Ground Improvement with Vibro Compaction Method to Mitigate the Liquefaction Potential, Case Study

Abstract

Vibro Compaction (VC) method is a cost efficient, fast, and environmental friendly solution to mitigate the liquefaction potential. This study explains the basics of this technique and discusses the advantages, challenges, and limitations of this method. Then the in situ confirmatory tests widely used for Quality Control of VC projects as well as assessment procedure of the results with respect to the Liquefaction Potential are elaborated in this paper. Depending on the ground condition, liquefiable depth, and projects requirements, the confirmatory methods could be any or a combination of penetration test (e.g., CPT, SPT, DPH, Shear Vane Test, Dilatometer) and load test (ZLT or PLT). For evaluation of the test outcomes generally, there are two main approaches; fixing a “Target Curve” for ground’s resistance, and assessing the “Functional Requirements” of the project in that evaluation of Liquefaction Potential is also included. Finally, as a remarkable Case Study, an 8.2 million m3 VC Project with up to 20 m treatment depth done on a reclaimed island near the UAE coast is introduced in this study together with its Compaction Scheme. Since the ground contained large fraction of cobbles and boulders, CPT—which was initially foreseen—was not possible. Therefore, SPT and DPH testing were proposed and adopted as alternatives. Regarding the application and sensitivity of the structures on the island, the project area was divided into three design zones with three different seismic requirements; Water Fronts, Shipping Terminals, and general area (residential, hotels, infrastructures, green space, etc.). One of the widely implemented Liquefaction Analysis Procedures (NCEER) was used in this project. However, due to the calcareous nature of the reclaimed sand and high percentage of boulders, those methods were adopted with some modifications and adjustments.