angle pipe meaning in English

接角管
曲管
弯管

Using fem ( finite element method ) , the paper makes mechanical analyses on bench cut method and side heading method , it also makes mechanical analyses on some auxiliary construction methods , such as big pipe - roof protection , horizontal roll - spraying , big and small angle pipe - roof protection and surface grouting
论文采用有限元的分析方法，主要对台阶法、侧壁导坑法进行了力学分析，也选择了大管棚法、水平旋喷法、大小外插角管棚法和地表注浆加固四种辅助工法进行力学分析。