Evaluating Ground Improvement after Blast Densification: Performance at the Oakridge Landfill
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 142, Issue 1
Abstract
Blasting has long been used as a ground improvement technique to densify loose granular soils. Explosives detonated at depth induce liquefaction in the target sand followed by pore pressure dissipation and attendant consolidation. Improvement typically is verified via measured surface settlements and increased penetration resistance with in situ tests such as the cone penetration test (CPT). However, an increase in penetration resistance is often not observed for months or even years after blasting. The results of instrumentation at a production blast zone at the Oakridge Landfill are reported herein. Instrumentation included surface settlements, pore pressure measurements inside and outside the blast zone, preblast and postblast piezocone () soundings, and gas concentrations of pore fluid. No increase in penetration resistance with the was detected 53 days after the final blast, despite more than 0.5 m of settlement and an increase in relative density to 80% or more in some areas. Results of gas chromatography tests on the collected pore fluid samples showed that gas produced by the explosives was trapped in the target layer and saturated the groundwater with . Consequently, no more could dissolve into solution, and gas existed as occluded bubbles. The presence of occluded bubbles created an unsaturated condition, which in turn affected the mechanical behavior of the densified soil and reduced the CPT tip resistance during postblast testing.
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Acknowledgments
Funding for this study was provided by the National Science Foundation through Grant No. CMMI 1235440. The support of Dr. Richard Fragaszy, program director at NSF, is greatly appreciated. The authors would like to thank Waste Management for allowing access to the site. In addition, the authors would like to thank Dr. Robert Bachus and Dr. Majdi Othman of Geosyntec Consultants for their interest and help with this work, and Mr. Will McBryde of GeoSyntec Consultants and Randy Phillips of AE Drilling for their help and cooperation during the field portion of this study.
References
ACC (Atlantic Coast Consulting). (2010). “2010 annual groundwater and methane monitoring report.” Roswell, GA.
Alley, W. M. (1993). Regional ground-water quality, Van Nostrand Reinhold, New York.
Almon, E., and Magaritz, M. (1990). “Dissolved common gases in groundwaters of the Appalachian region.” J. Hydrol. 121(1–4), 21–32.
Aravena, R., Schiff, S. L., Trumbore, S. E., Dillon, P. J., and Elgood, R. (1992). “Evaluating dissolved inorganic carbon cycling in a forested lake watershed using carbon isotopes.” Radiocarbon, 34(3), 636–645.
Bachus, R. C., Hebeler, T. E., Santamarina, J. C., Othman, M. A., and Narsilio, G. A. (2008). “Use of field instrumentation and monitoring to assess ground modification by blast densification.” Proc., 15th Great Lakes Geotechnical/Geoenvironmental Conf. Applications of Geotechnical Instrumentation for Performance Evaluation of Constructed Facilities, ASCE, Reston, VA.
Blicher-Mathiesen, G., McCarty, G. W., and Nielsen, L. P. (1998). “Denitrification and degassing in groundwater estimated from dissolved dinitrogen and argon.” J. Hydrol., 208(1–2), 16–24.
Camp, W. M., Mayne, P. W., and Rollins, K. M. (2008). “Cone penetration testing before, during, and after blast-induced liquefaction.” ASCE, Sacramento, CA, 10.
Charlie, W. A., Rwebyogo, M. F. J., and Doehring, D. O. (1992). “Time dependent cone penetration resistance due to blasting.” J. Geotech. Eng., 1200–1215.
Cirpka, O. A., and Kitanidis, P. K. (2001). “Transport of volatile compounds in porous media in the presence of a trapped gas phase.” J. Cont. Hydrol., 49(3–4), 263–285.
Cosby, B. J., Hornberger, M., and Galloway, J. N. (1985). “Modeling the effects of acid deposition: Assessment of a lumped parameter model of soil water and streamwater chemistry.” Water Resour. Res., 21(1), 51–63.
Deutsch, W. J. (1997). Groundwater geochemistry: Fundamentals and applications to contamination, Lewis, New York.
Dowding, C. H., and Hryciw, R. D. (1986). “A laboratory study of blast densification of saturated sand.” J. Geotech. Eng., 187–199.
Fordham, C. J., McRoberts, E. C., Prucell, B., and McLaughlin, P. (1991). “Practical and theoretical problems associated with blast densification of loose sands.” Proc., 44th Canadian Geotechnical Conf. of the Canadian Geotechnical Society, Richmond, BC, Canada, 92–98.
Fortuin, N. P. M., and Willemsen, A. (2005). “Exsolution of nitrogen and argon by methanogenesis in Dutch ground water.” J. Hydrol., 301(1–4), 1–13.
Fredlund, D. G., and Rahardjo, H. (1993). Soil mechanics for unsaturated soils, Wiley, New York.
