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Jiujiang, China

Zou J.,The 5th Engineering Co.
Modern Tunnelling Technology | Year: 2014

As for the large deformation of a soft rock tunnel engineering in tertiary silty clay, the test results of laboratory morphology and microscopic structure show that this clay contains a large number of laminated clay minerals which may induce the large deformation; and the direct shear rheological test at the site proves that the tertiary silty clay has a rheological property. Therefore, the effect of rheology on the safety of tunnel structure is studied by the numerical analysis, and in order to complete the rheology induced main tunnel deformation before the construction of secondary lining, the tunnel design and construction technology should be improved by strengthening the supporting intensity, and increasing the reserved deformation allowance between the preliminary support and the secondary lining. Finally, the optimized tunnel supporting design and construction technology are verified by the field testing results. ©, 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved. Source

The pile caps and piers for the non-navigable span bridge of the Hong Kong-Zhuhai-Macao Bridge over the shallow water area are the shallowly embedded precast structures. The height of the piers ranges from 19.143 m to 42.974 m and the dimensions of a pile cap is 15.6 m×11.4 m×4.5 m. The maximum height of the pile cap plus the bottom segment of the pier shaft is 18.5 m and the maximum weight is 2370 t. All the piers of the bridge are the rectangular hollow structures and the concrete used for the pile caps and pier shafts is respectively of C45 and C50. The pile caps and pier shafts were integrally precast. In the workshop of automatic reinforcement processing, the reinforcement were processed by the computer numerical control (CNC) bending machines. After the processed reinforcement were inspected and accepted, the reinforcement were transported to the designated places in the factory where the reinforcement were then bound and installed. The bound reinforcement for the pile caps were integrally and transversely shifted onto the precasting beds while the reinforcement for the pier shafts were integrally lifted and inserted into the reinforcement of the pile caps by the gantry crane. The formwork for the pile caps and pier shafts were installed and the concrete for the pile caps and pier shafts was cast in integrity in one time. After the concrete reached the designed strength, the formwork were stripped and the precast pile caps and pier shafts were shifted to their storage beds. Presently, the construction of the 32 pile caps and pier shafts has been completed and the construction quality is so far so good. Source

Zhang H.-Y.,The 5th Engineering Co.
Bridge Construction | Year: 2014

The non-navigable span bridge of the Hong Kong-Zhuhai-Macao Bridge over the shallow water area is a 85-m span continuous composite girder bridge that is totally 5 440 m long and has 64 spans. For each pier of the bridge, 6 composite pile steel pipes are provided and there are altogether 372 steel pipes for the whole bridge. The diameters of the steel pipes in the areas of the low piers and high piers are respectively 2.0 m and 2.2 m and in addition to the length of the driving section, the total length of a steel pipe is greater than 60 m. To meet the precision requirement for construction of the steel pipes over the surging sea, it was determined through comparison that the integral guide frame method was to be used to set and drive the steel pipes. Firstly, the guide frame was transported to the pier site and was initially positioned. The frame was positioned for the second time, using the adjusting system of the frame and at this time, 4 positioning piles were set and driven by the APE400B hydraulic pile hammer. Then the guide frame was fixed on the positioning piles, was positioned for the third time, using the fine adjusting device of the frame. After the guide frame was positioned, the steel pipes were set and driven to the designed elevation. In the construction, the plane locations and inclination of the steel pipes were ensured by the techniques of the hydraulic system, guide devices, RTK positioning survey and the three times of positioning of the guide frame and finally the construction precision of setting and driving the steel pipes satisfactorily met the technical specification of the project. Source

Xiao G.,The 5th Engineering Co.
Modern Tunnelling Technology | Year: 2014

Based on the construction of the first immersed tunnel in north China, i. e. Haihe river tunnel on central avenue of Tianjin, this paper summarized and analyzed the key construction techniques for the deepest bulkhead wall protection structure at home, extra-large deep foundation pit in soft rock, prefabrication of element with bulk mass and thin-wall structure, and foundation treatment under 23 m of water, thus providing experiences for the design and construction of similar projects. ©, 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved. Source

The non-navigable span bridge of the Hong Kong-Zhuhai-Macao Bridge over the shallow water area is a 85-m span steel and concrete continuous composite girder bridge. The substructure of the bridge is composed of the steel pipe composite piles, precast pile caps and rectangular hollow piers. There are totally 62 piers for the whole bridge of the bridge and each pier is supported on the 6 steel pipe composite piles. To resolve the problem that the construction of the substructure would be adversely affected by the sea conditions and to shorten the construction time period and ensure the construction quality, the following techniques were applied to the construction. When the steel pipes of the composite piles were set and driven, the steel pipes were positioned in three times, using the integral guide frames aided by the support piles. The boring construction of the composite piles was carried out on the integral truss boring platforms. The pier shafts and pile caps were precast, using the integrated automatic opening and closing formwork and the concrete of the pile caps and base segments of the pier shafts was cast integrally in one time. The pile caps and base segments were installed in the new type of the interlocked double-wall steel boxed cofferdams without internal bracings and the pier shafts and pier caps were installed by the rapid method, using the floating vessels aided by the long and short guide fames. © 2016, Wuhan Bridge Research Institute. All right reserved. Source

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