Pre-split roof caving method based on collaboration of foam fracturing and blasting for coal mines

A pre-split roof caving method based on the collaboration of foam fracturing and blasting for coal mines, comprising the following steps:

• S1:
• construction of a borehole:
• constructing the borehole for foam fracturing fluid transportation and pressure boosting in an appropriate position of a top rock stratum of a coal bed according to characteristics of a roof rock stratum and requirements of a coal mining process;
• S2:
• preparation of a foam fracturing fluid:
• preparing and foaming the foam fracturing fluid by means of a foam preparation device, and injecting a combustible gas during foaming of the foam fracturing fluid;
• S3:
• fracturing:
• arranging a fracturing system in the vicinity of the borehole, injecting the foamed foam fracturing fluid into the borehole by means of the fracturing system to destroy an interior of the roof rock stratum to form fractures with a specified size, and enabling the foamed foam fracturing fluid to enter the fractures under the action of the fracturing system;
• and
• S4:
• roof caving by blasting:
• when the fractures in the roof rock stratum satisfy blasting requirements, stopping injection of the foam fracturing fluid, and then performing ignition for blasting.