Two Technical Methods for Improving The Bearing Capacity of Rotary Drilling Piles

The bearing capacity of rotary bored piles directly affects the stability of the building foundation and is related to the safety and quality of the project. Facing complex and diverse geological conditions, mastering effective technical methods is of vital importance for enhancing the bearing capacity of rotary drilling piles.

1.Optimize the design of the pile body. According to the geological investigation report, determine the pile length, pile diameter and reinforcement reasonably. Increasing the length of the pile can penetrate into a harder bearing stratum, and increasing the diameter of the pile can increase the force-bearing area, thereby effectively enhancing the bearing capacity.

2. Improve the bearing stratum at the pile end. For soft soil foundations, grouting reinforcement can be adopted by injecting cement slurry and other curing agents to improve the physical and mechanical properties of the soil and enhance the bearing capacity of the pile end.

3. Adopt the post-grouting technology. After the cast-in-place pile is formed, cement slurry is injected into the bottom or side of the pile through the pre-embedded grouting pipe to fill the sediment at the bottom of the pile and the voids on the side of the pile, enhancing the friction between the pile and the soil and the end bearing capacity.

4. Control the quality of hole formation. Maintain the stable drilling of the rotary drilling rig to prevent the collapse of the hole wall and the reduction of the diameter. When cleaning the hole, thoroughly remove the sediment to reduce the weakening of the bearing capacity at the pile end caused by the sediment.

5. Improve the performance of concrete. Select the appropriate concrete mix ratio and add admixtures to enhance the strength and fluidity of the concrete. Ensure the concrete is poured densely to prevent defects such as honeycombs and holes.

6. Set the expansion head. At the end of the pile, an expanded bottom drill bit is used to form an expanded head shape, increasing the force-bearing area of the pile end. It is like putting larger "shoes" on the pile, significantly enhancing the end load-bearing capacity of the pile.

By adopting the above technical methods and implementing comprehensive measures in multiple aspects such as design, construction and materials, the bearing capacity of rotary drilling piles can be significantly enhanced. In practical engineering, these methods should be flexibly selected or combined based on specific geological conditions and engineering requirements to lay a solid foundation for the project.