The Control Of Construction And Project Application For Shallow Tunnel Under Unsymmetrical Pressure Based On The Random Method

Shallow tunnel under unsymmetrical pressure is a usual problem in the highway tunnel construction, which especially occurs on the import and exit of tunnel or site along mountain and beside river. The rock of shallow tunnel under unsymmetrical pressure is almost gradeâ…£or higher soft rock, which mechanics property is complex, and ground stress distributes un-symmetrically being influenced by unsymmetrical pressure, therefore it is difficult to analyse stability of shallow tunnel under unsymmetrical pressure and realize construction safe control. At present, the research of construction safe control method of shallow tunnel under unsymmetrical pressure is still not mature and profound around the world, and there is much insufficiency of usual adopted methods.According to the insufficiency of usual safe control methods, a new construction safe control method of shallow tunnel under unsymmetrical pressure is built, which includes safe control before construction and under construction. The main study and results are as follows:â‘ Before tunnel construction, a safe control model is built according to the insufficiency of usual method. Basing on the rock mechanics property of shallow tunnel under unsymmetrical pressure, a load-structure model is used to calculate internal force and displacement of tunnel lining. The calculated internal force of tunnel lining could judge the stability of tunnel lining by criterion; viewing the rock of shallow tunnel under unsymmetrical pressure as random medium, the random medium formulae of shallow tunnel under unsymmetrical pressure are deduced based on actual engineering, then taking the results of analytical method into the formulae, and the displacement of rock can be calculated which could analyse stability of tunnel rock by the plane limit balance method.â‘¡During the construction of tunnel, FLAC numerical simulation is used to analyse the stability of shallow tunnel under unsymmetrical pressure for safe control. Considering the randomness and fuzziness of tunnel rock, the random-fuzzy method is used to deal the measuring data, which will be fitted for FLAC results, and original rock parameter could be fitted. Taking the fitted parameter into FLAC program, the variety of internal force and displacement of tunnel supporting structure and rock can be analysed from inflicting supporting structure to construction over, and considering release of rock stress and together action of rock and supporting structure during the construction of tunnel. The stability of supporting structure and rock could be analysed and concluded by the relativity of time and FLAC iterative step after construction of shallow tunnel under unsymmetrical pressure, therefore the construction safe control of tunnel would be come true. According to analyse, it can be concluded that the combination of dealing measuring data by random-fuzzy method and FLAC numerical simulation could easily forecast the internal force and displacement of each note of tunnel section, so the method is practicable.Contrasting the results of analytical method to the results of numerical method, it is concluded that the forecasting results of analytical method have some difference with...