特定角度组合节理岩体卸荷力学特性试验研究

发布时间：2018-04-09 12:47

本文选题：节理岩体　切入点：非贯通　出处：《三峡大学》2015年硕士论文

【摘要】：自然界中的岩体在漫长的地质演变过程中，往往被大小、形状、方向各异的结构面纵横切割，而形成具有一定结构特征的不连续岩体，由于结构面的存在，显然不连续岩体的力学特性要比完整岩石复杂很多。本文对特定非贯通节理岩体试件进行了单轴压缩试验、常规三轴压缩试验和卸荷试验，研究了特定非贯通节理岩体的加卸载条件下的力学特性，论文具体研究内容如下： 1)对完整试件以及不同连通率(k=0.30、 k=0.45、 k=0.60)、不同节理数量及角度(β=30°、β=45°、β=60°、β=30°+45°、β=30°+60°)非贯通节理试样进行单轴压缩试验、不同围压水平(2MPa、4MPa、6MPa、8MPa、10MPa)常规三轴压缩试验、卸荷(峰前卸荷)试验；研究不同节理连通率、不同节理倾角、不同节理数量非贯通节理岩体试件加卸载条件下的力学特性，并与完整试件进行对比分析。结果表明在加卸载条件下非贯通节理岩体均表现出各向异性力学特性，这种各向异性特性表现随着节理连通率的增大更为明显。 2)非贯通节理岩石试件在加卸载试验中所表现出来的力学特性、破坏形态、力学参数等具有明显差异，岩体加卸荷状态下具有不同的破坏机理；在卸荷条件下非贯通节理岩体试件均表现出明显的脆性破坏特征，并且随着连通率的增大这种特征表现得更加明显。双节理试件主要沿较大倾角节理面发生破坏。直线型Mohr-Coulomb强度准则和Hoek-Brown强度准则均能较好地表述非贯通节理岩体主应力之间的相互关系。 3)运用节理试样三轴卸荷试验的研究成果，对大岗山水电站某边坡进行二维有限元计算，，对比监测值与计算位移值表明：计算位移以及变化趋势与监测值一致，其量级也与监测值一致，说明计算中选取模型和计算方法是合理的。
[Abstract]:In the long process of geological evolution, rock mass in nature is often cut vertically and horizontally by structural planes of different sizes, shapes and directions, and discontinuous rock masses with certain structural characteristics are formed because of the existence of structural planes.It is obvious that the mechanical properties of discontinuous rock mass are much more complicated than that of complete rock mass.In this paper, uniaxial compression tests, conventional triaxial compression tests and unloading tests are carried out on the specimens of certain non-transfixible jointed rock masses. The mechanical properties of specific non-transfixible jointed rock masses under loading and unloading conditions are studied. The main contents of this paper are as follows:The mechanical properties of rock mass specimens with different joint connectivity, different joint inclination and different joint number under loading and unloading conditions are studied and compared with the complete specimens.The results show that the unconnected rock masses exhibit anisotropic mechanical properties under loading and unloading conditions, and this anisotropic property is more obvious with the increase of joint connectivity.2) there are obvious differences in mechanical properties, failure patterns and mechanical parameters of non-through jointed rock specimens in loading and unloading tests, and there are different failure mechanisms under loading and unloading of rock masses;Under unloading condition, the specimens of non-through-jointed rock mass all show obvious brittle failure characteristics, and with the increase of connectivity, this characteristic is more obvious.The failure of double joint specimens mainly occurs along the large inclined joint surface.Both the linear Mohr-Coulomb strength criterion and the Hoek-Brown strength criterion can describe the relationship between the principal stresses of non-transfixion jointed rock mass.3) based on the research results of triaxial unloading test of jointed specimens, a slope of Dagangshan Hydropower Station is calculated by two-dimensional finite element method. The comparison between the monitoring value and the calculated displacement value shows that the calculated displacement and the variation trend are consistent with the monitoring values.The order of magnitude is the same as the monitoring value, which shows that the selection of model and calculation method is reasonable.
【学位授予单位】：三峡大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45

【参考文献】