论文部分内容阅读
岩石热破裂是高放废物地质处置工程中需深入研究的课题。对我国高放废物重点预选场址甘肃北山的花岗岩开展室内热破裂模拟试验研究,采用多通道温度测试仪、声发射、波速层析成像和数码显微镜等手段研究了该花岗岩热破裂过程。试验表明,(1)热破裂从试件端部开始产生,逐步向内缓慢扩展,表现出分段性和独立性;(2)根据声发射撞击率可将热破裂可分为稳定热损伤、宏观裂纹形成、宏观裂纹扩展、裂纹冷却闭合4个阶段,声发射定位的时空演化规律清楚地揭示了裂纹从试件上端部向内部扩展的规律;(3)波速层析成像指示了宏观裂纹位置及高温对岩石造成显著损伤的区域,热应力产生的损伤集中在试件边界,范围小,损伤严重,高温造成的损伤集中在钻孔附近高温区,范围较大,损伤略轻微;(4)监测多通道温度,获得了试件内的温度场并为数值模拟参数选取提供验证,采用有限元程序进行了热力耦合数值模拟,从机制上初步解释了热破裂现象,研究认为综合声发射实时监测热破裂过程和波速层析成像能实现对热损伤的量化的特性可实现岩石热破裂的动态监测和损伤量化,为今后地下实验室相关试验的开展和认识高放废物处置长期稳定性做了有意义的探索。
Thermal cracking of rock is a topic that needs further study in the geological disposal of high level radioactive waste. The thermal rupture of granite in Beishan, Gansu province, which is the pre-preselected site for high level radioactive waste, was simulated. The multi-channel temperature tester, acoustic emission, wave velocity tomography and digital microscope were used to study the thermal rupture process of granite. The results show that (1) the thermal rupture begins to occur from the end of the specimen and gradually expands inward gradually, showing segmentality and independence; (2) The thermal rupture can be divided into stable thermal damage, Macroscopic crack formation, macroscopic crack propagation and crack cooling closure. The temporal and spatial evolution of acoustic emission clearly revealed the regularity of the crack propagation from the upper end to the inner part of the specimen. (3) The wave velocity tomography indicated the location of macroscopic crack And high temperature caused significant damage to the rock area, the thermal stress generated damage concentrated on the specimen boundary, the scope of small, serious damage, high temperature damage caused by concentrated in the drilling near the high temperature zone, a large range of damage slightly; (4) The multi-channel temperature was monitored, the temperature field in the specimen was obtained and verified by the selection of numerical simulation parameters. The thermal coupling numerical simulation was carried out by the finite element program. The thermal rupture phenomenon was initially explained from the mechanism. The real- Thermal rupture and tachymetry imaging can quantify thermal damage, which can dynamically monitor the thermal rupture of rocks and quantify the damage. It is of great significance for future related laboratory tests To carry out and recognize the long-term stability of high-level radioactive waste disposal made a meaningful exploration.