Zhong Da Consulting has compiled the knowledge of architectural knowledge column of this website. The following is the related content of subgrade width compiled by Zhong Da Consulting:
First of all, let's understand the basic situation of road subgrade width:
Subgrade width The width of highway subgrade is the sum of the width of pavement and its shoulders on both sides. In the process of road subgrade construction, what are the requirements for construction? The main contents are as follows:
1. Subgrade construction survey
The distance between two leveling points should be kept at about 500m m.
(1) Resume centerline measurement.
(2) Nail-line external pile. 0.5 ~ 1.0m outside the road sideline.
(3) elevation measurement
2, fill (square) subgrade
(1) Humus soil, domestic garbage soil, silt, frozen soil and saline soil shall not be used for subgrade filling. The filler shall not contain grass, tree roots and other sundries, and the clods with particle size exceeding 10cm shall be broken.
(2) Remove the accumulated water in the original area, and remove the roots, weeds and silt. Properly handle the grave pit and fill it in layers to the original base surface.
(3) The filling section shall be leveled in advance. When the ground slope is steeper than 1: 5, it should be made into steps with a width not less than 1.0m, and the top surface is inclined inward; In sandy areas, there is no need for steps, but the topsoil should be turned loose.
(4) Layered filling and compaction.
(5) When the filling length reaches about 50m, check the width and thickness of the paved soil layer. If it is qualified, it can be rolled. The rolling should be light before heavy, and the final rolling should not be less than 12t roller.
(6) The top surface of pipe culvert within the range of filling height can only be rolled by a roller when the backfill is more than 500mm. If it is insufficient, reinforce the pipeline.
(7) When the last layer of filled soil is reached, the earthwork thickness shall be controlled according to the designed section and elevation, and it shall be rolled and trimmed in time.
3, dig (square) subgrade
(1) According to the survey centerline and side pile excavation, each side is 300 ~ 500 mm wider than the road surface.
(2) The excavation section shall not be overbreak. Roots and other sundries within 600mm below the design elevation of subgrade must be removed, and backfilled and compacted with good soil and other materials.
(3) The roller shall be no less than 12t, and it shall be rolled from both sides of the road to the center of the road until there are no obvious wheel tracks on the surface.
(4) When rolling, according to the degree of dryness and wetness of the soil, measures such as sprinkling water, changing soil and airing are decided.
⑤ The rainwater branch pipe crossing the street shall be constructed before subgrade rolling. Around the branch pipe trench and inspection well, lime soil or lime fly ash gravel shall be used to fill it.
4) Quality inspection
Quality acceptance items (main control items: compactness and deflection value; General items: profile elevation, centerline deviation, width, flatness, cross slope, side slope, etc. ).
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