This project was approved by the National Development and Reform Commission in June 65438+1October 65438+August this year. The tunnel connects Xuejia Island in Huangdao District in the south, Tuandao Island in the main city of Qingdao in the north, and goes under Jiaozhou Bay. The maximum water depth of the bay mouth is 40m, and the total length of the tunnel is about 7800m, including the submarine section of 3950m and the land section of 3850m. Set up two-way six lanes, with a design speed of 80 km/h, and adopt the drilling and blasting method for construction, with a total investment of 365.438+0.8 billion yuan (excluding the investment in urban connecting lines).
As a legal person of tunnel project, Guo Xin Company has made a lot of solid and effective preparations around the goal of building a first-class subsea tunnel this year. First-class tunnel experts, including 1 1 academicians and foreign research and consulting institutions, have been invited for many times to discuss and demonstrate tunnel survey, design, construction, risk management and other issues, and to extensively absorb experts' opinions and suggestions. The excellent domestic survey team was selected, and the geological conditions of Jiaozhou Bay were surveyed in detail in more than three months, and the geological conditions of the tunnel route were accurately found out. Select excellent design units through public bidding and carefully design tunnels. Authoritative universities and scientific research institutes in China were entrusted to carry out a series of special studies on soil and water conservation, geological disasters and advanced geological prediction, which provided technical parameters and basis for the project. The scientific, serious and rigorous preparation has been widely praised by experts, which has minimized the construction risk and laid a solid foundation for the safe and smooth construction of the tunnel project.
The construction period of Jiaozhou Bay Tunnel is about three to four years. It is understood that this is the second subsea tunnel started in China after the Xiang 'an subsea tunnel in Xiamen.
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Experts evaluate Jiaozhou Bay Tunnel
During the preparation of JIAOZHOU bay tunnel, the company invited designers such as Wang, Wang, Wang Sijing, Xu Shizhe, Zhang Zonghu, Lu Yaoru, Feng Shuyu, Zhang Chuhan, (from Russia), Shi Yuxin and Cui Qiujian to attend seminars or demonstration meetings in Qingdao to solicit opinions on the survey, design, construction and scientific research of JIAOZHOU bay tunnel.
Experts believe that JIAOZHOU bay tunnel is technically feasible in design and construction, with comprehensive risk consideration, effective and feasible preventive measures, short construction period and low cost, so it is the best choice for the tunnel to cross the bay mouth. In the feasibility study stage of Qingdao Jiaozhou Bay subsea tunnel, a lot of land and offshore engineering geological survey and geophysical exploration work were completed, and the topography, geological structure and stratigraphic structure characteristics of the proposed subsea tunnel site and its vicinity were basically found out, and the engineering properties and site stability of the main rock and soil layers were analyzed and evaluated, which laid a good foundation for the next detailed survey work. At the same time, experts believe that the survey methods used in the detailed geological survey of Jiaozhou Bay Tunnel are appropriate, especially many new technologies, new methods and various survey methods have met the relevant requirements.
Geological conditions of Jiaozhou Bay tunnel
According to reports, the section that JIAOZHOU Bay Tunnel passes through belongs to a relatively stable area with hard rock lithology, little structural influence, complete rock mass and good overall conditions. The land of the tunnel site is mainly granite, and there are also dikes such as porphyry and syenite, and the thickness of the strongly weathered zone is generally less than 3m. In the sea area, volcanic rocks and subvolcanic rocks are mainly ejected, as well as dikes such as syenite, diabase and syenite. The thickness of fully-weakly weathered zone of bedrock is generally less than 15m, and the main adverse geological phenomena are bad geological bodies such as fracture zone, dense zone of joints and fissures and diabase, with low weathering resistance.
Relevant experts believe that the survey methods used in the detailed geological survey of Jiaozhou Bay Tunnel are appropriate, especially many new technologies, methods and various survey methods have met the relevant requirements.
The tunnel can resist earthquakes of magnitude 7 or above.
Regarding the safety of the cross-harbour tunnel, experts said that after the completion of the cross-harbour tunnel, people will walk 70 meters below the sea level (including at least 25 meters deep seabed rock layer and the deepest seawater of more than 40 meters). Before compiling the feasibility study scheme of the cross-harbour tunnel, the well-known domestic experts were entrusted to make a special investigation and study on the safety performance of the tunnel, and it was considered that the cross-harbour tunnel was built according to the safety standards of the national engineering code, and the seismic grade was above 7.
It is understood that the cross-harbour tunnel adopts a V-shaped slope, the lowest elevation of the tunnel is -70.5 meters, 44.5 meters away from the seabed surface (the distance from the sea level to the seabed), and the minimum buried depth of the tunnel is 25 meters (the distance from the top of the tunnel to the seabed).
Memorabilia of Jiaozhou Bay Tunnel
On September 19, 2005, Qingdao Municipal Government approved Qingdao Guo Xin Industrial Co., Ltd. as the legal person of Qingdao Jiaozhou Bay Tunnel Project with document Z [2005] 120, and determined that the operating period of Qingdao Jiaozhou Bay Tunnel was 25 years.
In June, 2006, 65438+1October, 65438+August, the National Development and Reform Commission approved the Qingdao Jiaozhou Bay Tunnel Project with the document of Development and Reform Investment [2006]95.
On April 25, 2006, the geological exploration of Qingdao Jiaozhou Bay Tunnel was carried out in Tuandao and Xuejia Island at the same time, and the field work of geological exploration in this sea area was completed on July 27.
On June 7, 2006 165438+ 10/kloc-0, the tender for the design of Qingdao Jiaozhou Bay Tunnel was opened at the Municipal Construction Engineering Trading Center, and China Railway Tunnel Survey and Design Institute Co., Ltd. won the bid.