流固耦合作用下裂隙砂岩蠕变损伤特征及颗粒流模型研究

Study on Creep Damage Characteristics of Fractured Sandstone and Particle Flow Model under Fluid-Structure Coupling

自然界中的裂隙岩体常与裂隙水形成耦合作用,对岩体工程的长期稳定性产生严重影响。为分析富水环境下裂隙砂岩的蠕变损伤特征,对预制裂隙砂岩开展流固耦合蠕变试验,并基于颗粒流基本原理构建PSC-CFD流固耦合蠕变模型。利用PSC-CFD模型开展流固耦合数值模拟,进一步分析了裂隙岩体流固耦合作用下裂纹的扩展规律,提出蠕变损伤的定量评价方法。研究结果表明,随着渗透水压的增加,裂隙岩体的蠕变特征越来越明显,随着裂隙倾角的增加,裂隙岩体损伤破坏特征出现先增后减的趋势;PSC-CFD模型对衰减速率β1、β2为及拉伸强度σa尤为敏感,平行黏结断裂时间主要受三者控制;岩体损伤变量随渗透压力的增加而逐渐减小,随裂隙倾角的增加出现先增后减的趋势,当裂隙倾角为30°左右时达到最小值。研究成果可为岩体工程大变形机理分析及长期稳定性控制提供一定的理论依据及参考。

Fractured rock masses in nature often have a coupling effect with fissure water,which seriously affects the long-term stability of rock engineering.To analyze the creep damage characteristics of fractured sandstone in a water abundance environment,fluid structure coupling creep tests were conducted on prefabricated fracture sandstone,and a PSC-CFD fluid structure coupling creep model was constructed based on the basic principle of particle flow.The PSC-CFD model was used to conduct numerical simulation of fluid-structure coupling,further analyzing the propagation law of cracks in fractured rock masses under fluid structure coupling,and proposing a quantitative evaluation method for creep damage.The research results indicate that with the increase of seepage water pressure,the creep characteristics of fractured rock mass become more and more obvious.As the inclination angle of fractures increases,the damage and failure characteristics of fractured rock mass show a trend of first increasing and then decreasing.The PSC-CFD model is particularly sensitive to the decay ratesβ1 andβ2,as well as the tensile strengthσa,and the parallel bonding fracture time is mainly controlled by these factors.The damage variable of rock mass gradually decreases with the increase of seepage pressure,and shows a trend of first increasing and then decreasing with the increase of fracture angle.The minimum value is reached when the fracture angle is around 30°.The research results can provide theoretical basis and reference for the analysis of large deformation mechanisms and long-term stability control in rock engineering.