Study On Large Deformation And Supporting Technology Of Soft Broken Surrounding Rock Tunnel

Highway tunnel in the process of the excavation support often encounter deformation,even vault landslides engineering problems,such as construction workers on the interaction between tunnel support and surrounding rock to do a lot of research,bolt(tube)applied in the control of deformation in weak rock tunnel is more and more widely,which is of great significance to improve the engineering safety and economy.Although the application of various support technologies is gradually mature,the application of bolt(pipe)in tunnel construction is still in the stage of exploration and discovery.Some engineering support strength is too large,resulting in waste;Some strength is too low,will cause harm to the project.With the rapid development of computer technology,we have been able to use numerical simulation method to analyze the form of support in the tunnel,through the numerical model to show the support structure and surrounding rock stress and deformation.The numerical simulation results are combined with the measured data to provide a basis for the design.In this paper,combined with the construction section of wenbishan tunnel in lijiang,yunnan province,which adopts the method of grouting anchor and excavating underground steps,finite element analysis software is used to study the initial support settlement of the tunnel in the construction section of weak surrounding rock.Step method due to reasons such as blasting excavation of the tunnel will cause the tunnel surrounding rock near the constraints is broken,and form a state of relaxation,so the steps needed support during tunneling method construction of tunnel,and under the condition of weak rock tunnel monitoring settlement increases obviously,so we settlement of large section bolt support for numerical simulation analysis under different working conditions.Firstly,the driving Angle of guided locking bolt is controlled,and then different lengths of bolt and different material grades of arch are taken to study the supporting effect of the tunnel after the change.The main contents and achievements include the following:(1)select sections with large settlement under monitoring quantity to collect data of sections under actual construction conditions.The measurement data are sorted out and analyzed,the engineering geological environment of the project location is sorted out,and the supporting function theory of anchor bolt(pipe)with locking foot is analyzed.Corresponding to the tunnel numerical simulation and measured data under various working conditions,comparative analysis is made.(2)by means of numerical simulation method,the influence of different driving angles and lengths of tunnel locking bolt corresponding to different working conditions on the control of tunnel deformation was studied,and the tunnel deformation caused by this form of support was obtained.At the same time,different arch and different length bolts are used to compare the settlement under the original working condition.(3)combined with the comparison between simulated support data and actual support data under various working conditions,under the condition of large tunnel deformation,the changes of bolt support direction,bolt length and arch material.Compared with the original working condition,it is verified that the change of support technology form is beneficial to the construction of the project.