A real-time high-temperature true triaxial test system and its application
MA Xiao1，2，MA Dongdong1，HU Dawei1，ZHOU Hui1，CHEN Sili2，YU Zhipeng3，TAN Xianfeng4
(1. Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China；
2. School of Architecture and Civil Engineering，Shenyang University of Technology，Shenyang，Liaoning 110870，China；
3. School of Civil Engineering，Architecture and Environment，Hubei University of Technology，Wuhan，Hubei 430064，China；
4. Shandong Province Lunan Geological Engineering Investigation Institute，Jining，Shandong 272100，China)
Abstract：To investigate rock mechanical properties under high temperature and stress coupling，which is one of the research hotspots in the field of deep resource exploitation，a real-time high-temperature true triaxial test system was developed. The system，mainly composed of three subsystems including rigidity mechanical loading system，high temperature control system and servo control and data acquisition system，can realistically simulate the thermal-stress coupling environment of deep rock masses and perform various stress paths such as uniaxial，conventional triaxial，true triaxial，creep，cyclic loading and unloading with a standard rock sample of 50 mm×50 mm×100mm at a highest rock sample surface temperature of 460 ℃. The maximum loads of three loading directions(?1，?2，?3) which can be independently controlled are respectively 1 000 MPa，200 MPa and 200 MPa. The high temperature control system consists of a six-circuit detachable flexible heating element and an aerogel insulation cover，of which each circuit is separately monitored by the temperature control box to realize real-time heating and monitoring of rock samples. Thermoplastic mold steel and water-cooled circulation system is used to ensure the overall rigidity and working stability of the test system at a high temperature，and high-precision closed-loop servo control system with magnetic displacement sensors can accurately monitor displacement and pressure in three directions for multiple stress path tests at a high temperature in real time. High temperature in real time true triaxial tests were conducted and the effect of temperature and intermediate principal stress(?2) on mechanical properties of granite were studied. It is shown that 400 ℃ temperature can enhance the strength and elastic modulus of granite and that the intermediate principal stress(?2) can enhance the strength and peak strain of granite at 400 ℃ temperature. Meanwhile，the intermediate principal stress(?2) can enhance the strength but decrease the peak strain in the third main stress direction of granite at RT. The reliability and stability of the high temperature in real time true triaxial test system were verified by comparing the test results by the developed system and the conventional triaxial test system，and the research results can provide theoretical and technical supports for the development and utilization of dry hot rock resources，nuclear waste repository construction and deep rock mass engineering.
马 啸1，2，马东东1，胡大伟1，周 辉1，陈四利2，余志鹏3，谭现锋4. 实时高温真三轴试验系统的研制与应用[J]. 岩石力学与工程学报, 2019, 38(8): 1605-1614.
MA Xiao1，2，MA Dongdong1，HU Dawei1，ZHOU Hui1，CHEN Sili2，YU Zhipeng3，TAN Xianfeng4. A real-time high-temperature true triaxial test system and its application. , 2019, 38(8): 1605-1614.
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2019, Vol. 38 
