What are the detection methods of shotcrete thickness in tunnels?

Detection method of shotcrete thickness in tunnel;

A, spray layer thickness can be checked by drilling or laser profilometer, light belt photography and other methods.

Second, check the number of sections. Check at least one section every 10 linear meter, and then check a point every 2 meters from the center line of the vault.

Qualifying conditions:

A, according to the statistics of each arch and wall, the sprayed layer thickness of all inspection holes should be no less than 60% of the design thickness, the average thickness should not be less than the design thickness, and the minimum thickness should not be less than 1/2 of the design thickness. In the weak and broken surrounding rock area, the thickness of shotcrete layer should not be less than the minimum thickness specified in the design, and the thickness of shotcrete with steel mesh should not be less than 6cm.

B, when cracks, shedding, rebar exposure and water leakage are found on the sprayed concrete surface, it should be repaired, chiseled, re-sprayed or rectified.