Experimental study on the disturbance and control of cluster jet pile construction on existing railroad bridge foundations

This study examines the impact of cluster jet grouting pile construction on adjacent railway lines and the control of pile body deviation through the use of stress relief holes (SF), which is critical for ensuring the safe operation of high-speed railways. Based on a construction project involving a new sewage well reinforced by jet grouting piles at a specific station, the study investigates the disturbance effects of regional cluster jet grouting pile construction on surrounding soil and the adjacent high-speed railway line, controlling variables such as the number of jet grouting piles and injection pressure. Test results indicated that the soil squeezing influence distance for a single pile is approximately 7.5 times the pile diameter (R = 0.8 m), while for the construction of four rotary jet piles, the influence distance increases to approximately 16.25 times the pile diameter. Horizontal soil pressure decreases with distance from the pile core, demonstrating a negative correlation with the soil squeezing effect. Vertically, the maximum lateral displacement occurs at specific depths due to variations in soil properties, leading to exponential relationships between cumulative lateral displacement and the number of piles. Earth pressure increases vertically but decreases horizontally, with injection pressure affecting lateral displacement at a depth of 3 m. Additionally, an exponential relationship was observed between the number of stress relief hole rows at 3.5 m depth and the shrinkage displacement difference for bridge foundation disturbance control. Increasing the number of stress relief hole rows alone does not fully restore cumulative lateral displacement to its initial value without significantly impacting deviation correction or increasing costs.