Abstract:

in order to solve the traditional line drawing method construction three-centred arch line drawing big workload, poor precision. the author according to the similarity of elliptic with three heart round, using elliptical definition and setting two line of control measures by using only nine data control three heart arch fork excavation contour size(alleys excavation after entering the fork, only add three memory data). up to the three-centred arch construction line drawing quick, convenient and accurate.Make arch tunnel excavation three-centred arch of the contour line efficiency improved dozens of times and three heart arch fork construction of forming quality has been improved.