Study On Post-Grouting Technology Of Cast-in-Place Pile In Engineering Application

As a main one of types of foundation pile, drilling piles have been extensively used in foundation engineering. However, some defects such as bottom settlings and mud around pile shaft arise from traditional piles construction technology, which cause decrease of the pile endpoint resistance and pile side friction. Therefore, post grouting pile technique arises at the historic moment. The post-grouting pile combines injecting paste technique with pile foundation technique, which makes cement paste through injected pipe into the pile point and the pile wall under high pressure. It can solve the bad impact of settlement and mud effectively and enhance the ultimate pile bearing capacity largely. But the current situation is that the theory research is far below the engineering practice. As a result, the study on construction technique and working mechanism of bored piles with post-grouting has a great significance both in theory and practice.This thesis, based on a wide review of relevant researches home and abroad, taking Shenyang Xiagong City square engineering as a background, combines test data analysis with numerical simulation method to present a study on the load-bearing characteristics of post-grouting bored piles. The work includes:the mechanism of improving single pile bearing capacity is discussed by using the analysis of pile-soil interaction theory, meanwhile, the technology of post-grouting pile construction is summarized and grouting quantity test data of100root piles is analyzed; three kinds of calculation methods,which utilizes post-grouting single pile ultimate bearing capacity, are applied to calculate the vertical ultimate bearing capacity of No.1-118pile,at the same time, the main factors affecting post-grouting pile bearing capacity of pile endpoint are analyzed. This thesis utilazing FLAC3D finite element software, simulates the influence of bearing capacity of pile and analyzes the influence of bearing capacity of post-grouting under the different pile loads, pile lengths and grouting quantities by establishing the numerical models of bored piles end post-grouting; Lastly, the simulation results of Shenyang Xiagong City square engineering’s test piles with the static load test results are compared. Research results show that the main factor of bearing capacity of post grouting cast-in-place pile was lengths and grouting volume.