蒙华铁路高家山危岩特征成因及裂隙变形分析

为研究蒙华铁路高家山隧道洞口危岩的稳定性,利用不连续介质二维离散程序进行模拟分析,选取洞口典型危岩块体,对组成危岩体的泥岩、砂岩按照岩体质量分级进行物理力学参数赋值,得出在初始应力平衡条件下,边坡体仅出现少量裂隙,而在风化卸荷作用下,边坡体表层20 m范围内出现朝临空方向变形的应力张拉区,特别是在泥岩附近的陡崖与陡坡过...

Analysis of the Formation and Crack Deformation of Gaojiashan Dangerous Rock in Menghua Railway

The 2D discrete program of discontinuous medium was used to simulate the stress and strain state of the dangerous rock at the entrance of the Gaojiashan tunnel of Menghua railway under two conditions:the initial stress state and the weathering unloading state.By selecting typical dangerous rock blocks at the entrance of the cave and assigning the physical and mechanical parameters of mudstone and sandstone according to the classification of rock mass quality,there were only few cracks under the initial stress state.In the weathering unloading state,within 20 m of the surface of the slope body,a stress tension zone deformed toward the airspace appeared,especially in the transition zone between the cliff and the steep slope near the mudstone.Several cracks with significant displacement appeared,and the developed depth was 25 m to 40 m.The displacement from the inside to the outside increased from 4 mm to 22 mm,and the deformation direction changed mainly from pointing to the outside of the slope and downward to horizontal,and finally led collapse and fall of the side of the slope rock.The research profoundly reveals that the mudstone weathered rock cavity is the main reason for the formation of fissures and finally leads to the collapse of the dangerous rock.The later falling position and direction are also located in the upper part of the weathering cavity.The research results provide a basis for scientific and effective treatment of the dangerous rock.