Technical Exchange Training-Business Segments-CHUWA BUSSAN

A brief introduction to technical exchange and training

Utilizing the construction technology advantages of China and Japan, uniting many large-scale research institutes of consulting design, Chuwa Bussan Co. Ltd. offers technical support to engineering construction of port/road/bridge/tunnel through design construction scheme, tackle problems in key technologies and configuring scheme of equipment.

Case: The Island Tunnel Project of Hong Kong-Zhuha

Chuwa Bussan provides the foundation treatment technology of sand compaction pile, immersed-tube foundation bed leveling technology, underwater sound shielding technology, immersion surveying and monitoring technology and reinforced bar processing technology from Japan, and has organized Japanese technicians to train the project personnel. At the same time, Chuwa Bussan Co. Ltd. introduces many kinds of operation vessels and construction machinery such as the vessel of sandcompaction pile, rubble leveling equipment, steel bar bender, immersion surveying and monitoring equipment and friction welding press to this project.

Japan’s sand compaction pile
foundation treatment technology

The immersed-tube foundation
bed leveling technology

Underwater acoustic screening
technology

Immersion measurement and
control technology

In order to meet the strict requirement for environmental protection of Lingdingyang of Pearl River Estuary in the Hong Kong-Zhuhai-Macau Bridge Project, the foundation treatment for the island tunnel project has adopted the environment-friendly method of sand compaction pile.

The construction of the E1 tube foundation bed leveling task of the west man-made island, a node project in the construction of Hong Kong-Zhuhai-Macau Bridge, was smoothly completed on March 30, 2013, marking that the installation of the first section of the immersed-tube possess the condition to bear the foundation bed. Due to the relatively narrow operation space of the immersion butt joint of the first section of immersed tube and the west man-made island, , the huge leveling vessel was unable to do the mechanical construction. As a result, the sea floor broken stone laying of this island tunnel project had to be done through manual methods. In addition, this part of the foundation bed on the sea floor should not be paved into a plane, it needs a slope of 2.996% for the tube body to pave, which could be rated as a world-level difficulty. 36 diving operators finished the constructing task requiring high accuracy with their bare hands. They first put the slide-way on the sea floor with the elevation error controlled at a range from +5mm to -5mm; and then used the 9.5-meter-long scraper to level it accurately, before laying the broken stone bedding course to realize the elevation control between +4cm to -4cm. The manual leveling construction lasted two weeks, representing the largest single time diving operation in the scale since the building of Hong Kong-Zhuhai-Macau Bridge started, and also a unique operation mode in island tunnel project ever. The smooth completion of the manual leveling construction, marked the installation of the first section of the immersed-tube having the condition to bear the foundation bed.

Underwater acoustic screening technology

Immersion measurement and control technology

Case: China Nanjing Weisan Road River-Crossing Tun

River-crossing tunnel of Weisan Road in Nanjing adopted super-diameter slurry-pressure-balance TBM, with a diameter of 14.93 meters in the digging construction. Our company has provided technical support for the construction of shield machine for this project, and organized Japanese technical experts to train the project personnel. Tianhe Mechanical Equipment Manufacturing Co., Ltd., invested by our company, serves as main contractor to manufacture shield machine. This project represents the world-class project among shield tunnels in Yangtze River basin, with the features of most difficult technology, most complicated geological conditions, and maximum technical difficulties and challenges.

The development and fabrication of
the complete machine

The development and fabrication of
the cutterhead

Thereport on tunnel boring

The slurry air pressure balanced compound tunnel boring machine with a diameter of 14.93 meters can satisfy the construction technical requirement of the Yangtze River tunnel totaling 4,137 meters, with water pressure up to 0.74Mpa, the pebbly sand layer with quartz content up to50%, the rock and clay layers with a strength of 120Mpa and the 742- meter composite stratum which is soft on the top and hard in the bottom, and what’s more, the 25%possibility of deteriorating geological state must be considered in the construction. As the largest machine of its kind in our country, it can meet the boring speed of 5cm/min and the highest construction speed of 20 meters daily. It has become the most advanced and complicated machine in the world and only takes 14 months to manufacture.

The boring distance of the first-installed cutter blade is 3 times that of the existing tunnel boring machine based on the similar geological condition. The ingenious combination of fixed cutter, main cutter and replaceable cutter can meet the requirement without changing the cutting tools while the whole tunnel is full of clay/sand and cobble stone stratum: on the basis of 19-inch knurling tool, we have creatively developed push-out knurling tool, to replace the knurling tool whose exterior has been worn for 2 times, thus reducing the change of the cutter under pressure by more than 3 times in the composite stratum, and it can also expand the boring distance and accelerate the construction speed, shortening construction period. This is the first of its kind in the world.

“Tianhe No.1” and “Tianhe” were successfully put into operation for the first time in the river-crossing tunnel of Weisan Road of Nanjing on July 20, 2012 and September 28, 2012 respectively.By the beginning of December, they bored more than 900 meters and more than 500 meters respectively. The Machine named “Tianhe” constructed by CCCC Second Harbor Engineering Company Ltd., created a record hight of 26 meters in the same type of domestic shield machines on December 17.