Effect of cyclic Load on california bearing ratio of soaked clay

Abstract

The quality of pavement is affected mostly by the type of subgrade soil and in many countries the subgrade soil is weak. One way to measure the strength of the subgrade soil is the California Bearing Ratio test which is a penetration test under continuous uniform loading. But the real traffic surcharge on roads is simulated to be more cyclic load than uniform load. Our objective is to perform the CBR test on different clayey soil samples under cyclic load. This will be done by loading the soil sample to a penetration of 0.in. then to stop the loading for a while. After it, the CBR plunger will penetrate again the soil. This cycle of loading – unloading – reloading will be repeated two times in order to study the effect of the cyclic load on the CBR values. After this, the same procedure will be repeated on the other sample of the same soil but under 0.2in. penetration. Moreover, one normal CBR test under continuous loading will be performed on the same soil in order to compare the results. To achieve our objective, we collected six clayey samples from different Lebanese zones. Proctor test was done first on each soil in order to find the optimum moisture content OMC which will be used to compact the soil for CBR test. The comparison of different tests performed on the same soil appears to be very fruitful. In fact, the loading – unloading – reloading cycle applied to clay tends to enhance the CBR values.