Study on the ground pressure and control method for openings in soft and broken rocks in Jin Chuon Mine No. 2

This paper elucidates the theory and proclice of opening mainteance insoft and broken rocks. Its main peints are as follows.
(1) The radical Cause of failure of viarous type of supporting structure in soft and broken rocks in Jin Chuon Mine before 1978 has been found to be that the stabilizing problem of rheological rocks around openings was simply regarded as a structure problem of conventional supporting.
(2) The soft and broken rocks in Jin Chuon Mine is a kind of rheological materials which may readily become loose material. So it is necessary to use secondary supports for the openings in such rocks.
(3) The ground prossure around the openings in soft and broken rocks in Jin chuon Mine is recognized as a deformation pressure of rheological amaterial.
(4) The basic regularity of ground pressure in Jin Chuon Mine is determined there are two compressed and compacted regions,one slack region, and one broken region around the openings in 12 meters deep. The compressed and compacted regions are bearing circles and play a critical part in stabilizing the openings around.
(5) An information design method, field supervision and control method is used in Jin Chuon Mine.
(6) The supporting principles and design methods of openings in softs and broken rocks in Jin Choun Mine are put forward. It is important to us-information design method to make support property and construction tech-nic to fit deformation condition of rocks around the opening.lt is also important to restrain rock deformation and slabilite the apening through anal ysis of regularity of ground pressure in accordance with different rock properties and ground perssure type.