(2) According to the test results, appropriate excavated materials are used for subgrade filling. Various materials should not be mixed. Inappropriate materials should be treated in accordance with the provisions of soil treatment.
(3) Earthwork excavation shall be carried out from top to bottom, regardless of the excavation amount and depth, and it is not allowed to dig indiscriminately. It is forbidden to dig a hole to borrow soil.
(4) In the process of cutting excavation, in case of soil change, if it is necessary to modify the construction scheme and slope gradient, it shall be submitted for approval in time.
(5) There are organic soil, soil which is not easy to dry and compact, soil whose CBR value is less than the minimum strength and maximum particle size table of subgrade filler, or soil which is not suitable for subgrade.
(6) The settlement caused by compaction should be considered in the construction elevation of excavation subgrade, and its value should be determined through experiments.
(7) Earthwork cutting excavation, according to the depth and longitudinal length of cutting, can be carried out according to the following transverse excavation methods, using loaders and dump trucks, and the slope should be equipped with graders or manually leveled in layers.
(8) When underground water is encountered in cutting construction, it shall be handled according to the following provisions:
In case of underground aquifer in the excavation section, it should be implemented according to the actual situation of the site, the principle of drainage and seepage prevention facilities and the relevant provisions of groundwater removal.
When the top of cutting road bed is located in the soil layer with high water content, it should be replaced with materials with good water permeability, and the replacement depth should meet the design requirements, and the bottom surface of the trench should be leveled, and seepage ditch should be set to lead groundwater out of the road surface, and then backfill and tamp it in layers.
(9) Disposal of spoil shall meet the following requirements:
The slope of the spoil pile should not be greater than 1: 1.0, and the top surface should have a cross slope of not less than 2% and its height should not be greater than 3m.
The distance between the inner slope toe of dry and hard soil and the top of abandoned soil pile beside the cutting should not be less than 3m; For soft wet soil, it should not be less than the cutting depth plus 5m.
(10) The road bed is smooth.
1, when the embankment filling is close to the design elevation of the road bed, the thickness of the filled soil should be gradually controlled so that the compaction thickness of the last layer on the top surface is not less than10cm; ; When the cutting excavation is close to the design elevation, it will be leveled manually with a grader. It is forbidden to overbreak, and check its overall strength and compactness. If it does not meet the design requirements, it shall be filled in.
2. Leveling subgrade manually with grader, rolling with vibratory roller, and repeating until all test data meet the requirements of technical specifications.
3. Assign special personnel to conduct traffic control on the leveled subgrade until the project is completed. In order to avoid the damage to the subgrade surface caused by vehicle driving in rainy season.
When the temperature is lower than 10℃ during construction, the mixture shall not be paved.