METHOD AND DEVICE FOR TREATING EXCAVATION SURPLUS SOIL

PURPOSE:To augment the reuse of excavation surplus soil and lighten the influence on environment entailed by extracting pit sand or discarding surplus soil by a method wherein carbon dioxide is added to the surplus soil resulting from treatment of calcined lime to neutralize its alkalinity and prevent the excessive hardening so as to optimize the bearing power of the soil. CONSTITUTION:The surplus soil 1 resulting from excavation for calcined lime is charged into a hopper 2 and sent in prescribed portions therefrom through a rotary valve 3 into a reacting machine 4 having a motor driven rotary blade 4a incorporated therein. Carbon dioxide is introduced through a carbon dioxide line 5 into the reacting machine 4, whereby the surplus soil 1 is stirred by the rotary blade 4a to uniformly react with carbon dioxide for neutralization. The surplus soil 1 thus neutralized is sent in prescribed portions into a neutralized soil receiving hopper 7 by a rotary valve 6. The neutralixation of the surplus soil 1 attained in this way can prevent the contamination with alkali of underground water at the time of reusing the surplus soil or an excessive hardening of the soil after backfilling.