Ultimate Bearing Capacity of Bottom Sealing Concrete in Underwater Deep Foundation Pit: Theoretical Calculation and Numerical Analysis
, Xiaohan Zuo 1, Yan Liu 3, Haiping Yuan 1 and Yixian Wang 1,3,*Round 1
Reviewer 1 Report
The paper is of sufficient novelty. The topic is actual and interesting.The thread is clear even if in the introduction it is not well highlited.
However the paper is flawed due to the following issues.
In my opinion, the proposed analytical method is not theoretically plausible as it refers to a model not consistent with the case study.Besides, the influence of the holes in the bottom-sealed concrete is not considered as reported by the authors. Therefore, the proposed method cannot be analytical but approximate.
All the terms in eqs. 3-8 must be explained.
From the discussion it seems that the traditional method is more reliable from an engineering point of view.
Author Response
Reviewer 1:
The paper is of sufficient novelty. The topic is actual and interesting. The thread is clear even if in the introduction it is not well highlited.
Response: Dear Reviewer 1, the authors are deeply grateful for your time spent on strictly reviewing our manuscript and offering valuable suggestions for further modification of this manuscript. Following your suggestions, we have made a substantial modification which we hope meet with approval. The response to your specific comments is listed below. The changes made in response to your comments have been marked up in the revised version of the manuscript by using the “Track Changes” function. Thank you again for everything you’ve done on our manuscript. We wish you a happy life. Best regards.
However the paper is flawed due to the following issues. In my opinion, the proposed analytical method is not theoretically plausible as it refers to a model not consistent with the case study.
Response: The authors appreciate that you pointed this out, and the explanation on this issue is as follows. Indeed, the calculation method for the ultimate bearing capacity of the bottom sealing concrete proposed in this manuscript is not an accurate analytical solution, but an approximate calculation method. This is because, at present, in the field of elasticity, there is no accurate analytical solution to the stress problem of a thin plate with many holes. In consideration of the above reasons, the idea of this manuscript is to simplify the problem to the stress problem of a rectangular thin plate without holes, so as to approximate the internal maximum stress of the bottom sealing concrete. Although this is not exactly the same as the actual situation, and the maximum stress calculated is slightly larger than the actual situation, it is safe and feasible in the construction of the engineering, and the results obtained by this method are closer to the stress data monitored in the engineering than the traditional method (as can be seen from table 2 of the manuscript). Therefore, this manuscript is committed to finding a more accurate approximate calculation method than the traditional method and ensuring that it is closer to the actual situation in the engineering. In this sense, the calculation method proposed in this manuscript is an optimization of the traditional method, which is also a progress for the research of the ultimate bearing capacity of the bottom sealing concrete.
Besides, the influence of the holes in the bottom-sealed concrete is not considered as reported by the authors. Therefore, the proposed method cannot be analytical but approximate.
Response: As you said, the calculation method proposed in this manuscript for the ultimate bearing capacity of the bottom sealing concrete is an approximate calculation method, not an accurate analytical solution. We have changed the description about "analytical solution" of this method in the manuscript to "approximate solution". The changes have been marked up in the revised version of the manuscript by using the “Track Changes” function.
All the terms in eqs. 3-8 must be explained.
Response: The authors are really sorry for this carelessness. All the terms in Eqs. 3-8 have been explained. Please see Line 143-151, Page 5 in the revised version of the manuscript.
From the discussion it seems that the traditional method is more reliable from an engineering point of view.
Response: The approximate solution proposed in this manuscript is to simplify the bottom sealing concrete into a complete rectangular thin plate, while the traditional method directly simplifies the bottom sealing concrete into a concrete beam of unit width. Obviously, the simplification of traditional method is more radical. This also leads to the maximum stress calculated by the traditional method being much larger than the engineering monitoring data, and the data obtained by the approximate calculation method proposed in this manuscript is closer to the engineering monitoring data (as can be seen from the data in Table 2 of the manuscript). Based on the above situation, if the traditional method is adopted, the amount of concrete required during construction will be much larger, which will cause waste of materials. Therefore, this does not mean that the traditional method is more reliable, although it has been applied to engineering. Besides, we have revised the relevant statements in the discussion. Please see Line 281-284, Page 10 in the revised version of the manuscript.
Reviewer 2 Report
This manuscript proposes theoretical calculation and numerical simulation for analyzing the ultimate bearing capacity of bottom sealing concrete in underwater deep foundation pit. Based on a construction case of bridge engineering, this manuscript also performs finite element analysis to validate the proposed theoretical calculation. In general, this manuscript is well written and organized. The conclusions drawn from this study can provide some useful reference for the similar engineering practice. Considering the quality of this manuscript, I recommend a minor revision of this manuscript before accepting it for possible publication in this journal. The revision should consider the specific comments listed below.
