基于颗粒流异性层面剪切特性及演化机理研究

Research on Shear Characteristics and the Evolution Mechanism of Bedding Planes Between Two Different Rock Types Based on Particle Flow Code

为研究巴东组异性层面剪切特性的影响因素及其作用规律,并探讨其剪切破坏的细观演化机理,以巴东组典型粉砂质泥岩和泥灰岩间异性层面为研究对象,在室内试验成果的基础上确定壁岩细观参数,基于颗粒流软件开展直接剪切数值试验,结果表明:巴东组典型异性层面剪切曲线介于粉砂质泥岩和泥灰岩同性层面;异性层面剪切力学特性受到表面形态、法向应力和壁岩组合的影响;此外,异性层面的剪切破坏演化过程受表面形态影响,锯齿状异性层面的剪切破坏主要沿软弱壁岩从两侧向中部逐渐演化,平直状异性层面的剪切破坏主要沿接触面软弱壁岩一侧均匀同步演化。提出了异性层面与软岩同性层面抗剪强度之比与壁岩组合系数及法向应力之间的关系表达式,认为巴东组异性层面层间滑动是导致该组易滑地层岩体失稳破坏的重要原因。

To research the influencing factors of shearing properties and the micro-evolution mechanism of shear failure,we carried out direct shearing numerical experiments on the bedding planes between silty mudstone and marlite in Badong formation using particle flow software based on wall rock＇s micro-parameters determined by laboratory experiment results.The research results are as follows：the shearing curve of bedding planes between two different rock types in Badong formation is between silty mudstone and marlite isotropic planes; the shearing mechanical properties of bedding planes between two different rock types are influenced by the surface morphology,normal stress and the wall rock combination.In addition,the shear failure evolution process of bedding planes between two different rock types is influenced by the surface morphology.The shear failure of zigzag bedding planes between two different rock types develops mainly along the weak wall rock gradually from both sides to the middle.The shear failure of flat bedding planes between two different rock types evolves evenly along one side of the weak wall rock.Based on the results,an expression is given to describe the relationship among the ratio of shearing strength of bedding planes of two different rock types to that of normal joint in soft rock,rock combination coefficient,and normal stress.It＇s concluded that inter-formational sliding of bedding planes between two different rock types in Badong formation is an important factor that leads to the rock mass failure of this stratum.