Simplified Relation Model of Soil Saturation Permeability Coefficient and Air-Entry Value and Its Application

Round 1

Reviewer 1 Report

The Authors carried out study on the SWCC fractal model with the existing permeability model, and further established the model of constant of proportionality for permeability coefficient.  The works are theoretical and they are based on certain type of soils. The topic will benefit researchers in general. However, there are several things need revisions and clarifications. Current version of manuscript can not be accepted for publication.

1. Please provide a typical range of kc for different soil
2. The determination of saturated permeability indirectly is affected by particle size distribution. Please review past studies on the effect of pore size distribution and particle size distriution on the estimation of saturated permeability, such as:
   https://doi.org/10.1016/j.enggeo.2018.09.031
3. Provide unit for AEV and ks in Table 1
4. Provide unit for ks in Figure 1a
5. Please check the sentence in Figure 139. It should be removed from the manuscript
6. Figures 2a, 2b and 2d show that the saturated permeability do not have good correlation with air-entry value. Please provide explanation. Is it because of mineral content of the soil, structure of the soil, etc?
7. Please briefly explain why higher density is associated with higher air-entry value (Line 175-177)
8. Show the value of inflection point in Figure 3.
   Please provide definition and explanation of inflection point in the manuscript
9. What is the meaning standard soil-water characteristic curve in Line 182?
10. Tables 3 to 7 show different soil type, but the range of air-entry value is so small, between 0.3 kPa and 15 Kpa. The air-entry value for clay is normally higher than 50 kPa. Please provide index properties including particle size distribution and atterberg limit from each soil in Tables 3 to 7. Please explain why clay has low air-entry value, less than 20 kPa.
11. Figure 4 shows the comparisons between predicted and measured values. Provide the criteria that is used to assess the performance of the equation to generate the predicted value. The examples of criteria that the Authors can use are R square, Average relative error, root mean square error, etc
12. The proposed equation from the study does not explain the prediction of air-entry value for gap-graded soil. Gap-graded soils can be associated with bimodal or unimodal SWCC. Please revise the paper on gap-graded soil which is related to unimodal SWCC. The Authors need to provide limitation of study which only applicable for soil with unimodal particle-size distribution. Please review the following paper for Authors reference.
    https://doi.org/10.1016/j.sandf.2017.08.009

Author Response

See cover letter.

Author Response File: Author Response.docx

Reviewer 2 Report

Summary

 

This study that air-entry value impose to predict permeability on SWCC, and it is so fine. In fact, many SWCC models have been established using various parameters. Suggested model is simplified and comprehensive formula and it effectively to correspond to solve many practice problems. It is evaluated highly to consider air-entry value, which is one strong parameters on soil physical properties. Physical parameter air entry value is required from experimental works results that high technical measurement technique is provided on suction controlling technique. The air entry value is of water retention activity, and consist of stress variables. The subjection is significant matter to study sol of ground surface.

 

 

Section 1 Introduction  Line 37

You describe some portions on SWCC such as boundary effect zone, transition zone and residual zone in conventionally. The concept is derived from Prof. Vanapalli, who is one of pioneers, please would you like introduce results obtained from him.

 

Section 1 Introduction

The term “air entry value” is center of this study to develop current model. Thus, air entry value is so significant parameter that it is suggest to you defining the air entry value on scientific theory.

 

Line 90

The absolute viscosity of water is considered , and if you have moderate in possible, please verify the influence of temperature on the viscosity of water.

 

Line 123

VG is common in widely to use solving the hydraulic conductivity, and it is simplified formation such as similar to character S. If you have represent both merit and demerit to VG models. Reviewer remain to use from many engineers that it is considerable simple.

 

Line 111

Why did you choice that saturated permeability coefficient is comprehensive proportional constant ? It concern that comprehensive value often take missing to correct behavior ?

 

Line121

Please would you like to explain reason, common without air-entry value to predict the hydraulics conductivity on conventional data base soft ware.

 

Line 152

Revise double space between sand and and.

 

Figure 2

All of figure 2 are so small to display and taking understanding the results

 

Section  4 Discussion

It is wonder to provide the advantage to TK models, and should indicate the degree of contribution on using TK model for many geotechnical engineers and to solve further problems.

 

It is seem to be clear that saturated permeability is further key parameter, and the effort of air -entry value is less than saturated permeability coefficient. To focus on air entry value is interesting as journal paper as well as saturated permeability. Reviewer expect that author demonstrate the effort of THE AIR ENTRY VALUE.

 

 

Author Response

See cover letter.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The Authors have addressed the comments from Reviewer and they have revised the manuscript significantly. The current version of manuscript can be accepted as is