受静载荷的岩石在周期载荷作用下破坏的试验研究

为了研究受静载荷的岩石在周期载荷作用下破坏及变形发展规律，在Instron电液伺服材料试验机上进行了红砂岩的单轴动静组合加载试验。采用自制的一维水平静压加载装置，配合Instron电液伺服材料试验机进行了红砂岩的二维动静组合加载试验。试验表明，受静载荷的红砂岩在周期载荷作用下的破坏形态因所受静载荷的状态不同而不同，在周期载荷作用下的应力-应变曲线表现为滞回圈先疏后密再疏，直至破坏；相同条件的受静载荷的红砂岩受不同周期载荷作用时，尽管其应力-应变曲线表现为不同的滞回圈数和不同的全应变，但仍与岩石在周期荷载作用下疲劳破坏的极限变形规律一致，并且破坏岩石所消耗的有效全应变能有向相同值发展的趋势。

Experimental investigation on failure of statically loaded rock subjected to periodic load

In order to investigate the law of failure and deformation of statically loaded rock under periodic load, by using the Instron electro-hydraulic and servo-controlled material testing machine, uniaxial test of red sandstone subjected to static-dynamic coupling loading is carried out. Furthermore, by way of combining uniaxial horizontal static loading device made by self and Instron electro-hydraulic and servo-controlled material testing machine, biaxial test of red sandstone subjected to static-dynamic coupling loading is performed. Experiment indicates that the failure mode of statically loaded red sandstone under periodic dynamic load changes according to different static stress states. The hysteresis loop of stress-strain curves of statically loaded red sandstone under period dynamic load is first sparse, and then dense, and then sparse, afterwards rock failure appears. Although the number of hysteresis loop and the value of complete strain of stress-strain curves of the same statically loaded red sandstone under different periodic dynamic loads are different, deformation of statically loaded red sandstone under period dynamic load obeys to the law of ultimate deformation of rock under period load; and there is tendency to the same equivalent complete strain energy of rock failure.