| In order to exploit the solid mineral resources under ultra-deep soil layer,the thesis took the shaft construction in 2000 meters depth soil layer as the engineering background,based on the feasibility analysis of existing special shaft sinking method,put forward the frozen wall and concrete curtain joint protection shaft sinking method.The temperature,stress and deformation law of shaft lining was studied by combining theoretical analysis and numerical calculation.Firstly,in view of the engineering background,the feasibility analysis of freezing method,drilling method and concrete curtain method was conducted.Then combined with the developing trend of related technologies at home and abroad,the frozen wall and concrete curtain joint protection shaft sinking method was proposed with the control criterions of frozen wall average temperature,shaft wall floatable thickness,concrete strength and shaft wall thickness.Also,the main construction was given.Secondly,the numerical calculation model of shaft lining temperature field and temperature stress field considering freezing and cement hydration was established.The relationship between shaft lining temperature and freezing days as well as the relationship between shaft lining temperature stress and freezing days,pouring temperature and shaft lining thickness were obtained.Meanwhile,the measures to prevent temperature cracks were put forward.The research confirms that the frozen wall and concrete curtain joint protection sinking method will not produce temperature cracks in shaft lining.Thirdly,according to the new sinking technology,the linear elastic model and elastic-plastic model of multi-layer cylinders were established,the analytical solutions of stress and deformation of shaft lining and frozen wall were deduced,and the development laws of plastic zone under different yield criteria were analyzed.When other parameters are fixed,and the shaft lining and surrounding soil are linear elastic models,the main factor affecting the stress and deformation of shaft lining is its thickness,and the properties of surrounding soil and the frozen wall have little impact.That is to say,the main function of the frozen wall is to seal water.Based on that,the elastic model of the interaction between shaft lining and surrounding soil could be simplified to the model of the single layer shaft lining subjected to external load,the three-layer cylinder model of the interaction between the shaft lining,frozen wall and surrounding soil could be simplified to the two-layer cylinder model of shaft lining and frozen wall under external load,The four-layer cylinder model of the interaction between the shaft lining,unfrozen soil,frozen wall and surrounding soil could be simplified to the three-layer cylinder of the shaft lining,unfrozen soil and frozen wall subjected to external load.Under the state of the elastic-plastic models of shaft lining and surrounding soil,the plastic zone starting from the inner edge of shaft lining and gradually develops to the outer edge.The frozen soil and the unfrozen soil on the outer side are in linear elastic state with the local plastic shaft lining.When the shaft lining is full plastic,the surrounding soil may still be in the linear elastic state.When the strength of shaft lining concrete is lower than a certain value,the frozen soil and the unfrozen soil could enter the plastic state.Finally,the numerical calculation models of stress and deformation of surrounding soil,frozen wall and shaft lining during excavation were established.Stress and deformation laws of shaft lining under different technologies were compared and analyzed,and the results were compared with the theoretical analysis results.The results show that the theoretical analysis and numerical calculation results are in good agreement.The research results in this dissertation are of signifiant reference value for the shaft sinking technology in 2000 meters depth soil layer. |
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