Deformation mechanism and settlement analysis method of reinforced- hoop-gravel-pile composite ground under flexible foundation

The reinforced-hoop-gravel-pile composite ground is a new method for treating soft soil ground, and its settlement analysis method is an important basis of the ground foundation reinforcement design. Firstly, the mechanical mechanism of the reinforced-hoop-gravel-pile composite ground under flexible foundation is discussed based on its engineering characteristics. The composite ground is divided into three sections: reinforced-hoop section, unreinforced-hoop section of gravel-pile and substratum section. A settlement analysis model for the reinforced-hoop-grave-pile composite ground is developed. Secondly, the pile-soil relative slip of the reinforced-hoop section and the radial deformation (e.g., lateral displacement of gravel pile) of the unreinforced-hoop section are taken into account. An analytical model with typical pile-soil element is imported, and the compressive deformation analysis methods for the reinforced-hoop and unreinforced-hoop sections are established respectively. Therefore, a new settlement analysis method for the reinforced-hoop-gravel-pile composite ground under flexible foundation is put forward. Finally, the settlement calculation and analysis of a practical engineering are carried out by means of the proposed method and other existing analytical methods. The analytical results are compared with the measured settlement values. It is shown that this proposed method can better reflect the reality of engineering practice than the other methods and overcomes the defect that the calculated results by the other existing methods are more dangerous.