Experimental Study on Mechanism of Wave-Induced Liquefaction of Sand-Clay Seabed
Round 1
Reviewer 1 Report
The paper presents an experimental study about the wave-induced liquefaction of sand-clay seabed. The study is interesting because it reports experimental results which can be rarely found in the literature. I have just some minor comments on some crucial geotechnical concepts which can improve the work.
In real cases application, the liquefaction condition is verified with reference to the initial vertical effective stress, not to the mean value (see Boulanger and Idriss, 2014 as the main reference). Please, update Table 3 accordingly but no dramatic differences in the results are expected; It is not clear what the Authors mean for “time of pressure dissipation” and “time of soil consolidation” and, consequently, what is the difference between these two parameters and how the values have been estimated in the experiments; Regarding the soil fabric, relevant contents for the paper can be found in Wiebicke et al. (2017) and added to the paper; Please, add more details about eq. 5 to improve the readability of the text; Spelling check is recommended (e.g., row 220 “larger”).
References
Boulanger, R.W., and Idriss, I.M. (2014). CPT and SPT liquefaction triggering procedures. Report No UCD/GCM-14/01, University of California at Davis, California, USA.
Wiebicke, M., Andò, E., Salvatore, E., Viggiani, G., & Herle, I. (2017). Experimental measurement of granular fabric and its evolution under shearing. Paper presented at the EPJ Web of Conferences, 140 doi:10.1051/epjconf/201714002020
Author Response
1.In real cases application, the liquefaction condition is verified with reference to the initial vertical effective stress, not to the mean value (see Boulanger and Idriss, 2014 as the main reference). Please, update Table 3 accordingly but no dramatic differences in the results are expected;
Response: We agree that the initial vertical effective stress is more used in engineering practice, because of the convenience of calculation. We added this and the calculation method for the initial vertical effective stress in Table 3. In addition, Sumer et al. (2012) discussed the criterion for the onset of liquefaction in details. The initial mean normal effective stress is more referential in experiments. For the convenience of comparison with other studies, both these two parameters were listed in Table 3 in the revised manuscript.
2.It is not clear what the Authors mean for “time of pressure dissipation” and “time of soil consolidation” and, consequently, what is the difference between these two parameters and how the values have been estimated in the experiments;
Response: In fact, the difference between “time of pressure dissipation” and “time of soil consolidation” was pointed out in Line 194 and 195 . The term “time of pressure dissipation” means the time point when EPP starts to drop and “time of soil consolidation” means the time point when EPP drop to the lowest point, which represents the completion of the consolidation. The value of these two parameters was determined from Figure 6, where point C and point D were identified.
3.Regarding the soil fabric, relevant contents for the paper can be found in Wiebicke et al. (2017) and added to the paper;
Response: The reference of Wiebicke et al. (2017) has been cited regarding the soil fabric in Line 292 of the revised manuscript.
4.Please, add more details about eq. 5 to improve the readability of the text;
Response: To address the reviewer’s concern, more details were added to the description of Equation 5 in Line 229, as below:
EPP oscillated sinusoidally because of the wave action. In order to obtain a clearer tendency of EPP, the curve of EPP was smoothed by averaging the value over a wave period.
5.Spelling check is recommended (e.g., row 220 “larger”).
Response: Corrected in Line 220.
Reviewer 2 Report
The phenomena of liquefaction is very important to establish safety code for structures with soft ground. However there were few works to provide liquefaction of soft clay. This study focused on clay contents. It is so interesting with large wave apparatus. This work did to compare sand and clay. Consideration using micro fabric is good that results became to be clear.
Question
Table 2
Indicated density of soil particles for samples were low, in generally, density of soil particle is around 2.5 g/cm3. Please would you like to mention why reason.
Equation (4)
How to determine Ko
Figure 4
Five different samples described change of EPP. Please would you like to prove any tendency?
Figure 10 and 11
Authors supplied newly concept related to wave mechanics. If authors have constitutive model, please would you like to add new sentences.
Author Response
1.Table 2
Indicated density of soil particles for samples were low, in generally, density of soil particle is around 2.5 g/cm3. Please would you like to mention why reason.
Response: Density of soil particle is around 2.5-2.6g/cm3, while indicated density, , is the density of soil sample, a mixture of sand, clay and water. This information has been added in Line 144.
2. Equation (4)
How to determine Ko
Response: It was described in Line 147 that represents the coefficient of lateral earth pressure at rest, and is given by , where is the friction angle and is obtained by triaxial shear test.
3. Figure 4
Five different samples described change of EPP. Please would you like to prove any tendency?
Response: The comparison has been discussed in Line 216 as below:
With the increase of CC, the accumulation of EPP was slowed down. As a result, the value of final EPP accumulation became smaller and the amplitude of EPP as well.
4. Figure 10 and 11
Authors supplied newly concept related to wave mechanics. If authors have constitutive model, please would you like to add new sentences.
Response: Constitutive model is incomplete.
