| It is unavoidable that surrounding rock section of thin horizontal layers will bepenetrated, traditional vertical anchorage design and construction method are easy tohurt workers and the quality of construction is hard to control in tunnel construction.The article has proposed combined anchorage system adopts the multidirectional tilt andhorizontal thin layered surrounding rock tilt to the combination of vertical rock bolt andanchor to support surrounding rock. Complete the anchoring construction ofsurrounding rock and ensure the construction safety through optimizing the design ofInclined to anchor and vertical anchor on spatial layout, construction time, Theoreticalanalysis, mechanics formula deduction and numerical simulation are applied in thearticle to carry out the following works:(1) Analysis the structure characteristics and instability mechanism of thinhorizonal layered rock mass, it is main damaged by Structural plane and t beddingplane, which common failure mode is bending longitudinal tensile fracture and caveroof damage. Four kinds of tunnel surrounding rock stability discriminant basis and theinfluence factors of instability of surrounding rock have been proposed and themechanics model has been set up specifically illustrates the phenomenon and affectthe instability of the related factors of thin horizonal layered surrounding rock.(2) Bolting surrounding rock can effectively reduce the radial displacement ofsurrounding rock has been proved through theory analysis and mechanics formula,which has important implications of maintaining the stability of surrounding rock. Aimat anchorage support applied in thin horizontal layered surrounding rock tunnel andsummarizes the corresponding bolt anchoring mechanism of action(3) Propose the space arrangement and setting mode of multidirectional tiltcombined type anchoring system in horizontal thin layered surrounding rock, Verifiedby theoretical calculation it has the same effect of surrounding rock as the traditionalway of vertical rock anchor anchorage.(4) Take a thin horizontal layered surrounding rock tunneling as researchbackground, use FLAC3D software to carry on the numerical simulation, study theeffect of multidirectional tilt combined inclined bolt anchoring system in different angleand different distance of surrounding rock, Combined with the actual tunnelconstruction for the new anchorage system parameters are optimized, and the specificarrangement and setting method has made the detailed instructions.(5) Combined the thin horizontal layered surrounding rock tunnel construction，proposed the evaluation method of anchorage system quality, quality of anchor rod,anchor drilling quality and overall support effect with the new anchorage system.This article has made a systematic and comprehensive study of the stability of thin,horizontal layered surrounding rock tunnel. Based on the geological features of thin,horizontal layered rock tunnel, the mechanical characteristics of surrounding rock andthe shortage of the traditional vertical surrounding rock anchorage system,The tiltcombined-type anchorage system can not only meet the needs of the anchorage, also canreduce the risk from the construction, ensure the safety of workers and have a very goodguidance and reference for other constructions. In any construction, the safe must be putfirst, and the multidirectional tilt combined type anchoring system is working for it. |
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