RELATIONS BETWEEN WEAR LIFE OP RIPPERTIP AND ROCK MASS PROPERTIES

摘要

One of the most important problems in mechanical excavation of rock mass by bulldozer-mounted ripper is to estimate precisely the life of rippertip due to wear. Here, the methods of estimation of wear life of tip as well as the characteristics of shape variation have been studied for many different ripping operation sites. The properties of rock mass for wear of tip can be expressed by "Index of Rock Mass Strength for Wear σ_c" which is calculated by uniaxial compressive strength for non-fissured rock sample σ_(co), coefficient of crack of rock mass C_r, contents of quarz and hard rock forming minerals K_o, and other factors. σ_c = K · K_o~2 σ_(co) ( 1 – C_r ) The amount of wear and the wear length of tip increase approximately with linear relationship to the ripping operation time. The angle of each slope varies respectively according to the Index of rock mass strength for wear. And, the characteristics of shape variation of tip varies also with the index σ_c. The rippability of rock mass are expressed by the indexσ_c, and the wear life of tip T_c can be estimated by the function of index of rock mass strength for wear σ_c. For light wear zone ( 0 <σ_c≤43 kg/cm~2) T_c =4.10 × 10~2·(σ_c)~(-0.33) For heavy wear zone (σ_c≥43 kg/cm~2) T_c =2.40 × 10~5·(σ_c)~(-2.03). And, the in-situ test method of measuring amount of wear of tip is more valuable than that of measuring wear length of tip for estimating the life of tip due to wear.