人工冻结竖井中底鼓问题的弹塑性计算

Elastoplastic Calculation of Bottom Heave in Artificially Frozen Shaft

When a frozen shaft is sunk after negative freezing period, vertical and horizontal earth pressures are primary factors causing bottom heave. Based on this, a mechanical model is proposed for calculating the deformation of frozen shaft. Using elastoplastic methods, we obtained semianalytic formulas about the bottom heave u(h1) the maximum radius displacement of frozen soil wall um and lead displacement ub: Results of the simulating calculation are in good agreement with results observed in the No.3 Tongfeng shaft, Panji, which shows the model feasible. The calculated results can also explain why freezing tubes are frequently destroyed in the clayey soil layer of calyey-sandy alteruating layers. The semianalytic formulas can be applied to predict the deformation of a frozen shaft at any depth and provide the theoretical reference results for engineering designer.