What do you think of the subgrade cross section?

The green part at the bottom of the map is the depth range of subgrade; The red line is the excavation line; The yellow circle in the side ditch is masonry or block; When calculating the excavation area, it is calculated in red, not yellow.

According to the design of the plane and longitudinal section of the route and the calculation of superelevation and widening, the transverse dimensions and design elevation of each part in the road width are obtained, so as to determine the filling and excavation of the subgrade cross section, and then the shape and size of the part outside the road width are determined according to the geological and hydrological conditions. It is precisely because of the differences in topography, geology, hydrology and filling and excavation that the cross section of subgrade presents various forms.

With the extension of expressway from flat area to mountainous area, the selection and design of subgrade cross-section forms, which are mostly arranged in steep slopes and vertical and horizontal valleys on one side of the mountain, have added new contents and connotations.

Extended data:

Using the advantage of dividing the subgrade into upper and lower parts, it has a unified and coordinated horizontal and vertical alignment and fixed interval, one part of which uses bridges, and the other part uses half filling and half digging, or filling or digging. This is a "combination" idea.

Half-bridge subgrade has the advantages of less land occupation, less mountain cutting, less engineering investment, relative independence, coordination and unification from top to bottom, and close lateral connection, and is widely used in expressway and highway reconstruction and expansion projects in mountainous areas, especially in sections with steep terrain and cross slopes. Survey and design should pay attention to the coordination of the two, the connection between the two ends and the treatment of interception.

The subgrade of light anchor retaining wall is a steep foundation section of mountain slope. In order to reduce the excavation surface or disturbance range of semi-filled and semi-excavated geotechnical engineering foundation, it is an "overhead" idea to expand the stress surface of structural foundation by using the principle of anchor rod to reduce the number of subgrade projects.

The subgrade of light retaining wall has the characteristics of small excavation surface, simple construction, low engineering investment, easy control of backfill quality behind the wall and engineering safety. It is especially suitable for semi-filling and semi-digging in steep slope sections with good bedrock integrity.

Baidu Encyclopedia-Subgrade Cross Section