破碎磷矿体力学特性及等效损伤规律研究

Study on Mechanical Properties and Equivalent Damage Law of Broken Phosphorus Ore Body

针对宜昌地区磷矿体破碎、节理裂隙发育等特点,进行多围压三轴压缩试验,建立三轴压缩等效耦合损伤变量模型,研究不同围压作用下破碎岩体压缩变形特性和损伤规律,揭示破碎岩体节理裂隙、围压大小、损伤特性、力学强度的相互影响关系。研究表明:围压的增加,可有效提高破碎岩体力学强度,并减小岩体损伤变量的谷值。在高围压作用下,破碎岩体应力应变曲线峰值处近似“折线状”,峰值处呈脆性破坏,破坏后峰值强度迅速衰减;低围压作用下,峰值处岩石试样呈现弹塑性破坏,峰值强度衰减缓慢。

According to the characteristics of phosphorus ore body fracture and joint fracture development in Yichang area,triaxial compression tests are carried out under different confining pressures,and the equivalent coupling damage variable model of triaxial compression is established to study the deformation characteristics and damage laws of fractured rock mass under different confining pressures,and to reveal the mutual influence of joint fracture,confining pressure size,damage characteristics and mechanical strength of fractured rock mass.The results show that the increase of confining pressure can effectively improve the mechanical strength of broken rock mass and reduce the valley value of rock damage variable.Under the action of high confining pressure,the peak value of stress-strain curve of fractured rock mass is approximately“fold line”,the peak value is brittle failure,and its strength decays rapidly after failure.Under the action of low confining pressure,the rock sample at the peak presents elastic-plastic failure,and its strength decays slowly.