Mechanical Properties and Microstructure of Shotcrete under High Temperature
Round 1
Reviewer 1 Report
The research in this paper intends to give guidelines to the assessment performance of shotcrete in extreme environments, with particular reference to high temperature conditions, which may result in shortening the service life of shotcrete structures.
This paper identifies the causes which contribute the formation of high temperature environment by a heat conduction model regarding heat as a non-steady-state fluid.
Discussing the effects of high temperature on mechanical and micromechanical properties of shotcrete, the Authors concluded that the mechanical properties, namely compressive strength, tensile strength, bond strength, shear strength are affected by the critical temperature: below the critical temperature, such properties showed an increasing trend with increasing temperature; above the critical temperature, a brittle response takes place, apparently induced by the phenomenon of shrinkage.
Performance optimization of shotcrete under high temperature and cooling technology aspects are explored in order to mitigate the effects of current high temperature construction environment.
The paper is quite interesting and well-written and it is worth of minor revisions.
To make the paper more complete the Authors may insert some considerations on either size-scale effects possibly affecting the critical temperature or the use of acoustic-emission technique as detecting technique of pre-failure indicators.
See e.g. the following documents:
- Naus, D. J. The Effect of Elevated Temperature on Concrete Materials and Structures - a Literature Review. United States, 2006. doi:10.2172/974590.
- Geng J., Sun Q., Zhang W., Lü C. Effect of high temperature on mechanical and acoustic emission properties of calcareous-aggregate concrete. Applied Thermal Engineering, 2016; 106:1200-1208. doi: 10.1016/j.applthermaleng.2016.06.107
- Grosse C., Ožbolt J., Richter R., Periškić G. Acoustic emission analysis and thermo-hygromechanical model for concrete exposed to fire. J. Acoustic Emission, 2010; 28: 188-203.
For a general overview on the acoustic emission technique they could still take inspiration from the following paper:
-Carpinteri A., Lacidogna G., Pugno N. Structural damage diagnosis and life-time assessment by acoustic emission monitoring. Engineering Fracture Mechanics, 2007; 74: 273-289.
Author Response
Dear Reviewer
Thank the reviewers for reviewing this manuscript. Your review comments are of great help to us, especially your proposal to use acoustic emission technology to evaluate concrete structures. We have carefully read the references provided by you. The research of these authors provides us with new reference ideas for our next research, which is very beneficial to the establishment of concrete thermal damage prediction model. Thank the reviewers for giving us the opportunity to revise the manuscript.
Comment: To make the paper more complete the Authors may insert some considerations on either size-scale effects possibly affecting the critical temperature or the use of acoustic-emission technique as detecting technique of pre-failure indicators.
Responses: Thank you very much for your kindly advice. Here are some revisions we made to the paper.
- In Section 3.1 of the paper, we add the related content of using acoustic emission technology to evaluate concrete structures. The added content is “In view of the critical size effect of concrete under temperature, scholars proposed to use acoustic emission technology to evaluate the internal structural defects and damage of concrete [57-59]. Relevant conclusions show that there was a negative correlation between temperature and acoustic emission signal. Before the compressive strength of concrete reached the critical point, the acoustic emission number and energy of concrete showed an increasing trend until the concrete members were completely destroyed [60].”
- We added AE technology as a method for establishing temperature damage prediction model in the “Microscopic properties of shotcrete” part of the challenge.
References
[57] Naus, D. J. The Effect of Elevated Temperature on Concrete Materials and Structures - a Literature Review. United States, 2006.
[58] Carpinteri A., Lacidogna G., Pugno N. Structural damage diagnosis and life-time assessment by acoustic emission monitoring [J]. Engineering Fracture Mechanics, 2007; 74: 273-289.
[59]Grosse C., Ožbolt J., Richter R., Periškić G. Acoustic emission analysis and thermo-hygromechanical model for concrete exposed to fire [J]. J. Acoustic Emission, 2010; 28: 188-203.
[60] Geng J., Sun Q., Zhang W., Lü C. Effect of high temperature on mechanical and acoustic emission properties of calcareous-aggregate concrete [J]. Applied Thermal Engineering, 2016; 106:1200-1208.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
1. It should be clear from the abstract that the article is purely a review of the literature. In places, it sounds like the author's own achievements.
2. Many, sometimes very many, references were collected for the article and summarised in a few sentences. However, the authors neither draw conclusions from the available material nor question any of it. It is a pure reproduction of the content, without any further use.
