短边测量对隧洞横向贯通的影响

本文目的在于用理论及数据说明短边测量对隧洞横向贯通影响的程度，进而引起测绘工作者对短边测量的注意，同时提出一些解决的方法。

Effect of Short Side Survey on Through of Tunnel

Two equations are derived,of which one is used for calculating the quadratic mean error of survey angle and the other one is for calculating the lateral deviation value in through face caused by short side survey.In order to further illustrate the effect of short side survey and arouse the attention of surveyor,the quadratic mean error of the survey angle and the lateral deviation value are listed in such a case that the quadratic mean error of centring is 1.0mm,the length of short side is 20-200m,the adjacent side is 200m long,and the distances between two tunnel mouths are 1-4,4-8,8-10,10-20,20-30,30-40km respectively.Finally,some measures such as avoiding the occurrence of short side as far as practicable,adopting the three-connecting scaffold method when the tunnel is relatively short,and installing the forced centring plate in primary ploygonal points when the tunnel is very long are given to reduce the effect of short side survey.