An Investigation of the Relationship between Standard Penetration Test and Shear Wave Velocity for Unsaturated Soils (A Case Study of The Earthquake Prone Area of the Albertine Graben)
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Date
2014
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Publisher
Earthquake Engineering and Seismology Istanbul
Abstract
When an earthquake occurs, seismic waves radiate away from the source and travel rapidly through
the earth’s crust. When these waves reach the ground surface, they cause shaking that may last from a
few seconds to minutes. The nature and distribution of earthquake damage is strongly influenced by
the response of soils to dynamic loading. This response is controlled to a large extent by the dynamic
soil properties such as stiffness, damping, Poisson’s ratio and density. The prediction of ground
shaking at soil sites requires knowledge of the soil expressed in terms of shear wave velocity (Vs). It is
preferable to measure Vs by in situ wave propagation tests. However, it is often not economically
feasible to conduct these tests at all locations. On the other hand the Standard Penetration Test (SPT)
is the most common in situ site geotechnical test which is carried out in most site investigations.
Hence a reliable correlation between Vs and SPT would be of considerable advantage, reducing the
cost of site investigations. This paper presents, therefore, the development of an empirical relationship
between Vs and SPT N-value for the soils of Kasemene Oil exploration area located in Buliisa District
in Uganda. As part of an attempt to mitigate the effects of earthquakes in the area, a model is needed
to predict Vs required for site response analysis. The effect of correcting Vs and SPT N-values on the
model was evaluated and the model was also compared with published models. The process involved
correlating 273 data pairs of Vs and SPT N-values which were measured at the same depth. The
extensive Vs measurement was carried out using the Multichannel Analysis of Surface Waves
(MASW) technique. The SPT N-value data was measured from boreholes drilled within the
boundaries of the MASW survey lines. Results show that the relationship between Vs and
SPT N-value depends on the effective overburden stress, and that ignoring the influence of effective
overburden stress creates bias in the model. It was also found out that none of the published models
fitted the data well and there is tremendous difference in the Vs values predicted by these models. The
model exhibits good prediction performance and can be used to predict shear wave velocity for soils
within the study area or for areas with a similar soil type.
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Citation
TUMWESIGE, R., GIDUDU, A., BAGAMPADDE, U., & RYAN, C. (2014). AN INVESTIGATION OF THE RELATIONSHIP BETWEEN STANDARD PENETRATION TEST AND SHEAR WAVE VELOCITY FOR UNSATURATED SOILS (A CASE STUDY OF THE EARTHQUAKE PRONE AREA OF THE ALBERTINE GRABEN). In Second Conference on Earthquake Engineering and Seismology Istanbul (pp. 25-29).