Influences of variations in the sledgehammer trajectory and collinearity of the geophone array in an MASW survey on the shear-wave velocity profile
Tóm tắt
In professional activities aimed at seismic site classification, geophysical methods based on measurements of surface waves are often used to measure the shear-wave velocity (Vs), with the MASW survey being one of the most common techniques employed for this purpose. An MASW survey is characterized by an in-field configuration that requires a relatively simple setup; however, several uncertainties that arise are related to the survey execution process. Thus, surface irregularities and/or obstacles on the ground surface in conjunction with possible human-related errors can result in alterations to the MASW survey execution. Therefore, it is necessary to possess a clear understanding of the variables that can potentially produce alterations in Vs profiles. The purpose of this study was to evaluate, based on a field measurement campaign, the effect of the repeatability of the sledgehammer trajectory prior to striking the plate and the effects of variations in the collinearity of the geophone arrays on the Vs profile in consideration of various forced alterations commonly encountered in practice. The repeatability of the active source trajectory plays a significant role in the quality and reliability of Vs measurements. Likewise, altering the collinearity of the geophone array leads to reductions in the amplitude at low frequencies, thereby hindering the interpretation of the test. The recorded effects become more relevant depending on the local conditions and whether the surveyed terrain exhibits possible heterogeneity.
Tài liệu tham khảo
ICC (2012) IBC International Building Code. International Code Council, ICC, USA
CEN (2004) EuroCode 8: design of structures for earthquake resistance—part 1: general rules, seismic actions and rules for buildings. European Committee for Standardization, Brussels
NZS (2004) Structural design actions NZS 1170.5, Part 5, Earthquake Actions New Zealand. New Zealand: Standards New Zealand
INN (2012) Earthquake resistant designs of buildings, NCh 433Of1996 Mod. 2012. The Chilean National Standards Institute, Chile
Ismail R, Ibrahim A, Hamid HA, Majid TA, Adnan A (2015) Seismic Site Classification of JKR Bridge at Sungai Sepang Using Multichannel Analysis of Surface Wave (MASW). In: Yusoff M, Hamid N, Arshad M, Arshad A, Ridzuan A, Awang H (eds) InCIEC 2015. Springer, Singapore
Karabulut S (2018) Soil classification for seismic site effect using MASW and ReMi methods: a case study from western Anatolia (Dikili -İzmir). J Appl Geophys 150:254–266
Moffat R, Correia N, Pastén C (2016) Comparison of mean shear wave velocity of the top 30 m using downhole, MASW and bender elements methods. Obras y Proyectos 20:6–15
Park C, Miller R, Xia J (1999) Multichannel analysis of surface waves. Geophysics 64(3):800–808
Foti S, Lai C, Rix G, Strobbia C (2014) Surface wave methods for near-surface site characterization. CRC Press, London
Xia J, Miller R, Park C (1999) Estimation of near surface shear-wave velocity by inversion of Rayleigh waves. Geophysics 64(3):691–700
Moss RES (2008) Quantifying measurement uncertainty of thirty-meter shear-wave velocity. Bull Seismol Soc Am 98(3):1399–1411
Foti S, Hollender F, Garofalo F et al (2018) Guidelines for the good practice of surface wave analysis: a product of the InterPACIFIC project. Bull Earthq Eng 16(6):2367–2420
Garofalo F, Foti S, Hollender F, Bard PY, Cornou C, Cox BR, Ohrnberger M, Sicilia D, Asten M, Di Giulio G, Forbriger T, Guillier B, Hayashi K, Martin A, Matsushima S, Mercerat D, Poggi V, Yamanaka H (2016) InterPACIFIC project: comparison of invasive and non-invasive methods for seismic site characterization. Part I: intra-comparison of surface wave methods. Soil Dyn Earthq Eng 82:222–240
Foti S, Cox BR, Garofalo F, Hollender F, Bard PY, Cornou C, Ohrnberger M, Sicilia D (2015) Uncertainties in Vs profiles from geophysical tests and their influence on seismic ground response analyses: results from the interpacific blind test. In: 6th International Conference on Earthquake Geotechnical Engineering, Christchurch, New Zealand
O’Neill A (2003 Full-waveform reflectivity for modelling, inversion and appraisal of surface wave dispersion in shallow site investigations. Perth, Western Australia: University of Western Australia, 420. (Ph.D. Thesis)
Olafsdottir EA, Erlingsson S, Bessason B (2018) Tool for analysis of multichannel analysis of surface waves (MASW) field data and evaluation of shear wave velocity profiles of soils. Can Geotech J 55(2):217–233
Diaz-Segura EG (2015) Effect of MASW field configuration on the estimation of shear wave propagation velocity in a sloped terrain. Geotech Lett 5(1):21–27
Geometrics, 2012. Operation and reference manual for geometrics seismograph models V. 9.30. Geometrics, USA
Keiswetter D, Steeples D (1995) A field investigation of source parameters for the sledgehammer. Geophysics 60(4):1051–1057
Miller R, Pullan S, Waldner J, Haeni F (1986) Field comparison of shallow seismic sources. Geophysics 51(11):2067–2092
Duran F, Villalobos MJ (2015) Evaluation of the uncertainty of the measuring process of the propagation shear wave velocity. Valparaíso, Chile: Pontificia Universidad Católica de Valparaíso. (Thesis for the degree of civil engineer—in Spanish)
Marosi KT, Hiltunen DR (2004) Characterization of spectral analysis of surface waves shear wave velocity measurement uncertainty. J Geotech Geoenviron Eng 130(10):1034–1041