The supporting works of the project pipe network, the rainwater and sewage pipe networks are widely distributed, the pipeline quantity is large, and the main construction needs to be carried out alternately, so the coordination workload is large; Some pipelines are close to the structure foundation and cross the existing road, so strong safety protection measures must be taken, so the main line shall be excavated first, and then the branch ditch. At the intersection of rainwater and sewage pipes, sewage pipes shall be excavated first. Due to rain and sewage pipes