Comparative Analysis of Basic and Extended Power Models of Boreholes Expansion Dependence on Explosive Charge in Blasting in Clay Soil
Round 1
Reviewer 1 Report
The results presented in the paper can be used in geotechnical practice.The main benefit is improved mathematical description of dependence of expansion of a borehole to explosive charge. For clearer conclusions, however, more experiments are needed.
Rows need to be corrected:
12 explsove - explosive
100 the researche - the research
145, 195 inroduction - introduction
216 geotehnical - geotechnical
Author Response
We would like to thank Reviewer 1 for kind revision and suggestions, which are all implemented in revised article.
Response to Reviewer 1 Comments
The results presented in the paper can be used in geotechnical practice.The main benefit is improved mathematical description of dependence of expansion of a borehole to explosive charge. For clearer conclusions, however, more experiments are needed.
Rows need to be corrected:
Point 1.: 12 (new line 12) explsove - explosive
Response 1: The change is done in the text
Point 2.: 100 (new line 157) the researche - the research
Response 2: The change is done in the text
Point 3.: 145, 195 (new line 213, 276) inroduction - Introduction
Response 3: The change is done in the text
Point 4.: 216 (new line 298) geotehnical - geotechnical
Response 4: The change is done in the text
Author Response File: 
Author Response.docx
Reviewer 2 Report
The paper describes the fitting of an exponential curve to the charge - volume expansion curve of two explosives used for expanding cavities in clay. This is a follow up of a previously published paper. The authors add an additional term that pins the initial volume of at zero charge. They apply the Akaike Information Criteria to find the best fit of three options. Adding the additional parameter improves the R2 by 0.004 to 0.012, which seems to be quite negligible. This is probably because the fit to the exponential model is already fairly good at 0.8.
The methodology seems adequate as it is essentially the fitting of two curves in Statistica. Since it is an exponential curve there should be discussion of the approach used in Statistica for non linear fitting
The paper is interesting if the key previous reference (Geosciences 0900383) has not been seen previously, but could be significantly improved by adding information about the hole set up, the geotechnical properties of the clay and the explosive formulations. In reality, it would be really impressive if one model could predict the effect of both explosives by including some relative energy term.
The authors should consider that there is significant work done on the expansion of the explosive energy from a charge in the literature e.g. Hustrlid's Vol2 and relevant ISEE literature.
Also the importance of the geotechnical properties should be included into the model if there is data on different clays.
Comments for author File: 
Comments.pdf
Author Response
We would like to thank Reviewer 2 on comments and suggestions, which are mostly implemented in revised article.
Response to Reviewer 2 Comments
The paper describes the fitting of an exponential curve to the charge - volume expansion curve of two explosives used for expanding cavities in clay. This is a follow up of a previously published paper. The authors add an additional term that pins the initial volume of at zero charge. They apply the Akaike Information Criteria to find the best fit of three options. Adding the additional parameter improves the R2 by 0.004 to 0.012, which seems to be quite negligible. This is probably because the fit to the exponential model is already fairly good at 0.8.
Point 1.: The methodology seems adequate as it is essentially the fitting of two curves in Statistica. Since it is an exponential curve there should be discussion of the approach used in Statistica for non linear fitting
Response 1: To be able to compare the models and values in the article Težak D. et al. 2019 and the models obtained in this article the same processing criterion, the Akaike's Information Criteria, was applied. A comparison of the values for AIC and AICc was also performed. The program package Statistica V 13.5 was used in the processing of the obtained data. The model of the extended power model passes through some point on the ordinate of the coordinate system. Values of model parameters are determined by least square method in package Statistica V 13.5. (see line 182 to 184). And since it is a polynomial function, we do not understand Your objection that it is an exponential function.
Point 2.: The paper is interesting if the key previous reference (Geosciences 0900383) has not been seen previously but could be significantly improved by adding information about the hole set up, the geotechnical properties of the clay and the explosive formulations. In reality, it would be really impressive if one model could predict the effect of both explosives by including some relative energy term.
Response 2: The research was carried out on the exploitation field Cukavec II, where exploitation of clay has been carried out for more than 50 years. The structure of the deposit is dominated by kaolinite, quartz, feldspar and chlorite, and the granulometric composition shows that the mineral raw material contains about 75% of the clay component, while the rest is silt. The geotechnical properties of the clay soil were determined as part of the research. Cohesion c, internal friction angle φ and volume weight γ were determined. Cohesion is c = 23.4 KN/m2, internal friction angle φ = 19.8˚ and volume weight
γ = 18.7 KN/m3. Since the clay is hydroalumosilicate, which means that it absorbs water and therefore becomes brittle, the exploitation of the clay can only be carried out in dry months and when the air temperature is above 0 ˚C [13]. Spherical cavity blasting is rare in hard rocks. Namely, the effect of smaller explosive charge for spherical cavities is in principle different than continuously filled borehole in mining and blasting operations. Detonation of smaller explosive charge crushes the material in proximity of activated explosive charge. With the increase of distance from the explosive charge, the released energy in not enough for crushing materials, but instead compacts it.
The energy of the explosives was taken from the manufacturer. It is not done comparison of energy explosives in relation to the referente explosives. TNT is most commonly used as the referente explosive. However, a model that could predict the effect of both explosives by including some relative energy term could be the subject of our further research.
Point 3.: The authors should consider that there is significant work done on the expansion of the explosive energy from a charge in the literature e.g. Hustrlid's Vol2 and relevant ISEE literature.
Response 3: Certain technical parameters of explosive such as velocity of detonation, brisance, the work capability, as well as the volume and specific explosion pressure, detonation pressure and density, all have a decisive impact on the results obtained when spherical cavity blasting is performed.
The data sheet for the explosives used in the research was taken from the manufacturers. Primarily, data on the density of the explosives, velocity of detonation, the heat of explosion and the volume of the gases.
In order to be able to make good conclusions, it would be necessary to carry out a series of additional researches regarding which of the above-mentioned technical parameters have a greater impact on the resulting volume and diameter of expansion, and which one on deepening gained by spherical cavity blasting. For this purpose, it is also necessary to consider the knowledge of the detonation process, where the detonation front seems to have the most significant role (Sućeska M., 2001; Dobrilović M., 2008).
What is undoubtedly proven is that detonation of equal mass of Permonex V19 having a higher density and detonation velocity produce a larger volume and diameter of expansion than detonation of Pakaex having a lower density and detonation velocity.
The dependences of the volume of the resulting spherical cavity on the mass of the explosive charge and the type of explosive used were determined according to the utilized data from the manufacturer on certain important technical parameters.
Point 4.: Also the importance of the geotechnical properties should be included into the model if there is data on different clays.
Response 4.: We got some preliminary results. However, since core drilling is expensive, it has been done only on 3 locations. Therefore, we did not want to include it in this article.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
They have addressed my points in a limited manner, but sufficient to make it publishable. The paper could be much better. It is up to the editor to decide if they want to accept the incremental nature of the paper.
