Depth of influence of the impact roller for improving ground in situ and for thick layer compaction

What is it about?

This technical paper addresses the need for the applications of: - improving ground in situ; and - compaction of soil in thick layers to be treated separately as they are two distinctly different problems (but are often confused). Relationships are proposed to predict depths to which rolling dynamic compaction can improve ground in situ, and predict layer thicknesses that can be compacted. The results from a full-scale field research trial undertaken in homogeneous soil are used to verify the relationships, which are also in broad agreement with published case studies over the past four decades that have used the 8-tonne 4-sided impact roller

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Photo by Clay Banks on Unsplash

Photo by Clay Banks on Unsplash

Why is it important?

Key findings or contributions to knowledge from this paper include: • Pressures were measured up to depth of 3.85 m below the ground surface using buried earth pressure cells. • The largest magnitudes of pressure were confined to the top 2 m beneath the ground surface. • This paper examines two common applications of rolling dynamic compaction: improving ground in situ and compaction of soil in thick layers. This paper highlights that the two applications need to be treated separately. • Relationships are presented to predict: - the effective depth of improvement; appropriate for determining the depth to which ground can be significantly improved in situ. - the depth of major improvement; appropriate for determining the layer thickness that can be compacted. • The predictions from the relationships and the results of the case study presented in this paper are in broad agreement with published papers that have used the 8-tonne 4-sided impact troller over the past forty years.

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