hercularc lining

hercularc lining

[′hər·kyə‚lärk ‚līn·iŋ]
(mining engineering)
A German method of lining mine roadways subjected to heavy pressures; a closed circular arch of wedge-shaped precast concrete blocks made in two sizes are erected so that alternate blocks offer their wedge action in opposite direction, the larger blocks toward the center of the roadway and the smaller outward.