A review & comparative study of some surface geophysical methods applied to the investigation of landfill sites

This report presents the findings of a comparative study of the effectiveness of geophysical techniques in the ground investigation of a 1andfi11 site. Part I of the report introduces the topic with a comprehensive introduction which includes a review of the nature of landfill and an explanation of the need for the investigation requirement. Part II describes trials using various geophysical methods to determine the position of a 1andfill boundary and its depth. It includes a review of similar applications reported in the literature. The geophysical methods were evaluated on a reclaimed domestic refuse tip formed in a sand and gravel quarry, at Panshanger near Welwyn Garden City, Hertfordshire. The methods employed were, seismic refraction, resistivity traversing and sounding, electromagnetic induction traversing and sounding, ground self potential traversing, magnetometer traversing and ground radar traversing. The report concludes that all the methods tried located the boundary, but that electromagnetic induction traversing and magnetic traversing are most successful in determining the boundary position precisely and are also quick to use. Quantitative interpretation of the depth of fill and dip of the boundary using resistivity sounding and seismic refraction surveys was not so successful; in the former case, due to insufficient resistivity contrast between the fill and the base material, and in the latter, due to poor energy propagation through the fill. Recommendations for the application of suitable methods to other categories of filled sites are given.

MPhil thesis.