A Study On Mechanical Characteristic Of Frozen Soil Wall And Shaft Lining As Well As Their Interaction Mechanism In Deep Alluvium

In recent years, the alluvium traversed by shaft in mine becomes thicker and thicker along with the development of deeper mine construction in Huang-huai area of China. Many problems such as the fracture of freezing pipe, the disrepair of outer shaft lining, etc. occur in the artificial frozen alluvium due to the thick frozen alluvium and the large deformation of frozen soil wall developing. All these problems decrease not only the pace of the shaft construction, but also result in the shaft penetrating water, emerging sand, submerging, etc. Therefore we face with challenge in related theory and key engineering technology, and we must study the methodology of engineering design and construction in the thick artificial frozen alluvium. With the methods of theory and experimentation and measurement in situ, this dissertation pays studies on the physical and mechanical properties of frozen soil, the stability of frozen soil wall, the structure shapes of the high strength shaft lining and their mechanical characteristics, the interaction mechanism of frozen soil wall and outer shaft lining, the regularity of frozen pressure, etc. in thick alluvium.Based on the creep property of deep frozen soil and the finite strain description of deformation, the formulas of Green strain and Kirchhoff stress are put forward for treating the triaxial creep experimental data of frozen soil. The finite strain constitutive relations of frozen soil are deduced and the parameters of creep in the equations are fitted with the results of triaxial creep experimentation of frozen soil. The obtained mechanical property of frozen soil satisfies the requirements of FEM simulation of the frozen soil wall in the deep alluvium.FEM analysis of frozen soil wall is performed with ANSYS software in which the finite strain constitutive equation of frozen soil and the parameters of creep in the equation are incorporated. The regularity of the radial displacements on the surface of frozen soil wall and in inner frozen soil wall is revealed. The displacement distribution on the working face is also obtained. The factors of influencing on the displacement distribution of frozen soil wall are analyzed. A formula is proposed for expressing the relationship of the maximum radial displacement of frozen soil wall with the thickness of frozen soil wall, the thickness of frozen alluvium, excavating segment height, exposure time of frozen soil wall, excavating...