### EPIM FOR THERMAL CONSOLIDATION PROBLEMS OF SATURATED POROUS MEDIA SUBJECTED TO A DECAYING HEAT SOURCE

Wang Lujun1,2, Ai Zhiyong1

1. 1. Department of Geotechnical Engineering, Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China;
2. Institute of Geotechnical Engineering, Key Laboratory of Soft Soils and Geoenvironmental Engineering of Ministry of Education, Zhejiang University, Hangzhou 310058, China
• Received:2016-09-28 Revised:2017-01-04 Online:2017-03-15 Published:2017-03-21

Abstract:

The thermal consolidation of saturated porous media subjected to a heat source is an important subject in civil engineering and energy engineering. For the complexity of the problem, the porous media are usually treated as homogeneous isotropic media and the heat source is assumed to be a heat source with constant strength in the existing studies. In engineering practice, natural saturated porous media usually show obvious layered characteristics and the heat source is decaying with time. In this case, the extended precise integration method (EPIM) is presented in this study to investigate the thermal consolidation problems of layered saturated porous media subjected to a decaying heat source. The partial differential equations are reduced to ordinary ones by means of the integral transform techniques. Combining the adjacent layer elements and considering the boundary conditions, the EPIM solutions in the transformed domain of the problems are deduced. With the aid of corresponding numerical integral inversion, the temperatures, excess pore pressures and vertical displacements in the physical domain are obtained. A numerical example with the corresponding calculation program is performed to compare with the existing results, which confirm the applicability and validity of the presented method in dealing with the thermal consolidation problems of layered saturated porous media. Finally, numerical examples are carried out to analyse the influence of the heat source's half-life and buried depth, as well as the stratification of medium on the thermal consolidation behaviour. Numerical results show that:the decay period of heat sources has significant influence on the peak values and peak time of temperature and excess pore pressure, the longer the decay period, the greater the peak values and the longer the peak time of temperature and excess pore pressure; burial depths have obvious influence on the variations of excess pore pressure and vertical displacement, the evolutions of vertical displacements against time on both side of the deeply buried heat source are symmetrical, while there is no such phenomenon for the shallow heat source; stratification characteristics of the saturated porous media shows prominent effects on the thermal consolidation.

Key words:

heat source|saturated porous media|thermal consolidation|extended precise integration method

CLC Number: