Subgrade Strength Recovery of Fine-Grained-Soil-Containing Roads in Western Oregon Forest

Round 1

Reviewer 1 Report

Comments

The paper refers to a very specific area of forest road pavements and their Subgrade Strength Recovery on Fine-grained Soils at West Oregon. It will be a beacon for forest engineers, after many years of absence on journal papers such kind of research, on how they can test road pavements in order to maintenance them by recovery the subgrade strength.

It would be interesting if there was a reference to the mother soil on which the road pavements has applied. Another hind is to combine the vehicle axels and the recovery of subgrade strength of the fine-grained soils.

It would be recommended; if it would be taken under consideration some of the following references:

Heinimann H. (2017). Pavement Engineering for Forest Roads: Development and Opportunities. Copyright © 2017 by Croatian Journal of Forest Engineering, doi: 10.5552/crojfe.2021.860, volume: 42, issue: 1, pp: 17

Kelesakis, D., Marthoglou, K., Grammalidis, N., Daras, P., Tsiros, E., Karteris, A., & Stergiadou, A. (2023, September). A holistic framework for forestry and rural road detection based on satellite imagery and deep semantic segmentation. In Ninth International Conference on Remote Sensing and Geoinformation of the Environment (RSCy2023) (Vol. 12786, pp. 126-134). SPIE.

Stergiadou, A., Boutsoukis, G., Tsiloglou, N., & Kolkos, G. (2020). Forest Fire Prevention and Suppression Using Optimum Routes and Speeds of Firefighting Vehicles: Case Study the Peri-Urban Forest of Thessaloniki, Greece.

Author Response

The Heinimann paper has been added to the literature.  The others suggested are not relevant to this work.

The results are described for the data that we have.  They have been extrapolated to similar soils, construction and climate types.  We believe that no universal statement can be made on most forest engineering applications due to the local variations found in the environment

Reviewer 2 Report

Dear authors,

Interesting idea of the article, but unfortunately conducted only on one road segment and therefore with limiting conclusions. I propose a bigger sample (field study was done in 2007?) thus enhancing the overall study, conclusions etc.

Author Response

There was limited funds for this research; therefore, we selected a typical sample of soil and construction practices in the area.  We believe the results are interesting to hopefully support further research in this area.

Reviewer 3 Report

Dear authors,
I hope this message finds you well. I recently had the opportunity to review your article titled "Subgrade Strength Recovery on Fine-grained Soils Contained Roads in Western Oregon Forest". Your exploration of subgrade strength recovery in the context of roads within the Western Oregon forest area is intriguing, but I have a number of concerns about the manuscript.
- I noticed that the manuscript includes information about the costs related to rock placement in 2019 (line 38-39). I was wondering where this information was sourced from or what the exact basis for it is. Has it been derived from previous studies, government reports, or other sources?
- The "Literature Review" section is lengthy. Please begin with the introduction and summarize this section more concisely.
- In lines 131-171, the article discusses two methods for water drainage in newly constructed roads in the absence of vegetation.
- What was the reason for choosing sampling from late spring after winter rains to autumn before the return of wet weather?
- Was the CBR done in saturation? Why was the winter season, when the soil is in the worst condition in the forest and the soil is completely saturated, not chosen?
- Please write the ASTM standard number of CBR test (ASTM D-1883-99).
- The conclusion is written very briefly. Explain the limitations of the research, the applications of the research.
- The sources are old and related to before 2016! Use new sources (from 2020 to 2024).

Author Response

Much of the work in this area was performed by the USDA Forest Service, but they abandoned their work in the mid 1990s.  There is limited work since then. 

The measurement began after the end of winter and spring rains ended when the road was near saturation and measure until the fall rains returned the road near saturation.  It is a Mediterranean climate with wet Fall through spring and dry summers.   The field CBR were measured in place throughout the spring and summer to measure the actual conditions of the road.  Two CBR were measured in the laboratory, one was at saturation according to the standard.  The second was measured after the sample was exposed to drying.

The conclusion has been expanded.

The ASTM standard for CBR has been added.

Reviewer 4 Report

I read the article carefully. As a case study, everything is correct and the results are not unexpected. Still, in conclusion, it should be emphasized that the results obtained and the limited changes in resistance, and moisture resulting from temperature changes and drought are related to the conditions and characteristics of the soil studied and cannot be generalized. The final and definitive result of this study regarding the changes in road resistance in dry and rainy seasons should be determined for different soils, different qualities of road construction (compaction), and also the location of the road in different geographical directions so that a decision and planning regarding type and intensity of road use can be made.       

Author Response

The conclusion has been expanded.   I agree the results are not unexpected for those with a background in soil mechanics.  However, there is a lot of “folk knowledge” in the forestry surrounding forest roads that “heal” themselves over time and a 1 psi overburden from rock will result in increased strength due to consolidation.  Part of the motivation was to bring data to these problems to allow for better decision making.