Research And Application On Post Grouting Pile Parameter In The Layer Of Saturated Gravel Mixed With Clayey Soil

Pile tip post grouting can improve the bearing capacity of single pile, reduce settlement, and has been widely used in bridge pile foundation at home and abroad.The theoretical system of pile tip post grouting has improved in the process of research,and the current standard of post grouting technology have been take some general provisions for water cement ratio, grouting quantity, grouting pressure and so on.However, there is still lack of detailed research on the relationship of the post groutingparameters and the influence of the parameters on the bearing capacity of the pile foundation.The soil properties in different regions are different, so there are significant differences in the corresponding parameters of grouting,which is the starting point of this paper.Modern pile foundation technology is the combination of traditional pile and modern science and technology, and plays an extremely important role in the engineering. The post grouting technology of bored pile is the perfect combination of pile foundation and modern technology.Through the pile tip or pile lateral grouting can eliminate many unfavorable factors of the bearing capacity of piles, thereby reducing the settlement of the pile foundation, improve the bearing capacity.The soil layer of pile tip is differently, the grouting mechanism is not the same.After a lot of systematic research, the mechanism of the post grouting can be divided into filling, penetration, splitting, compaction, and corresponding grouting mechanism of several kinds of different soil layers were preliminarily summarized in this paper.The test pile bearing layer of Yueqing Bay Bridge is gravel with cohesive soil, and the bearing capacity of bridge pile foundation is enhanced by post grouting, and the bearing capacity of the pre-and post-grouting test piles are tested by the self-balancing method. Based on the result of post grouting project in Yueqing Bay Bridge, the influence of grouting parameters on the bearing capacity of pile foundation are fully studied in order to provide guidance for the coming grouting work.Water cement ratio, grouting pressure and grouting volume are three important parameters in post grouting. By observing and analyzing these three parameters, we can know the process and state of the pile tip grouting and predict the bearing capacity of the grouting pile.In the pile tip grouting, cement slurry is generally used as the slurry,when the water cement ratio is relatively large, it is a Newtonian fluid, when water cement ratio is relatively little, it is a false plastic fluid. The rheological property of cement slurry is closely related to water cement ratio, and the choice of proper water cement ratio can increase the success probability of the slurry process.The pressure is another important parameter of grouting. In the process of grouting,the slurry into the soil need someexert pressure,and according to the variation of grouting pressure, engineer can judge whether grouting is abnormal.Grouting is the most important parameters of grouting pile, the increase of bearing capacity of pile foundation is closely related to Grouting volume.In the process of grouting, the amount of slurry can be pressed into the pile tip is the key to the success of the grouting project.Inthis paper, discusses three kinds of grouting parameters,And the undisturbed soil of Yueqing Bay has been studied by a lot of indoor experiments.