Improvement in physical properties for ground treated with rapid impact compaction

Abstract

Ground improvement has been used on many construction sites to densify granular material, in other word to improve soil properties and reduce potential settlement. This paper evaluates the efficiency of rapid impact compaction (RIC), which is an improvement on the process of deep dynamic compaction, in improving soil properties and controlling soil settlement. In this technique ground improvement is achieved by impacting the ground with a 7 ton weight, 35 times/min, and drop height of 0.8 m at 2.5 m c/c square grid spacing. Evaluation of improvement in soil properties was based on field data bycomparing pre-treatment and post-treatment cone penetrometer test (CPT) soundings. An interpretation of soil properties from CPT was made using interpretation software to assess the degree of improvement achieved. Load test was conducted to estimate soil settlement. It was found that the RIC succeeded in improving soil properties like relative density from 45 to 70%, increase the friction angle of soil by an average of 3° and reducing soil settlement criteria by 50%. Key words: Rapid impact compaction (RIC), granular soils, physical properties, ground improvement, in-situ testing, soil compaction, improvement depth, cone penetration test, soil settlement, load test.