Laboratory model test on artificial freezing characteristics of sand layer under seepage
Artificial freezing method has been widely because of its good water sealing property,wide adaptability and small impact on the environment.However,groundwater seepage will seriously affect the freezing effect,and the influence of seepage on artificial freezing has not been considered in the design code.In order to study the characteristics of artificial freezing under seepage,indoor model tests of artificial freezing process under different seepage velocity and temperature gradient were carried out based on the self-developed double pipe freezing physical model test system.Through the model tests,the development laws of the temperature difference of inlet and outlet water,the cooling capacity exchange rate and temperature field changing with the initial temperature of the ground layer,the temperature of the refrigerant and the seepage velocity are revealed.The intersection time and the critical seepage velocity under different temperature gradients and seepage velocities are determined.The critical flow velocities of the three tests are 16.81,10.22 and 13.33 m/d.Furthermore,the changes of the shape,thickness and average temperature of the frozen wall with the temperature gradients and the seepage velocity of groundwater are analyzed.The research results can provide reference for the application and design of artificial freezing technology under seepage conditions.
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