Research On Structural Optimization Of "Anti-Sliding Shed Tunnel" For Super High Steep Dip Bedding Soft Rock Slope

This thesis takes the treatment of super-steep inclined bedding soft rock slope as the background,firstly,the deformation and failure modes of this kind of slope are analyzed.Based on the project of land disaster control along the mountain road of Chongqing West Station,the deformation and failure mechanism of this kind of slope is studied by combining field experiment,theoretical analysis,data arrangement and numerical simulation calculation."Anti-slide shed tunnel" is proposed to solve the treatment problem of such slope.Then,the structural optimization of this new structure is studied by combining theoretical analysis with numerical simulation.Finally,the effect of this new structure on the treatment of super-high and steep inclined soft rock slope is verified by the application of this new structure in the project of land disaster control along the mountain road of Chongqing West Station.The main research results are as follows:(1)The deformation and failure types of steep bedding slopes can be basically divided into two categories: collapse mode and toppling mode.Collapse mode is influenced by the excavation unloading,slope height,rock strength and shear strength,which occurs when the slope angle is close to the steep inclined level;Slope instability in toppling mode generally occurs when the slope angle is smaller than the steep layer;(2)The support structure of a toppling deformed slope should meet two requirements:1)Provide sufficient structural stiffness to suppress further toppling deformation of the slope;2)Provide sufficient structural strength to withstand the corresponding sliding force after deterioration occurs.(3)The structural calculation model of "anti-sliding shed tunnel" can refer to the semi underground frame structure model,and can be solved theoretically through structural mechanics methods and pile elasticity theory.(4)The larger the span of the "anti sliding shed tunnel",the more unfavorable the stress on the pile;The reasonable height span ratio of the structure is between 0.4 and 0.8,and the pile embedding depth is about 1/2 of the cantilever length,which can meet the requirements of soft rock geology;Under the same embedded length,the foundation support stiffness is not sensitive to the deformation and internal force of the structure;The stiffness ratio of pile and beam should be 1-2,which is more reasonable.(5)Under the same conditions,the multi-layer structure is better than the singlelayer structure in the anti-slide shed tunnel.Arch structure is better than rectangular frame structure in force of anti-slide shed tunnel.(6)According to the application of supporting engineering,the treatment of super high and steep dip bedding soft rock slope is realized by using the "anti-sliding shed tunnel" of arch structure.After engineering verification,the results are safe and reliable.