Using In situ penetration tests to improve the performance of TBM in long tunnels-Case study of Golab water transfer Tunnel

One of the challenges in mechanized excavation of long tunnels is facing a variety of geological units withdifferent boreability indices. This kind of variety brings about diversity of excavation conditions, and in casesufficient recognition of boreability index is not provided and improper excavation parameters are chosen, itcould cause inefficient excavation and sometimes a rise in disc cutter consumption. In order to improve theunderstanding of effective factors, in addition to frequent monitoring of geological conditions in tunnel duringexcavation, carrying out periodic in situ penetration tests can markedly reduce the relevant consequences. Inthis research by dint of several in situ penetration tests, excavation conditions in some principle geologicalsections of Golab water transfer tunnel were compared and analyzed. By taking advantage of test results,Specific Rock Mass Boreability Index (SRMBI) was estimated. Besides, according to Specific Energy (SE)variations in different thrust forces, the optimum thrust force in various rock masses were determined, andfinally a correlation between the optimum thrust force and SRMBI in hard rocks was presented. Based onachieved results, the Crystalline Limestone, Monzodiorite and Conglomerate have the highest SRMBI andSlates and Phyllites have the lowest values.

کلیدواژه ها:

In situ penetration test ، Specific Rock Mass Boreability Index ، Optimum thrust force ، Golab Tunnel ، Specific Energy (SE)