SELF-STABILIZING UNDERGROUND EXCAVATION CROSS SECTION

Award Information
Agency: National Science Foundation
Branch: N/A
Contract: N/A
Agency Tracking Number: 14419
Amount: $224,503.00
Phase: Phase II
Program: SBIR
Awards Year: 1993
Solicitation Year: N/A
Solicitation Topic Code: N/A
Solicitation Number: N/A
Small Business Information
400 Wakara Way, Salt Lake City, UT, 84108
DUNS: N/A
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 Ziqiong Zheng
 Project Manager
 () -
Business Contact
Phone: () -
Research Institution
N/A
Abstract
UNDERGROUND EXCAVATION IN ROCK WHICH IS SUBJECTED TO STRESSES THAT ARE A SIGNIFICANT FRACTION OF THE ROCK STRENGTH CAN CAUSE FAILURE ADJACENT TO THE EXCAVATION. RECENT RESEARCH ON BOREHOLE BREAKOUTS HAS SHOWN THAT A STABLE BREAKOUT IS CHARACTERIZED BY A STRESS DISTRIBUTION WHICH IS GREATLY REDUCED FROM THE ORIGINAL STRESS STATE AT LOCATIONS NOT DIRECTLY IN FRONT OF THE BREAKOUT "TIPS". ALSO, THE STRESSES IN FRONT OF THE "TIPS" ARE ALMOST HYDROSTATIC. SUCH A SHAPE IS STABLE AND SELF-SUPPORTING. IF TUNNELS OR UNDERGROUND EXCAVATIONS INCORPORATE A CROSS-SECTIONAL SHAPE SIMILAR TO A STABLE BREAKOUT, THE COST OF SUPPORT AND LONGTERM MAINTENANCE COULD BE GREATLY REDUCED OR POSSIBLY ELIMINATED. THE PROPOSED RESEARCH WOULD EVALUATE THE LOAD BEARING CAPACITY OF DIFFERENT EXCAVATION SHAPES AND THE FEASIBILITY OF USING A GENERIC BREAKOUT SHAPE AS AN EXCAVATION SHAPE IN ORDER TO REDUCE COST, TIME IN CONSTRUCTION AND MAINTENANCE. IF THIS PHASE OF THE RESEARCH SUGGESTS PRACTICAL AND ECONOMIC FEASIBILITY, PHASE II OF THE RESEARCH WOULD BE LARGE SCALE EXPERIMENTS (A CUBIC METER AND LARGER) AND PHASE III WOULD BE THE COMMERCIALIZATION OF A TUNNEL BORING OR OTHER EXCAVATION MACHINES, SPECIFICALLY DESIGNED FOR EXCAVATION OFA STABLE (BREAKOUT) CROSS-SECTION.

* Information listed above is at the time of submission. *

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