砂岩蠕变破裂多尺度演化试验研究  

Experimental study on multi-scale creep rupture evolution of sandstone

作　　者：赵娜[1] 张怡斌 王来贵[1] ZHAO Na;ZHANG Yibin;WANG Laigui(College of Mechanics and Engineering,Liaoning Technical University,123000 Fuxin,China)

机构地区：[1]辽宁工程技术大学力学与工程学院,阜新123000

出　　处：《应用力学学报》2023年第1期87-95,共9页Chinese Journal of Applied Mechanics

基　　金：国家重点研发计划资助项目(No.2017YFC1503101);辽宁省重点科技创新基地联合开放基金资助项目(No.2020-KF-13-06);辽宁省教育厅资助项目(No.LJ2020JCL013)。

摘　　要：岩石随着外载荷的增大发生变形和破坏,当外载荷保持不变时,变形并未停止,仍会持续增加,发生蠕变变形,其根本原因是岩石的非均匀性。岩石蠕变破裂是由岩石内部原始非均匀性引起的微观尺度破裂、细观尺度裂纹扩展和贯通、宏观尺度变形增大和破坏的过程,因此需要对岩石蠕变破裂的多尺度演化机理进行研究。本研究以砂岩为研究对象,从蠕变破裂宏观演化试验和破裂断口微细观扫描试验出发,分析砂岩试样不同尺度变形破裂机理。通过砂岩蠕变破裂宏观演化试验可以看出,在初始蠕变和等速蠕变阶段,岩石表面无裂纹,主要为微、细观裂纹的萌生和扩展。当宏观破裂面形成后进入加速蠕变阶段,在加速蠕变阶段,沿破裂面产生摩擦滑动,最终发生破坏。通过对典型破裂断口的微、细观结构特征分析及不同分析点位的组成成分和元素特征分析可以得出,岩石微观孔隙、裂隙等缺陷发育的结构非均匀性和组成成分的非均匀性是造成砂岩微观破裂和细观裂纹扩展的主要原因。多尺度分析的结果直观的反映了岩石内部裂纹扩展空间位置和扩展方向。这对深入研究岩石蠕变破裂演化机理是十分有意义的。Rock deformation and failure occur with the increase of external load.When the external load remains unchanged,the deformation does not stop,and it will continue to increase,resulting in creep deformation.The fundamental cause is the heterogeneity of rock.Rock creep fracture is a process of micro-scale fracture,meso-scale crack propagation and penetration,macro-scale deformation increase and failure process caused by the original heterogeneity of rock.Therefore,it is necessary to study the multi-scale evolution mechanism of rock creep fracture.Taking sandstone as the research object,this paper analyzes the deformation and fracture mechanism of sandstone samples at different scales from the macro-evolution experiment of creep fracture and the micro-scanning experiment of fracture.Through the macroscopic evolution experiment of sandstone creep fracture,it can be seen that there are no cracks on the surface of rock in the initial creep and constant velocity creep stages,but mainly the initiation and propagation of micro-and micro-cracks.When the macro-fracture surface is formed,it enters the accelerated creep stage.In the accelerated creep stage,friction sliding occurs along the fracture surface,and finally failure occurs.The microscopic analysis of the micro-composition and fracture characteristics of the sandstone can be obtained by analyzing the micro-composition and micro-fracture characteristics of the sandstone.The results of multi-scale analysis directly reflect the spatial position and direction of crack propagation in rock.This is of great significance for further study of the evolution mechanism of rock creep rupture.

关 键 词：多尺度 蠕变破裂 演化规律 非均匀性 

分 类 号：TU45[建筑科学—岩土工程]