Research On Key Technology Of Maglev Gyroscope Orientation Measurement For Super Long Tunnel Under Complex Environment

As an inertial instrument which can determine the true north by measuring the rotational-angular velocity of the earth,gyro total station is widely used in the breakthrough surveying in underground engineering.However,due to the complicated geological conditions of the super-long tunnel,such as the high geothermal temperature,high atmospheric pressure in the tunnel,pressure eddy current,humidity,dust,refraction effect and construction vibration,which influenced the orientation accuracy of the gyroscope and increased the risk of tunnel breakthrough.Therefore,it is important to study the influence of these complex environments on gyro north-seeking data and to optimize the data processing method of gyro north-seeking.To improve the reliability of north-seeking and orientation accuracy of maglev gyroscope total station(GAT)in complex environments and ensure the super long tunnel breakthrough,this thesis focuses on the key technology of orientation measurement of GAT in complex environment.The main research contents and achievements are as follows:1.The force analysis of the rotor signal of GAT in complex environment was carried out,and the external environmental factors affecting the orientation accuracy of GAT are explored.According to the principle of regression analysis,the detection model of the rotor completeness is established.2.Based on the theory of wavelet transform and Hilbert-Huang transform,a GAT signal filter model was designed and optimized.The spectrum analysis of GAT anomalous signal revealed the physical influence mechanism of the forced movement of the rotor from the time domain perspective,which improved the environmental stability of the precision of GAT.3.Based on Monte-Carlo model,the method estimating of breakthrough error for the control network with gyro observation was proposed.The factors such as centering error,vertical deviation and refraction error were simulated and analyzed quantitatively,so as to improve the efficiency of breakthrough error estimation.The concept of variable precision gyro observation was put forward,and an adjustment for the survey network with individually weighted gyro observations(AIG)was proposed to optimize the correction efficiency of gyro bearing to underground control network and improve the breakthrough error of the tunnel.4.Taking the national major tunnel breakthrough project as an example,such as the Hong Kong-Zhuhai-Macao Bridge immersed tunnel Project and the Qinling super long tunnel(98.3 km)of Hanjiang to Weihe River Project,the feasibility of the above-mentioned filtering model,error estimation model and adjustment model were analyzed.Compared with the classical methods in the previous studies,the gyro data processing method proposed in this thesis has been proved to be practical in the super long tunnel breakthrough survey.