Gallant, A. P. (2014). “A field and numerical evaluation of blast densification at a test section.” Ph.D. dissertation, Northwestern Univ., Dept. of Civil Engineering, Evanston, IL, 395.
Gandhi, S., Dey, A., and Selvam, S. (1999). “Densification of pond ash by blasting.” J. Geotech. Geoenviron. Eng., 889–899.
GeoSyntec Consultants. (2005). “Ground improvement results of optimized blast densification program.”, Oakridge Sanitary Landfill, USA Waste Services, Dorchester, SC.
Gohl, W. B., Howie, J. A., and Everard, J. (1996). “Use of explosive compaction for dam foundation preparation.” Proc., 49th Canadian Geotechnical Conf., Vol. 2, Canadian Geotechnical Society, Richmond, BC, Canada, 758–793.
Gohl, W. B., Howie, J. A., Hawson, H. H., Diggle, D. (1994). “Field experience with blast densification.” Proc., 5th U.S. National Conf. on Earthquake Engineering, Vol. 4, Earthquake Engineering Research Institute, Oakland, CA, 221–231.
Gohl, W. B., Jefferies, M. G., Howie, J. A., and Diggle, D. (2000). “Explosive compaction: Design, implementation and effectiveness.” Geotechnique, 50(6), 657–665.
Gohl, W. B., Tsujino, S., Wu, G., Yoshida, N., Howie, J. A., and Everard, J. (1998). “Field application of explosive compaction in silty soils and numerical analysis.” Proc., Geotechnical Earthquake Engineering and Soil Dynamics III, GSP 75, ASCE, Reston, VA, 654–665.
Grozic, J. L., Robertson, P. K., and Morgenstern, N. R. (1999). “The behavior of loose gassy sand.” Can. Geotech. J., 36(3), 482–492.
Hall, C. E. (1962). “Compacting a dam foundation by blasting.” J. Soil Mech. Found. Div., 88(3), 33–51.
Handford, G. T. (1988). “Densification of an existing dam with explosives.” Proc., Hydraulic Fill Structures, ASCE, Reston, VA, 750–762.
Heaton, T. H. E., and Vogel, J. C. (1980). “Rate of oxygen removal in some South African groundwaters.” Hydrol. Sci. B, 25(4), 373–377.
Heaton, T. H. E., and Vogel, J. C. (1981). “Excess air in groundwater.” J. Hydrol., 50, 201–216.
Holocher, J., et al. (2002). “Experimental investigations on the formation of excess air in quasi-saturated porous media.” Geochim. Cosmochim. Acta, 66(23), 4103–4117.
Hope, D., Dawson, J. J. C., Cresser, M. S., and Billett, M. F. (1995). “A method for measuring free in upland streamwater using headspace analysis.” J. Hydrol., 166(1–2), 1–14.
Hryciw, R. D., and Dowding, C. H. (1987). “Cone penetration of partially saturated sands.” Geotech. Test. J., 10(3), 135–141.
Jamiolkowski, M., Ladd, C. G., Germaine, J. T., and Lancellotta, R. (1985). “New developments in field and laboratory testing of soils.” Proc., 11th Int. Conf. on Soil Mechanics and Foundation Engineering, Transportation Research Board, Washington, DC, 57–153.
Jassal, R., Black, A., Novak, M., Morgenstern, K., Nesic, Z., and Gaumont-Guay, D. (2005). “Relationship between soil concentrations and forest-floor effluxes.” Agric. For. Meteorol., 130(3–4), 176–192.
Kimmerling, R. E. (1994). “Blast densification for mitigation of dynamic settlement and liquefaction.”, Washington State Dept. of Transportation, Olympia, WA.
La Fosse, U., and Rosenvinge, T. V., IV (1992). “Densification of loose sands by deep blasting.” Proc., Grouting, Soil Improvement and Geosynthetics, ASCE, Reston, VA, 954–968.
Liao, T., and Mayne, P. W. (2005). “Cone penetrometer measurements during Mississippi embayment seismic excitation experiment.” Earthquake Eng. Soil Dyn., 133(158), 1–12.
Lindsay, W. L. (1979). Chemical equilibria in soils, Wiley, New York.
Lyman, A. K. B. (1941). “Compaction of cohesionless foundation soils by explosives.” Trans. ASCE, 107, 1330–1348.
Macpherson, G. L. (2009). “ distribution in groundwater and the impact of groundwater extraction on the global C cycle.” Chem. Geol., 264(1–4), 328–336.
Mesri, G., Feng, T. W., and Benak, J. M. (1990). “Postdensification penetration resistance of clean sands.” J. Geotech. Eng., 1095–1115.
Mitchell, J. K., and Solymar, Z. V. (1984). “Time-dependent strength gain in freshly deposited or densified sand.” J. Geotech. Eng., 1559–1576.
Narsilio, G. A., Santamarina, J. C., Hebeler, T., and Bachus, R. (2009). “Blast densification: Multi-instrumented case history.” J. Geotech. Geoenviron. Eng., 723–734.
