The Research On Tunnel Monitoring Measurement And Data Back Analysis

Along with the further implementation of the western development strategy, theconstruction of the tunnel met unprecedented opportunities for development, in thecentral and western mountainous areas. As one of the three elements of "new Austrianmethod", tunnel monitoring has a vital significance in the process of tunnelconstruction. But in actual construction process, monitoring measurement, in mostcases also stay on paper, which is far from achieving its due effects for constructionguiding and ensuring the safety of the construction. As a result, research on tunnelconstruction monitoring and the monitoring data reverse application has an importantpractical significance and research value.Before excavation, the ground is in a stable stress environment, namely in theoriginal stress state. Tunnel excavation destroys the original state of static equilibriumof rock mass, due to the self stability effect of surrounding rock and supportingstructure, the tunnel surrounding rock will achieve a new mechanical equilibrium.With the equilibrium conversion, the tunnel surrounding rock changes to the center ofthe tunnel. Therefore, according to the rules of tunnel deformation, it is easily to judgeif the tunnel structure is stability or not and the tunnel excavation and supporting iscorrect or not. This is also the tunnel construction monitoring work’s existence roleand significance.When formulating tunnel construction monitoring scheme, it should be firstlyunderstand the rock’s basic situation where tunnel project is located. The rock’s basicsituation include: topography conditions, formation lithology, geological structure,hydro geological situation and so on. These are usefully to understand the rock’sstress state, the level states of surrounding rock. Tunnel construction monitoringscheme include: the monitoring contents, monitoring methods, measuring line layout,frequency of measurement, data processing, report generation, etc. InShanghai-Kunming guest designed railway Guizhou12mark tunnel engineeringmonitoring, the monitoring group of Beijing University of technology use3D laserscanner for monitoring. It is a new exploring for finding new instruments to do thetunnel monitoring, and it also achieved a good results.Monitoring data processing is a key content of tunnel monitoring measurement,and also cost the most of manpower. In the process of data gathering, due to theexternal environment and personnel factors, the monitoring result usually has certainerror with the real result. Although it is unable to completely eliminate this error, butit a can be effectively reduced by using mathematics methods. Among themathematics methods, regression analysis is an effective one, and it is also a data processing method stipulated in the relevant specifications. But because our countryhas a huge area, different areas have big differences in hydrological geology,topography, the law of the displacement of tunnel deformation cannot be confirmedby a certain regression function. Therefore, according to the actual monitoring data tochoose suitable regression function in the regions has a great significance.In the tunnel monitoring, the amount of the monitoring sections, lines and themonitoring frequency, this can decide the amount of the tunnel monitoringmeasurement data. According to engineering experience, as the huge volume ofmonitoring data is, manual calculation is almost impossible. Even using EXCEL tocalculate and store data, the workload is very huge. Therefore, making full use ofcomputer’s data processing function to serve the monitoring work is urgently needed.In this premise, monitoring group of Beijing University of technology have developeda monitoring and data processing system based on Access database, which is greatlyconvenient for monitoring data processing and application. Using this system, itmakes monitoring data to effectively guide the construction be possible.The in-situ stress condition of tunnel engineering can decide the tunnel’sconstruction parameters and the supporting parameters. However, because of thelimited money and time conditions, using limited drilling to determine the mechanicalparameters of surrounding rock often have a great gap with the real situations. Usingthe fault construction and supporting parameters is likely to lead to an accident. Intunnel monitoring, the displacement of surrounding rocks can be measured relativelyaccurate and easy. So it is easy to use the displacement data to calculate themechanical parameters of surrounding rock, namely displacement back analysis. It isan effective way to determine the construction parameters and supporting parameters.Furthermore, using this way can also ensure the long-term stability of the constructionand support.