Modification of a Constitutive Model for Gassy Clay
Round 1
Reviewer 1 Report
The researchers presented an update of Hong's model for gassy soils, showing significant differences in the prediction of gassy soil behaviour. Due to the structural characteristics of gassy soils, their mechanical properties differ significantly from those of saturated and unsaturated soils. The assumptions of the improved model were based on more undrainded triaxial testsin with a greater range of effective confining pressure .The results of the presented research can support the design of structures located in the seabed, especially as there is currently an intensification of activities in this field related to the construction of offshore wind power plants.
I have basically one question and one suggestion.
With an increased proportion of gas in the sample volume, the modelling result underestimates the actual strength of the soil, while with a lower proportion of gas the strength is overestimated. What could be the reasons for this? This was briefly summarised in one sentence without any possible reasons, whereas this result seems surprising.
A more detailed literature review could benefit the paper. Recent article Tao Liu, Xiaotong Yang, Yan Zhang - A Review of Gassy Sediments: Mechanical Property, Disaster Simulation and In-Situ Test. https://doi.org/10.3389/feart.2022.915735 is closely related to this area.
Author Response
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Author Response File: 
Author Response.doc
Reviewer 2 Report
General comment
A submitted paper is written well and the trials to improve the model developed previously by another researcher would be interesting/valuable. It is however that the improved model constructed in the present study does not seem to be perfect one and there would be necessary for further improvements to revise the model for better agreement with the experimental data. A reviewer recommends clarifying the subjects for future improvement for update the model based on the results conducted in the present study in Section 5. It is therefore that the paper should be revised as the moderate revision before acceptance. Specific comments identified are also noted in the followings.
Specific comments
- Title of Table 1: Replaced as “Test conditions for the triaxial compression”.
- Caption for Figure 1: Solid lines are calculated by equation 4 and dotted lines are predicted by Hong et al. Caption should be revised as “Solid lines: equation 4” and “Dotted lines: Hong et al.” since the current caption is just only corresponded to one condition (i.e., orange data). Missing some dotted lines on the figure. If hidden (duplicated), add the remarks for the title of Figure.
- Caption for Figures 2 to 5: As like the above, caption should be corrected as “Solid lines: modified model”.
Author Response
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Author Response File: Author Response.doc
Reviewer 3 Report
This manuscript discusses the behavior of gassy clay in shallow marine sediments. The authors modified an elastoplastic model of gassy clay to better present the undrained shear behavior under relatively high effective confining pressures. The authors conducted several triaxial tests on gassy kaolin and improved the model by updating the expressions of the stress-dilatancy function and yield surface. Although the manuscript has some positive aspects, significant improvements are necessary to meet the acceptance criteria of the Journal of Marine Science and Engineering. The manuscript can be accepted after major revision.
1. The abstract requires revision. The abstract should highlight key content areas, your research purpose, the relevance or importance of your work, and the main outcomes.
2. The introduction should be extended by adding more relevant studies, highlighting the research problem, research gap, and novelty, and clarify the significance of the presented study, which is currently not evident.
3. The references cited in the study are predominantly outdated, and a significant portion of them date back to the 1900s. The authors need to add the recent five years studies to highlight the recent development in the area.
4. To clearly indicate the tests that are being carried out, it is suggested to present your study in a flow chart format that includes the testing process as well.
5. The authors haven’t mentioned the test protocols, it is necessary to highlight the test standard that has been followed in this study.
6. The soil gradation has not been indicated, and it is essential to present the liquid limit, plastic limit, shear strength, optimum moisture content, and soil stress and strain curve.
7. The absence of visual documentation of the collection of gassy soil specimens from the seabed, preparation of gassy soil samples, and the equipment used for triaxial testing is a significant omission. It is essential to provide a pictorial representation of the step-by-step process from sample preparation to sample testing.
8. The testing and results have not been presented in a clear manner, and it is necessary to organize the results in a tabular format.
9. Validate your model through statistical modeling with various statistical indices, such as R2, p-value, F-value, and RMSE etc.
10. There is no discussion on the results/model. There is a need to add a section (Results and Discussion) to discuss the implementation of the current study/results.
11. Conclusion section must be expanded to include the main findings and advantages of the methodology. Also, some detail must be given for novel, practical applications of the title problem.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Round 2
Reviewer 3 Report
The authors significantly improved the quality of the manuscript. Hence, I recommend the acceptance of the manuscript. However, the manuscript should be checked by a native speaker to ensure a cohesive presentation of the content.
