The invention discloses a high-pressure holepacking and pressure relief protection method for
coal strata. The method comprises the following steps: firstly, a hole is drilled, and a hole packer is extended into thedrilled hole; secondly, water is injected into thehole to pack thehole; thirdly, the hole packer keeps pressure of the packed hole to fracture the
coal strata; fourthly, fracturing is stopped; fifthly, the hole packer keeps pressure and reduces and releases pressure stage by stage; and sixthly, the hole packer is recovered. A one-way
safety valve is changed into a two-way
safety valve, the valve is controlled by cooperation with a
pipe, conventional high-pressure water can be injected into the drilled hole to seal the hole and fracture the
coal strata, pressure keeping and relief of the hole packer can be conducted, and
water pressure in the drilled hole is acquired by a pressure gauge; when fracturing is stopped, the two-way
safety valve of the hole packer cooperates withtheone-way valve to maintain pressure of the hole packer stopping water injection; stage-by-stage pressure relief is achieved by adjusting an external
pipe cut-off valve and a pressure regulating valve,high-pressure water infracturing holes can flow out through the two-way safety valve, in-situ pressure maintenance and pressure relief of the hole packer is achieved, a high-pressure rubber expansionhose is less likely to be ejected from the drilled hole,high-speed friction with the fractured holes is prevented, and the service life is long.