Study On Stress Characteristics And Safety Evaluation Method Of Large Diameter Vertical Shaft Wall

Vertical shaft provides a pathway from underground to ground surface,and more and more vertical shaft have been constructed with great depth and super large diameter in recent years.However,the damage of vertical shaft wall with large diameter located at complex stress condition is a common geological disaster widely existing in the mining engineering,especially,the stress characteristics and the mechanism of damage in the vertical shaft buried in deep overburden are worth further study.In this paper,five issues,including dynamic feedback analysis for stress state and stress characteristics during construction process,analysis of influence factors during usage stage,safety factor analysis of the wall’s using process based on the orthogonal test method and safety evaluation model analysis of the wall based on multivariate statistical methods,have been studied,as well as the large diameter vertical shaft wall’s mechanical characteristics in construction process and whole using process.According to the above studies,the following main results were obtained:1.Based on dynamic feedback analysis for stress state and stress characteristics during construction process,stress deformation characteristic curve of the wall’s different construction process stages is obtained.The shaft wall is always in a three-way compression state in the process of construction and emplacement,and the annular pressure strain is greater than the vertical pressure strain.2.Based on the thick wall cylinder theory,the stress-strain of the wall in different construction process stages and considering influence factors,such as horizontal ground pressure,vertical additional force,temperature stress and weight of the wall in using process,the theory calculation formula are established,and revealed the stress’s change rule of the wall in using process.Obviously,these results can locat the wall’s most dangerous section and the breakage mechanism of the seasonal.3.At last,based on the orthogonal experiment design method and THM multi-field coupling numerical simulation method,the safety evaluation indexes for large diameter vertical shaft wall,key factors and the safety evaluation mode by multivariate regression analysis method have been established,the proposed methods in this paper could predict and evaluate the wall’s safety and reliability to some extent.According to field testing,theoretical analysis and numerical simulation,this paper studies the mechanical characteristics and safety evaluation methods of large diameter shaft lining during construction and operation,which has important theoretical significance and engineering application value.