| China is one of the biggest countries which have large area of cold regions, the area of permafrost and seasonally cold regions account approximately 75% of the total land area. With the increase of projects constructing in cold regions, many engineering problems involving frozen rock occur. However, the research work on frozen rock is very scarce since now. To deal with the engineering demands for solving problems occurred in cold regions, this paper bring forward a new research direction as to study the problems on frozen rock in cold regions. Based on experiment research, and combining theory with numerical simulation, this paper studies systematically the behaviors of mechanics and thermodynamics under conditions of low temperature and freeze-thaw firstly. Then the macro constitutive equation for damage rock due to freeze-thaw cycling is established according to the testing results. Lastly, on the background of large scale rock engineering in cold regions, e.g. the Kunlun mountain tunnel of Qinghai-Tibetan railway, the mathematical models of temperature-fluid coupling and temperature-fluid-mechanics fully coupling are set up by taking into account the macro constitutive equation for damage rock due to freeze-thaw cycling, and a number numerical simulations are proceeded on frozen rock engineering by adopting finite element method. Synoptically, the main research works are introduced in the dissertation as following:Two typical rocks that are red sandstone and shale were obtained from engineering sites, and they were prepared as standard specimens of 50mm in diameter and 100mm in length. The uniaxial compression tests and triaxial compression tests were conducted on the two types of rock at different frozen temperature and different moisture state(absolute saturated and dry). The test temperature of uniaxial compression test is +20℃,0℃,-5℃,-10℃,-20℃,respectively, and that of triaxial compression test is +20℃,-5℃,-10℃. The deformation and failure of rock, the relationship between stress and strain, and the depending on temperature of the uniaxial compression strength, Young's modulus, triaxial compression strength, and the shear strength parameters(cohesion c and inner friction angle ?) under uniaxial and triaxial compressive test are analyzed, the relatively fitting expressions are formulated. Furthermore, the ultrasonic tests and thermal tests were performed at different low temperatures and different moisture states on the two types of rock as to study the P-wave velocity and thermal parameters changing with different temperatures.The freezing and thawing tests were conducted at opening saturating conditions on red sandstone and shale, one cycle of freeze-thaw test including 12 hours freezing at -20℃in freezer chamber and 12 hours thawing at 20℃in distilled water. Based on the freeze-thaw tests, the damage and failure due freezing and thawing are analyzed, and two deterioration modes, i.e. scaling mode for red sandstone and fracturing mode for shale, are found. The uniaxial compression tests are also conducted on the two types of rock subjected to different freeze-thaw cycles (0, 5, 10, 20, 30 cycles) at room temperature(20℃). The deformation and compression strength of rocks varied with different cycles of freeze-thaw are recorded, and the resistance to freeze-thaw of the two types of rock are analyzed. The relations of uniaxial compression strength and elastic modulus and numbers of freeze-thaw cycle are formulated according to the test results, respectively. On the basis of the test results and pre-existed research works, the mechanism and influence factors of rock deterioration due to freeze-thaw...
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