The 15.07m-diameter TBM named Pioneer and developed by China Railway Construction Heavy Industry Corporation Ltd (CRCHI) broke through on the eastern tunnel on July 15.
Nine days earlier, a high-precision breakthrough was made on the first 3.86m-diameter cross passage.
TBM Pioneer, which is 130m long and weighs 4,300 tons, was assembled on February 20 last year and launched less than three months later, and two months after the launch of the TBM for the western tunnel. During tunnelling, which took a month less than for the western line, TBM Pioneer achieved a maximum daily advance of 16m and a maximum monthly advance of 324m.
The Haizhu Bay Tunnel project is the first large-diameter bored tunnel in Guangzhou. It is 4.35km long, including the 2.1km TBM section which passes through the fracture zone of the Pearl River Channel twice, a long section of mudstone and muddy siltstone formations, and under buildings and piles.
The six cross passages are 14.8-18.1m long. The main tunnel segments are C60 high-strength segments, with the cross passages buried more than 45m deep and at an oblique angle to the main tunnel.
The cross passage TBM, also manufactured by CRCHI, features technologies such as rapid breaking of oblique intersection lining, synchronous construction layout, high-pressure sealing, rapid posture adjustment, and high-precision guidance correction. Its highest daily progress was two ring segments in less than three hours, and it set a record for cutting into the main line tunnel segments.
The total cost of the Haizhu Bay Tunnel project is approximately 11.68 billion yuan (£1.27bn). Once completed, the tunnel will reduce the driving time from downtown to Guangzhou South Railway Station to 15 minutes. It is scheduled to open to traffic in 2025.
