【摘要】 岩石热破裂是一类极为普遍的自然与工程现象。利用"600℃20MN伺服控制高温高压岩体三轴试验机系统"进行砂岩和花岗岩在常温至600℃范围内的声发射特征和渗透性演化规律的试验研究,揭示岩石的热破裂规律与渗透性的相关特征,其结果如下:(1)花岗岩和砂岩受热作用,在常温到600℃区间,其热破裂存在一个清晰的门槛值。从声发射特征来看,永城细砂岩与鲁灰花岗岩的热破裂门槛值分别为170℃和65℃。(2)岩石热破裂门槛值之后,随温度升高,热破裂呈间断性与多期性变化特征,从常温到600℃,既非单调增加,也非单调减少,一般存在2个以上的峰值区间。(3)随着温度的升高,伴随岩石峰值破裂段的发生,岩石的渗透率也呈现出同步的多个峰值段,伴随着声发射平静期滞后出现渗透率相对降低区,但渗透率仍然维持在一个较高水平,而且随着声发射剧烈期出现次数的增加,渗透率愈来愈大。更多还原

【Abstract】 Thermal cracking of rock is a very common natural phenomenon in engineering.The experiments on acoustic emission(AE) characteristics and permeability evolution of sandstone and granite were carried out at temperature ranging from room temperature(RT) to 600 ℃ by using 600 ℃ 20 MN servo-controlled rock triaxial testing machine with high temperature and high pressure (HTHP);and it reveals the related features between thermal cracking law and induced permeability.The results show as follows:(1) There exists a thermal-cracking threshold value in the heating process from RT to 600 ℃ as a result of thermal effect.According to AE characteristics induced by rock thermal cracking,the cracking threshold temperature of granite from Pingyi,Shandong Province in China is 65 ℃ and the one of fine-grained sandstone from Yongcheng,Henan Province in China is 170 ℃,respectively.(2) The behavior of rock thermal cracking is discontinuity and multi-period from RT to 600 ℃ with temperature rising over the threshold temperature.It neither increases nor reduces monotonously in the heating process;and there exist more than two peak value areas.(3) The rock permeability appears multi-peak value area because of the multi-period of thermal cracking with temperature increasing.The relative lowering permeability lag occurs after the quietude of AE in the peak value area of permeability.But the permeability remains in a high level and it is more and more high with the increasing happening times of AE drastic period.更多还原