Reasons for mixed connection of rainwater and sewage

2.1 Reasons for mixed connection of rainwater and sewage pipe networks

(1) Reasons for lack of understanding: the ground is more important than the underground, the construction is first followed by the supporting drainage system, and the supervision is not in place;

(2) Reasons for design standards: Before the 1980s, rainwater and sewage were designed in a confluence system;

(3) The reason for the increase in drainage: the increase in the surrounding buildings of the drainage pipe network caused the increase in drainage flow;

(4) Reasons for terrain change: Buildings along the street are demolished and rebuilt, and deep foundation construction has an impact on the pipe network;

(5) Reasons for road widening: the drainage pipe network originally designed on the sidewalk is in the center of the new road, and the load of the original pipe network increases;

(6) Reasons for large-scale underground projects: the impact of urban underground sidewalks, subways, and underground civil air defense facilities;

(7) Material reasons during project construction: the materials used for drainage pipes are limited by production technology;

(8) Causes of damage to the drainage pipe network: the intrusion of tree roots in the drainage pipe network, and structural damage to the rainwater and sewage pipe networks at the same time;

(9) Reasons for engineering construction management: drainage pipeline construction without design, supervision, acceptance, etc.;

(10) Reasons of the construction unit: The construction unit cannot strictly follow the design requirements for construction, the pipeline foundation is not constructed according to the requirements, there is no protective sand layer around the chemical pipeline, and the backfilling of the pipeline is not dense, resulting in disconnection, settlement, pipeline siltation, collapse, collapse,