【摘要】 在 40 0 MPa围压及 2 0～ 850℃的温度范围内 ,研究了花岗岩的变形破坏及声发射时序特征。结果表明 ,随环境温度的升高 ,岩石强度降低 ,破坏方式从突发式失稳逐渐转变为渐进式 ,破坏类型亦从脆性剪切破裂逐渐转变为半脆性、半延性和延性破坏。声发射数量随温度升高迅速减少 ,出现 AE活动及 AE活动明显增强的差应力水平亦有所提高。温度不太高时 ( 2 50℃以下 ) ,随破坏强度的临近 ,破前 AE累计频度指数增长 ,其指数增长速率随温度增加而减小 ;650℃以上的高温条件下破前已无 AE记录。温度对 AE序列的 b值具有重要的影响作用 ,总的来看b值在低温时较高而在高温时较低。研究结果还显示 ,AE时间序列具有明显的多标度多分形特征 ,其性质主要决定于 AE的时间密集部分 ;标度指数α的分布范围随温度增加而扩大 ,表明AE时间序列的标度类型随温度升高而增加 ,其时间结构趋于更加复杂、无序。更多还原

【Abstract】 Under the condition of 400 MPa confining pressure and different temperatures (from room temperature to 850℃), features of failure and AE temporal sequences of granite have been studied. The results show that rock strength of granite decreases gradually with rising of temperature. The sample failure mode changes from abrupt instability to gradual failure and the failure types of medium changes from brittle shear fracture into semi brittle, semi ductile and ductile failure. With rising of temperature, the numbers of AE events decrease quickly. Meanwhile, the level of differential stress at which AE emerges also has a little increase. Below 250℃, the cumulate number of AE before the failure correspond to the exponential increasing model while the failure approaching, and the rate of exponential increasing minimizes with rising of temperature; there is no AE events has been recorded at the high temperature (650℃ and above). There is obvious influence of temperature on b value of AE temporal sequences. The b value is higher at low temperature than that at high temperature. It has been pointed out that the AE temporal sequences represent obvious multifractal characteristics, which mainly controlled by the temporal cluster feature of AE sequences. Distribution ranges of index α extend with rising of temperature, this means the scaling types of AE temporal sequences increase with rising of temperature, and its temporal structures become more complicated and disordered.更多还原