基于统计试验设计下花岗岩两种本构模型研究

Research on Two Constitutive Models of Granite Based on Statistical Test

针对颗粒离散元在研究岩石材料过程中细观本构模型表现出的差异性问题,以新疆奇热哈塔尔过水隧洞片麻状花岗岩的力学参数为基础,建立二维离散元模型,通过统计学的试验方法,对比分析PB模型与FJ模型在宏观力学参数及破坏模式的差异性与稳定性,为后续改进本构模型以及选取合适的本构模型进行岩石数值模拟提供研究依据。研究表明,两种本构模型均能做到较为准确描述花岗岩的宏观力学参数,从计算稳定性角度来讲,PB模型计算结果更具有确定性,但表征不出准确压拉比;从统计学分析结果以及破坏模式来看,利用PB模型研究均质性较强且抗拉强度较高的硬岩材料的力学行为时具有一定优势;而对于均质性较弱且压拉比较高的硬岩材料,FJ模型由于其破坏模式的不确定性更能表现出岩石材料的非均质性。结果说明,PB与FJ两种本构模型各有优劣,今后在进行花岗岩等硬性岩石数值试验时,可根据岩石特性以及研究内容,选择合适的本构模型。

In view of the differences for the discrete particle in the meso-constitutive model in process of studying rock materials, heatwaves in xinjiang ha thar mechanical parameters ofa water tunnel gneissic granite, on thebasis of two-dimensional discrete element model is established, through statistical test methods, the differencesand stability of macroscopic mechanical parametersand failure modesbetween the PB modeland the FJ modelarecomparedandanalyzed, the researchbasis is provided for the subsequent improvement of theconstitutive modeland the selection ofa suitable constitutive model for rock numerical simulation. The results show thatalthoughbothconstitutive modelscan describe the macroscopic mechanical parameters of rock materials accurately, thecalculation results of the PB modelare more deterministic than those of the PB model,but theycannotbe characterizedaccurately;from the results of statistical analysisand the failure mode, the PB model hascertain advantages in the study of the mechanicalbehavior of hard rock materials with high homogeneityand high tensile strength, whereas hard rock materials with relatively low homogeneityand relatively high pressure pulls havecertain advantages, the FJ modelcan show the heterogeneity of rock materialsbecause of the uncertainty of its failure mode. The results show that twoconstitutive models of PBand FJ have theiradvantagesand disadvantages, theappropriate constitutive modelcanbe selectedbased on the rock properties in the futureand the researchcontent when performing the numerical tests on hard rocks.