Research On Deformation Mechanism And Control Technology Of Intersection Construction In Large Cross-section Tunnel

With the vigorous exploiting of the country's transportation resources,the rapid development of railway construction has been achieved.As the national resources tilted to the west now,mountain tunnels and bridge erection are essential in the railway construction.Furthermore,the proportion of tunnel in the total line is been improved day by day.In order to shorten the duration,it is common to set up several auxiliary adit(inclined shaft)to increase the working face of the main tunnel during the construction of long and large tunnel.The surrounding rock stress is concentrated obviously and complicated because the section shape of tunnel excavation is irregular when the inclined shaft is placed into the main tunnel.It is hard to complete construction of the intersection.There are many difficulties and potential dangers in the construction of excavation and support in large cross-section tunnel intersection,especially in the bad geological sections.Incorrect excavating or supporting easily leads to substantial settlement of surrounding rock.And even worse,what referred to above will causes a serious accident owing to landslides.How to ensure the safety of construction,guarantee the stability of intersection surrounding rock,finish the construction rapidly,and reduce economic costs is a key and difficult point.Aiming at the key technical problem mentioned above,the thesis did some researches.Based on the engineering background which is the construction of intersection in No.1 inclined shaft of Guchengling tunnel,this paper studied the deformation mechanism and control technology of intersection construction in large cross-section tunnel.Main research contents of this article are as follows:(1)On the basis of predecessors' theory,mechanism of surrounding rock deformation and destabilization are analyzed and summarized.And several corresponding control method of surrounding rock deformation has been put forward.What mentioned above is provided for intersection construction as a theoretical basis.(2)MIDAS GTS NX of FEM software is used for 3D numerical simulation of construction scheme which is about intersection.First,the general law of displacement deformation is focused on analyzing to arrived at the weakest points of deformation and failure about surrounding rock.Then,the original scheme is optimized.Last,the optimal scheme is simulated to identify a reasonable and high efficient construction scheme after comparison and analysis.(3)In order to verify the rationality of the optimized scheme,it is applied to the typical test section in Engineering.And the monitoring measurement in informational management is used to support the process of construction.The data which is collected are analyzed and summarized.Finally,the rationality and high efficiency of optimal scheme is proved.And it is of certain reference value to the similar projects.