3. The reader is left with the question of the authors' scientific achievements, since they have merely gathered material. However, this is only one aspect of a scientific work.
Comments for author File: Comments.pdf
Author Response
Dear Reviewer
Thank the reviewers for their careful comments on the manuscript and giving us an opportunity to revise our manuscript. Your suggestions are very helpful to us. Point-by-point responses to the reviewers are listed below.
Problem 1: It should be clear from the abstract that the article is purely a review of the literature. In places, it sounds like the author's own achievements.
Response: thank you for your advice. We modified the abstract to make it more like a review than our own research results, as shown below.
High temperature is recognized as one of the extreme environments in the application of shotcrete, which significantly deteriorate the performance of shotcrete. The paper reviewed the mechanical properties and microstructure of shotcrete under high temperature. First of all, this paper reviewed the cause of formation of high ground temperature. Based on these causes, the author established the heat transfer model with spiral shape by introducing the multidimensional morphological formula in heat conduction process. Then, the paper reviewed the influence of high temperature on the mechanical and micro properties of shotcrete, the cooling technology under high temperature and the optimization research technology of shotcrete. The author discussed the influence of high temperature on the thermal parameters and the deformation of shotcrete from the perspective of thermodynamics. Multiple studies had shown that the irregular movement and disorderly overlapping of molecules in the shotcrete caused by high temperature environment resulted in the premature termination of hydration reaction of cement in shotcrete. Finally, the author suggested the challenges of high-temperature shotcrete in term of the process structure, the performance optimization and the application of special engineering fields. The research in this paper intends to give guidance to the workers of shotcrete research under high temperature, and to promote the further development of shotcrete technology.
Problem 2: Many, sometimes very many, references were collected for the article and summarized in a few sentences. However, the authors neither draw conclusions from the available material nor question any of it. It is a pure reproduction of the content, without any further use.
Response: Thank you for your suggestions. Your advices are very useful for improving the quality of this paper. With your requirement, we added the draw conclusion in the paper, as shown in Section 3.1, Section 3.2, Section 3.3. The details are as follows:
Section 3.1
The above research only expounds the deterioration law of shotcrete from the macro phenomenon, but does not explain the causes of deterioration from the micro level.
In order to deeply study the influence of high temperature on the deterioration of shotcrete, scholars analyzed the deterioration mechanism of shotcrete from the perspectives of carbonation depth and early hydration products of cement.
The above research lacks the research on the micro void structure of shotcrete. As we all known, the change of micro void structure affects the mechanical properties of shotcrete. With the development of new detection technology, scholars use SEM, CT and mercury intrusion method (MIP) to measure the change of voids in shotcrete, so as to further explain the influence mechanism of high temperature on concrete deterioration.
At present, in terms of mechanical properties of shotcrete, scholars have studied the impact of low temperature on concrete to ultra-high temperature. The span of temperature basically covers the range of environmental changes on site. Scholars not only studied the macro cracks, but also deeply analyzed the deterioration mechanism of shotcrete from the perspective of micro void structure. However, the correlation between the macro phenomenon and microstructure of shotcrete in high temperature environment is few. It is necessary to further strengthen the relationship between two, especially the macro and micro relationship model, so as to better provide a theoretical basis for the research of shotcrete in high temperature environment.
Section 3.2
Scholars have studied the effect of void structure on bond performance of shotcrete by using CT technology, which is of certain significance for analyzing the mechanical failure of shotcrete. However, there are relatively few studies on the interface between shotcrete and rock (coal) based on macro and micro, especially the effect of parameters of different sprayed surfaces (such as roughness, density and chemical composition) on the bonding performance of shotcrete needs to be further studied.
Section 3.3
There are many researches on the mechanical properties of shotcrete under high temperature, and a large number of research results have been obtained to explain the macro phenomenon from the micro point of view. However, most studies only focus on the single mechanical properties of shotcrete. The overall research on comprehensive properties is relatively few, and the correlation between various mechanical properties needs to be further discussed. It is suggested that when studying various mechanical properties of shotcrete at high temperature, the detailed micro research can be listed separately to serve the macro changes of various mechanical properties. This may be a relatively clear research method, rather than a microstructure study every time a mechanical property is studied.
Problem 3: The reader is left with the question of the authors' scientific achievements, since they have merely gathered material. However, this is only one aspect of a scientific work.
