Shanghai R&D world's largest section-type rectangular shield machine "Yangming" originated

Recently, the world's largest section of the earth pressure balance rectangular shield "Yangming" originated in the construction of the Ningbo subway site. This is China's first self-developed rectangular-like shield. Compared with the traditional circular shield, it has many advantages: it saves underground space resources, and can effectively control settlement and reduce the impact on the surrounding environment.

Construction of "Yangming" Shield Machine at the First Phase of Ningbo Rail Transit Line 3 Project

To the surprise of the industry, this new type of construction equipment jointly developed by Shanghai enterprises and universities has only been used for less than a year from scratch to construction.

Meet new demands for residents' demands

The shield is a weapon for excavating tunnels. “Shield” refers to the pressure of the equipment to withstand the soil in all directions like a shield when the equipment is underground. The “construction” refers to the equipment that can splicing the concrete members while supporting the soil to support the tunnel. Shanghai started very early in the field of shield manufacturing. The earth pressure balance shield and the large-diameter mud-water balance shield have always been in the leading position in the country. The products have been exported to Singapore, India and other countries.

Zhu Yanfei, chief engineer of Shanghai Tunnel Engineering Co., Ltd. introduced that in April 2014, Ningbo Rail Transit Group Co., Ltd. found them and consulted the problems encountered by Ningbo Metro Line 4 project. According to the plan, this line passes through the narrow old town of the street. After the public announcement, the residents along the line had great opinions, worried about the settlement of the house, and worried about the close-range noise and vibration after the opening of the car. Indeed, if two single-circle shields are used, the tunnel will invade the lower houses along the street; if a double-circle shield is used, the settlement control capability may be insufficient. To this end, Ningbo Rail Transit hopes that Shanghai Tunnel Company will propose a new technical solution.

"Rectangular Shield", Shanghai Tunnel Company proposed this kind of equipment that China has not yet. The section of the tunnel excavated is close to a rectangle, and the width is similar to that of the two single-circle shields next to the excavated tunnel. The height is much smaller than the large circular tunnel that accommodates the double line, and the invalid space in the circular section tunnel is removed. .

Since 1995, Shanghai Tunnel has begun to develop special-shaped (non-circular) tunnel boring machines with many technical accumulations. Internationally, Japanese companies have developed rectangular, rectangular-like (Japanese called composite circular) shields, which are used in rail transit, highway tunnels, water supply and drainage pipelines, pedestrian tunnels, etc., and the construction effect is very good.

After listening to the introduction of Shanghai experts, Ningbo Rail Transit sent people to Japan to investigate and confirm that the rectangular-shaped shield can solve the problem of Line 4. However, Japanese companies do not have ready-made equipment for sale.

Integrated bidding to improve innovation efficiency

Under this circumstance, Ningbo Rail Transit made an innovative move to organize R&D-like rectangular shield equipment and construction complete sets of technology through the integrated bidding method of scientific research, design and construction. Zhu Yanfei lamented, "The equipment is still not there, the construction bidding will begin."

The characteristics of the domestic construction industry system are controlled in stages and each performs its duties. The so-called "segment control" is divided into four stages: project approval, engineering feasibility study, preliminary design, construction drawing design and construction. “All the duties” means that the construction unit guarantees that the procedure is legal, the design unit ensures that the design drawings conform to the specifications, the construction enterprise constructs according to the drawings, and the experts play the role of “decision maker” in the whole system. Is this system conducive to innovation? Some industry insiders believe that with the innovative design and construction schemes, it seems that the project can be won, but in practice, there are mutual interests of the approver, construction unit, design, construction, etc. Restrictions make the road between technology innovation and application not smooth.

The integrated bidding method for scientific research, design and construction has broken through the existing system, allowing large construction companies to take the lead in integrating these three links and truly become the mainstay of innovation. In January 2015, Shanghai Tunnel Engineering Co., Ltd. successfully bid. Subsequently, the company led the organization of the industry-university research team, combined with Shanghai Tunnel Engineering Rail Transit Design and Research Institute, Tongji University, Shanghai Jiaotong University and Shanghai Shield Design and Research Center Co., Ltd. to jointly develop rectangular shield and engineering application programs.

Zhu Yanfei said that this kind of bidding method has realized the integration of technology research and development and experimental application, and has rationalized the interests of all parties, allowing large construction enterprises to lead technological innovation and significantly improve innovation efficiency.

Intellectual property sharing harvest bonus

According to the contract signed by Ningbo Rail Transit and Shanghai Tunnel Shares, the Shanghai team raised 77 million yuan to build prototypes. Ningbo has undertaken research funding and is responsible for implementing the verification project. If the verification project fails, Ningbo Rail Transit will bear 50% of the prototype cost; if successful, Ningbo Rail Transit promises to amortize the prototype in the next 4000m tunnel construction. The intellectual property rights obtained by R&D are shared by both parties. If the rectangular-shaped shield is applied in cities other than Ningbo, Shanghai Tunnel shares will pay 10,000 yuan/meter of royalties to Ningbo.

"All said that Ningbo people will do business, from this contract, it can be seen." Liu Qin, deputy inspector of Shanghai Science and Technology Commission, said that Ningbo Rail Transit, as an engineering contractor, dared to take risks and adopt new ones to meet the demands of the citizens. Technical solutions, and designed a risk sharing and benefit sharing mechanism, which is worth learning from Shanghai.

Practice has shown that Ningbo's innovation has achieved good results. In the nine months after the signing of the two enterprises, China’s first earth pressure balance rectangular shield was delivered. The excavated tunnel has a section length of 11.83 meters and a width of 7.27 meters. The head has four cutterheads, which can achieve 100% full-section non-extrusion excavation. Humin Enterprise United has applied for 40 invention patents and 4 software copyrights for this equipment, forming a patent group protection.

After the factory-like rectangular shield was shipped from the factory, it was first used for the verification project of Ningbo rail transit arrangement. It was “tested” 400 meters below the proposed demolition plant on the subway line 3 to test the settlement of the building. If the settlement control is good, it will be constructed on Metro Line 4 and will be promoted in subsequent lines.

This shield is suitable for central and urban areas where roads are narrow, buildings are dense, and shallow underground spaces are increasingly saturated. Relevant units in Zhengzhou, Shenyang and Kunming have sent people to the construction site in Ningbo, and companies in Suzhou and Wenzhou have also indicated that they are going to visit. It is predicted that by 2020, the market size of rectangular-like shields will reach more than 1 billion yuan. Ningbo enterprises are expected to harvest “innovation dividends” through the intellectual property sharing mechanism.

Concerned about surprises

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