Field-Test Study on Ground Deformation in Continuous Construction of Jet Grouting

As an effective method of foundation reinforcement, the jet grouting method is applied to various engineering fields such as foundation pit, tunnel, subgrade construction and so on. During the construction of jet grouting piles, the grouting pressure is large and the continuous injection of cement slurry will disturb the surrounding soil, causing soil deformation and endangering the safety of existing structures. Continuous jet grouting construction tests were carried out on soft soil foundation in Ningbo City, China, and the surface deformation of surrounding soil caused by continuous jet grouting construction was studied. An automatic total station is used to monitor the deformation of surrounding soil during the construction. The monitoring results show that the maximum lateral displacement of the ground surface is 180.31 mm, and the surface heave is 179.54 mm. The cumulative maximum vertical displacement and lateral displacement of the ground surface both decrease with the increase of the distance from the adjacent jet grouting pile. Under the same distance, the closer to the center line of the construction area, the greater the displacement. The completed jet-grouting piles can reduce the disturbance caused by subsequent construction of jet-grouting piles. Based on the monitoring results, some methods to reduce the impact of jet grouting construction are proposed.