Impact of punch penetration indices on hard rock tunnel boring machineperformance: A case study

Two key factors in order to examining a given tunnel boring machine’s performance, especially in hard rock arethrust force and penetration rate. In recent years various indices have been developed from the analysis of the forcepenetration curve of the penetration test to present rock drillability, boreability, and brittleness. In the present study,a series of punch penetration tests were performed to explore the effect of punch penetration test indices on TBM’sfield performance parameters using compiled data from Kerman water tunnel. The samples were collected fromrock chips during boring time in ۸ different lengths of the tunnel. After performing tests, three indices wereextracted from the result of experiments and one of them was new index that is developed in present study. Allindices were considered in investigations to obtain relevant to TBM parameters, including thrust force andpenetration rate. Besides tunnel boring Machine’s parameters, field penetration index (FPI) as an adjusted indexwere compared with these indices. Comparisons showed PSI and Area under graph (AUG) gave the bestrelationships with thrust. On the contrary, new developed brittleness index had good correlation with penetrationrate. Likewise, these investigations illustrated a good agreement between Field penetration index and punchpenetration tests indice