ISO 24057:2022

Geotechnics — Array measurement of microtremors to estimate shear wave velocity profile

This document specifies requirements for equipment, survey procedure, data analysis and reporting of array measurement of microtremors which is one of the non-destructive testing methods with an array of sensors deployed on the ground surface. This document applies to the array measurement of microtremors to estimate a 1D shear wave velocity profile. This document specifically describes array measurement of microtremors using vertical ground vibration to estimate an S-wave velocity profile by processing microtremor records based on the fundamental mode of Rayleigh waves.

Géotechnique — Mesure du bruit de fond sismique en réseau pour estimer un profil de vitesse des ondes de cisaillement

Ce document spécifie les exigences relatives au matériel, à la procédure d’acquisition, d'analyse et au rapport d’étude de la mesure du bruit de fond sismique en réseau, qui est l'une des méthodes d’essais non destructives à l’aide d’un réseau de capteurs déployés à la surface du sol. Ce document s'applique à la mesure du bruit de fond en réseau pour estimer un profil de vitesse d'onde de cisaillement 1D. Plus particulièrement, ce document décrit la mesure du bruit de fond en réseau par l’enregistrement des vibrations verticales du sol et de l'analyse du mode fondamental des ondes de Rayleigh.

General Information

• Status: Published
• Publication Date: 03-Nov-2022
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: ISO/TC 182 - Geotechnics
• Drafting Committee: ISO/TC 182/WG 9 - Geotechnical aspects of geophysical methods
• Current Stage: 6060 - International Standard published
• Start Date: 04-Nov-2022
• Due Date: 11-Oct-2022
• Completion Date: 04-Nov-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 24057
First edition
2022-11
Geotechnics — Array measurement of
microtremors to estimate shear wave
velocity profile
Géotechnique — Mesure en réseau des microtrémors pour estimer un
profil de vitesse des ondes de cisaillement
Reference number
© ISO 2022
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Symbols and abbreviated terms . 2
4 Equipment . 3
4.1 General . 3
4.2 Sensor . 3
4.3 Time calibration equipment . 4
4.4 Data logger . 4
4.5 Distance and location measuring instrument . 4
4.6 Protective products . 4
5 Survey procedure .5
5.1 General . 5
5.2 Preparation . 6
5.2.1 Desk study . 6
5.2.2 Array design . 6
5.3 Field observation . 6
5.3.1 Huddle test . 6
5.3.2 Setting of sensors. 7
5.3.3 Recording . 7
5.4 Data organization after field observation . 8
5.4.1 Quality control of the microtremor record. 8
5.4.2 Data storage . 8
6 Data Analysis . 8
6.1 Data organization after field observation . 8
6.2 Phase velocity analysis. 8
6.3 Inversion analysis to S-wave velocity profile . 10
6.4 Uncertainty of phase velocity and S-wave velocity profile . 10
7 Reporting .11
7.1 General . 11
7.2 Field report . 11
7.3 Analysis report . 13
Annex A (informative) Example of a figure and a table schematic figure of array
measurement of microtremors .15
Annex B (informative) Example of microtremor records and analysis results .16
Annex C (normative) Array design .18
Annex D (informative) Frequency characteristics of sensors in huddle test .22
Annex E (informative) Examples of good and poor quality microtremor records .23
Annex F (informative) Methods for phase velocity analysis .25
Annex G (informative) Method for inversion analysis to S-wave velocity profile .32
Annex H (informative) Uncertainty .34
Bibliography .38
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 182, Geotechnics.
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iv
Introduction
This document provides the specifications on the equipment, survey and analysis procedure of array
measurement of microtremors in order to estimate shear wave velocity profile.
This document is intended for use by administrators of infrastructure facilities (public sector
institutions, such as national and local governments, and private institutions), building constructors,
house builders, consultants, academia, and public/private research institutions. The array measurement
of microtremors deliverable described in this document can be useful in various engineering fields such
as the
— estimation of geotechnical site conditions for construction;
— stability assessment of foundations;
— evaluation of the risk for soil liquefaction;
— evaluation/prediction of earthquake ground motions.
Array measurement of microtremors is one of the geophysical measurements using surface waves,
and it is a non-destructive testing method described in an application manual of geophysical methods
[5]
to engineering and environmental problems for estimating S-wave velocity profile from dispersive
characteristics of the surface waves. Reliability of the method has been evaluated by blind tests and
[6],[12]
numerical simulations in several international projects .
The array measurement of microtremors is a passive method using natural and artificial ambient
vibrations. Since power of the ambient vibrations is highly variable from one site to the other, it
will possibly not be applicable to a site where the ambient vibration level is less than internal noise
of measuring instruments. The array measurement of microtremors using vertical ground vibration
to estimate an S-wave velocity profile by processing microtremor records based on the fundamental
mode of Rayleigh waves is the most common surface wave method. In addition to the fundamental
mode, including the processing of higher modes of the Rayleigh waves improves the reliability of
the estimated S-wave velocity profile. However, a procedure for identifying the higher modes from
observed microtremors is not authorized in academics yet. Hence, analysing the higher mode of the
Rayleigh waves is out of scope in this document. Love waves is another type of surface waves extracted
from horizontal ground vibration. Joint use of the Rayleigh waves and the Love waves also improves
the reliability of the estimated S-wave velocity profile. However, the surface wave method using Love
waves is not widely used in practice. Hence, the measurement and the analysing of the Love waves are
out of scope in this document. Therefore, the array measurement of microtremors using vertical ground
vibration and the data analysis of the microtremor records with an assumption of the fundamental
mode of Rayleigh waves are described in this document.
This method provides a vertical S-wave velocity profile. The depth range of the S-wave velocity profile
varies depending on the wavelength of observed s
...