Stability Analysis Of Surrounding Rock With Different Intersection Angle Of Dolomite Bedding And Tunnel

Bedding dolomite is a typical sedimentary rock,widely distributed in Hunan,Hubei,Guangdong,Yunnan,Guizhou,Sichuan,Chongqing,Guangxi,etc.,which greatly affects the construction of geotechnical engineering and the building of underground engineering in these areas,It's physical and mechanical properties and it's impact on engineering need to be explored urgently.Therefore,it is necessary to study the physical and mechanical characteristics of bedding dolomite from the angles of theory,experiment and numerical simulation to obtain the deformation,strength characteristics and destruction rules of dolomite under the influence of bedding.With the implementation of the strategy of a powerful transportation country,it is of considerable application value to study the stability of surrounding rock with different intersection Angle of Dolomite bedding and Tunnel in the Yungnan and Guizhou.The heading of this article comes from one of the sub-projects of the National Natural Science Foundation of China(NSFC)"Stability Analysis of Surrounding Rock and Supporting Measures for bedding controlled Dolomite Tunnel"(51608141),this article relying on the Zhaolu Expressway TJ1-2(the engineering is in Zhenxiong County,Zhaotong City,Yunnan province),used the complex variable function theory,uniaxial compression test,triaxial compression test and numerical simulation calculation as research methods to study the stability of the surrounding rock with different intersection Angle of Dolomite bedding and Tunnel.The main work content is as follows:(1)Based on the uniaxial compression test of dolomite,the failure mode of dolomite is the coexistence of shear failure and tensile failure,but mainly the tensile failure,and the failure mode of bedding dolomite includes tensile failure(0°,15°bedding dolomite),shear failure(30°,45°and 60°bedding dolomite),coexistenceof tensile failure and shear failure(75°bedding dolomite)and mainly tensile failure(90°bedding dolomite);(2)Based on the triaxial compression test of dolomite,it is found that the confining pressure has a significant effect on the failure mode of the rock mass.The confining pressure is increased from 3MPa to 30 MPa,and it undergoes three types of split failure,split-shear failure and shear failure form;(3)By carrying out numerical simulation calculations on construction scheme of an tunnel engineering project,it is found that when there is no bedding in the surrounding rock,the horizontal stress on the arch top and the arch legs on both sides is large,and the vertical stress on the arch waist on both sides is large.i recommended to make temporary support during site operation to ensure the stability of surrounding rock;when there is bedding in the surrounding rock,the displacement and stress of the surrounding rock at the initial stage of excavation and unloading are significantly affected by the bedding,and the bias pressure effect becomes more and more obvious as the bedding angle increases,but when the bedding angle is 45°,the anchor has minimum axial stress;(4)Based on the rock beam theory,the rock mass between the horizontal bedding and the rectangular or horseshoe tunnel is simplified into a constant cross section beam and a variable cross section beam respectively.I constructed a theoretical calculation model for calculating the displacement of surrounding rock in the horizontal bedding tunnel arch,and the results of the theoretical model are compared with the numerical results,and the two are in good agreement,which verified the application and accuracy of the theoretical model;(5)Based on the complex variable function theory and the ??????????equivalent layer method,I constructed the stress analysis model of the surrounding rock of the deep buried rectangular tunnel in two layers of different rock masses,and derived the analytical functions ?(?)and ?(?)for calculating the stress of the surrounding rock.Finally,I analyzed The influence of factors such as lateral pressure coefficient and ratio of height to width on the surrounding rock stress and pressurearch.