| 摘要 |
A method of lining an underground duct includes towing an assembly of duct enlarging apparatus (10) and lining pipe sections (14) through the duct (12) by passing a chain (18) through the whole assembly and attaching it to a plate (42) placed over the rearmost pipe section (14A). In this way, tensile overloading of the joints between the pipe sections (14) due to frictional contact of the sections against the wall of the duct (12) is avoided. As the assembly is moved through the duct (12), new pipe sections (14) are periodically attached at the rear by releasing the tension on the chain (18), removing the plate (42), threading the chain (18) through the new section (14), and replacing the plate (42). To reduce snaking of the lining pipe when under compression, a clamp is included inside the leading apparatus to clamp the chain (18) and limit the compression of the pipe sections (14). |
