Device and method for detecting permeability of dimension stone roadbed

The detection device comprises a gas injection pipe and monitoring equipment, one end of the gas injection pipe is connected with a gas source generation device, the other end of the gas injection pipe is inserted into a rock block layer of a roadbed to be detected, and the end head of the end, inserted into the roadbed to be detected, of the gas injection pipe is closed; a gas guide hole is formed in the side wall of the gas injection pipe, the forming direction of the gas guide hole faces the monitoring equipment, and the monitoring equipment is arranged in a to-be-detected roadbed block stone layer and used for monitoring the wind speed and the wind pressure injected into the to-be-detected roadbed; according to the device, high-pressure gas is injected into the to-be-detected roadbed block stone layer only through the gas injection pipe, the device is closed except the gas guide hole, gas in the gas injection pipe is prevented from escaping towards the bottom of the roadbed, monitoring equipment is arrang