The Dynamic Response of the Vibrating Compactor Roller, Depending on the Viscoelastic Properties of the Soil

Round 1

Reviewer 1 Report

This paper conducted the rheological modelling of vibrating equipment for soil compaction. I would suggest the following suggestions:

1. Abstract need to be rewritten to report about the main and new findings obtained in this paper briefly.
2. The conclusion is too long and should be shortened moderately. The discussion section can be moved elsewhere.
3. The results of the study should be compared with other studies.

Author Response

Answer to the reviewers requirements, expressed in the reports 1 and 2 of 5^th of June 2020 and 9^th of June 2020, respectively.

Modifications, additions and some clarifications were introduced in the text.

Also, in the bibliography new titles are added that were taken into account for the paper

The numerical data contained in the figures of the response curves were discussed and presented as of practical importance. Some of these were experimentally verified at frequency of 30 Hz and there were included in the text.

Clarifications regarding the current state of the art regarding the European requirements were made. 

Currently, the Romanian National Road Company continues the researches in this domain, the author, together with a research team, is responsible for the solving of the new aspects of the "in situ" optimization process.

Reviewer 2 Report

Overall, the paper submitted is of real interest to the academic community and is well-written and presents an interesting case study.

But, I would like to recommend the following observations:

1. in the literature review it is suggested to include a summary of other studies, compiling the applied methodology and the main conclusions. The literature review should be improved, as should the concepts and conceptual scheme that supports the research that is not even referred to.
2. the methods should be more detailed from a statistical point of view and suggested a greater support in the applied methodology;
3. it is suggested that in the discussion of the results a comparison be made with other studies presented in the state of the art, carrying out a comparative discussion with the literature review;
4. Please exactly explain how the results of this paper can be capitalised for practical engineering purposes (line no 260 from article). Please describe the methods with sufficient details to allow another researcher to reproduce the results.
5. In the methods sections, more detail is needed about your data analysis, both qualitative and quantitative.
6. English also needs some improvements.

Author Response

Answer to the reviewers requirements, expressed in the reports 1 and 2 of 5^th of June 2020 and 9^th of June 2020, respectively.

Modifications, additions and some clarifications were introduced in the text.

Also, in the bibliography new titles are added that were taken into account for the paper

The numerical data contained in the figures of the response curves were discussed and presented as of practical importance. Some of these were experimentally verified at frequency of 30 Hz and there were included in the text.

Clarifications regarding the current state of the art regarding the European requirements were made. 

Currently, the Romanian National Road Company continues the researches in this domain, the author, together with a research team, is responsible for the solving of the new aspects of the "in situ" optimization process.

Round 2

Reviewer 2 Report

No further comments.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The paper reports about a study on the dynamic response to the compaction process of natural and filling soils. This process is performed by a typical equipment that is a vibrating compactor roller made by a rotating eccentric mass and having variable angular velocity; it is commonly used in order to reach the required degree of compaction for the soils apt for construction and characterized by Voigt-Kelvin linear rheological models.

During the compaction process, the soil layers with certain compositions of clay, sand, water and stabilizing substances change their rigidity and / or amortization. The study analyses on the basis of experimental tests and numerical models, and aim to propose special results and practical engineering conclusions with regard to the interaction between vibrator roller and compacted ground.

The research started by considering that up to 90% of experimental studies on at least 25 categories of land of the cases showed dynamic response of the vibrating compactor roller that matches the Voigt-Kelvin linear viscoelastic. In situ and laboratory experiments were conducted on natural soils with admixtures of lime, cement, black pigment, natural or chemical liquid stabilizers. From the synthesis of the parameter values of stiffness and damping obtained by these studies, significant and representative dynamic responses were obtained as families of the response curves of the amplitude and generated force, in relation to the variation of the excitation frequency and stiffness and damping after each passage over the same layer of soil. These parameters were plotted both by numerical simulation and experimentally in situ; mathematical representation and characteristic curves of these responses were proposed too.

The topic of the paper is quite interesting because the compaction process is a common procedure in civil engineering works that need to be optimized as possible. However, in my opinion, the research approach and the objectives of the study are not clear enough.

In particular, the paper does not consider and adequately discuss the previous studies and experiences in the same field. The articles proposed in the references are not properly cited and specified in the text; they do not actually seem to lead the design and the development of the research. In addition, most of them come from a few authors and face almost always the same topics.

The main problem of the research is the lack of relationship with the practical procedures and operational conditions of the soil compaction in the construction process. The special results and practical engineering conclusions, that are promised in the abstract, are not actually present in the conclusions. These last, in fact, essentially consist in a synthesis of the mathematical parameters that characterize the rheological models but are not actually suitable to be directly transferred to the operating compaction processes in constructions works.