Study On The Stress And Deformation Law Of Inclined Shaft Frozen Wall And Shaft Lining During Freezing Sinking

In order to meet the requirement of shaft lining sinking in water-bearing strata by freezingmethod in western China, the research on the law of load and deformation of inclined shaft frozenwall and shaft lining during freezing sinking is carried out with the combination of numericalsimulation and field measurement.Firstly, based on elastic-plastic and viscoelastic-plastic models, vertical freezing and inclinedfreezing models are established to analyze the law of load and deformation of inclined shaft frozenwall and shaft lining respectively, in which, the influence of shaft excavation width, frozen wallthickness of each side, lining elastic modulus, lining thickness and model depth is taken intoconsideration. Besides, reaction coefficient is applied to the plane model, and the unsupportedlength is used for the3d model. Numerical analysis shows that the shaft excavation width andmodel depth have very significant impact on frozen wall deformation and shaft lining hoop stressand radical displacement, through which the law of deformation and load of each typical pointscan be accelerated; however, lining elastic modulus has little influence. Shaft lining thickness hasthe greatest influence on radical displacement of G-point, followed by J-point. The influence onhoop stress of C-point, E-point and H-point is the greatest, followed by B-point. The roof, bottomand side frozen wall thickness has great impact on frozen wall deformation, however, it makessmall difference to stress and displacement of shaft lining; unsupported length has significantimpact on frozen wall deformation and shaft lining hoop stress and radical displacement whoselaw of deformation and load of each typical points is of decay type.The analysis result of vertical and inclined freezing models shows that, the maximumdeformation difference of frozen wall occurs in F-point, A-point deformation difference takes thesecond place, and B-point takes the last; G-point of shaft lining has the greatest displacementdifference, followed by J-point; G-point and F-point of shaft lining have the maximum hoop stressdifference, followed by I-point and B-point. Compared with elastic-plastic model, the frozen walldeformation of viscoelastic-plastic is greater. In addition, the deformation variation of frozen wallis greater when frozen size is unchanged, however, the frozen wall deformation variation is lessthan the results in elastic-plastic mode.Secondly, based on the site condition, field measurement of inclined shaft is conducted toanalyze the law of frozen wall deformation and shaft lining stress and strain. As is indicated by thefield measurement, the law of frozen wall deformation rate is attenuated and wall pressure is lowin reasonable process, while in unreasonable process, the unsupported length and time is longerwith the length larger than40meters in this project, the rate law is accelerated with the significantgrowth of wall pressure and shaft lining stress and strain; After the shaft lining is concreted, the frozen wall is melted by hydration heat, on one hand, it reduces the wall strength, leading to thegrowth of deformation stress, on the other hand, it weakens the wall structure, resulting in theincrease of axial stretch stress. By the end of monitoring, the increasing range of radialdisplacement in F-point is above1200με, and that in F-point is above100MPa, accordingly, theshaft lining floor structural design needs to be optimized. Meanwhile, the comparison of numericalanalysis and field measurement shall be conducted, resulting in the similar law of frozen walldeformation and shaft lining stress and strain as well as the small value difference.In conclusion, the factors above-mentioned all have different levels of impact on the load anddeformation of frozen wall and shaft lining during freezing sinking, especially the shaft excavationwidth, model depth, shaft lining thickness and unsupported length. Reasonable unsupported lengthand time can reduce the frozen wall deformation and pressure effectively. Therefore, the invertedarch shaft lining floor should be used.