Ground improvement

When the behaviour of the fill mass (after deposition) and/or the underlying soil does not meet the required design criteria, ground improvement techniques can be implemented to improve the properties of the fill and/or subsoil. 

The selection of an adequate soil improvement technique requires understanding of the fundamental behaviour of soils, knowledge of various ground improvement techniques, comprehension of soil-structure interaction and acquaintance with the performance and limitations of available equipment (Chu et al, 2009). This specific combination of knowledge, expertise and experience may require consultancy of a Contractor specialised in ground improvement techniques. 

Ground improvement of hydraulic fills may include the fill mass itself, the subsoil underlying the fill or both. It is typically carried out to  

If design studies show that ground improvement does finally not result in the required fill mass behaviour, then the (technical) feasibility of the project may depend on the possibility to re-design the foundations of the superstructures. The input for such a design should then be based on the existing and/or improved soil conditions. 

This chapter presents the purpose and principles of the most common ground improvement methods used in reclamation projects. For more techniques reference is made to Table 7.1 and the paper prepared by Chu et al. (2009). 

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Over a decade has passed since publication of the second edition. During this time the major changes have been the movement of chemical grouting from remedial use to preventive use, and the development and growing use of other methods of ground improvement. Although new grouts have been developed, silicates and acrylics still dominate the domestic market. 

Geotechnical Special Publication Number 113, Foundations and Ground Improvement, ASCE, June 9, 2001. 

Source Bergato, D.T. et al, "Soft Ground Improvement", p 24, ASCE Press, 1996. Reproduced by permission of ASCE, Reston, VA. 

Schaefer, V. R., Ground Improvement, Ground Reinforcement, Ground Treatment Developments, 1987-1997, Geotechnical Special Publication No. 69, ASCE, NY. 

Rathmayer, H., Deep Mixing Methods for Soft Subsoil Improvement in the Nordic Countries, Proceedings 2nd International Conference on Ground Improvement Geosystems, Tokyo, Japan, May, 1996. 

Figure 9.10 Soilcrete arch above tunnel structure. (Billings, T., et al., "Grouting Program Bridges New Building Loads over Unused Railroad Tunnel," Foundations and Ground Improvement, Geotechnical SP No. 113, June 2001, p 126. Reproduced by permission of ASCE, Reston, VA.)...

Mixtures of naturally deposited sand, medium plasticity clay, and bentonite with recycled rubber produced composite materials suitable for use in ground improvement (Becker and Vrettos, 2011). Mechanical properties of soils relevant to the application of such composites in geotechnical engineering problems were investigated. The compaction, permeability, compressibility, and flexural and shear strength were determined for typical mixtures along swelling of the bentonite-mbber mixtures. 

Nashed, R., Thevanayagam, S., Martin, G. R. (2009). Densification and Liquefaction Mitigation of Saturated Silty Soils by D5mamic Compaction -Design. Ground Improvement Journal, Institute of Civil Engineers, UK. 

Coelho, P.A.L.F., Haigh, S.K., Madabhushi, S.P.G., O Brien, A.S. (2007). Post-earthquake behaviour of footings when using densification as a liquefaction resistance measure. Ground Improvement Journal - Special Issue on Ground Improvement techniques, 77(1), 45-53. 

Cortlever, N.G. 2001. Design of double railway track on Augeo Pile System. Symposium on Soft Ground Improvement and Geosynthetic Application, AIT, Bangkok. 

The classification principles established are applicable to natural soils as well as similar man-made material in situ and re-deposited, to be used in all engineering works (roads, ground improvements, embankments, drainage systems, foundations and dams). 

Moseley, M. and Kirsch, K. 2004. Ground Improvement. Second Edition, Spon Press, London. 

Kulhawy, F.H. Prakoso, WA. 2000. Foundations in carbonate rocks karst. In Brandon TL (ed.) Found ground improve (GSP 113), ASCE, 1-15. 

Universiti Tun Hussein Onn Malaysia (UTHM) sits on deep deposit of soft marine clay with low strength and high compressibility. Pre-treatment of the soil by ground improvement is necessary before construction works can commence on these grounds. Various ground improvement techniques are available in the market, such as vertical drains with surcharge, stone columns, mass replacement, stabilisation, etc. 

To build a scaled model showing the ground improvement method, dimensions 30 cm x 30 cm, NOT exceeding 20 cm high. 

To identify problems encountered in soft soils and formulate solutions using ground improvement techniques. 

To design and model a ground improvement method for the UTHM site. 

Review relevant literature on the ground improvement methods applicable - background study. 

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