Overcoming the Yellow River's complex geology

Innovatively creating a pile foundation "muscle-building tool"

The Yellow River's geology is complex, with abundant fine silty sand. Driving a tripod-style pylon central tower with a hundred-meter tower height into the Yellow River bed is like "sticking chopsticks into sand," and ensuring pile foundation stability is a huge challenge.

Faced with 3-meter super-large-diameter, 106-meter ultra-deep bored cast-in-place piles and pain points such as easy hole collapse and difficult hole cleaning, the project team of the Municipal Group of Tunnel Engineering Co., Ltd. used specially formulated PHP mud to "protect the hole," paired with hydrocyclones, sand separators and other "hole-cleaning wonders," strictly controlling the sand content of the mud to within 0.2% in a single cleaning pass to ensure pile quality meets standards.

Among them, the 3-meter super-large-diameter piles of the auxiliary bridge adopted "distributed pile-tip and pile-side post-grouting" technology, automated equipment and an intelligent control system, with grouting volume, pressure and other data uploaded in real time for remote monitoring, directly increasing pile bearing capacity by about 20%—truly a "muscle-building tool" for pile foundations.

Massive pile caps fear "fever"

Intelligent "temperature control system" for precise temperature regulation

The Yellow River Bridge's pile caps are mass concrete caps with a total pour volume of 8,067.9 cubic meters, poured in two layers, with a large single-pour volume. To reduce hydration heat, the traditional method is to install internal cooling pipes, but this often fails to adjust cooling water flow in time according to internal temperature changes, causing excessive temperature differences between inside and outside and thus cracks. Such a massive pour posed a considerable "temperature control challenge" to the project team.

In response, the project team of the Municipal Group of Tunnel Engineering Co., Ltd. reduced hydration heat by optimizing the concrete mix design and other means, lowering total heat release and peak temperature to prevent temperature rise in mass concrete; at the same time, it independently developed an intelligent temperature control system, arranging four layers of cooling pipes along the concrete thickness direction and, based on measurement and remote automatic control technology, using variable-frequency pumps to control in real time the cooling water flow in the concrete cooling circuits, achieving precise regulation of the core temperature and inside-outside temperature difference of the pile cap concrete and ensuring the construction quality of the mass concrete pile caps.

Doing "subtraction" on welding of deck slab wet-joint connections

Saving more than 30 days of construction time

To address the large welding volume and difficult quality control of more than 500,000 joint welds in the wet joints of precast concrete deck slabs on the main bridge, auxiliary bridge and east approach embankment bridge, the Municipal Group of Tunnel Engineering Co., Ltd., together with the design unit and Tongji University, introduced a welding-free scheme that reduced welding volume by more than 65%. This innovation not only lowered labor intensity for construction workers but also shortened welding time by 2 days per installation segment, significantly improved welding quality, and cumulatively shortened the construction period by more than 30 days by the time of closure.

Tunnel people will continue to strive for excellence

Toward the goal of full opening to traffic

Working hard and continuing to advance