Research And Engineering Application Of Supporting Structure In The Initial Excavation Of Mining Machinery

With the continuous development of China's economic construction,more and more cities have built subways in China,and the lines built have become longer and longer.People gradually realize the importance of subway construction.In the construction of subways,there are various construction methods.The mining method is a very common and widely used tunnel construction method in construction.The traditional mining method uses mostly manual operations,including earthwork excavation,small pipe erection,steel arch erection,etc.It has high operation intensity,high construction risk,and low construction efficiency.In response to this problem,a mechanical device has been developed that can integrate multiple functions into one,reduce the labor intensity of workers,and improve the operating efficiency.The daily footage can reach 1.5-2 times that of traditional manual footage.However,there are still many problems at present.The mining method is based on the relaxation principle,making full use of the self-supporting capacity of the surrounding rock and the spatial constraint of the excavation surface.Excavation of large footage leads to increased disturbance of the surrounding rock,which will inevitably affect the release of the surrounding rock load And the final deformation of the surrounding rock,so the support structure that can guarantee the stability of the cave and control the deformation of the surrounding rock needs to be reconsidered.Based on this,this article carries out research and elaborate in the following aspects:(1)A traditional mining tunnel has a construction cycle footage of 0.5m,and a maximum of 4 cycles can be applied in a single day.Mining machinery excavation can be increased by1.5-2 times,and a single day can reach 5-6 construction cycles.However,in practice,the0.5m footage is still used,which only makes the efficiency of excavation soil faster,and the efficiency of excavation and support does not play out,but we cannot blindly increase the footage to the maximum.The disturbance is too large,which is easy to cause the risk of tunnel collapse.In order to obtain a reasonable footage,the FLAC 3D,the most widely used finite difference software in underground engineering,is used to establish the tunnel excavation model.Six kinds of footage conditions are selected and numerical simulation Comparing the deformation of surrounding rock,deformation of supporting structure and stress of various working conditions,a reasonable footage is selected.(2)In the case of a reasonable footage,it is necessary to analyze the dynamic action relationship of the surrounding rock support of the tunnel,and get suggestions for optimization of support.This paper adopts the most widely used convergence constraint method in the design theory of underground structures.Analyze the tunnel excavation process to obtain the effect of footage elevation on the surrounding rock support interaction,the key points of tunnel support design,and the principles of tunnel support timing selection,and substitute the convergence constraint calculation model through matlab to obtain thesurrounding rock support for each working condition The precise solution of the protective effect,in order to provide suggestions for the optimization of the supporting structure.(3)At present,in the design of supporting structure,it relies too much on construction experience.For the role of longitudinal connecting bars in the supporting structure,the difference between the use of grids and steel in the supporting structure,and the steel frame The impact of subsections on the support is not yet clear,and the optimization of the support is not available.The simulated tunnel support structure in this paper has studied these three problems through indoor experiments,and based on the above recommendations for the support structure The optimization gives the support structure with the most improved support stiffness.Finally,the mechanical properties and applicability of the support are evaluated based on the convergence constraint method.(4)Advancement of the footage.When the digging efficiency is improved,the management ability also needs to be improved.Therefore,the introduction of BIM technology can realize the visualization of construction management progress,project measurement statistics,and project progress management to improve project management capabilities.(5)Apply in actual projects,record key technological processes,and verify the rationality of construction methods through actual engineering monitoring and measurement.