On May 16, with the completion of the final truckload of concrete pouring, all pile foundations of the Weifang Baotong Street Expressway railway-crossing section project—supervised by the Weifang Municipal Transport Bureau and constructed by China Railway 25th Bureau—were fully completed, marking the project's formal entry into the construction phase for substructure elements such as pile caps, pier columns, and bent caps.

According to on-site staff from the municipal transport bureau, throughout the construction process, in order to accelerate progress and ensure the pile foundation work was completed on schedule, the project deployed 3 rotary drilling rigs, 3 trailers, 7 truck cranes, 10 water trucks, and 20 dump trucks, and set up 5 rebar processing yards, with rebar fabrication carried out in rotating day and night shifts. Because the project is located within the urban area, to avoid excavating numerous mud pits and causing significant environmental impact, steel plate-welded mud tanks were used instead of pits, with each drilling rig equipped with 2 mud tanks that moved along with the 3 rigs. Based on site conditions, one spoil pit was set up for every two pier foundations to temporarily store drilling spoil; once full, dump trucks were arranged to haul it away promptly, ensuring construction progress while meeting safety, environmental protection, and civilized construction requirements.

On-site construction personnel explained that the project's bored cast-in-place piles use the rotary drilling process, with the main workflow as follows: site leveling → pile position setting-out → casing installation → drilling → hole cleaning → rebar cage and sonic logging tube installation → tremie pipe installation → sediment thickness inspection → secondary hole cleaning → concrete pouring → pile testing. The project's bored cast-in-place piles for the Fangzi branch line overpass total 144 (non-core railway-crossing section), with pile diameters of 1.2 m, 1.5 m, and 1.8 m, pile lengths ranging from 21.5 m to 47.5 m, and pile type being rock-socketed piles with an embedment depth of no less than 1 times the pile diameter. The main reinforcement and stiffening bars of the piles are HRB400-grade rebar, the spiral stirrups are HPB300-grade rebar, the main reinforcement uses mechanical connections, and the net concrete cover thickness of the piles is 68 mm. To ensure drilling safety and prevent borehole wall collapse, bentonite-based mud was used for wall protection, and during pile pouring the mud pump extracted mud promptly to ensure no mud overflow or leakage. Steel casings at the hole mouth were set at 5 meters, with casing depth appropriately adjusted according to the drilling geological conditions.

"The accuracy of the bored pile plan position, drilling verticality, pile depth, and pile top elevation, the prevention of collapse in drilling sand layers, the prevention of pile breakage during concrete pouring, and the quality of rebar cage fabrication and concrete pouring are all key issues we focus on during pile foundation construction," said Zhang Shoujun, head of the contractor China Railway 25th Bureau. He noted that the project had only been established for just over a month, and facing unfavorable conditions such as a tight schedule, heavy tasks, and inadequate capital turnover, they fully leveraged the internal management advantages of a central state-owned enterprise, strictly followed design and specification requirements, and maximized high-quality and efficient construction. While accelerating construction, they strictly controlled safety, environmental protection, and quality, strengthened standardized management, and ultimately completed the pile foundation work smoothly.

At present, work on pile caps, pier columns, and precast box girders is proceeding in an orderly manner. The Weifang Baotong Street Expressway is an important east-west traffic artery running through the central urban area; once completed, it will be of great significance for achieving rapid east-west access in the main urban area, optimizing the urban road network structure, and improving the road traffic environment.