Response: Thanks for your careful suggestions. Your advices are very useful for improving the quality of this paper. The 2th and 3th problem are revised according to the suggestions of the reviewer in the PDF file of the manuscript, as shown below.
Comment 1: Enhanced support ability improves the stability?
Response 1: Thanks for your advice. The sentence " As a supporting material of roadway, shotcrete can not only prevent the oxidation of surrounding rock, but also enhance the support ability of the initial structure of roadway, which greatly improves the stability of roadway." shall be revised as " As a supporting material of roadway, shotcrete can not only prevent the oxidation of surrounding rock, but also plays a supporting role for the roadway."
Comment 2: The graphic is superfluous and of inferior quality. One wonders if it is meant to serve as proof ?
Response 2: Thanks for your reminding and advice. Fig.1 in the original manuscript was deleted.
Comment 3: As expected, diagram actually superfluous. Positions of the points not clear and moderate quality of the diagram. Why are there connections between the points?
Response 3: Thanks for your reminding and advice. Fig. 2 is redrawn. The Figure shows that the variation between temperature and depth in underground projects was a nonlinear relationship. This phenomenon may be caused by different rock properties and possible large fault zones in deep environment.
Comment 4: Syntax
Response 4: Thanks for your reminding and advice. The sentence "Lee and Yang et al. [11-12] studied the variation of shear properties of shotcrete with the roughness and temperature of granite cementation surface. The results showed that the shear strength increased first and then decreased with the increase of roughness grade and temperature of granite cementation surface. Among the temperature is the most important experiment factor." Lee and Yang et al. [11-12] studied the variation of shear properties of shotcrete with granite cementation surface roughness and temperature. The results showed that there were critical values for the effects of granite cementation surface roughness and temperature on shear strength. Moreover, the temperature was the most important factor affecting the shear performance of shotcrete."
Comment 5: The physical variable is called permeability
Response 5: Thanks for your advice. The sentence "Wang et al. [13] studied the impermeability of shotcrete under standard working conditions and variable temperature conditions, and concluded that temperature would affect the impermeability of shotcrete and destroy the dense structure inside the shotcrete." was revised as " Wang et al. [13] studied the impermeability of shotcrete under standard working conditions and variable temperature conditions. The results showed that the temperature destroys the dense structure inside the shotcrete, resulting in the increase of impermeability of shotcrete."
Comment 6: The list is a little too long given the content of the statement
Response 6: Thanks for your good advice. The sentence "Akca et al. [21] studied the structural performance of high-performance shotcrete under high temperature, and concluded that the overall strength of shotcrete showed an upward trend under high temperature, and high temperature will make the structure of shotcrete change." was revised as "Akca et al. [21] studied the structural performance of high-performance shotcrete under high temperature, and concluded that the overall strength of shotcrete showed an upward trend under high temperature."
Comment 7: The objective of the article sounds very unspecific
Response 7: Thanks for your advice. The research purpose of the paper was modified to “Although there are many researches on the performance changes of shotcrete under high temperature, there are few systematic reviews on the mechanical and micro properties of shotcrete. Therefore, this article systematically describes the development of mechanical properties and microstructure of shotcrete under high temperature. The research in this paper intends to give guidance to the workers of shotcrete research under high temperature, and to promote the further development of shotcrete technology.”
Comment 8: Syntax
Response 8: Thanks for your reminding and advice. The sentence "Then the heat that goes through the rock to the earth's surface." was revised as "Then heat is transmitted through rocks to the earth's surface."
Comment 9: Degrees per what?
Response 9: Thanks for your reminding and advice. The sentence "the temperature difference may reach 2 ~ 4 °C." was revised as" the temperature difference may reach 2 ~ 4 °C/100m."
Response 10: Thanks for your reminding and advice. Formulas 1 and 2 are mainly due to system typesetting errors. Thank you for pointing out the mistake.
Comment 11: Because what?
Response 11: Thanks for your reminding and advice. The sentence "Because heat can be seen as a fluid" was revised as" Heat can be imagined as a fluid"
Comment 12: bracket
Response 12: Thanks for your reminding and advice. The sentence" it will affect the selection of construction materials and the durability of shotcrete [31-32" was revised as" it will affect the selection of construction materials and the durability of shotcrete [31-32]"
Comment 13: poor Quality
Response 13: The information in Fig.4 has been modified.
