Behavior of a gravel-sand material on cyclic way

This article has the results of the cyclic triaxial compression tests to study the potential of liquefaction of a gravel-sand material. The last part is devoted to the not drained cyclic tests and their analyses. Many articles are devoted to the tests on the standard sand of laboratory Hostun in particular for the study of liquefaction or on reconstituted clays but few tests are carried out on a natural material. The scarcity of cyclic tests on such rough natural materials shows the difficulty of assessing the seismic risk. Faced with these difficulties, the use of tests such as the CPT provides a different but very practical approach. The overall results show a trend of relatively high liquefaction of the material, even under conditions of moderate stress (qc / 2s'3 = 0.2). This trend is growing very strongly when the rate of cyclic loading reached 0.3. The CPT test also shows a great tendency to liquefaction with a safety factor of well below 1.