Research On Thermal-mechanics Coupling Effect Of Shaft Freezing Engineering By Physical Model And Numerical Analysis In Thick Alluvium

To be aimed at the evolution regularity and stability of frozen clay wall of thick alluvium under the condition of three rings of freezing pipes, the study of three-dimentional physical model, theoretical analysis and numerical simulation have been conducted. Based on similarity theory, similarity criteria of temperature field of three rings of freezing pipes has been deduced. The evolution regularity of temperature filed, stress field and displacement field under three rings of freezing pipes have been obtained through the laboratory model tests, and the distribution patterns of temperature filed has also been obtained. Based on Mises yield criterion, rheological theory of frozen soils and Hooke’s law of deviatoric tensor of equivalent stress-equivalent strain, the analytical formula of stress field and displacement field of nonlinear viscoelasto-plastic frozen clay wall under the interaction of outer shaft lining, frozen wall and surrounding earth mass in unloaded state are derived. And then the mechanical model of frozen wall is received. The mechanical model is suitable to frozen clay wall of thick alluvium. The deformation and the calculating model for the thickness of finite length frozen wall under the influence of excavation unloading and excavation section under the interaction of the outer shaft lining and overlaying bedrock has been explored. Finally, the evolution and distribution laws of temperature filed and displacement field of frozen clay wall of thick alluvium have been analyzed through numerical simulation. The results show that the evolution and distribution laws of temperature filed of numerical simulation are consistent with the physical model.