Comment 14: This paragraph could shed more light on the actual mechanisms at work, but instead it is rather general.
Response 14: Thanks for your reminding and advice. Since Section 3.1 of the original manuscript is an explanation of the crack mechanism. Therefore, Section 3.1 and Section 2.3 are combined in this revision to explain the mechanism and process of cracks in shotcrete under high temperature.
Comment 15: Explanation is developable
Response 15: Thank you. We revised the explanation as suggested. Combined with the high-temperature deterioration mechanism of shotcrete, the development direction is added as follows：
The sentence “The lining shotcrete of high temperature heat damage roadway is easy to deteriorate in the process of pouring and curing. The reason is that the shotcrete lining is in contact with the high temperature surrounding rock, and the shotcrete structure has large temperature stress under the influence of continuous high temperature, which makes the shotcrete easy to crack.“ was changed as “The lining shotcrete under high temperature heat damage roadway is easy to deteriorate in the process of pouring and curing. One reason is that the high temperature makes the water in the fresh concrete evaporate rapidly, forming large voids or cracks; another reason is that when shotcrete adheres to high-temperature surrounding rock, it has high temperature stress. In addition, high temperature changes the hydration products and progress of cement. These reasons are worthy of in-depth study.”
Comment 16: is shown
Response 16: Thanks for your reminding and advice. The sentence ”As shown in Fig. 5, the XRD spectra of shotcrete at 30 °C and 60 °C was shown” is changed as “The XRD spectra of shotcrete at 30 °C and 60 °C is shown in Fig. 5,”
Comment 17: blank space
Response 17: Thanks for your reminding and advice. The sentence “It shows that the hydration degree of shotcrete cement is better at 60 °Cand more C-S-H gel is generated.” is changed as “It shows that the hydration degree of shotcrete cement is better at 60 °C and more C-S-H gel is generated.”
Comment 18: The list is a little too long given the content of the statement. The illustrations add only little value.
Response 18: Thanks for your good suggestion. The sentence “As shown in Fig. 6, D'Aloia et al. [41] carried out numerical simulation on cracking performance of tunnel lining shotcrete. It is found that early creep has good effect. When the creep is ignored, the thermal damage occurs in a large range of shotcrete lining structure; by comparing the simulation results of thermal shrinkage and autogenous shrinkage, it is concluded that thermal shrinkage is the main cause of early transverse cracks.” was changed as “D'Aloia et al. [41] carried out numerical simulation on cracking performance of tunnel lining shotcrete. The results showed that early creep has good effect (Fig 6a). When the creep is ignored, the thermal damage occurs in a large range of shotcrete lining structure (Fig 6b); by comparing the simulation results of thermal shrinkage and autogenous shrinkage (Fig 6c), it is concluded that thermal shrinkage is the main cause of early transverse cracks. Therefore, under high temperature environment, the shrinkage phenomenon occurs in the roadway wall concrete under the influence of temperature, resulting in cracks in the shotcrete.”
Comment 19: Page break
Response 19: Thanks for your reminding and advice. The mainly due to system typesetting errors. Thank you for pointing out the mistake.
Comment 20: where is "at home"?
Response 20: Thanks for your reminding and advice. The wrong term “scholars at home and abroad” shall be revised as “some scholars”.
Comment 21: Chapter 3 is far too long. No conclusions are drawn from the literature references and they are not put into context with the author's own work.
Response 21: Thanks for your good suggestion. We merged Sections 3.1 and 2.3 of the original manuscript.
Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript presents an interesting review regarding to the affection of high temperature on mechanical properties and microstructure of shotcrete. The comments of this reviewer are the following ones:
-It is highly recommended that a brief definition, history, dosages, and types of production of shotcrete must be given in the introduction.
-The section entitled “2.2. Conduction process of formation temperature” is not mentioned and non-related to any of the cites used later on the manuscript. It stablishes the type of heat transmission process, but this is not latter referenced by any cites or the authors ,as far as this reviewer has understood. If that is so, I recommend that this section could be synthetize or removed.
-In page 5 out of 23, there is a misunderstanding in version 2 in addressing figure 4. Please check it. Furthermore, the portlandite presence does not guarantee that more C-S-H are generated, so more hydration degree is reached. Portlandite could vary for many reasons, for instance, it can be increased by carbonation process. I have tried to find Qin´s research but I did not succeed.
