Field Pull-Out Tests of Percussion Driven Earth Anchors (PDEAs)

Round 1

Reviewer 1 Report

1. By comparing the result of an experiment with the value obtained from the empirical equation (Equation 1), it cannot be stated that the C_u values found from the in-situ TCP values give a better estimate of the ultimate pull-out load. More results should be compared. By drawing a graph of the results obtained in the field and the values obtained from the equation, the amount of error and accuracy should be determined. Additionally, the C_u obtained from other laboratory or field tests may provide better results. The authors did not mention it in any part of the paper.

2. C_u in Equation 1 shows the undrained cohesion of clay. Why did the authors use the UCS test to calculate it? It is clear that the C_u obtained from the UCS test cannot be a suitable value for undrained cohesion in engineering designs.

3. References need to be revised.

·       References 3-12 (Line 61) or 14-29 (Line 70) have been used to refer to a sentence and no results of these studies have been presented. Many of these references seem unnecessary.

·       Figure 1 is not available in reference 2. Correct the reference.

·       Figure 8 is from which reference (the bottom part of the figure)?

4. There are no comments regarding some design considerations. How deep is the critical failure plane? How does pore water pressure affect design? What is the desired factor of safety?

5. Isn't the undrained cohesion obtained from the UCS test half of the uniaxial strength (C_u=q_u/2)? How is the value of undrained cohesion in Table 1 obtained?

6. The maximum displacement indicates which point in the graphs? The point where the ultimate pull-out resistance occurs or the point where failure occurs? Why is the maximum displacement value reported in Table 2 different from the values presented in the figures and text in some cases? For example: Line 275, Figure 13, and Table 2.

7. Considering that the amount of C_u is an important value in Equation 1, it is better to present the graph or Equation that you have obtained the value of C_u based on the Texas Cone Penetration (TCP) in the paper.

8. There is no comment about the reasons for the difference in the obtained undrained cohesion (C_u) that led to the difference in the ultimate pull-out resistance in Equation 1.

9. Lines 32-36 in the abstract should be corrected based on the above comments. Such a result cannot be obtained by comparing an experiment and an equation.

10. The conclusion section is not appropriate for a research article. According to the above comments, especially comments 1, 2, and 8, the authors should improve the conclusion section.

11. The quality of figures 3, 5, 7, and 8 should be improved. In Figure 11, the description of Figures a, b, c, and d should be presented.

12. In the introduction, in some cases “H/D” is written, and in other cases “H/B”. Define the parameters correctly in the article.

13. In line 322, how can the width be greater than the length?

14. Please correct the following.

·       In line 145, Figure 3b is probably meant (not Figure 4).

·       In line 272, “Figure 13” is correct.

·       In line 315, cm is correct for “L”.

·       Line 255, “7.6 cm” is correct.

·       In Figure 14, series or stroke? Please correct.

·       Line 492: “Civil engieering”: Civil engineering

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

This manuscript discussed about the percussion driven earth anchors (PDEAs) that are driven into soils using an installation steel hammer rod. Three duckbill soil anchors were field tested after being installed in lean silty clay, the type of soil dominant on the project site. The work is generally well written with a clear organization. Some minor issues needed discussion.

1.    In practice, the size of anchor head may play an important role for the mobilization of wire tendon. How do the authors think that the current size of anchor head is an optimum size?

2.    Figure 5 is unclear.  

3.    Natural soil is often spatially variable (as the moisture shown in Figure 7). Many papers discussed about this kind of non-uniformity and its effect on slope stability (e.g. papers entitled “Effect of in situ water content variation on the spatial variation of strength of deep cement-mixed clay”, “Three-dimensional large deformation modelling of landslides in spatially variable and strain-softening soils subjected to seismic loads”). Will the non-uniformity of natural soil effect the performance of this type of PDEAs?

4. Most of the cited references were published 5 years ago. Some relevant papers/references published within recent 5 years are recommended to be cited if the authors want to show that this topic is still an active one.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors responded to all the comments from my previous review.