Ground improvement engineering – the state of the US practice: part 1. Methods

Abstract

The US practice of ground improvement is divided into six main categories: densification, consolidation, reinforcement, chemical treatment, thermal stabilization and biotechnical stabilization. Densification, which applies mainly to granular soils, includes vibrocompaction, dynamic compaction, blasting and compaction grouting. Consolidation is basically achieved through preloading and the use of vertical drains. Soil reinforcement is divided into two groups: those involving compacted fill such as mechanically stabilized backfill systems, and those applied in situ such as soil nailing, element walls, micropiles and stone columns. The chemical treatment methods discussed are those applied at depth such as permeation grouting, jet grouting, deep soil mixing and lime columns. Thermal stabilization is covered through ground freezing and its use in urban construction. Finally, biotechnical stabilization, which is one of the latest developments in the field, is briefly presented. Discussed in the paper are the applications, advantages, limitations, design and construction aspects of each ground improvement method as well as the durability and long-term performance of the improved ground. The use of ground improvement in environmental engineering is briefly highlighted.