Design Optimization in Underground Coal Systems. Interim Report,October--December 1975. Section 1. Structural Parameters of Coal Measure Rocks. Section 2. Longwall Mining System Strata Simulator. Section 3. Design Criteria for Underground Roof-Truss Support Systems.

摘要

The major thrust of this quarter's efforts was the development of the data cross-reference computer program which is now 75percent complete and operational. The purpose of this program is to reduce experimental results obtained from coal testing and store this data on a disk along with all other pertinent data associated with the coal sample. To date program plots of load vs. edge length,and averages of modulus of elasticity,ultimate stress,and edge length have been made. Work has continued on refinement of the two-dimensional,body-loaded,photoelastic longwall model. Stress-strain characteristics for the model chock,developed the previous quarter,were determined experimentally for the expected loading range. Additional roof support tests have been performed analyzing the effects of blocking points,the depth of anchor placement,the thicknesses and sequencing of roof strata,and the opening height. The height of the opening has no effect on the model roof truss characteristics. Multiple blocking points were slightly more efficient than collar blocking points in the model. The depth of placement of the truss anchor had little influence on the performance of the model roof truss. The thickness and sequence of roof strata can have an important effect on roof support. Weak immediate thick layers overlain by weak thin layers as well as thin immediate roof layers overlain by thicker layers can be supported well by the roof truss. (ERA citation 01:025285)