EXCAVATION AND AGITATION OF GROUND

PROBLEM TO BE SOLVED: To eliminate preparation works at every element in the excavating and agitating works of the ground. SOLUTION: When an excavation shaft 10 and agitation shafts 12, 14 are inserted to penetrate the ground to a specified depth, the pushing work by a vertically moving mechanism is brought to a stop and the agitation shafts 12, 14 are rotated and a hardening agent is injected from respective jet holes 12c, 14c of the agitation shafts 12, 14. In this operation, existing soil is agitated by the agitation blades 12b, 14b of respective agitation shafts 12, 14 and the injected agent is mixed with the soil. A driving mechanism 22 is driven after agitating and mixing the soil and the agent to transfer a traveling base 18 along a guide rail 30 and parallelly shift the excavation shaft 10 and the agitation shafts 12, 14. A pair of excavation shafts 10 are reversely rotated against each other by a rotary drive so as to transfer the excavated soil to the first agitation shaft 12 side by the screw blade 10b. When the above works advance in some extent and a mixture zone of the excavated soil and the hardening material is formed at the rear side of the second agitation 14, a core material like a wide-flange shape steel is buried in the mixture.