天城坝隧道进口近距离揭煤层群开挖方式安全可行性论证

The Coal Seam Group is Uncovered Near The Entrance of Tianchengba Tunnel, and the Safety And Feasibility of the Excavation Method is Demonstrated

天城坝隧道进口左线近距离揭煤层群,含煤9~13层,自上而下编号为C5、C6、C7(含C7-1、C7-2、C7-3)、C8(含C8-1a、C8-1b、C8-2)、C11和C12。该段含煤地层段为突出煤层,为确保瓦斯抽采治理效果,分多轮次对煤层群进行瓦斯抽采治理。由于各煤层层间距较近,确保安全垂距的前提下,根据隧道大断面开挖特点,制定了多台阶开挖方式并确保了安全垂距。实践证明,多台阶开挖方式是安全可靠的。

Tianchengba tunnel entrance on the left line of the coal seam group,coal-bearing layers 9~13 are num?bered C5、C6、C7(including C7-1、C7-2、C7-3)、C8(includingC8-1a、C8-1b、C8-2)、C11 and C12 from top to bottom.The coal-bear?ing strata in this section are outburst coal seams.In order to ensure the effect of gas drainage,the coal seams were treated by gas drainage in several rounds.Due to the close distance between each coal seam and the premise of ensur?ing safe vertical distance,according to the characteristics of large cross-section tunnel excavation,the multi-step ex?cavation was made and the safety vertical distance is ensured.The excavation method is safe and reliable.