(1) Please optimize the English expression of the full text. For example, in Line 89-97 of Section 2, please describe the stress state of the bottom sealing concrete clearly.
(2) In Section 2.2, it is said that the force between the bottom sealing concrete and the cofferdam can be ignored. It is suggested to explain clearly why it can be ignored.
(3) In Line 173-178 of Section 2.2, it is said that there are very few studies on the bonding stress between the concrete and the steel pipe pile. This part should be put in Section 1 instead of here.
(4) In Section 3, it is suggested to put the relevant parameters of the engineering case in a table.
(5) In Section 3, please mark the reference of the engineering case.
(6) In Section 3.2.1, please specify the specific value of the relative error.
Author Response
Reviewer 2:
This manuscript proposes theoretical calculation and numerical simulation for analyzing the ultimate bearing capacity of bottom sealing concrete in underwater deep foundation pit. Based on a construction case of bridge engineering, this manuscript also performs finite element analysis to validate the proposed theoretical calculation. In general, this manuscript is well written and organized. The conclusions drawn from this study can provide some useful reference for the similar engineering practice. Considering the quality of this manuscript, I recommend a minor revision of this manuscript before accepting it for possible publication in this journal. The revision should consider the specific comments listed below.
Response: Dear Reviewer 2, the authors are deeply grateful for your time spent on strictly reviewing our manuscript and offering helpful suggestions for further modification of this manuscript. Following your suggestions, we have made a substantial modification which we hope meet with approval. The response to your specific comments is listed below. The changes made in response to your comments have been marked up in the revised version of the manuscript by using the “Track Changes” function. Thank you again for everything you’ve done on our manuscript. We wish you a happy life. Best regards.
(1) Please optimize the English expression of the full text. For example, in Line 89-97 of Section 2, please describe the stress state of the bottom sealing concrete clearly.
Response: The authors appreciate that you pointed this out. All the English expression of the full text have been checked and optimized. The changes have been marked up in the revised version of the manuscript by using the “Track Changes” function. The stress state of the bottom sealing concrete has been described clearly. Please see Line 95-106, Page 3 in the revised version of the manuscript.
(2) In Section 2.2, it is said that the force between the bottom sealing concrete and the cofferdam can be ignored. It is suggested to explain clearly why it can be ignored.
Response: The authors appreciate that you pointed this out, and the explanation on this issue is as follows. In fact, the bottom sealing concrete is in static equilibrium under the combined action of gravity, buoyancy and friction (including the friction exerted by the cofferdam and the steel sleeves). However, due to the different types of cofferdams and materials used, the friction between cofferdam and concrete is usually difficult to determine. For example, for the steel sheet pile cofferdam, lubricant will be added between adjacent steel sheet piles during construction, and the friction between steel sheet piles and concrete will be reduced due to the presence of lubricant. In this case, the friction between the steel sleeves and the concrete should be focused first. In addition, because the friction between the cofferdam and the concrete can be ignored, the friction between the steel sleeve and the concrete obtained by the calculation will be slightly larger, so it is safer for the engineering design and conforms to the engineering practice. The explanation has been added. Please see Line 183-190, Page 6 in the revised version of the manuscript.
(3) In Line 173-178 of Section 2.2, it is said that there are very few studies on the bonding stress between the concrete and the steel pipe pile. This part should be put in Section 1 instead of here.
Response: Thank you very much for your valuable suggestion. That part you mentioned has been put in Section 1. Please see Line 81-86, Page 2 in the revised version of the manuscript.
(4) In Section 3, it is suggested to put the relevant parameters of the engineering case in a table.
Response: The authors are deeply grateful for your helpful suggestion. The relevant parameters of the engineering case have been put in Table 1. Please see Line 227, Page 7 in the revised version of the manuscript.
(5) In Section 3, please mark the reference of the engineering case.
Response: The authors are really sorry for this carelessness. The reference of the engineering case has been marked. Please see Line 210, Page 7 in the revised version of the manuscript.
(6) In Section 3.2.1, please specify the specific value of the relative error.
Response: The authors appreciate that you pointed this out. The specific values of the relative error have been added in Table 2. Please see Line 265, Page 9 in the revised version of the manuscript.
Round 2
Reviewer 1 Report
The paper has been sufficiently revised.
