| Rock mass produces lots of structural planes during the long geologicalprocess,such as cracks,joints,etc. Structural planes have a great influence onstrength，stiffness and stability of rock mass. Aiming at the engineering demands incold regions, this dissertation focus on freezing-thawing jointed rock mass.Based onthe study on experinment,analysising the change law of physical and mechanicalproperties with freezing-thawing, and researching on damage constitutive model offreezing-thawing jointed rock mass.In the end,the paper calculates the result oftemperature field and stress field of jointed rock mass by finite-element software.The main research works are introduced in the dissertation as following：(1) Putting freezing-thawing test and uniaxial compression test on specimenswhich have been precasted with different joint dip angle, joint discontinuity degree,joint filling and without joint specimens.During the process of experinment,recordingthe quality and wave velocity of typical specimens.Meanwhile,the strength, damagefailure modes and parameters of physical and mechanics of rock mass varied withdifferent cycles of freezint-thawing are recorded and researched.On the basic of testresults and research works,the mechanism and influence factors of rock massdeterioration are analyzed.(2) Based on the continuum theory and phenomenological statistical method,considering the adverse action of freezing-thawing and joint and compression loadson rock mass as damage.Proposing the damage constitutive model offreezing-thawing jointed rock mass under uniaxial compression test while consideringthe joint sur-face can pass on part of compressive stress and shear stress. Theproposed constitutive model is verified and has certain practical significance by thestress-strain relationship of calculating comparing with the test.(3)Researching the fracture properties of jointed rock mass under the action offrost-heave force and the relationship between frost-heave force and crackpropagation on the point of energy. The fracture properties of freezing-thawingjointed rock mass under uniaxial compression are stated by maximum tensile stresscriterion including friction coefficient,the degree of crack closure and T-stress whichis a non-singular stress term and parallels to main crack tip.The effect of parameterson fracture properties is also stated.At the end of this chapter, the formula of freezingand thawing jointed rock mass fracture energy is reduced. (4) The distribution of temperature of freezing-thawing jointed rock mass issimulated by finite element software and the temperature and mechanics fields arestudied.At the same time, the action of specimens are simulated under uniaxialcompression,and the result of stress and failure mode are also analysed. |
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