Okamura, M., and Soga, Y. (2006). “Effects of pore fluid compressibility on liquefaction resistance of partially saturated sand.” Soils Found., 46(5), 695–700.
Okamura, M., and Teraoka, T. (2004). “Shaking table tests to investigate soil desaturation as a liquefaction countermeasure.” Proc., Seismic Performance and Simulation of Pile Foundations in Liquefied and Laterally Spreading Ground, ASCE, Reston, VA, 282–293.
Peck, A. J. (1969). “Entrapment, stability, and persistence of air bubbles in soil water.” Aust. J. Soil Res., 7(2), 79–90.
Prugh, B. J. (1963). “Densification of soils by explosive vibrations.” J. Constr. Div., 89(CO1), 79–100.
Puckett, L. J., and Hughes, W. B. (2005). “Transport and fate of nitrate and pesticides: Hydrogeology and riparian zone processes.” J. Environ. Qual., 34(6), 2278–2292.
Rad, N. S., and Lunne, T. (1994). “Gas in soil. I: Detection and profiling.” J. Geotech. Geoenviron. Eng., 697–715.
Rad, N. S., Vianna, A. J. D., and Berre, T. (1994). “Gas in soil. II: Effect of gas on undrained static and cyclic strength of sand.” J. Geotech. Geoenviron. Eng., 716–736.
Raju, V. R., and Gudehus, G. (1994). “Compaction of loose sand deposits using blasting.” Proc., 13th Int. Conf. on Soil Mechanics and Foundation Engineering, ASCE, Reston, VA, 1145–1150.
Rebata-Landa, V., and Santamarina, J. C. (2012). “Mechanical effects of biogenic nitrogen gas bubbles in soils.” J. Geotech. Eng., 128–137.
Robertson, P. K., Campanella, R. G., Gillespie, D., Grieg, J. (1986). “Use of piezometer cone data.” Proc., Use of In-Situ Tests in Geotechnical Engineering, S. P. Clemence, ed., ASCE, New York, 1263–1280.
Rollins, K. M., and Anderson, J. K. S. (2008). “Cone penetration resistance variation with time after blast liquefaction testing.” Geotechnical Earthquake Engineering and Soil Dynamics IV, GSP 181, ASCE, Sacramento, CA, 10.
Schmertmann, J. H. (1987). “Discussion of ‘time-dependent strength gain in freshly deposited or densified sand.’” J. Geotech. Eng., 173–175.
Sherif, M. A., Ishibashi, I., and Tsuchiya, C. (1977). “Saturation effects on initial soil liquefaction.” J. Geotech. Eng., 103(GT8), 914–917.
Solymar, Z. V. (1984). “Compaction of alluvial sands by deep blasting.” Can. Geotech. J., 21(2), 305–321.
Tebbutt, T. H. Y. (1992). Principles of water quality control, 4th Ed., Pergamon Press, Oxford.
Vega-Posada, C. A. (2012). “Evaluation of liquefaction susceptibility of clean sands after blast densification.” Ph.D. dissertation, Northwestern Univ., Dept. of Civil Engineering, Evanston, IL, 209.
Vega-Posada, C. A., Finno, R. J., and Zapata-Medina, D. G. (2014). “Effect of gas in the mechanical behavior of medium dense sands.” J. Geotech. Geoenviron. Eng., 04014063.
Weems, R. E., Lemon, E. M., Jr., and Nelson, M. S. (1997). “Geology of the Pringletown, Ridgeville, Summerville, and Summerville Northwest 7.5-minute quadrangles, Berkeley, Charleston, and Dorchester Counties, South Carolina.” USGS, 1–9.
Weymann, D., et al. (2008). “Assessment of excess and groundwater emission factors of nitrate-contaminated aquifers in northern Germany.” Biogeosciences Discuss., 5, 1263–1292.
Wild, P. A. (1961). “Tower foundations compacted with explosives.” Electr. World, 66, 36–38.
Xia, H., and Hu, T. (1991). “Effects of saturation and back pressure on sand liquefaction.” J. Geotech. Eng., 1347–1363.
Yager, R. M., and Fountain, J. C. (2001). “Effect of natural gas exsolution on specific storage in a confined aquifer undergoing water level decline.” Ground Water, 39(4), 517–525.
Yoshimi, Y., Tanaka, K., and Tokimatsu, K. (1989). “Liquefaction resistance of a partially saturated sand.” Soils Found., 29(3), 157–162.
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Journal of Geotechnical and Geoenvironmental Engineering
Volume 142 • Issue 1 • January 2016
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© 2015 American Society of Civil Engineers.
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Received: Aug 12, 2014
Accepted: May 4, 2015
Published online: Jul 6, 2015
Discussion open until: Dec 6, 2015
Published in print: Jan 1, 2016
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