Experimental study on the reinforcement mechanism and wave thumping resistance of EICP reinforced sand slopes

Abstract

Sand slope is an important part of coastal zone and islands, which is severely affected by wave erosion and causes problems such as degradation of coastal zone and reduction of island area. Enzyme-induced calcium carbonate precipitation (EICP) technology is a new reinforcement technology with environmental friendly and excellent effect, which has been widely studied in the field of geotechnical engineering in recent years. In this research, we focus on the coastal or reef sand slopes in marine environments. The EICP reinforcement of representative sand slope units and large scale flume wave thumping experimental study are conducted indoors. By analyzing the physical and mechanical properties, erosion resistance, and microstructure of EICP-reinforced sand slopes, the mechanism of EICP reinforced sand slopes is revealed, the feasibility of EICP reinforced sand slopes is confirmed, and a feasible solution for EICP reinforced sand slopes is finally obtained. Results show that: (1) EICP reinforcement effectively enhances the surface strength and erosion resistance of sand slopes. Higher calcium carbonate content in the sand slopes corresponds to greater surface strength and improved erosion resistance. When the calcium carbonate content is similar, using low-concentration reinforcement twice is more advantageous than using high-concentration reinforcement once due to its superior uniformity. (2) The intensity of waves, the angle of the sand slope, and the severity of erosion damage are interrelated. Higher wave intensity, steeper sand slope angles, and more serious erosion damage require stronger reinforcement measures. (3) Scanning Electron Microscope (SEM) image analysis reveals that the reinforcing effect of sand slopes primarily depends on the amount of calcium carbonate crystals cemented between sand particles. A higher content of calcium carbonate crystals leads to better erosion resistance in the sand slope.

Keywords

Enzyme induced calcium carbonate precipitation (EICP) / Sand slope / Wave thumping / Erosion resistance

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Chuangzhou Wu is an editorial board member for Biogeotechnics and was not involved in the editorial review or the decision to publish this article.

Acknowledgments

The authors gratefully acknowledge the financial support provided by the National Natural Science Foundation of China (No. 42177141).

The authors gratefully acknowledge the technical support in image processing provided by Professor Hui Huang and Master Yi Yang from Zhejiang University.

References

[1] Almajed, A., Abbas, H., Arab, M., Alsabhan, A., Hamid, W., & Al-Salloum, Y. (2020). Enzyme-Induced Carbonate Precipitation (EICP)-Based methods for ecofriendly stabilization of different types of natural sands. Journal of Cleaner Production, 274, Article 122627.

[2] Cheng, L., Cord-Ruwisch, R., & Shahin, M. A. (2013). Cementation of sand soil by microbially induced calcite precipitation at various degrees of saturation. Canadian Geotechnical Journal, 50(1), 81-90.

[3] Chu, J., Stabnikov, V., & Ivanov, V. (2012). Microbially induced calcium carbonate precipitation on surface or in the bulk of soil. Geomicrobiology Journal, 29(6), 544-549.

[4] DeJong, J. T., Fritzges, M. B., & Nüsslein, K. (2006). Microbially induced cementation to control sand response to undrained shear. Journal of Geotechnical and Geoenvironmental Engineering, 132(11), 1381-1392.

[5] Hamdan, N., & Kavazanjian, E.,Jr (2016). Enzyme-induced carbonate mineral precipitation for fugitive dust control. Géotechnique, 66(7), 546-555.

[6] He, J., Fang, C., Mao, X., Qi, Y., Zhou, Y., Kou, H., & Xiao, L. (2022). Enzyme-induced carbonate precipitation for the protection of earthen dikes and embankments under surface runoff: Laboratory investigations. Journal of Ocean University of China, 21(2), 306-314.

[7] Ivanov, V., & Chu, J. (2008). Applications of microorganisms to geotechnical engineering for bioclogging and biocementation of soil in situ. Reviews in Environmental Science and Bio/Technology, 7, 139-153.

[8] Jiang, N. J., Yoshioka, H., Yamamoto, K., & Soga, K. (2016). Ureolytic activities of a urease-producing bacterium and purified urease enzyme in the anoxic condition: Implication for subseafloor sand production control by microbially induced carbonate precipitation (MICP). Ecological engineering, 90, 96-104.

[9] Kou, H. L., Liu, J. H., Zhang, P., Wu, C., Ni, P., & Wang, D. (2022). Ecofriendly improvement of coastal calcareous sandy slope using recycled shredded coconut coir (RSC) and bio-cement. Acta Geotechnica, 17(12), 5375-5389.

[10] Kou, H. L., Wu, C. Z., Ni, P. P., & Jang, B. A. (2020). Assessment of erosion resistance of biocemented sandy slope subjected to wave actions. Applied Ocean Research, 105, Article 102401.

