Construction Technology of Segmented Grouting for Large-diameter and Super-long Cast-in-place Piles

During the construction of large-diameter and super-long cast-in-place piles, the hole-forming time is relatively long, and the wall protection mud will form a relatively thick mud skin on the hole wall. Meanwhile, the quality of the sediment from hole cleaning is hard to guarantee, which directly affects the bearing capacity of the pile. To address this issue, this paper studies the post-section grouting construction technology of large-diameter and super-long cast-in-place piles based on the pile foundation of a certain housing construction project, aiming to enhance the bearing capacity of cast-in-place piles and optimize the construction efficiency. This paper conducts a detailed analysis of the technological principles and key technical points of the post-section grouting construction for large-diameter and super-long cast-in-place piles. After the pile body is formed, by using the segmented layout of grouting pipes and the post-grouting process in stages, pressure grouting is carried out on different sections of the pile bottom and side to achieve multi-depth and multi-point discrete grouting of the pile body. Meanwhile, by comparing economic benefits and conducting static load tests on pile foundations, the economic efficiency and technical effectiveness of this construction process are verified. The research results show that by adopting the segmented layout of grouting pipes and the post-grouting process in stages, the distribution of grout in the pile body can be made more uniform, effectively reinforcing the bearing stratum at the bottom of the pile and the soil within a certain range on the pile side. After the static load test of a single pile, the characteristic value of the compressive bearing capacity of the test pile has increased by 30.5%. Compared with the traditional cast-in-place pile construction, under the same pile foundation bearing capacity requirements, the new technology can reduce the pile length, thereby lowering the construction cost. In the case project, the construction cost was reduced by 6.4% and the construction period was shortened by 39.5%. This construction technology has a good grouting effect and can significantly enhance the bearing capacity of cast-in-place piles. This technology has strong applicability, a simple operation process, can significantly improve construction efficiency, and has good economic and technical effectiveness. It is worthy of promotion and application in similar projects.