Underground mortar column prodn. - by drilling with auger through which hardenable suspension is fed

摘要

A mortar colum is formed in the ground by (a) drilling with an auger (10) to a certain depth with soil displacement but not upward transport; (b) shearing off soil from the borehole wall at location between the auger thread by rotating the auger (10) without advancement and simultaneoulsy feeding hardenable suspension through the auger tip for mixing with the llose soil to form a slurry column (18) of consistency avoiding upward transport of liq., the auger rotation direction being the same as or opposite to that used in drilling or being repeatedly alternated; (c) forming a cylindrical sleeve-like filter cake (16) by diffusion of particles from the column (18) into the surrounding earth to produce a support body; (d) repeating the above steps until the final depth is attained, extensions being added to the auger; and (e) rotating the auger during withdrawal to effect homogenisation of the slurry column. ADVANTAGE - Formation of the supporting sleeve lining is improved.