FDEM-TM方法模拟岩石热破裂

Simulating thermal cracking of rock using FDEM-TM method

岩石热破裂研究在地热开采、核废料处置、石油开采中具有重要的工程应用价值和理论价值。基于FDEM（finite discrete element method）方法,用建立的FDEM-TM（finite discrete element method with thermo-mechanical coupling）方法对一个圆筒试样在两种不同温度边界条件下的热破裂进行了分析。研究表明,当内边界温度保持不变,外边界温度不断增大时（Tr0〈TR0）,起裂前,圆盘内侧处于受压状态,而圆盘外侧处于拉伸状态;当拉应力超过材料的抗拉强度时,从圆盘外边界起裂,从外向内扩展,形成发散裂纹。当外边界温度保持不变，内边界温度不断增大时（Tr0〉TR0），起裂前，圆盘内侧处于受压状态，而圆盘外侧处于拉伸状态；当拉应力超过材料的抗拉强度时，从圆盘外边界起裂，从外向内扩展，形成从外向内扩展的径向裂纹。模拟结果和已有文献结果保持较好的一致性，验证了FDEM-TM方法模拟岩石热破裂的有效性。

The studies on thermal cracking of rock are of important theoretical and engineering application value in geothermal exploration,underground disposal of nuclear waste and oil exploitation.Based on the FDEM-TM method for simulating the thermal cracking of rock,the thermal cracking of a cylindrical specimen under two different temperature boundary conditions is analyzed.The results show that when the inner boundary temperature remains constant and the outer boundary temperature increases（Tr0〈TR0）,the outer side of the disc is in the compressed state and the inside of the disc is in the tension state before crack initiation.When the tensile stress exceeds the tensile strength of the material crack initiates from the inner boundary of the disc and extends to the outside, forming divergent cracks finally. When the outer boundary temperature remains constant and the inner boundary temperature increases （Tr0〉TR0）, the inside of the disc is in the compressed state and the outer side of the disc is in the tension state before crack initiation. When the tensile stress exceeds the tensile strength, crack initiates from the outer boundary of the disc and extends to the inside, forming radial cracks from the outside to the inside finally. The simulated results are in good agreement with those of the existing literatures, which further validates the effectiveness of the FDEM-TM method to simulate the thermal cracking of rock.