Method for measuring relative density of naturally-graded coarse particle dam construction material

Abstract

The invention provides a method suitable for measuring the extreme dry density of naturally-graded coarse particles on an earth and rockfill dam construction field. The method for measuring the extreme dry density of a naturally-graded coarse particle dam construction material comprises the following steps of: measuring the extreme dry density of the naturally-graded coarse particle dam construction material on the basis of the vibrating compaction energy delivering mechanism of a heavy-duty vibrating roller and paving and rolling testing on the dam construction field; and calculating relative density according to a designed dry density. On the basis of the input energy mechanism of a field vibration rolled real dam body, the extreme dry density of the naturally-graded coarse particle damconstruction material is calculated under a given construction rolling condition, so that the compaction characteristic of the naturally-graded coarse particle dam construction material is controlledby using a relative density index. A practicable method for controlling the field compaction quality of an earth and rockfill dam is provided.

Description

technical field [0001] The invention belongs to the technical field of earth-rock dam construction in the water conservancy and hydropower industry, and relates to the evaluation of earth-rock dam filling index and filling quality, in particular to the measurement of the maximum dry density of the original gradation coarse-grained dam body using the heavy vibrating roller compaction technology method. Background technique [0002] With the emergence of heavy-duty vibratory roller compaction technology in the 1950s, the gradation range of coarse-grained materials for dam construction is wider (maximum control particle size d max ≤1.2m), which makes the compacted rockfill or gravel material have higher strength and deformation modulus, leading to the rapid development of modern roller compacted high earth-rockfill dams. [0003] For the compaction of non-cohesive and free-draining sandy soil, Mr. Terzaghi, the father of soil mechanics, proposed as early as 1943 that relative ...

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Problems solved by technology

[0004] Although the use of relative density to control the quality of dam filling has been adopted by relevant codes for earth-rock dams in my country, there are problems with the use of relative density indicators due to the existence of super-sized particles of coarse-grained materials for dam construction.

As we all know, the earth-rock dams filled with modern heavy-duty vibration rolling technology, such as Bikou, Xiaolangdi, Tianshengqiao, Shuibuya and other projects, have a maximum particle size of 1.0m of coarse-grained materials. The test procedure (DL / T 5356-2006) stipulates that the maximum particle size of the indoor dry density extreme value test is generally 60mm, and the original graded coarse aggregate must be scaled down. The scaling effect of the dry density and the indoor test method and field The difference between the actual rolling techniques makes the maximum dry density (index density) measured in the laboratory test low. R.J.Stepenson conducted laboratory experiments on the Carters Dam and Editors Ronald on the Cougar Dam, and found that the maximum dry density is lower than that of field compaction. Filling density, the calculated relative density value is greater than 1, this phenomenon has also been verified in domestic Tianshengqiao, Nalan and other projects, making the filling quality of earth-rock dam coarse-grained materials unable to be controlled by relative density

For this reason, Shi Yanwen et al., based on the indoor relative density test results of coarse aggregates with different particle sizes in the small particle size group, used different methods such as the Humphrety formula method and the model gradation series extension method to extrapolate the maximum dry density of the original gradation. Since the substantive problems such as the dry density scaling effect brought about by the grading scaling of coarse aggregates are not solved, it is difficult to popularize the actual engineering application

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