Densification of hydraulic sand fill by vibro hammer and quality control by cone penetration test : a case study

Abstract

Densification of Hydraulic Sand Fill by Vibro Hammer and Quality Control by Cone Penetration Test Ground improvement techniques are widely adopted in Sri Lanka and are increasingly being used for a vast variety of projects with particular emphasis on infrastructure projects such as roads, ports and harbors. Ground improvement schemes work with the existing ground rather than bypassing it. They can be tailored to meet specific bearing capacity and/or settlement requirements and are generally much more cost-effective than other traditional methods such as piling. The process:  Reduces foundation settlement  Increases bearing capacity  Mitigates liquefaction potential  Provides slope stabilization  Prevents earthquake-induced lateral spreading Layer by layer compaction by means of roller or portable compactor is a widely used compaction method. However this method has limitations to undertake to a greater depths due to ground water problems that may be encountered. It is time consuming too. Under such circumstances the deep vibro compaction method is superior to the roller compaction methods. Vibro techniques consist of large depth vibrators, typically about 300 to 500mm in diameters, which penetrate the ground to suitable depth. Vibrocompaction known also as Vibroflotation in some references and countries consist on the in-situ densification of loose granular soils, such as loose sand, gravel and hydraulic fills, using vibro compaction equipment but without the addition of granular material.