On December 29, at the construction site of Beijing South Third Ring Caoqiao subway station, the “Jingtuo No. 2” shield machine of LNSS emerged from the soil, symbolizing the first shielding section of the entire Metro Line 19 had achieved double-line penetration.
The main construction section of Metro Line 19 is located in the Old Urban Area of Beijing, making it difficult to be built. There are 1,380 risk sources in the whole line, including 19 special-level risk sources and 433 first-level risk sources. The two risk sources account for 32.7% of the total number of risk sources. During the construction process, the risk sources such as the South Third Ring Road, the Macao River and the Caoqiao Bungalow Area are characterized by long distance and abundant groundwater volume, which is one of the most difficult sections in the whole line.
This penetration subject is the section left-line tunnel, and the right line being parallel to it has been penetrated on December 9th. In this section, our company's two shield machines with a diameter of 6.68 meters have run through the South Third Ring Road for nearly 1 km since the construction in July this year, and the traffic above is not affected. Our company's shield machine has run through the Macao River twice, quickly and steadily, and its crossing distance is nearly 80 meters, and the shallowest depth is only 6.73 meters during the river crossing. It also crossed the Caoqiao Bungalow Area twice, which has been built for a long time and gathers outdated houses. No one of the houses has been cracked, and the major risk sources have been removed one by one. At the phase of the shield machine approaching the end point, we also overcame the curve with a turning radius of about 450 meters, which was like a 90-degree sharp turn on a heavy-duty truck.