- In figure 7, C-S-H is detected as mineralogical phase in the diffractogram, this quite difficult since C-S-H is an amorphous mineralogical phase. I have tried to find [45] ref I did not succeed.
-In page 14 out of 23. Colling technology has been addressed, but it is just mentioned its relationship with mechanical properties and microstructure when ref [83] is cited. The rest of text, as well as Figure 17 and Table 2, are not related to the aim of the review, mechanical properties and microstructure in shotcrete.
-If the comments above are taken into account, conclusions are suggested to be rewritten.
Author Response
Dear Reviewer
Thank the reviewers for their careful comments on the manuscript and giving us an opportunity to revise our manuscript. Your suggestions are very helpful to us. Point-by-point responses to the reviewers are listed below.
Problem 1: It is highly recommended that a brief definition, history, dosages, and types of production of shotcrete must be given in the introduction.
Response: thank you for your advice. We added basic information about shotcrete in the first paragraph, as shown below.
Shotcrete is a kind of concrete formed by mixing concrete materials, such as gel material, aggregate and so on, into the ejection equipment, by means of compressed air or other power transmission, and sprayed to the spray surface at high speed [1]. Shotcrete technology was first used in mining and civil engineering by the United States in 1914. It has a history of more than 100 years. This method is used in underground and tunnel support, infrastructure repair and rehabilitation, slope stabilization, and in areas difficult to reach with conventional concrete such as bridge piers, beam soffits [2].
Problem 2: The section entitled “2.2. Conduction process of formation temperature” is not mentioned and non-related to any of the cites used later on the manuscript. It stablishes the type of heat transmission process, but this is not latter referenced by any cites or the authors, as far as this reviewer has understood. If that is so, I recommend that this section could be synthetize or removed.
Response: Thank you for your advice, which is very helpful to us. We have fully considered your suggestions, integrated sections 2.1 and 2.2, and further introduced the heat transfer process. The specific amendments are as follows:
Heat can be imagined as a fluid, and the fluid can be divided into steady-state type and non-stationary type in the process of transmission [30]. The heat transfer process is an unsteady state. Fig. 2 shows the physical structure model of heat transfer. Luo et al. [35-36] analyzed the heat transfer phenomenon in the flow process, results showed that heat flow is a process of energy exchange. Therefore, the author divides the heat transfer process into three types: linear, curved and spiral. Due to the thermal conductivity of rock, the heat transferred from the deep to the ground is mainly linear [37-38]. In the process of tunnel construction, the heat is mainly curved and spiral; the heat flow transferred by curve will continue to diffuse around; the heat transferred in this form is not stored much in the rock. The heat transferred by spiral type will not disappear, but will accumulate continuously in the process of transmission, which will enhance the heat storage capacity of rock. At the same time, spiral transmission is also the dominant part of deep high temperature.
Problem 3: In page 5 out of 23, there is a misunderstanding in version 2 in addressing figure 4. Please check it. Furthermore, the portlandite presence does not guarantee that more C-S-H are generated, so more hydration degree is reached. Portlandite could vary for many reasons, for instance, it can be increased by carbonation process. I have tried to find Qin´s research but I did not succeed.
Response: Thanks for your careful suggestions. Your advices are very useful for improving the quality of this paper.
The sentence " As shown in Fig. 4, The XRD spectra of shotcrete at 30 °C and 60 °C is shown in Fig. 5" was revised as " The XRD spectra of shotcrete at 30 °C and 60 °C is shown in Fig. 4" .In addition, Due to the different contents of various components in different Portland cements, the increase of C-S-H content may be caused by moisture content or external conditions (such as high temperature). Therefore, thank you for your questions. We will continue to study cement products. Your comments are very useful to us.
This reference is shared. [36] Qin Li, Li Min, Ding Jing-nan. The Effect from Curing of High Temperature and High Humidity to Durability of High Strength Concrete [J]. Journal of Northeast China Institute of Electric Power Engineering, 2016, 36(01):18-22. Doi:10.19718/j.issn.1005-2992.2016.01.004
Problem 4: In figure 7, C-S-H is detected as mineralogical phase in the diffractogram, this quite difficult since C-S-H is an amorphous mineralogical phase. I have tried to find [45] ref I did not succeed.
Figure 7. XRD spectra of different curing systems [14].
Response: Thanks for your careful suggestions. Because alkali will stimulate the early hydration of materials, C-S-H phase is generated after concrete hydration. In literature [14], the author detected C-S-H phase at 0-60 °C.
