METHOD OF UNDERGROUND CAVITY EXCAVATION CONSTRUCTION BY STRESS CONTROL THAT USE ADVANCE SLOT EXCAVATION

摘要

An underground excavation method which reduces or eliminates the need for roof supports includes the cutting of one or more slots in a radial direction ahead of the advancing underground excavation. The plane of the slot is disposed perpendicular to the tangential stress that is expected around the prospective opening, so that the tangential stress is removed prior to the excavation of the opening, eliminating the potential damage to the boundary. The stress envelope finally formed after the excavation is radially expanded by the advanced slots, and can be made to stress- relieve the ground surrounding the excavation by controlling the length, number, and orientation of the advanced slots. The stress- relieved ground may be utilized as lining material by solidification with cement grouting or very limited anchor bolting.