How to implement safe tunnel blasting and excavation under complex geological conditions?
Step 1: Exploration before excavation, adhere to the safe operating procedures of 30 meters exploration and 20 meters excavation in front of the tunnel, front top, front left, front right, and front bottom.
Step 2: Reserve emergency supplies for tunnel mud, water, and gas outbursts.
Step 3: Pay close attention to the signs of "three outbursts". If ominous signs are found, stop drilling and blasting immediately, continue to explore in advance and make detailed records.
Step 4: If a small area of "three outbursts" is found, the face should be immediately closed and the grouting pipeline should be pre-buried to prevent the accident from further expanding.
Step 5: After the closed body solidifies, inject high-grade cement slurry and quick-setting agent into the pre-buried grouting pipeline, or adopt the freezing method to fill the water, mud, and gas outburst space, and solidify the soil and rock mass of the tunnel contour surface.
Step 6: Chisel a small observation hole in the closed body of the face, re-explore the soil and rock mass in front in detail, and after confirming that there are no hidden dangers, carry out excavation with a small advance and provide timely support.
