The Research And Application Of Freezing Methodology In Extremely Soft Rock Water Tunnel Rescue TBM

boundary conditions’restricts, the planar isotropic heat conduction governing differential equations which considered the latent heat of phase change was used to build the mathematical model.3. The current thermo-solid coupling of artificial stratum freezing methodology was stated. The Mises plastic reinforcement principles and Prandtl-Reuss fluent laws were used to solve the incremental relations of stress-strain in the plastic field. The changing of physical parameters’elasticity modulus and Poisson’s ratio were considered and solved after the phase change of the soil.4. The large-scale finite element analysis software ANSYS 14.0 was used to simulate the temperature field. The freezing frontal surface’s development, the changing of isotherm and the formation of frozen soil wall were simulated and analyzed under 115d,116d,125d, 150d,180d and 245d. The simulated temperature was basically consistent with the actual measurement, which could provide the technical references for the later TBM rescue.5. The changing of displacement field and stress field caused by the rescue operation under the condition of frozen soil wall’s protection in the TBM rescue stretch were simulated. In the designed condition, which means the 245d later of artificial freezing, the construction safety was insured and each key point of excavation face was in the safety principle.6. The artificial freezing time before the rescue operation was optimized. The rescue operations after the freezing of 115d,145d,195d and 215d were simulated. During the rescue operation of freezing of 115d,145d and 195d, the displacements of excavation face key points were relatively big, which could not conform to the specification. But during the rescue operation after 215d, the displacements of excavation face key points could conform to the specification, which was partly because of the enough freezing time of frozen soil wall after enough freezing. In this condition the rescue operation could processed safely, but the conclusion could only be taken as a reference.