Interpretation of data from uphole refraction surveys

Franklin, A. G. (Arley G.)

Please use this identifier to cite or link to this item: https://hdl.handle.net/11681/10143

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DC Field	Value	Language
dc.contributor.author	Franklin, A. G. (Arley G.)	-
dc.date.accessioned	2016-06-20T13:52:52Z	-
dc.date.available	2016-06-20T13:52:52Z	-
dc.date.issued	1980-06	-
dc.identifier.uri	http://hdl.handle.net/11681/10143	-
dc.description	Miscellaneous Paper	-
dc.description	Abstract: The conventional interpretation of the data from an uphole refraction survey is based on the similarity between a plot of contours drawn on uphole arrival times and a wave-front diagram, which shows successive positions of the wave front produced by a single shot location at the ground surface. However, the two are alike only when the ground consists solely of homogeneous strata, oriented either horizontally or vertically. In this report, the term "Meissner diagram" is used for the plot of arrival times from the uphole refraction survey in order to maintain the distinction between it and a true wave-front diagram. Where departures from the case of homogeneous, horizontal strata exist, the interpretation of the Meissner diagram is not straightforward, although a partial interpretation in terms of a horizontally stratified system is usually possible. A systematic approach to the interpretation problem, making use of such a partial interpretation, is proposed. It consists of: (A.) determination of a tentative set of layer velocities and thicknesses on the basis of the wave-front interpretation; (B.) computation of theoretical travel times for the uphole refraction survey with these layer parameters; (C.) generation of an anomaly diagram by contouring the differences between observed and theoretical travel times; and (D.) identification of causative geological features by comparison with anomaly diagrams representing known or hypothesized geological conditions. Meissner diagrams and companion anomaly diagrams are presented for cases of subsurface cavities of different sizes in rock of different velocities, ridges and depressions on the bedrock surface, vertical offsets, dipping strata, and various errors of interpretation and measurement. Examples of field data from two sites are presented. Algorithms for computer generation of Meissner diagrams and anomaly diagrams are presented in Appendix A. On the basis of the studies described, it is concluded that the interpretation of uphole refraction data can be aided by the use of anomaly diagrams and that the nature of many geological features may be identified by comparison with anomaly diagrams representing hypothetical cases. While seismic travel times are affected by the presence of subsurface cavities and large cavities are identifiable, the sensitivity of the method is marginal for practical use in cavity detection. Some cavities large enough to be of engineering significance (e.g., a tunnel of 4-m diameter) may be practically undetectable by this method.	-
dc.publisher	Geotechnical Laboratory (U.S.)	-
dc.publisher	Engineer Research and Development Center (U.S.)	-
dc.relation	http://acwc.sdp.sirsi.net/client/en_US/search/asset/1042191	-
dc.relation.ispartofseries	Miscellaneous paper (U.S. Army Engineer Waterways Experiment Station) ; GL-80-5.	-
dc.rights	Approved for public release; distribution is unlimited.	-
dc.source	This Digital Resource was created from scans of the Print Resource	-
dc.subject	Refraction	-
dc.subject	Uphole refraction	-
dc.subject	Seismic refraction	-
dc.subject	Seismic refraction method	-
dc.subject	Seismic surveys	-
dc.subject	Subsurface exploration	-
dc.subject	Seismology	-
dc.subject	Geophysical surveys	-
dc.title	Interpretation of data from uphole refraction surveys	-
dc.type	Report	en_US
Appears in Collections:	Miscellaneous Paper

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