Method for measuring gas pressure of close-distance seam group simultaneously

A method for measuring gas pressure of a close-distance seam group simultaneously, comprising the following steps of:

• (1) constructing a drill hole in a direction near to a lower seam in a roadway;
• the drill hole being obliquely set, and a bottom of the drill hole entering a base plate of the seam for a certain distance;
• and adopting a water suction pump after the drill hole construction being completed, and pumping out accumulated water in the drill hole by connecting the pump with a flexible pipeline;
• (2) lowering a first seam piezometer tube in the constructed drill hole;
• sequentially lowering a baffle and a polyurethane blocking material along the first seam piezometer tube after a tube head of the first seam piezometer tube reaching a position of a lowermost seam;
• and installing a corresponding gas pressure gauge on the first seam piezometer tube after the polyurethane blocking material solidifying;
• (3) lowering a second seam piezometer tube;
• after a tube head of the second seam piezometer tube reaching a position of a second layer of seam in relative to the lowermost seam, sequentially lowering the baffle and the polyurethane blocking material at this seam position along the second seam piezometer tube;
• and installing a corresponding gas pressure gauge on the second seam piezometer tube after the polyurethane blocking material solidifying;
• (4) lowering a nth seam piezometer tube;
• sequentially lowering the baffle and the polyurethane blocking material along the nth seam piezometer tube after a tube head of the nth seam piezometer tube reaching a position of a nth layer of seam in relative to the lowermost seam;
• and installing a corresponding gas pressure gauge on the nth seam piezometer tube after the polyurethane blocking material solidifying;
• (5) injecting a high-water and quick-solidifying material into the drill hole through a grouting pipe;
• and after injecting the high-water and quick-solidifying material into an orifice, stopping grouping and removing the grouting pipe;
• and
• (6) connecting various gas pressure gauges through optical fibers, and connecting the gas pressure gauges with a ground control system;
• wherein in step (5), the high-water and quick-solidifying material is composed of a material A and a material B which are mixed in a weight ratio of 1:1, after mixing, 90%-95% of water is added for use, wherein the material A comprises the following raw materials in parts by weight:
• 50-70 parts of monohydrallite and 5-10 parts of compound super-retarding dispersing agent, and the material B comprises the following raw materials in parts by weight:
• 10-30 parts of lime, 10-30 parts of gypsum, 5-10 parts of Baifang thiophanate methyl suspending agent and 5-10 parts of compound fast-setting early strength agent;
• the compound super-retarding dispersing agent comprises sodium hexametaphosphate, phosphine butanetricarboxylic acid and water, and a weight ratio of the sodium hexametaphosphate to the phosphine butanetricarboxylic acid to the water is (10-15):1:3;
• and the compound fast-setting early strength agent comprises lithium carbonate, calcium formate, desulfurized gypsum and sodium nitrite, and a weight ratio of the lithium carbonate to the calcium formate to the desulfurized gypsum to the sodium nitrite is 1:3:(15-20):(15-20).