Geotechnical Aspects of Explosive Compaction

Mahdi Shakeran,Majid Ahmadpour,Abolfazl Eslami

doi:10.1155/2016/6719271

Mahdi Shakeran, Majid Ahmadpour + Show 1 more

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https://doi.org/10.1155/2016/6719271

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Abstract

Explosive Compaction (EC) is the ground modification technique whereby the energy released from setting off explosives in subsoil inducing artificial earthquake effects, which compact the soil layers. The efficiency of EC predominantly depends on the soil profile, grain size distribution, initial status, and the intensity of energy applied to the soil. In this paper, in order to investigate the geotechnical aspects, which play an important role in performance of EC, a database has been compiled from thirteen-field tests or construction sites around the world, where EC has been successfully applied for modifying soil. This research focuses on evaluation of grain size distribution and initial stability status of deposits besides changes of soil penetration resistance due to EC. Results indicated suitable EC performance for unstable and liquefiable deposits having particle sizes ranging from gravel to silty sand with less than 40% silt content and less than 10% clay content. However, EC is most effective in fine-to-medium sands with a fine content less than 5% and hydraulically deposited with initial relative density ranging from 30% to 60%. Moreover, it has been observed that EC can be an effective method to improve the density, stability, and resistance of the target soils.

Highlights

Depending on the importance and load level of a structure, ground improvement may be a viable alternative to expensive foundations in conditions involving weak and problematic soil deposits
As for the soil classification graphs based on Cone penetration test (CPT) records, which are shown in Figure 13, Explosive Compaction (EC) had promising results for soils falling in the silty clay to silty sand zones defined by the Robertson et al (1986) chart and in the silty sand zone defined by Eslami and Fellenius (2004) chart
In the chart of Robertson et al (1986) the data records are spread over more zones, making it difficult to interpret the range of grain size distribution for soils suitable for EC treatment

Summary

Introduction

Depending on the importance and load level of a structure, ground improvement may be a viable alternative to expensive foundations in conditions involving weak and problematic soil deposits. The common options for improvement of weak soil layers at depth are as follows: vibro methods, Deep Soil Mixing (DSM), Deep Dynamic Compaction (DDC), jet grouting, and Explosive Compaction (EC). Modification of loose, saturated deposits at depth using methods such as Deep Soil Mixing and jet grouting is costly. Dynamic compaction involves dropping of heavy weights to improve soil and is effective to a depth of 15 m, its efficiency decreases with decreasing soil permeability. Soon after application of EC method in Franklin Fall Dam, the effectiveness of the method was approved and subsequently the method was successfully applied in the compaction of hydraulic deposits of Cape Cod Canal in Texas and Almond Dam in New York [2, 3]

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