EGRESS BORING MACHINE CUTTER DEVELOPMENT

THE PROGRAM GOALS FOR THE EGRESS BORING MACHINE REQUIRE A ROCK BORING SYSTEM WHICH WILL PRODUCE PENETRATION RATES OVER TEN TIMES GREATER THAN THOSE PRODUCED TO DATE UNDER SIMILAR CONDITIONS. THIS PROPOSAL IS TO DEVELOP A CUTTER SYSTEM WHICH USES THE CONCEPT OF AN INTERRUPTED DISC CUTTER. IT WILL TAKE FULL ADVANTAGE OF INDEXING BETWEEN CRATERS TO MAXIMIZE ROCK REMOVAL WHILE MINIMIZING THRUST REQUIREMENTS. SUCH REDUCTION WILL INCREASE THE LIFE OF BOTH THE CUTTING AND BEARING STRUCTURES. INTEGRAL TO THE STUDY IS THE DEVELOPMENT OF A REALISTIC MATHEMATICAL MODEL OF ROCK FAILURE MECHANICS DURING BORING. DEVELOPMENT OF THIS MODEL WILL PERMIT DEVELOPMENT OF AN OPTIMUM CUTTING STRUCTURE WHICH WILL HOLD PROMISE OF ACHIEVING THE PROGRAM GOALS. WITH DEVELOPMENT OF AN OPTIMUM CUTTING STRUCTURE, DESIGN OF THE REQUIRED BEARING AND SUPPORT STRUCTURES WILL BE POSSIBLE. SUCCESSFUL DEVELOPMENT OF THE PROPOSED CUTTER CAN PRODUCE SIGNIFICANT IMPROVEMENTS IN BORING TECHNOLOGY WHICH WILL ENHANCE BOTH ECONOMICS AND SAFETY OF SHAFT AND TUNNEL CONSTRUCTION.