On March 11, the shield machine "Shuanglong" on the right line of the 04 bid project of Chongqing Rail Transit Line 15 broke through the wall, marking the successful realization of the breakthrough goal in the shield section of Xiuhu Road Station ~ T3 Terminal Station. Xiu T section is the first shield project cooperated by China Railway First Bureau and Transportation Investment Leasing Company in Chongqing market, the right line shield section is about 3Km long, the shield excavation diameter is 8.8 meters, the shield section crosses Jiangbei Airport T3 terminal and runway, Shuanglong Lake and other complex geological risk sources, Shuanglong Lake rock thickness is 0.88 meters, is the shallowest buried depth of the lake bottom shield tunnel in China, the construction risk is extremely large, and the construction conditions are complex and changeable, through argillaceous sandstone and other clay content of large strata, the construction control measures are higher.

The project adopts a new technology - gram mud effect grouting to fill the outer void of the shield, adopts new environmental protection means - increases lake water purification equipment, reduces lake water pollution, and realizes the smooth breakthrough of the project with the excellent results of "zero settlement, zero deformation, and leading speed", and has won high praise from the industry. Since 2021, the transportation leasing company and China Railway First Bureau have successively carried out extensive cooperation in the field of shield machine/TBM equipment, including the introduction and provision of multiple high-performance earth pressure balance shield machines and "earth pressure-slurry" dual-mode shield machines, supporting and enabling China Railway First Bureau to successfully complete construction tasks in multiple difficult shield sections such as Chongqing Urban Rail Express Line 15 and Line 27. On the basis of the previous cooperation, the two sides will further carry out more in-depth cooperation in professional subcontracting, industry-finance collaboration, construction method upgrading and business promotion, so as to jointly grasp the market opportunities for rail transit construction in the Chengdu-Chongqing Economic Circle, achieve mutual benefit and win-win results, and help the construction of the Chengdu-Chongqing Economic Circle.