Study And Application Of Cast In-situ Method For Pipeline And Manhole Trenchless Rehabilitation

Cast In-situ Trenchless Rehabilitation Technology(CITR)is wide application compared with normal trenchless rehabilitation methods,which can be used for any kind of sewer pipelines,manholes,culverts,tunnels and other underground structures rehabilitation.The relative high performance mortar materials,technology processes as well as the design theories of the CITR technology were systematically studied in this thesis;which enriched the existing trenchless rehabilitation technology system.1.In this thesis,brief descriptions on the status of underground infrastructure and researches on trenchless rehabilitation were given and the concept of Cast In-situ Trenchless Rehabilitation Technology(CITR)was brought forward for the first time in China,and also gave a detailed description of the CITR technique principles.2.Laboratory researches were conducted on the high performance mortar material,and some valuable results were obtained from the research.Bonding strength will get higher when the increasing the roughness between the HPM liner and the existing structure surface,which is beneficial to for the rehabilitation.The flexural strength will increase when add tensile strength material in the HPM specimen,but the increase value of curved specimen is far smaller than the straight;it was also found that,the broken features of the strengthened specimens were very similar with the tensile failure of the tensile material itself,the influence of flexural strength by putting sever layers tensile material sheets separately in one specimen is just same as put only one layer.3.Theory and practice researches were conducted on the CITR method for circular pipelines rehabilitation(also named “Pipe Shield”).Detailed description on the technical characteristics and application conditions were given.Considering the different conditions of the old pipeline,basic principles and theories for high performance mortar liner design are concluded.And also,a DN2,000 collapsed sewer pipeline rehabilitation case studies was presented,it was concluded that CITR is an excellent solution for pipeline rehabilitation.4.CITR method for rectangle pipeline rehabilitation was studied systematically,pipeline structural form and loading status were also analyzed;basic principles for rectangle pipeline rehabilitation were concluded.In the thesis,the theoretical model of rectangle liner is treated as “closed rigid frame” during design;and a detailed technical processes and calculation procedure was draw by a rectangle pipeline rehabilitation case study.5.Made detailed description for the common manhole rehabilitation techniques,and some studies on the failure of manholes were carried out.Centrifugal cast in-situ rehabilitation technology for manhole was presented,theories model for manhole liner design and calculation was established;till now,near 500 manholes were rehabilitated use this technology.