A Thermal-solid Coupling Numerical Model Based On Disk DDA And Its Applications

Thermal stress is an important factor causing rock fracture,which involves the underground disposal of nuclear waste,the development of geothermal energy,the exploitation of oil and gas,the exploitation of deep underground minerals and so on.This kind of geotechnical engineering problem is essentially a thermal solid coupling process of geotechnical skeleton(solid)and thermal interaction.The numerical method has more development prospects than experimental and theoretical methods because of its low cost,easy repetition and adaptability to various complex conditions.Therefore,the study of thermal solid coupling numerical model suitable for geotechnical problems is of great practical significance for geotechnical disaster prevention and control.Combined with discontinuous deformation analysis(DDA)method and discrete temperature element method(DTEM),a DDA-DTEM thermal solid coupling numerical model which can simulate geotechnical engineering related problems is established in this paper.The main research contents are as follows:Firstly,the discrete temperature element method(DTEM)is used to simulate the heat conduction process of two-dimensional granular materials.Secondly,based on the discrete temperature element method,an efficient algorithm which can improve the efficiency of heat conduction calculation is proposed,and the CPU parallel calculation process based on Open MP is realized,which significantly improves the calculation efficiency.Then,a new DDA-DTEM thermo solid coupling model is proposed,in which the motion of particles is simulated by DDA and the heat conduction is simulated by DTEM.The influencing factors of particle heat transfer in the case of disk stirring heat transfer are analyzed.Finally,a discontinuous numerical model of thermal solid coupling is proposed,which can be used to simulate the fracture process of rock mass under the change of temperature field.The simulation results are in good agreement with the existing experimental results,which verifies the correctness of the proposed coupling numerical model and preliminarily shows the engineering application value of the proposed numerical model.The main innovation of this paper is that the coupling model of disk particle DDA and DTEM and disk particle DDA and PHCM is established for the first time,which shows the application value of this coupling method in geotechnical engineering.