岩石内部结构随温度升高的变化会导致其物理力学性质的改变。利用MTS伺服试验机和高温炉进行常温至800℃花岗岩物理力学参数随温度变化特征试验。研究结果表明:(1)岩石物理力学性质随温度变化可划分常温~100℃和100℃~300℃,300℃~500℃,500℃~600℃,600℃~800℃五个阶段;前3个阶段的温度范围分别对应岩石内附着水、结合水和结构水汽化逸出的温度区间。(2)岩石物理力学性质(抗压/抗拉强度,渗透率,波速等)在400℃~600℃的温度范围内会有显著变化;受石英由相变为相的影响,岩石体积增大,微裂隙大量增加,在573℃附近存在强度和波速下降的加速点。(3)温度大于600℃后,岩石强度和波速会继续降低,其与固体矿物膨胀和金属键断裂引起矿物熔融破裂及相变有关。
The change of rock internal microstructure along with temperature increasing leads to the variation of physico-mechanical properties.The experiments on physico-mechanical properties evolution of granite were carried out at temperature ranging from room temperature to 800 ℃ by using MTS servo-controlled testing machine and heating furnace.The research results indicate that:(1) The rock physico-mechanical properties change with temperature can be divided into five stages:i.e.room temperature to 100 ℃,100 ℃ to 300 ℃,300 ℃ to 500 ℃,500 ℃ to 600 ℃ and 600 ℃ to 800 ℃.The first three stages of temperature range correspond to the vaporization escaping interval of adhered water,and bound water and structural water.(2) The phsyico-mechanical parameters of rock have larger changes in temperature between 400 ℃ to 600 ℃,specially at the temperature of 573 ℃,where quartz has a phase transformation,from α phase to β phase.In this process,it is leaded to the increase of rock internal microcracks,which can be described as increasing of volume,reducing of bearing capacity,increasing of permeability,and the mutation of wave velocity.(3) After the temperature higher than 600 ℃,rock strength and wave velocity continue to reduce,which is influenced by solid mineral inflation and fracture of metallic bonding.