Research On Interaction Between Freezing Wall And Shaft Lining Of Jurassic Formation

Northwest is the main part of our current well construction, commonly uses the freezing method on shaft sinking, but there is seldom shaft research on sinking through the Jurassic strata. The low-temperature physical and mechanical properties of the strata, the characteristics of temperature field of frozen wall, the study on interaction between frozen wall and sidewall are still in the exploratory stage. This paper based on the background of Jurassic strata that freezing airshaft got through the BoJiangHaizai mine in Inner Mongolia, combing laboratory experiments and field measurement to study the interaction of the frozen wall and the sidewall.Derived by laboratory experiments:when the rock of Jurassic strata at low temperatures, its uniaxial compressive strength has increased a bit, but nonlinear increase with temperature; the rock has a certain strength and stability, the frost heave is small, there is frozen shrinkage phenomenon on the rock. Through the field measurement of the temperature in frozen wall and sidewall, the freezing pressure of outer shaft wall, the stress variation of perpendicular reinforcement and ring ribs of outer shaft wall, the analysis conclusion:the start time and duration of the concrete hydration heat in the outer shaft wall, the affection of concrete hydration heat on frozen wall temperature, the frozen wall refreezing time, the range of melting, the concrete curing time and other characteristic parameters; the average of freezing pressure on the outer shaft wall in two horizontal was0.47MPa and1.12MPa; Ring ribs force was lager than the vertical reinforcement, the maximum force of ring ribs was102.70MPa, the vertical reinforcement is61.21MPa during the jacket inner wall shaped, they were both lower than the design value of the Ⅱ grade steel, the sidewall was in safe operating condition.This paper shows some of the basic law of the interaction between the frozen wall and the sidewall of Jurassic strata in Inner Mongolia, come to the freezing pressure of the strata and sidewall force were small and other features, freezing method was more favorable, and these provide the reference for the construction of the freezing method in the similar strata of Inner Mongolia region.