渝黔铁路天坪隧道软岩大上半断面法快速掘进施工技术

Rapid Construction Technique for a Large Upper-Section of the Tianping Tunnel in Soft Rocks

文章结合渝黔铁路天坪隧道软岩段施工实例,针对原设计Ⅲ级、Ⅳ级、Ⅴ级围岩开挖工法存在的作业空间受限、大型机械化配套设备无法应用等情况,对传统的两台阶法进行了优化,形成了一种大上半断面法,并对其施工组织进行了阐述,制定了合理的钻爆技术方案,确保了进度和成本的最佳组合;总结了软岩隧道及不良地质地段施工的技术措施,实现了天坪隧道软岩段的快速安全施工。

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 rea- sonable 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.