On April 17, the installation of the first waterstop was completed for the eastwest axis immersed tunnel in Xiangyang, Hubei Province, undertaken by CCCC Second Harbour Engineering Co., Ltd. The waterstop and the immersed concrete were successfully engaged. This is the first time for China’s independently researched and developed high-performance rubber waterstop to be used in the construction of immersed tunnels.
It is learnt that China Communications Construction Company Ltd. (“CCCC”) and Zhuzhou Times New Materials Technology Co., Ltd., a subsidiary of CRRC Group, have successfully developed OMEGA waterstop products with completely independent intellectual property rights after two years of trials, filling in the domestic gap and breaking the international monopoly. The test results show that the sealing performance, water resistance, stability and other performances of the waterstop have all reached European standards, and some indicators even exceed European standards.
Immersed tunnel is a new type of pathway crossing stream (river, sea). It puts several sections of prefabricated square immersed tubes (such as containers) into the water bottom to splice to form a channel. Waterstops are used to bond gaps between immersed tubes and to prevent immersed tubes from leaking. It is one of the core technologies for the construction of immersed tunnels. Prior to this, only few countries such as the Netherlands, Japan, etc. had mastered the production technology of waterstop. All of the nearly 20 immersed tunnels currently constructed and under construction in China all adopt imported products for their waterstops.
Times New Materials took the opportunity of participating in the National Science and Technology Support Program project “Key Technology Research and Demonstration of Hong Kong-Zhuhai-Macao Bridge Cross-sea Cluster Engineering Construction”, established the Waterstop Project Department to fully develop the research, development and industrialization work of waterstop products for immersed tunnel engineering. The project staff successfully overcame the problems of product manufacturing, vulcanization process, etc., and completed the manufacture of full-scale samples and stress relaxation, compression performance, water sealing performance and other tests. Each performance of the samples can meet the actual needs, which is equivalent to the performance of the samples of top foreign manufacturers.
The waterstop installed this time is 75.5 meters long and weighs 4.2 tons. It hangs like a long looped noodle. To this end, the project department has designed special lifting appliance, with 32 lifting points on the waterstop to ensure the stability after lifting and exact match when engaged with immersed tubes.
It is learned that the eastwest axis immersed tunnel in Xiangyang is the first immersed tunnel in central China, with a total length of 1.01km and a two-way 6-lane design. Its construction is of great significance for leading the development of inland river immersed tunnel technology.
