Underwear, gravitational sewage requires a certain bias of the conditioned longitudinal profile, therefore, the possibility of its laying limits specific local conditions. Consider several applied solutions of passing collectors. This collector with an internal section of 1.3×1.5 m is built in an open trench. First, the concrete base is laid in two layers. The lower layer is planning, waterproofing is applied on the second layer of reinforced concrete pillow. On it is a design of prefabricated elements. The insulation is glued to the outer surface of the side wall and is laid by a protective brick wall.
On the one hand, heat center, water supply, electric cables, communication cables are held, on the other – only communication cables and electric cables. According to the project developed in England, the collector of the original design is made partially from the prefabricated elements, partly by concreting on the spot. Several significant conclusions can be removed from the experience of building structures in the past. This experience convinces that the traditional methods of building underground structures in open trenches are advisable only to a depth of 3-6 m. The specific boundary of rational and rather economical decisions in depth depends on the level of groundwater and the mechanical properties of soils. From the point of view of the depth of the laying, geometric conditionality exists only in sewer drains of the gravitational type. In recent years, development has been in the direction of using mainly pressure pipelines of sewage system: therefore, this obstacle should disappear in the future. When using a closed technology for the production of construction work, for example, methods for building tunnels using passage shields or pushing methods, total expenses are reduced by about 30-40 %, and the geometric requirements of gravitational sewage can be satisfied without much difficulty.