛祥超 李景龙[3] YANG Min;YANG Lei;LI Wei-shu;MEI Jie;SHENG Xiang-chao;LI Jing-long(Geotechnical and Structural Engineering Research Center, Shandong University, Jinan 250061, China;Tongyuan Design Group Co., Ltd., Jinan 250101, China;School of Civil Engineering, Shandong University, Jinan 250061, China)

机构地区：[1]山东大学岩土与结构工程研究中心,济南250061 [2]同圆设计集团有限公司,济南250101 [3]山东大学土建与水利学院,济南250061

出　　处：《科学技术与工程》2021年第32期13828-13836,共9页Science Technology and Engineering

基　　金：国家自然科学基金青年科学基金(51509146)。

摘　　要：干热岩储层改造过程中高温岩石处于反复升温-水冷状态,其破裂力学特性直接影响储层改造效果。基于室内试验和有限元数值模拟,研究了循环升温-水冷对花岗岩力学特征和破裂模式的影响,探讨了花岗岩的力学性能劣化规律和破裂过程。研究表明:温度对花岗岩力学特性影响显著,升温导致花岗岩强度和弹性模量呈降低趋势,整体塑性增强,而经多次升温-水冷处理后岩石脆性得到一定程度的提高,花岗岩弹性模量变化受升温温度及循环升温-水冷次数共同控制;随温度升高,花岗岩由劈裂-剪切复合破坏转变为剪切破坏,且破裂程度明显提高;当循环次数较低时,温度是影响花岗岩破裂模式的主导因素,伴随循环次数增多,花岗岩内部损伤加剧,在压缩荷载作用下呈现复杂的剪切-劈裂混合破坏模式。During the reformation process of hot dry rock reservoirs,the high-temperature rocks are in a state of repeated heating and water-cooling,and the mechanical properties and failure modes impact directly the reservoir reformation effect.Based on laboratory experiments and finite element numerical simulations,the effects of cyclic heating and water-cooling on the mechanical properties and failure modes of granite were studied,and the deterioration of mechanical properties and failure process of granite were discussed.The research indicates that the temperature has a significant effect on the mechanical performance of granite.An increasing temperature leads to the decrease of strength and elastic modulus,and the plasticity increases.However,the brittleness of granite is improved to a certain extent after several times of cooling treatments.The change of elastic modulus of granite is controlled jointly by the temperature and the cycle number of heating and cooling.With the increase of temperature,the failure of granite changes from the splitting-shear mixed mode to the shear mode,and the degree of fracture increases significantly.When the cycle number is small,the temperature is the dominant factor affecting the failure mode.With the increase of the cycle number,the internal damage of granite is intensified,showing a complex splitting-shear mixed failure modes under the action of compressive loading.

关 键 词：花岗岩 循环升温冷却 力学特征 破坏模式 室内试验 数值模拟 

分 类 号：TU452[建筑科学—岩土工程]