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In order to form a more rational design of shaft lining, a formula was put forward, in which the porosity of contact surface between shaft lining and surrounding rock np and ratio of radial unloading of surrounding rock η1 was taken into account, based on study of porosity of porous media. The influence of np and η1 on shaft lining was analyzed. The analysis shows that the influence becomes strong with increase of np and the impact of surrounding rock pressure becomes weak with increase of np. Raising η1 rationally under precondition of avoiding stripping of solid skeleton should be done in design and construction. The result of the new method is smaller than that of current method and smaller than the pore water pressure obviously. [ABSTRACT FROM AUTHOR]

In order to thoroughly investigate the load of outer shaft lining in deep aqueous bed rock area, in-situ measurements on freezing pressure of outer shaft lining were carried out in bed rock in Hujierte coalfield in Chinese Erdos. The in-situ measurement results reveal that the process of freezing pressure can be described by 4 periods: dramatic increase period, slow increase period, rapid increase period and gradual decrease period. The freezing pressure is mainly affected by rock moisture content and rock strength, but the rocks buried deep H affects little. The freezing pressure reaches 76.4% ~ 89. 8% of the maximum freezing pressure Pmax at 10 ~ 15 days after concrete pouring. Therefore, it is recommended using 7 days concrete strength index to guarantee the safety of outer shaft lining during the early period. The freezing pressure reaches the maximum value Pmax at 80 ~100 days after concrete pouring, the measured value of Pmax is 1.08 ~ 1.74 MPa. Pmax is much smaller than hydrostatic pressure P0 and the maximum freezing pressure Pω in deep alluvium. [ABSTRACT FROM AUTHOR]