But the compactness of backfill soil is divided into three parts: 0-80 cm below the top surface of subgrade, 80- 150, >150; The conflict between design and specification is based on design; If no design is specified, please follow the specification.
Check the specifications by layers (generally 20cm for manual compaction and 30cm for mechanical compaction).
Compaction standard
Compaction construction must first determine the degree of compaction and correctly select the degree of compaction, which is related to the stress state of soil foundation, the design requirements and construction conditions of subgrade and pavement, and must give consideration to both needs and possibilities, and emphasize economy and effectiveness.
The soil layer within the road bed bears the repeated action of strong traffic load, and the lower layer of subgrade mainly bears its own weight. Therefore, the compaction degree of the road bed range is required to be higher. ?
Embankment, cutting and embankment base should be compacted. Compactness of earth embankment (including earth-rock embankment) shall not be lower than the standards listed in Table l-6. Compaction standard of earth embankment (JTJ 033-95)
The replacement of 80cm in low-fill shallow excavation section should be subgrade. The evaluation index of compaction degree of rock-filled embankment is generally based on settlement difference directly, and is generally not converted into compaction degree. This is because the indoor compaction test of stone can not be carried out, because the particles are too large, the test tube has lateral restrictions, and the measured maximum dry density has great variability, which can not guide the compaction construction.