Problem 5: In page 14 out of 23. Colling technology has been addressed, but it is just mentioned its relationship with mechanical properties and microstructure when ref [83] is cited. The rest of text, as well as Figure 17 and Table 2, are not related to the aim of the review, mechanical properties and microstructure in shotcrete.
Response: Thanks for your careful suggestions. This suggestion is very helpful to us. This paper introduces that cooling technology is a method to change the high-temperature construction environment. When the temperature at the construction site is reduced through physical adjustment, the phenomenon of workers' work heat halo is avoided, the shotcrete efficiency is increased, which is conducive to the development of shotcrete strength and reduce the probability of concrete deterioration. Reduce the high-temperature construction environment and increase the air humidity in the construction site by physical or chemical means. It is mainly because the humid environment is conducive to the recovery of high temperature damaged concrete strength [94].
Problem 6: If the comments above are taken into account, conclusions are suggested to be rewritten.
Response: Thanks for your careful suggestions. We modify the conclusion of the article as follows:
(1) This paper first reviewed the causes of formation high temperature environment, and points out that formation temperature was a kind of heat conduction mode. The leading role of rock thermal conductivity on temperature transmission was deter-mined by introducing the multi-dimensional morphological formula in the process of heat conduction.
(2) The mechanical properties and micromechanical properties of shotcrete under high temperature were reviewed. Results concluded that the mechanical properties (Included compressive strength, tensile strength, bond strength, shear strength) of shotcrete were affected by the critical temperature, before the critical temperature, the mechanical properties of shotcrete showed an increasing trend with the increase of temperature; after the critical temperature, the mechanical properties of shotcrete appeared the phenomenon of shrinkage. Through microscopic analysis, multiple studies had shown that when the temperature exceeded the critical temperature, the internal molecules of shotcrete move violently and the molecules overlap disorderly, the hydration reaction of shotcrete cement was terminated prematurely and the brittle de-formation was enhanced, which led to the weakening of shotcrete strength.
(3) The cooling technology and performance optimization of shotcrete at high temperature are summarized. It is concluded that taking cooling measures for high-temperature construction environment will increase the recovery ability of concrete after deterioration and reduce the deterioration degree of shotcrete. In terms of optimizing the performance of shotcrete, adding inorganic materials, such as vitrified microbeads, foam fibers, expanded perlite and silica fume, will improve the heat insulation and heat resistance of shotcrete.
References
[1] Xiamen Academy of Building Sciences Group Co., Ltd. Technical specification for application of sprayed concrete JGJ/T 372-2016 [M]. China Construction Industry Press, 2016.
[2] Burns B, Dennis. Characterization of wet-mix shotcrete for small line pumping [J]. 2008.
[8] Zhang Chao, Zhao Lihong, Wu Zhaocai. Depth characteristics of Curie surface in the Eastern seas of China [J]. Journal of Shandong University of science and Technology (Natural science), 2019, 038 (004): 10-17.
[9] Wang Xiaoman, Li Xuping, Kong FanMei, et al. Metamorphism and tectonic evolution of the sedimentary-matrix mélange in the central Yarlung Zangbo Suture Zone, southern Tibet [J]. Journal of Shandong University of science and Technology (Natural science), 2020, v.39;No.187(02):16-27.
[35] Luo J, Qi Y, Qiang Z , et al. Investigation of Flow and Heat Transfer Characteristics in Fractured Granite[J]. Energies, 2018, 11(5):1228.
[36] Luo J, Zhu Y, Guo Q, et al. Experimental investigation of the hydraulic and heat-transfer properties of artificially fractured granite[J]. Scientific Reports, 2017, 7:39882.
[37]Rock heat-transfer model of high-temperature stopes and its solving process[C]// Proceedings of the International Young Scholars' Symposium on Rock Mechanics. 2008.
[38] Tan Yunliang, Zhang Qiang. Numerical Analysis of Surrounding Rock Deformation and Failure in Deep Roadway under the Condition of Thermal-solid Coupling [J]. Journal of Shandong University of science and Technology (Natural science), 2016, 35 (002): 29-37.
[94] Liu Lixian, LV long, Liu Zheng, et al. Investigation on the Mechanical Behavior of Concrete at and after Elevated Temperature [J]. Building science, 2005 (03): 16-20.
Author Response File: 
Author Response.docx
