On Feb. 13th 2015, Xiamen Construction Works Bidding Trade Website publicized a bid-winning result that CRL’s China Railway Tunnel Survey & Design Institute Co., Ltd. won the bid of Lot 1 of Civil Engineering Design for Rail Transit Line 3 in Xiamen (sea-crossing section tunnel included) with a contract price of RMB 44,000,000.

Xiamen Rail Transit Line 3 is a southwest to northeast trunk line connecting Xiamen Island and the sub-center of eastern Xiang’an. There was only one lot in the bid, i.e. Wuyuanwan Station (exclusive) to Xiang’an Dongjie Station. The lot includes two stations and two sections. The entire line is totally 6.71km in length, the sea-crossing section is 5.1km in length and the sea area section 3.7km in length. The overall investment is approximately RMB 2,200,000,000.

Upholding a rigorous and scientific attitude, China Railway Tunnel Survey & Design Institute Co., Ltd made careful planning in advance, organized employees properly and encouraged them to do their best, and created a precedent in China that two proposed construction methods, i.e. mine tunneling method and shield tunneling method, would be applied in the sea area tunnel. The combination of the above methods is able to overcome the problem of complex geological conditions in the sea area and varying surrounding rocks so that the underwater tunnel can go across fault zone F1, F2 and F3. Respective sections of the above two methods which join under the sea implies great technical difficulty and high construction risks. Survey work in the sea area, including engineering survey, surveying & mapping of topographic map and control network measurement, shall need relevant parties’ coordination and consider various factors and difficulties.

This is the second sea-crossing sectional tunnel for metro line undertaken by China Railway Tunnel Survey & Design Institute Co., Ltd following the sea-crossing sectional tunnel of Qingdao Metro Line 1 (7km in length and 3.5km in sea area length) and it is also China’s largest sectional tunnel for metro line in sea area. The company’s winning the bid further shows its leading role in the field of underwater tunnel design in China. It is also a vivid demonstration of CRL’s development concept “Cultivating Professional Brand & Enhancing Comprehensive Strength”.