自由测站边角交会网在隧道内平面控制中的应用研究

针对目前高铁隧道洞内导线环网多余观测量少、受旁折光影响大、控制点使用困难和横向误差大等问题，提出用自由测站边角交会网作为隧道洞内平面控制测量的新方法.推导了自由测站边角交会网的边长相对中误差和横向贯通误差计算模型，并进行了仿真计算.计算结果表明，这两项指标能够满足高速铁路工程测量规范的精度要求；隧道贯通精度提高了20%，并提高了测量效率；从定性和定量两方面证明了自由测站边角交会网可以代替洞内导线环网. 

Using Free-Station Linear-Angular Intersection Network in Tunnel Horizontal Survey of High-Speed Railway

To deal with the defects of loop traverse networks for the tunnel of high-speed railway, such as less redundant observations, great sensitivity to lateral refraction, difficult usage of control points and large lateral error, a new method using free-station linear-angular intersection network for the horizontal control survey inside tunnel was proposed. The calculation models for the two indexes,relative mean square error of distance and the lateral breakthrough error,were established for the free-station linear-angular intersection network. The simulation results show that the errors of two indexes can meet the accuracy requirements of the high-speed rail survey specifications. The tunnel breakthrough accuracy is increased by 20%, and also the efficiency of measurement is improved. Qualitative and qualitative analysis proved that the free-station linear-angular intersection network can substitute the loop traverse network.