清原抽水蓄能电站含裂隙花岗岩三轴力学特征影响研究

为研究抽水蓄能电站工程中含预制裂隙花岗岩的力学特征,采用人工预制裂隙方法,设计开展了裂隙倾角与裂隙数量两个因素影响下的花岗岩三轴力学试验。试验结果表明,裂隙倾角对花岗岩承载应力的影响在于轴向应力方向,裂隙倾角愈大,愈靠近轴向应力方向,试样承载应力愈低,同时试样应变愈大。裂隙数量对花岗岩承载应力具有节点阶段特征,当裂隙数量超过9条,花岗岩承载应力差幅才显著,低于9条时差幅较小。基于试验数据获得了含裂隙花岗岩试样抗剪强度特征变化,两个裂隙特征因素对抗剪强度特征的影响主要在于黏聚力,初始裂隙物理损伤主要作用于花岗岩颗粒间黏结性。研究成果可为探讨花岗岩力学特征及工程设计提供参考。

Effect of fractures on mechanical behavior of sand powder 3D printing rock analogue under triaxial compression

In practical engineering applications,rock mass are often found to be subjected to a triaxial stress state.Concurrently,defects like joints and fractures have a notable impact on the mechanical behavior of rock mass.Such defects are identified as crucial contributors to the failure and instability of the surrounding rock,subsequently impacting the engineering stability.The study aimed to investigate the impact of fracture geometry and confining pressure on the deformation,failure characteristics,and strength of specimens using sand powder 3D printing technology and conventional triaxial compression tests.The results indicate that the number of fractures present considerably influences the peak strength,axial peak strain and elastic modulus of the specimens.Confining pressure is an important factor affecting the failure pattern of the specimen,under which the specimen is more prone to shear failure,but the initiation,expansion and penetration processes of secondary cracks in different fracture specimens are different.This study confirmed the feasibility of using sand powder 3D printing specimens as soft rock analogs for triaxial compression research.The insights from this research are deemed essential for a deeper understanding of the mechanical behavior of fractured surrounding rocks when under triaxial stress state.

Mechanical and damage evolution properties of sandstone under triaxial compression

To study the mechanical and damage evolution properties of sandstone under triaxial compression, we analyzed the stress strain curve characteristics, deformation and strength properties, and failure process and characteristics of sandstone samples under different stress states. The experimental results reveal that peak strength, residual strength, elasticity modulus and deformation modulus increase linearly with confining pressure, and failure models transform from fragile failure under low confining pressure to ductility failure under high confining pressure. Macroscopic failure forms of samples under uniaxial compression were split failure parallel to the axis of samples, while macroscopic failure forms under uniaxial compression were shear failure, the shear failure angle of which decreased linearly with confin- ing pressure. There were significant volume dilatation properties in the loading process of sandstone under different confining pressures, and we analyzed the damage evolution properties of samples based on acoustic emission damage and volumetric dilatation damage, and established damage constitutive model, realizing the real-time Quantitative evaluation of samnles damage state in loading process.