Numerical replication of vibrations caused by dynamic compaction

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Journal Title

Journal ISSN

Volume Title

Insinööritieteiden korkeakoulu | Master's thesis

Date

2024-08-19

Department

Major/Subject

Geotechnical Engineering

Mcode

Degree programme

Master's Programme in Geoengineering (GEO)

Language

en

Pages

61+25

Series

Abstract

There have been few simulations of the vibration caused by dynamic compaction made. On top of scientific complexity, additionally, there is a lack of accurate data, and the issue is that simulations tend to be unique due to specific site soil properties and behaviour. Vibrations caused by dynamic compaction are also highly uncertain; hence, the method is usually applied only in remote areas. However, dynamic compaction is characterised by low carbon emissions and could be utilised in urban areas where nearby structures are vulnerable to vibrations. This study presents a comprehensive overview of wave propagation, introduces a constitutive model, and presents a Finite Element Method replication of the measured vibration caused by dynamic compaction. The introduced constitutive model considers a non-linear stress-strain relationship at small strains based on a constant reference stiffness degradation curve. The model's capabilities were demonstrated by replicating vibrations caused by dynamic compaction measured during construction in Gdańsk by the Menard Group. The study replicated vibrations from two falling heights of the tamper, 5 and 10 m, in a sandy soil area. The model can achieve high accuracy when calibrated correctly, providing a reliable tool for predicting wave vibrations. However, it is essential to note that the maximum shear modulus can significantly influence the result, and the dynamic properties of the soil are a crucial factor. The need for an accurate estimation of the damping ratio is evident. While the model can be applied in practice, paying attention to the importance of input parameters from the field is crucial, as they play a significant role in the model's performance and the accuracy of its predictions.

Description

Supervisor

Sołowski, Wojciech

Thesis advisor

Sołowski, Wojciech

Keywords

vibrations, dynamic analysis, dynamic compaction, FEM modelling, small strain non-linear constitutive model

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Citation