Study On The Numerical Simulation And The Principle Of Grouting Uplift

Grouting uplift can be described as the introduction of a fluid or semi-fluid material into the ground,increasing the local volume at the point of injection.This in turn causes upward movement by the build-up of grouting pressure,either leading to foundation strengthening.Based on previous studies, a mechanism summaryhas been made to explore the difference between fracture grouting,compactiongroutingand intrusion grouting.Furthermore,numerical simulation was conducted to examine grouting mechanism in soil,addressing the effect of various parameters on heaving induced by grouting.The major works are as follows:(1) This paper presents a review of grouting mechanism in soil,with reference to a number of domestic and foreign literatures,the mechanism of grouting uplift was learned. A range of different failure patterns in soil has been found in relation to types of grouting,the result illustrates the very existence of limit pressure which determines between compaction and intrusion grouting.(2) A series of numerical simulations were performed to assess the capability of fracture grouting,compaction grouting and intrusion grouting,respectively.The numerical results indicate that the stress history and failure behavior of soil can be modeled reasonably well.It shows that the magnitude and extent of pore pressure and minor principal stress generated during injection varied with grouting types. The results also help to acquire a better understanding of displacement mechanism in soil,providing a contrast between fracture,compaction and intrusion grouting for soil volume strain increment.(3) Based on the research of numerical simulation,the uplifting mechanism corresponding to grouting type has been analyzed.Factors including injection depth, soil elastic modulus and injection pressure were proved to be of significance to determine the magnitude and extent of grouting uplift.