基于非傅里叶定律的近场动力学热力耦合模型及花岗岩热损伤破裂模拟

Non-Fourier law-based peridynamic thermo-mechanical coupling model and simulation of thermal damage and fracture in granite

研究岩石的热损伤破裂特征对于地热开采等工程具有重要意义。在传统常规态基近场动力学理论框架内,通过引入双相滞后(DPL)模型,提出了基于非傅里叶热传导定律推导得到的热力耦合模型。通过平板瞬态热传导问题及Lac du Bonnet(LdB)花岗岩的热损伤破裂试验对模型进行了验证。分析了温度梯度弛豫时间和热流弛豫时间对岩石热损伤破裂特征的影响。结果表明:近场动力学热力耦合模型模拟结果很好地反映了LdB花岗岩的热损伤破裂特征及温度分布的不连续性;温度梯度弛豫时间对热传导起促进作用,试件热损伤破裂程度随温度梯度弛豫时间的增加而增大,随热流弛豫时间的增加而减小。研究为深入理解岩石的热损伤破裂行为、优化地热能开采工程提供了有益的探索。

It is of great significance to study the thermal damage and fracture characteristics of rocks for deep rock projects,such as geothermal exploitation.Within the framework of the traditional classical ordinary state-based peridynamic theory,a thermo-mechanical coupling model based on the non-Fourier heat conduction law is proposed by introducing a dual-phase-lag model.The model is validated through the transient heat conduction problems in the plate and thermal damage and fracture tests on LdB granite.It is found that the simulated results accurately reflect the thermal damage and fracture characteristics,as well as the discontinuity in temperature distribution,of LdB granite.Furthermore,through numerical analysis,it is observed that the temperature gradient relaxation time promotes heat conduction,leading to an increase in the degree of the thermal damage and fracture with an increase in the temperature gradient relaxation time,while it decreases with an increase in the heat flux relaxation time.This research provides valuable insights for a better understanding of the thermal damage and fracture behavior of rocks and offers beneficial explorations for optimizing the geothermal energy extraction projects.