New Method to Estimate Rock Mass Deformation Modulus Based on BQ System

Round 1

Reviewer 1 Report

Dear Editors and Authors,

The paper develops a relationship between the BQ rock classification system and the deformation modulus. A series of correlations are established based on the existing estimation formula and the relationship between BQ and other classifications. The authors recommend several formulas for estimating the deformation modulus of a rock mass using the BQ method. The paper can be accepted for publication after careful review, and the authors respond to the comments below:

1. The citation of the bibliographic references will be checked in the manuscript according to the template: the bibliographic reference is cited only by means of its number and not the authors (see, for example, lines 51–54; 102–103, etc.).

2. How was the BQ value calculated quantitatively at each test point? By measuring the seismic wave velocity?

3. What is the influence of strength anisotropy? Has this been taken into account?

4. Formula 16 does not appear in the paper. On line 277, instead of formula 16, formula 15 should be corrected.

5. The last part of the conclusions must be reformulated (lines 308-314) because it presents in a slightly modified form the last part of the Introduction section (lines 57-63).

Yours faithfully,

Moderate editing of English language required

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

In this comprehensive study, the authors investigate the estimation of rock mass deformation modulus using the Bieniawski Q-system (BQ) and in-situ measurements from three large hydropower stations in China. The study aims to establish a reliable formula for predicting the deformation modulus and assess the applicability of the BQ system in rock engineering projects. The article is well-structured, beginning with an introduction that outlines the importance of predicting rock mass deformation modulus in engineering applications. The methodology section provides clear details on the in-situ measurements conducted and the analysis performed to establish the relationship between BQ values and deformation modulus. The results section presents the findings succinctly, highlighting the establishment of a predictive formula (formula 3) that demonstrates a strong fit with values suggested by the Chinese engineering standard GB50487-2008. Additionally, the study explores indirect estimation methods based on the relationship between BQ and other classification schemes, providing further insights into predicting deformation modulus in general rock engineering projects. The discussion section effectively contextualizes the results within the broader field of rock mechanics and offers interpretations of the findings in relation to existing literature. The conclusion summarizes the key findings of the study, emphasizing the suitability of formula 3 for predicting deformation modulus in rock projects with significant loads and recommending specific formulas for general rock engineering applications. Overall, this article presents a rigorous investigation into the estimation of rock mass deformation modulus, utilizing a combination of field measurements and established classification systems. The methodology is robust, the results are clearly presented, and the conclusions are well-supported by the data. Therefore, I recommend this article for publication in its current form, as it makes a valuable contribution to the field of rock mechanics and engineering geology.

Author Response

Thank you for your positive evaluation of our study.

Reviewer 3 Report

The article contains an interesting research results determining the deformation modulus of rock mass for various hydropower stations in order to estimate the BQ value. The presented results with reference to other rock mass classifications are scientifically interesting and, moreover, have a practical aspect. A big advantage of the presented research results is their readability and the possibility of repeating the calculations. Below are some comments and suggestions:

1. In the introduction, please add two/three sentences relating to the rock mass classification for underground and open pit mining: in other words, please indicate which rock mass classifications are more preferred depending on the mining method;

2. In the second chapter, for table 2, please add a short description to the classification, especially what the limit values mean: Rock mass rating I and V due to maintaining the stability of the excavation;

3. In Chapter 3, it should be written whether the tests of deformation modulus of rock masses were carried out according to any standard/procedure. In addition, please add information whether the hydropower station are located in areas at risk of rock mass tremors;

4. Figure 2 - the description of the vertical axis should be corrected;

5. For Figure 3, please add fitting curves for all three hydropower stations: Maerdang, Laxiwa and Zhen'an;

6. In chapter five, please add a few sentences regarding the numerical modeling used to verify the deformation modulus - this will constitute a form of extension of the discussion of the results;

7. In the conclusions, please add one sentence referring to the future use of the BQ system for structures/excavations other than hydropower stations.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf