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岩石作为地下工程的主要研究对象,其物质组成和所赋存的复杂地质环境使其具有明显的流变特性。基于三维颗粒流程序(PFC3D),采用由开尔文模型和马克斯伟尔模型串联组成的伯格斯(Burgers)流变模型,通过控制变量法,分析了伯格斯模型中弹性系数(Em和Ek)、黏性系数(?m和?k)和摩擦因数f对瞬时强度特性和流变特性的影响;分析得出数值试样的瞬时强度特性主要受马克斯伟尔体弹性系数Em和摩擦因数f影响:弹性模量和单轴抗压强度与Em和f均呈正相关,泊松比与Em呈正相关,与f呈负相关;而流变特性与各参数均呈现负相关性。在此基础上,进行了红页岩分级增量蠕变试验的模拟,通过与室内蠕变试验结果的对比,验证了PFC3D中的伯格斯模型用于岩石蠕变试验模拟的可行性,并将该方法用于分级增量循环加卸载蠕变试验和三轴蠕变试验数值研究。该研究内容是利用离散单元法研究岩石流变特性的一种新的尝试。
Rock as the main research object of underground engineering, its material composition and the complex geological environment it has made it has obvious rheological properties. Based on the three-dimensional particle flow program (PFC3D), a Burgers rheological model consisting of a Kelvin model and a Maxwell model series is used to analyze the elastic coefficients (Em and Ek) in the Burgers model by controlling the variables. , Viscosity coefficient (? M and? K) and friction coefficient f on the instantaneous strength and rheological properties were analyzed; the instantaneous strength characteristics of the numerical sample were mainly affected by the Maxwell’s body elastic coefficient Em and the friction coefficient f The elastic modulus and the uniaxial compressive strength are positively correlated with Em and f, the Poisson’s ratio is positively correlated with Em and negatively correlated with f, while the rheological properties are negatively correlated with each parameter. Based on this, the simulation of graded incremental creep test of red shale was carried out. By comparing with the results of indoor creep test, the feasibility of Burgess model in PFC3D for simulating rock creep test was verified. The method is applied to the numerical study of gradual incremental unloading creep test and triaxial creep test. The research content is a new attempt to study the rheological properties of rock using discrete element method.