Evaluation of Cavity Formation and the Use of Cut-off Wall to Reduce the Risk of Washing Subsurface Fine Material


This study shows the results of mapping numerous cavities and distress which appeared and detected in Qassim area, Saudi Arabia. This phenomenon was observed near a school building and residential area and became a serious risk to occupants and residents. The survey was carried out applying geotechnical techniques which included advancing rotary boreholes to depths of 23 m to 30 m with sampling and testing. The evaluation process also included resistivity imaging profiles using 2D electrical resistivity measurements. Results obtained from this research showed a thick top layer of silty clayey sand soil rich of gypsum and carbonate presenting a hazardous and high-risk soil type. The percentage of fines that are likely to be washed out as a result of chemical disintegration and exposure to significant hydraulic gradient was of great concern. Assessment was made using combined geotechnical and geophysical approach in addition to chemical tests. Based on the data collected and analysis of test results a practical solution was suggested to solve this problem. The use of cut-off wall in order to reduce the level of subsurface scour and cajuvity formation were found appropriate. The depth of the cut off wall was determined based on the subsurface geological profile. Advantages of this approach and concerns need to be considered in adopting typical solutions that are presented.

Share and Cite:

Alfouzan, F. , A Dafalla, M. and Alharbi, A. (2013) Evaluation of Cavity Formation and the Use of Cut-off Wall to Reduce the Risk of Washing Subsurface Fine Material. Open Journal of Geology, 3, 71-76. doi: 10.4236/ojg.2013.32B015.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] H. Abdulrahman and Alghamdi, “An Investigation of the Structural Framework beneath Riyadh City Using Gravity and Aeromagnetic Evidence,” 2007, Unpublished thesis, KSU, Riyadh.
[2] R. W. Powers, L. F. Ramirez, C. D. Redmond and E. L. Elberg, “Geology of the Arabian Penisula. Sedimentary Geology of Saudi Arabia,” US Geological Survey Professional Paper, 560-D, 1966, p. 147.
[3] Z. Abu-Hassanein, C. Benson and L. Blotz, “Electrical Resisitivity of Compacted Clay,” Journal of Geotechnical Engineering, Vol. 122, No. 5, 1996, pp. 397-406. doi:10.1061/(ASCE)0733-9410(1996)122:5(397)
[4] R. J. Kalinski and W. E. Kelly, “Electrical-Resistivity Measurement for Evaluation Compacted-Soil Liners.,”Journal of Geotechnical Engineering, Vol. 120, No. 2 1994, pp. 451-457. doi:10.1061/(ASCE)0733-9410(1994)120:2(451)
[5] G. L. Yoona and J. B. Parkb, “Sensitivity of Leachate and Fine Contents on Electrical Resistivity Variations of Sandy Soils,” Journal of Hazardous Materials, Vol. 84, No. 2-3, 2001, pp. 147-161.
[6] W. M. Telford, L. P. Geldart and R. E. Sheriff, Applied Geophysics, second edition, Cambridge University Press, 1990. doi:10.1017/CBO9781139167932
[7] ASTM, American Standard Testing Methods, 2002, ASTM D 2487and ASTM D 5333. Annual Book of ASTM Standards, Vol. 04.08.

Copyright © 2024 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.