Study On The Interaction Between Horizontal And Vertical Freezing Wall In Deeply Buried Tunnel

Due to adverse geological effect, the TBM machine, used in Gansu Province Yin Tao Water Delivery first phase project 7# tunnel, was trapped in the slumping tunnel. Freezing method was implemented to rescue the TBM. Through constructing vertical freezing hole on upper sides of TBM on the ground, we formed a closed freezing curtain around the tunnel. Under the protection of the closed freezing curtain, we will carry out excavation, rescue the trapped TBM machine.Under the background of Gansu rescuing TBM project, the developments and changes law of vertical and horizontal freezing wall has been researched in this paper, through combined methods of numerical simulation and physical testing. The research content is divided into two modules, one module is the developments and changes law of freezing wall temperature field, another module is the law of displacement and stress of freezing wall after excavting the tunnel.Firstly, according to the pratical engineering data, the numerical simulation experiment was designed after reasonably choosed soil thermodynamic parameters to study the developments and changes law of freezing wall temperature field. When the freezing wall reached design requirements,Simulating the excavation with specific unsupported length to study the freezing wall’s distribution law of displacement and stress. considering the influence of freezing wall’s mechanical properties,especially the thickness of top and side freezing wall.The numerical analysis shows: the changes of vertical frozen wall thickness have very significant impact on horizontal frozen wall,in the same way, the changes of horizontal frozen wall thickness have very significant impact on vertical frozen wall.Through the numerical analysis,we find out the law of interaction between horizontal and vertical frozn wall. Under the interaction, based on a frozen wall of optimization design was carried out on the engineering example, it is concluded that the optimal combination.Secondly, according to the similarity theory,physical simulation experiment research has been carried out. According to the similarity criterion, designed the experiment model scaled of the prototype calculated. The developments and changes law of freezing temperature field has been researched through numerical simulation after the freezing pipes being layouted vertically. And the developments of deformation on top and side frozne wall after excavating tunnel.Finally, through comparative analysis on the results of numerical simulation and physical simulation experiment about the temperature and displacement data, consistent conclusions has been obtained and an improved optimization idea about the process of research has been put forward.