Abstract：
Based on the soft-rock section construction of the Tianping tunnel on the Chongqing- Guizhou high speed railway, the conventional two-bench method is optimized and a large upper-section method is presented in light of the confined work space and unavailability of large mechanical equipment regarding the original designed construction method for the rock mass of grades Ⅲ, Ⅳ and Ⅴ. The construction organization is described and a reasonable drill and blast scheme is established, guaranteeing an optimal combination of progress and cost. The technical measures for a soft-rock tunnel with unfavorable geological conditions are summarized, and ultimately the rapid construction of the Tianping tunnel in a soft-rock section is realized.
2017, Vol. 54 