Method for directly measuring gas pressure of coal bed of underground coal mine

The invention discloses a new method for directly measuring a gas pressure of a coal bed of an underground coal mine. The new method comprises the steps of: forming a big drill hole in a surrounding rock of a to-be-measured sealed coal bed by adopting a coal rock driller and fixing a flange plate by using a casing pipe outside the big drill hole; filling cement mortar in the big drill hole through a tee on the flange plate, and taking off the flange plate after the cement mortar is solidified and molded; forming a small drill hole in the big drill hole to serve as a pressure measuring drill hole, mounting the flange plate and performing gas tightness inspection on the small drill hole; mounting a pressure gage on the tee, measuring the gas pressure when the coal bed gas pressure gage is balanced and steady by utilizing a natural permeability principle of the gas in the coal bed; and observing the reading number of the pressure gage everyday and recording, stopping observing if the change of the reading numbers of the pressure gage on three continuous days is less than 0.015 MPa, and adding the last observed pressure reading number of the pressure gage with the 0.1 MPa barometric pressure to form the gas pressure of the coal bed. When being used for measuring the gas pressure of the coal bed, the new method for directly measuring the gas pressure of the coal bed of the underground coal mine, disclosed by the invention, has the advantages of high pressure measurement success rate, high precision, good safety and high efficiency.