Studies On The Time Effect Of The Settlement Of Single Pile Under Static Load

In this dissertation, the relationship between settlement and time of single pile under static load was studied. Some theoretical solutions were developed for the settlement of the pile subjecting to static load under different conditions, and the law of the settlement of pile varying with time is analyzed in detail. The main original work includes:1. The time effect of the settlement of single pile in a homogeneous soil was investigated. The interface between pile and soil was simulated by Voigt model, and the analytical relationship of settlement and time of single pile in homogeneous soil was obtained by the method of separating variables. Based on the analytical solution, the influence of all relevant parameters on the settlement behavior of single pile was analyzed and discussed.2. The time effect of the settlement of single pile in layered soil was studied. The influence of soil on the pile was simulated by Voigt model according to the layered characteristic of soil surrounding the pile. The semi-analytical solution for the relationship between the pile head settlement and time was obtained by Laplace transform method and Fourier inverse method. By using the solution, the influence of all relevant parameters on the pile settlement behavior was investigated and discussed.3. Generalized Voigt model was used to simulate the visco-elastic property of soil surrounding pile and the relationship between settlement and time of pile embedded in layered soil was investigated. A corresponding semi-analytical solution was obtained by Laplace transform method and Fourier inverse method. The parameters in the generalized Voigt model were connected with the conventional geotechnical parameters of soil and the behavior of pile settlement was then analyzed and discussed.4. With the consideration of practical soil-pile interaction, the soil around pile is modeled as a three-dimensional viscous-elastic continuous medium and the time effect of the settlement of single pile is studied. The semi-analytical solutions for vertical displacement of soil and for the relationship between settlement of pile head and time were obtained by Laplace transform method and Fourier inverse method, and the law of the settlement of pile head varying with time was then analyzed and discussed.5. By comparing the results obtained from the above solutions with these obtained from available theories for pile settlement and from field static load test of pile, the reasonability and practical value of the developed theoretical solutions were declared and verified.Based on the theoretical solutions developed herein, not only Q - s curve but also s - log(t) curve obtained from field static load test of pile can be simulated. This overcomes the shortcoming involved with available relevant theory for pile settlement that no time effect can be taken into consideration, and thus makes the theory for pile settlement more perfect.