| In addition to structural stress,the supporting structure of high-temperature tunnels is also subject to temperature stress caused by temperature differences,which makes its stress state different from that of ordinary tunnel linings.This paper uses ANSYS finite element analysis software to simulate the actual situation of the Gonggeer high-temperature diversion tunnel in Xinjiang,and compares the numerical simulation results with the previous monitoring results.The results show that the temperature and stress of the simulation and the previous monitoring results are in good agreement with each other.Then the parameters of the initial temperature of the surrounding rock,the diameter of the cave and the temperature of the water passing through the cave are analyzed by parameter expansion,and the distribution of the temperature,stress and displacement of the lining under the above different parameters is studied,and the following main conclusions are drawn:(1)With the passage of time,the changing law of the surrounding rock temperature regulation circle under different surrounding rock temperature,tunnel diameter and water temperature is basically the same.After 9 months of tunnel excavation,the radius of the temperature regulation circle basically no longer changes.(2)The surface temperature of the lining and surrounding rock is greatly affected by the operating state of the tunnel.When the tunnel enters different operating stages,the temperature of the lining and surrounding rock rises and drops sharply.During different periods of tunnel operation,the temperature of the surrounding rock 15 days before The temperature change is about 80%to 90%of the temperature change of the change of the whole stage,and the temperature change of the 15 days before the lining reaches about 40%to 50%of the temperature change of the whole stage.(3)The stress change law of the lining during the entire service cycle has a great correlation with the temperature change.When the temperature suddenly increases or drops,the lining stress also changes greatly;during the construction period,the lining gradually changes from the inside to the outside.Tensile stress transforms into compressive stress.The full section of the lining is stretched under the influence of low temperature and overwater during the operation period.During the inspection and repair period,when the diameter of the tunnel is less than 6m,the full section of the lining is subjected to tensile stress.When the diameter of the tunnel is greater than 6m,the side lining near the surrounding rock appears Compressive stress.(4)When the temperature of the surrounding rock and the temperature of the passing water change,the displacement of different positions of the lining increases or decreases linearly with the change of the initial temperature of the surrounding rock and the temperature of the passing water;under different cave diameters,the deformation of the vault lining varies with the diameter of the cave.The increase of the arch waist and the arch bottom shows a quadratic function relationship with the hole diameter.The minimum deformation of the arch waist at different periods occurs when the hole diameter is 4.7m、4.1m、4.1m,and the arch bottom The smallest deformation occurs when the hole diameter is 7.3m、7m、6.5m respectively.(5)Combining the results of the numerical simulation,the relationship between the temperature at any point in the lining and the physical quantities is derived,and based on the relationship between the different variables obtained by the numerical simulation and the stress and deformation of the lining,the temperature,stress,and deformation of the high-temperature tunnel are developed.The rapid deformation prediction platform was verified with the working conditions of the 1#test tunnel of the Gonggeer diversion tunnel,and the results showed that the error did not exceed 10%. |
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