Compaction of Soils and Granular Materials

This interdisciplinary volume comprises papers from several fields related to compaction. Topics include: soil compaction for pavements and roads; deep soil compaction by vibration, impact and underground explosion; compaction control; and compaction processes in engineering.

Le compactage a vécu une évolution historique dans la seconde moitié du XXe siècle. Après l'apparition des compacteurs vibrants, qui ont offert des performances à la hauteur des cadences des chantiers routiers ou ferroviaires modernes, on a observé un formidable développement des connaissances. La difficulté de compactage des matériaux et leurs propriétés sont mieux évaluées. Les progrès se poursuivent aujourd'hui également par des développements technologiques de plus en plus pointus chez les constructeurs, à la fois sur l'optimisation de l'efficacité des compacteurs, et sur la gestion de la qualité au moyen de dispositifs embarqués. Parallèlement, de nouveaux moyens de contrôle de la qualité en place apparaissent. Mais on constate aussi, entre les divers pays européens, que les spécifications sont formulées différemment, alors que la même qualité d'usage est recherchée. Il était dès lors important, sous l'égide du Comité technique européen ETC 11, de la Société internationale de la mécanique des sols et de la géotechnique (SIMSG), de permettre un échange entre les experts et les praticiens de différents pays, essentiellement sur les aspects : modélisation, propriétés des matériaux, et gestion du compactage et contrôle en continu. Tel est l'objectif principal du séminaire qui s'est tenu à Paris, en mai 2000, et dont le présent ouvrage rend compte des travaux.

Although it is known that impact compaction tests are not appropriate for granular soils, these tests continue to be widely used. Excessive settlements frequently occur in granular soils where specified field compaction is based on Standard Proctor (ASTM D 698; AASHTO T 99) maximum dry unit weights. A laboratory test program evaluated alternative test methods for granular soil compaction control and showed that a Vibrating Hammer method (similar to British Standard BS 1377:1975, Test 14) has great promise for laboratory compaction of these soils.

Objectives of this field study were to investigate means of compacting soils at near-zero water content. Two 125-ft-long test sections were constructed, each consisting of five test items 25 ft long with a 5-ft-deep test bed. In each test section, the first item consisted of 1.5 ft of crushed limestone (GW) over 3.5 ft of bomb-crater debris. The remaining four items consisted of 5 ft of silty clay (ML0, river sand (CL-ML), gravelly sand (SP), and sand tailings (SP), respectively. One test section was compacted with a single drum self-propelled vibratory roller and the other with a towed four-sided impact single drum sel-propelled vibratory roller and the other with a towed four-sided impact roller. Test results were not fully conclusive because of the difficulty in drying soils with fines, rotational slippage of the impact roller during testing, and precompaction of the soils in the vibratory roller test section during construction. However, it could be concluded that (a) compaction at low water content was feasible primarily with soils with few fines, (b) significant difficulty would be experienced in field-drying soils with high fines content, (c) both compactors generally gave acceptable results, but the rate of compaction of the impact roller was much higher than that of the vibratory roller, and (d) test results warranted further investigation of compaction with the impact roller.