The study of the influence of the rock mass heterogeneity on the stress-strain state of the shaft lining

Shafts often cross sections of a layered mass of rocks of different strength during the sinking. The article deals with the design case of interaction of monolithic concrete lining in the bottomhole zone of the shaft with a mass containing a rock layer with low stress-strain properties. To study its influence, spatial numerical models have been developed, which allowed us to consider several indicative positions of the «weak» layer referred to the shaft lining. The analysis of calculation results shows that in case of direct contact of the support with a «weak» layer, the increase in stress intensity in it can reach 5-fold values and is determined by the thickness of the «weak» layer and its stress-related characteristics. The most effective control action in this context is the advance hardening of the «weak» layer before its expo-sure during the sinking.