在对存疑焊口准确定位之后，进行操作坑开挖，操作坑的开挖应该在探坑基础上

After accurate positioning of the suspected welding joint, excavate the operation pit. The excavation of the operation pit should be continued on the basis of the exploration pit. After the welding joint is positioned, a marking line is made 1 meter away from the outside of the pipeline. Excavator excavation. The slope ratio of the operation pit is not greater than 1: 1: the distance between the pipe and the side wall of the pit is not less than 1200mm According to the pit bottom distance greater than 500mm (the distance between stone sections is greater than or equal to 300mm), the bottom of the pipe must be carried out manually. When cleaning the soil above the weld, manual cleaning must be used. Set up anti-collapse shed under the operation pit or use pile driving and support to reinforce the operation pit, and mechanically and manually excavate pedestrian passages with a slope of less than 15 ° along both sides of the axial end of the weld. During the excavation of the operation pit, in order to ensure the operation safety of the pipeline in service, a safety officer must supervise the whole station during the excavation process.

After accurate positioning of the suspect weld, the operation pit excavation, the excavation of the operation pit should continue on the basis of the pit, after the welding port positioning from the outside of the pipe 1 meter to make a marking line, marking the line outside the excavator excavation. The slope ratio of the operating pit is no greater than 1:1: the distance between the pipe and the side wall of the pit is no less than 1200mm. The bottom distance of the tube pit is greater than 500mm (the distance of the stone section is greater than or equal to 300mm), must be carried out manually, and when cleaning the soil above the weld, manual cleaning must be used. Under the operation pit, the anti-collapse shed is placed or the operation pit is reinforced with piling and support, and the axial passage smaller than 15 degrees is excavated by mechanical and manual excavation of the slope by mechanical and manual excavation at both ends of the welding port. In order to ensure the safety of the operation of the operation of the operation of the operation pit, the excavation process must have the safety personnel to supervise the side station.

After accurate positioning of the suspected welded junction, the operation pit shall be excavated. The excavation of the operation pit shall be continued on the basis of the test pit. After positioning of the welded junction, a marking line shall be made 1 m away from the outside of the pipeline, and the excavator shall be used for excavation outside the marking line. The slope ratio of operation pit shall not be greater than 1:1: the distance between pipeline and pit side wall shall not be less than 1200mm. According to the distance between the bottom of the pit and the bottom of the pipe is more than 500mm (the distance between the stonework sections is more than or equal to 300mm), it must be carried out manually. When cleaning the soil above the welded junction, it must be cleaned manually. The anti collapse shed shall be placed under the operation pit or the operation pit shall be reinforced by piling and supporting. At both sides of the axial end of the welded junction, the pedestrian passage with a slope of less than 15 ° shall be excavated by machinery and labor along the axial direction. During the excavation of operation pit, in order to ensure the operation safety of the pipeline in service, the safety officer must be on site for supervision throughout the excavation process.