不同含水率条件下花岗岩力学特性损伤规律研究

Study on the Damage Law of Granite Mechanical Properties Under Different Water Content Conditions

花岗岩在含水后的力学特性损伤规律对此类工程岩体稳定性评价具有重要的意义。选取某地花岗岩样,开展不同含水率花岗岩单轴压缩试验及断口扫描电镜试验,分析应力-应变特征,建立以单轴抗压强度和弹性模量进行量化的损伤演化规律,从微观角度分析不同条件下花岗岩的损伤机制。研究结果表明:该类花岗岩含水后力学性质发生明显的弱化,且单轴抗压强度累计损伤值均要大于弹性模累计损伤值,单轴抗压强度累计损伤为40.68%,弹性模量累计损伤为20.20%。破裂面矿物集合体体积发生膨胀,孔隙结构增多,结构变松散,断口表面呈糊状且均发生了不同程度的层状剥离。

The damage law of mechanical properties of hydrous granite is of great significance to the stability evaluation of this kind of engineering rock mass.The uniaxial compression test and SEM test of granite with different water content were carried out to analyze the stress-strain characteristics,established the damage evolution law quantified by compressive strength and elastic modulus,and analyzed the damage mechanism of granite under different water content conditions from the micro point of view.The results show that the mechanical properties of this kind of granite are obviously weakened after water cut,the cumulative damage value of uniaxial compressive strength of granite is greater than that of elastic modulus.The cumulative damage value of uniaxial compressive strength is 40.68%,and the cumulative damage value of elastic modulus is 20.20%.The volume of the mineral aggregate on the fracture surface expands,the pore structure increases,the structure becomes loose,and the fracture surface is mushy and layered peeling occurs in different degrees.