Key Points of Rotary Drilling Rig Selection and Efficiency Control Strategies for Pile Foundation Construction of High-Speed Railway Bridges

    As the core load-bearing foundation of high-speed rail bridge piles, the pile foundation of high-speed rail bridges has strict requirements for construction accuracy, hole-forming quality, and construction efficiency. Rotary drilling rigs, with their advantages of high efficiency, environmental friendliness, and stable hole-forming quality, have become the preferred equipment for pile foundation construction of high-speed rail bridges. Their selection rationality and efficiency control level directly affect the pile foundation construction period, engineering cost, and structural safety, which need to be accurately controlled in combination with the characteristics of high-speed rail construction.

    The selection of rotary drilling rigs for high-speed rail bridge pile foundations must focus on three core elements: 'pile parameters - stratum conditions - construction standards', and avoid blind selection. First, combined with the design parameters of the pile foundation, for conventional high-speed rail piles with diameters of 1.2-2.5m and depths of 30-80m, 280-360 type rotary drilling rigs should be prioritized to balance hole-forming accuracy and construction efficiency; if the pile depth exceeds 80m or the diameter is greater than 2.5m, 400-type or larger torque drills with high torque output stability should be selected. Second, adapt to the construction strata: for soft strata such as soft soil and sand layers, friction drill rods can be selected to improve lifting efficiency; for complex strata containing moderately weathered, slightly weathered bedrock or dense gravel layers, drilling rigs with mechanical lock drill rods should be selected to enhance rock-breaking capacity and force transmission efficiency. At the same time, environmental protection and noise reduction requirements of high-speed rail construction should be taken into account, and low-emission, low-noise models should be selected to avoid affecting the surrounding environment and construction compliance.

    Efficiency control is crucial for on-time delivery of high-speed rail bridge pile foundation construction. It requires efforts from three aspects: equipment management, process optimization, and on-site management, all while ensuring quality and safety. In terms of equipment management, a comprehensive inspection of the drill rigs must be conducted before construction, focusing on checking the wear of drill rods and drill bits, as well as the performance of hydraulic systems and power heads, to prevent breakdowns during construction. Regular maintenance should be carried out during construction, with timely cleaning of mud attached to drill tools to reduce equipment wear.

For process optimization, appropriate drill bits should be selected based on stratum characteristics: spiral drill bits for soft strata and roller cone drill bits for hard strata, to minimize bit wear and bit-changing time. The drilling speed should be reasonably controlled: uniform speed for soft strata to prevent hole collapse, and slow pressure application for hard strata to ensure hole formation. Meanwhile, optimizing the slurry ratio can enhance slag removal efficiency and reduce the time for cleaning sediment in the hole.

    In on-site management, construction processes should be rationally planned, implementing a 'one machine, one team' system with dedicated personnel responsible, clarifying operators' job responsibilities, improving operational proficiency, and reducing efficiency losses caused by human errors. On-site material storage should be optimized to ensure timely supply of consumables such as drill rods, drill bits, and slurry, avoiding stoppages due to material shortages. An equipment failure emergency mechanism should be established, with common spare parts pre-stocked to enable rapid response and disposal of failures, shortening downtime. Additionally, strict adherence to high-speed rail pile foundation construction specifications is necessary to avoid rework caused by quality issues such as hole deviation or collapse, which indirectly improves construction efficiency.

    In summary, the selection of rotary excavators for high-speed rail bridge pile foundations should be based on actual construction conditions to achieve precise matching between 'machine type, parameters, and stratum'. Efficiency control must balance equipment, process, and on-site management, maximizing construction efficiency while ensuring construction quality and safety, thereby facilitating the on-time and high-quality completion of high-speed rail bridge pile foundation projects.