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Abstract The weakly cemented soft rock has the characteristics of low strength，low frost heaving ratio and high theology effect. Traditional calculation method which substitutes average temperature for radial temperature gradient distribution of the frozen temperature field and substitutes average strength parameters for mechanical parameters radial hierarchical distribution can not reflect the deformation characteristic of the frozen wall in weakly cemented soft rock. The finite difference equation of layer model is given based on the model of power law constitutive relationship；and the implementation method of layer calculation model in FLAC3D is also given. The example analysis indicates that the results of layered calculation model are good agreement with the measured data. Based on the calculation result analysis in different working cases，the maximal displacement point of shaft wall in weakly cemented soft rock freeze sinking shaft is in the ranges of 0.36 h to 0.42 h. The h is the section height. The radial displacement of the free shaft wall is sensitive to the height of digging. With the increment of section height，surrounding rock deformation increases remarkably，and extends to deep freezing surrounding rock. An analysis of admissible free rib time shows that working face construction safety could not be assured during the normal shaft sinking time when the section height is more than 4.5 m.
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Received: 25 May 2011
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2011, Vol. 30 
