The construction of new Yan'an tunnel starts and the West Yan'an high speed railway officially enters the construction stage

Xiyan high speed railway officially entered the construction stage

our report (reporter Yang Xu) at about 11:00 a.m. on January 9, at the foot of Qiuyan mountain in Baota District, Yan'an City, with two excavators slowly driving into the mountain, the construction of the new Yan'an tunnel, a control project of the yijun-yan'an section of Xi'an-Yan'an high speed railway (hereinafter referred to as "Xiyan high speed railway"), marked the start of the construction of xiyan'an tunnel The high-speed railway has officially entered the construction stage. A 6031 a 6031 new Yan'an tunnel is located between Ganquan north station and Yan'an station of West Yan'an high speed railway. The tunnel passes through the Loess Liangmao gully area between Laoshan township of Ganquan County and Baota of Yan'an City, with a total length of 16 kilometers. It is designed as a single hole double line tunnel, with a maximum buried depth of about 250 meters and a minimum buried depth of 13 meters. The tunnel vault of about 4800 meters is located near the earth rock interface, which is the control of the whole line Institutional engineering, class I high-risk tunnel. In order to ensure the smooth construction of

, the new Yan'an tunnel adopts the three-step method for grade IV surrounding rock, and the three-step method for grade V surrounding rock to reserve core soil or three-step temporary inverted arch. According to the geological characteristics of horizontal rock stratum and earth rock interface, advance support and initial support are designed to be strengthened. The advance support adopts pipe shed plus small conduit grouting for pre reinforcement or double-layer small conduit grouting for pre reinforcement. At the same time, the initial support is closed in time to ensure construction safety. The

West Extension high-speed railway is an important part of the national high-speed railway network (Yinhai) high-speed railway channel. The total length of the line is about 300 km. The construction standard is double track passenger dedicated line, with a design speed of 350 km / h. After the line is completed and put into operation, the operation time from Xi'an to Yan'an will be shortened from the current two and a half hours to about one hour.