CAJ | 학술논문

基于物理和常规变形特性分析，认为某水电站坝基碎屑岩力学特性异常复杂，故采用岩石三轴伺服仪开展渗流-应力耦合作用下的流变和渗透特性试验研究。首先绘制流变全程试验曲线，探讨轴向、侧向及体积流变特性和速率变化规律；其次对流变过程中渗流规律和演化机制进行详细分析；最后，对破坏岩样开展微细观电镜扫描试验，研究宏微观破坏机制。结果表明，碎屑岩表现出显著的流变力学特性，流变曲线主要分为初始衰减和稳态流变两阶段，且最后级应力施加后呈现快速流变现象；应力和渗透压力增加导致流变变形加剧，围压对流变变形存在限制作用；最终破坏表现出轴向压缩变形过大、体积延性扩容明显、稳态流变速率较大等特点，且流变速率与应力符合指数增加关系。鉴于岩样的非均质性，加载作用导致渗透系数变化存在部分波动，但整体呈降低的趋势。稳态流变阶段，渗透系数恢复至平缓线性下降趋势，说明波动对渗透率的整体演化无显著影响，且围压增加导致渗透系数降低。试验结果旨在为渗流-应力耦合作用下岩石工程长期稳定分析及流变模型构建提供可靠的依据。
기우물리화상규변형특성분석，인위모수전참패기쇄설암역학특성이상복잡，고채용암석삼축사복의개전삼류-응력우합작용하적류변화삼투특성시험연구。수선회제류변전정시험곡선，탐토축향、측향급체적류변특성화속솔변화규률；기차대류변과정중삼류규률화연화궤제진행상세분석；최후，대파배암양개전미세관전경소묘시험，연구굉미관파배궤제。결과표명，쇄설암표현출현저적류변역학특성，류변곡선주요분위초시쇠감화은태류변량계단，차최후급응력시가후정현쾌속류변현상；응력화삼투압력증가도치류변변형가극，위압대류변변형존재한제작용；최종파배표현출축향압축변형과대、체적연성확용명현、은태류변속솔교대등특점，차류변속솔여응력부합지수증가관계。감우암양적비균질성，가재작용도치삼투계수변화존재부분파동，단정체정강저적추세。은태류변계단，삼투계수회복지평완선성하강추세，설명파동대삼투솔적정체연화무현저영향，차위압증가도치삼투계수강저。시험결과지재위삼류-응력우합작용하암석공정장기은정분석급류변모형구건제공가고적의거。
The mechanical properties of clastic rock of dam foundation in a hydropower station in virtue of conventional physical and deformation analysis are very complex. Triaxial rheological tests were therefore conducted using the automatic triaxial servo-instrument to investigate the rheological properties and permeability of such rock under hydro-mechanical coupling. The axial,lateral and volumetric deformation curves versus time were measured and the rheological deformation properties and rheological rate law were discussed accordingly. The evolution process of permeability during rheological period was analyzed in detail. The scanning electron microscope(SEM) experiments were performed for the rock specimens after failure to study the mechanism and mode of macro-micro failure. The results show that the clastic rock has a pronounced rheological behavior. The rheological curves have a transient period initially,a steady period thereafter and an accelerated period finally at the last loading step. The rheological deformation were increased when the stress and seepage pressure applied were increased and were reduced if the confining pressure was increased. The finally failed specimen have the characteristics of large axial compression deformation,obvious ductile volumetric dilation and large steady rheological rate. The relationship between the rheological rate and the applied stress can be described by an exponential function. The coefficients of permeability fluctuate during the rheological process possibly because of the heterogeneity of specimens,but overall decrease. During the stage of steady period,the coefficients of permeability decrease linearly. It is shown that the fluctuation has no significant effect on the permeability evolution. Furthermore,the permeability coefficients decrease as the confining pressures increase.