Research On The Key Control Techniques Of Super-long Diversion Tunnel Transfixion Error

With the rapid development of water conservancy projects in China,more and more super-long hydraulic tunnels have been excavated,and the length of the long tunnel is more and more long.However,due to the special measurement environment in the tunnel,there are still some technical problems that need to be solved urgently.Aiming at a series of problems faced in the practice of measurement and control engineering for long tunnels,it is urgent to do some corresponding research and discussion,and as soon as possible to form a scientific and reasonable measurement methods and technical standards for inside and outside the tunnel,instructs the scene construction.In view of this,the main contents of this thesis include the following points:Firstly,this thesis introduces the method of calculating the influence value of lateral piercing errors according to the outside the GPS network error.At the same time,the precise trigonometric leveling method of free station is introduced in detail,and compared the difference between the test results of the precise trigonometric leveling and the results of second order leveling measurements.Secondly,this thesis presents the accuracy simulation method of the horizontal control network considering the influence of centering error,and perfected the simulation calculation theory of control network accuracy.Based on this new simulation calculation technology,a new method for predicting the lateral piercing errors in the tunnel is proposed;and studied the effects of ranging error,direction measurement error and centring error on horizontal oscillation respectively by simulation calculation,The results show that the ranging error has little influence on the horizontal oscillation,but the direction measurement error and the centering error have great influence on the horizontal oscillation;According to the calculation experiments of changing the transverse space of traverse network,The results show that the lateral accuracy of the control network will not be reduced while avoiding the influence of the lateral refraction.Thirdly,the qualitative analysis is carried on the vertical deflection affects accuracy of connection survey,it is concluded the best way of control points arrangement outside the tunnel that avoid the effects of vertical deflections;and then,the measurement experiment of connection survey is designed,Based on the analysis of the test results,the optimum methods of connection survey and data processing are obtained;The simulation of the traverse with Gyro-sides in the tunnel is carried out,and the Best Position of Gyro-sides is determined;At the same time,it is also studied the influence of Gyro-sides on the accuracy of traverse network when the influence of Gyro-orientation error is considered,The results show that it has a remarkable optimization effect on controlling horizontal oscillation of traverse network with Gyro-sides in the tunnel.