Soil Compaction Effect of Bagged Grouting Piles in Saturated Soft Clay Subgrade

To study the soil compaction effect of bagged grouting piles in saturated soft clay roadbeds, field tests were conducted on roadbeds reinforced with bagged grouting piles to analyse the displacement of the soil and the applied super-static pore pressure occurring during pile formation. First, the horizontal displacement of the soil was monitored by using the inclined pipe, and the distribution characteristics of soil displacement and variation in soil displacement with grouting pressure and time were obtained. Second, the super-static pore pressure in the soil was monitored by using a sensor to measure the hole pressure, and the distribution and trend of the super-static pore pressure were obtained. The test results indicate that the horizontal displacement of the soil around the pile has a saddle-shaped distribution, and the soil exhibits maximum displacement at a distance of 0.1–0.3 times and 0.8–1.0 times the pile length. The range of influence of the horizontal displacement caused by soil compaction is approximately six times the pile diameter. After the pile has been cured, the grouting pressure has little influence on the compaction effect. Furthermore, after curing, the horizontal displacement of the soil around the pile shows a significant rebound, which amounts to approximately 40%–60% of the displacement on the day of grouting. The super-static pore pressure dissipates rapidly during the first 10 days and decreases linearly with increasing distance from the centre of the pile. The range of influence of the super-static pore pressure is approximately 10 times the pile diameter.