Abstract

Acoustic emission (AE) sensors have broadly used to monitor the damage of underground structures and tunnels. The reliability of measured signal is determined by the coupling condition of the AE sensors which are embedded in the target underground structure. To secure the reliability of health monitoring results, it is important to understand the characteristics of the coupling materials. In this study, laboratory tests were performed using portland cement, micro cement, and gypsum as coupling materials in order to verify the bleeding characteristics. The effective parameters for bleeding were determined to be water-cement ratio, material type, curing time, and injected volume of coupling materials. As a results of the experimental study, the bleeding rate increases with an increase in a water-cement ratio and an injected volume; for portland cement, water-cement ratio and injected volume effects are larger than the micro cement. However, curing time is not much effective for occurrence of the bleeding phenomenon. It is anticipated that this study may be useful for the selection of suitable coupling materials for installation of acoustic emission sensors.

Keywords

• Acoustic emission sensor;
• Sensor installation;
• Coupling;
• Bleeding

• AE 센서;
• 센서 설치;
• 커플링;
• 블리딩;

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Acknowledgement

Supported by : 국가과학기술연구회

References

1. Amitrano, D., Grasso, J.R., Senfaute, G. (2005), "Seismic precursory patterns before a cliff collapse and critical point phenomena", Geophysical Research Letters, Vol. 32, No. 8, L08314. https://doi.org/10.1029/2004GL022270
2. ASTM C940. (2010), Standard test method for expansion and bleeding of freshly mixed grouts for preplaced-aggregate concrete in the laboratory, ASTM International.
3. Axelsson, M., Gustafson, G., Fransson, A. (2009), "Stop mechanism for cementitious grouts at different water-to-cement ratios", Tunnelling and Underground Space Technology, Vol. 24, No. 4, pp. 390-397. https://doi.org/10.1016/j.tust.2008.11.001
4. Cheon, D.S., Jung, Y.B., Park, E.S. (2014), "Development of acoustic emission monitoring system for the safety of geotechnical structures", Journal of Korean Tunnelling and Underground Space Association, Vol. 16, No. 5, pp. 471-485. https://doi.org/10.9711/KTAJ.2014.16.5.471
5. Draganovic, A. (2009), Bleeding and filtration of cement-based grout, Royal Institute of Technology, Ph.D. Thesis, Div. of Soil and Rock mechanics, Stockholm, pp. 59-61.
6. Ge, M., Hardy, H.R., Wang, H. (2012), "A retrievable sensor installation technique for acquiring high frequency signals", Journal of Rock Mechanics and Geotechnical Engineering, Vol. 4, No. 2, pp. 127-140. https://doi.org/10.3724/SP.J.1235.2012.00127
7. Ghourchian, S., Wyrzykowski, M., Lura, P. (2016), "The bleeding test: a simple method for obtaining the permeability and bulk modulus of fresh concrete", Cement and Concrete Research, Vol. 89, pp. 249-256. https://doi.org/10.1016/j.cemconres.2016.08.016
8. Hoien, A.H., Nilsen, B. (2014), "Rock mass grouting in the Loren tunnel: case study with the main focus on the groutability and feasibility of drill parameter interpretation", Rock Mechanics and Rock Engineering, Vol. 47, No. 3, pp. 967-983. https://doi.org/10.1007/s00603-013-0386-7
9. Houlsby, A.C. (1990), Construction and design of cement grouting: a guide to grouting in rock foundations, John Wiley & Sons, New York, pp. 59-60.
10. Lee, H.B., Oh, T.M., Park, E.S., Lee, J.W., Kim, H.M. (2017), "Factors affecting waterproof efficiency of grouting in single rock fracture", Geomechanics and Engineering, Vol. 12, No. 5, pp. 771-783. https://doi.org/10.12989/gae.2017.12.5.771
11. Lee, J.S., Koh, K.T., Ahn, G.H., Kang, S.T., Kwon, S.H. (2016), "Effects of diameter of cylinder and the number of strand on the bleeding of cement paste", Journal of the Korean Recycled Construction Resources Institute, Vol. 4, No. 1, pp. 38-46. https://doi.org/10.14190/JRCR.2016.4.1.038
12. Massoussi, N., Keita, E., Roussel, N. (2017), "The heterogeneous nature of bleeding in cement pastes", Cement and Concrete Research, Vol. 95, pp. 108-116. https://doi.org/10.1016/j.cemconres.2017.02.012
13. Owino, J.O., Jacobs, L.J. (1999), "Attenuation measurements in cement-based materials using laser ultrasonics", Journal of Engineering Mechanics, Vol. 125, No. 6, pp. 637-647. https://doi.org/10.1061/(ASCE)0733-9399(1999)125:6(637)
14. Pelletier, L., Winnefeld, F., Lothenbach, B. (2010), "The ternary system Portland cement-calcium sulphoaluminate clinker-anhydrite: hydration mechanism and mortar properties", Cement and Concrete Composites, Vol. 32, No. 7, pp. 497-507. https://doi.org/10.1016/j.cemconcomp.2010.03.010
15. Shirlaw, J.N., Kay, W., Venu. P. (2014), "Rock fissure grouting in Singapore granite for building protection during station construction", Proceedings of the eighth International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground, Seoul, pp. 375-380.
16. Wang, H., Ge, M. (2008), "Acoustic emission/microseismic source location analysis for a limestone mine exhibiting high horizontal stresses", International Journal of Rock Mechanics and Mining Sciences, Vol. 45, No. 5, pp. 720-728. https://doi.org/10.1016/j.ijrmms.2007.08.009
17. You, K.H., Jie, H.K., Seo, K.W., Kim, S.J., You, D.W. (2012), "A study on the correlation between the rock mass permeability before and after grouting & injection volume and the parameters of Q system in a jointed rock mass tunnel", Journal of Korean Tunnelling and Underground Space Association, Vol. 14, No. 6, pp. 617-635. https://doi.org/10.9711/KTAJ.2012.14.6.617
18. Young, R.P., Collins, D.S. (2001), "Seismic studies of rock fracture at the Underground Research Laboratory, Canada", International Journal of Rock Mechanics and Mining Sciences, Vol. 38, No. 6, pp. 787-799. https://doi.org/10.1016/S1365-1609(01)00043-0