冬瓜山铜矿深部大理岩单轴压缩条件下的力学特性

Mechanical Characteristics of Deep Marble in Dongguashan Copper Mine under Uniaxial Compression

为研究深部岩石在单轴静载条件下的力学特性,选用英国INSTRON公司生产的1346型电液伺服材料试验机进行深部大理岩的单轴压缩试验。岩样取至冬瓜山铜矿井下900 m深处,试验时采用位移加载的方式加载,加载速率为0.03 mm/s。通过研究分析试验结果得出:深部岩石处于"三高一扰动"的复杂力学环境中,其内部构造复杂,导致单轴抗压强度值出现离散性;分析大理岩的全应力-应变曲线,得出曲线出现压密、弹性、塑性、破坏几个阶段;岩石破坏前出现扩容现象,即岩石破坏前的瞬间其体积应变会向正值或负值2个方向发展;单轴压缩条件下深部大理岩最终的破坏模式不同于浅部岩石,其出现3种破坏模式,即单斜面剪切破坏、"Y型"和"T型"剪拉破坏。

In order to investigate the mechanical properties of deep rock under static uniaxial loading,uniaxial comprehension test are carried out on the 1346 electro-hydraulic and servo-controlled material testing machine produced by British INSTRON company. Mechanical experiments of marble collected at the depth of 900 m from Dongguashan copper mine is loaded by way of load displacement with the loading rate of 0. 03 mm/s. The results show that deep rock in the complex mechanics environment with three ＂ high＂ and one ＂ disturbance＂ has a complicated internal structure,leading to the uniaxial compressive strength value appears discrete. The analysis on the complete stress-strain curves of marble indicated that it can be classified as compaction,elastic,plastic and failure stage. Dilatancy phenomenon appears before rock failure,that is to say,volume strain will immediately develop towards a positive or negative direction before failure. The ultimate failure mode of deep marble under uniaxial comprehensive condition is different with the shallow rock,and three failure modes appear,including shear failure with single inclined plane, ＂ Y＂ type shear tension failure and ＂ T＂ type shear tension failure.