[11] Li, Y., Li, Y., Guo, Z., Li, Y. B., & Liu, C. (2023). Durability of MICP-reinforced calcareous sand in marine environments: Laboratory and field experimental study. Biogeotechnics, 1(2), Article 100018.

[12] Liu, K. W., Jiang, N. J., Qin, J. D., Wang, Y. J., Tang, C. S., & Han, X. L. (2021). An experimental study of mitigating coastal sand dune erosion by microbial-and enzymatic- induced carbonate precipitation. Acta Geotechnica, 16, 467-480.

[13] Liu, L., Liu, H., Stuedlein, A. W., Evans, T. M., & Xiao, Y. (2019). Strength, stiffness, and microstructure characteristics of biocemented calcareous sand. Canadian Geotechnical Journal, 56(10), 1502-1513.

[14] Meng, H., Shu, S., Gao, Y., Yan, B., & He, J. (2021). Multiple-phase enzyme-induced carbonate precipitation (EICP) method for soil improvement. Engineering Geology, 294, Article 106374.

[15] Mentaschi, L., Vousdoukas, M. I., Pekel, J. F., Voukouvalas, E., & Feyen, L. (2018). Global long-term observations of coastal erosion and accretion. Scientific Reports, 8(1), 12876.

[16] Montoya, B. M., DeJong, J. T., & Boulanger, R. W. (2014). Dynamic response of liquefiable sand improved by microbial-induced calcite precipitation. Bio-and Chemo-Mechanical Processes in Geotechnical Engineering: Géotechnique Symposium in Print. ICE Publishing125-135.

[17] Neupane, D., Yasuhara, H., Kinoshita, N., & Unno, T. (2013). Applicability of enzymatic calcium carbonate precipitation as a soil-strengthening technique. Journal of Geotechnical and Geoenvironmental Engineering, 139(12), 2201-2211.

[18] Qabany, A. Al, Soga K. Effect of chemical treatment used in MICP on engineering properties of cemented soils. Bio-and Chemo-Mechanical Processes in Geotechnical Engineering:Géotechnique Symposium in Print 2013. ICE Publishing, 2014.

[19] Salifu, E., MacLachlan, E., Iyer, K. R., Knapp, C. W., & Tarantino, A. (2016). Application of microbially induced calcite precipitation in erosion mitigation and stabilisation of sandy soil foreshore slopes: A preliminary investigation. Engineering Geology, 201, 96-105.

[20] Shahin, M. A., Jamieson, K., & Cheng, L. (2020). Microbial-induced carbonate precipitation for coastal erosion mitigation of sandy slopes. Géotechnique Letters, 10(2), 211-215.

[21] Shanahan, C., & Montoya, B. M. (2014). Strengthening coastal sand dunes using microbial- induced calcite precipitation. In Geo-Congress 2014: Geo-Characterization and Modeling for Sustainability, 1683-1692.

[22] van Paassen, L. A., Ghose, R., van der Linden, T. J., van der Star, W. R., & van Loosdrecht, M. C. (2010). Quantifying biomediated ground improvement by ureolysis: large-scale biogrout experiment. Journal of Geotechnical and Geoenvironmental Engineering, 136(12), 1721-1728.

[23] Vousdoukas, M. I., Ranasinghe, R., Mentaschi, L., Plomaritis, T. A., Athanasiou, P., Luijendijk, A., & Feyen, L. (2020). Sandy coastlines under threat of erosion. Nature Climate Change, 10(3), 260-263.

[24] Wang, D. Y., Tang, C. S., Cui, Y. J., Shi, B., & Li, J. (2016). Effects of wetting-drying cycles on soil strength profile of a silty clay in micro-penetrometer tests. Engineering Geology, 206, 60-70.

[25] Whiffin, V. S., Van Paassen, L. A., & Harkes, M. P. (2007). Microbial carbonate precipitation as a soil improvement technique. Geomicrobiology Journal, 24(5), 417-423.

[26] Wu, C., Chu, J., Cheng, L., & Wu, S. (2019a). Biogrouting of aggregates using premixed injection method with or without pH adjustment. Journal of Materials in Civil Engineering, 31(9), Article 06019008.

[27] Wu, C., Chu, J., Wu, S., & Hong, Y. (2019b). 3D characterization of microbially induced carbonate precipitation in rock fracture and the resulted permeability reduction. Engineering Geology, 249, 23-30.

[28] Yasuhara, H., Neupane, D., Hayashi, K., & Okamura, M. (2012). Experiments and predictions of physical properties of sand cemented by enzymatically-induced carbonate precipitation. Soils and Foundations, 52(3), 539-549.