Effect of Degree of Weathering on Dynamic Properties of Residual Soils

Abstract

The process of soil formation in the tropics is quite different than that of more temperate regions. The weathering processes tend to be intensified by the warm and humid climates that are prevalent in tropical regions. Chemical weathering processes that dominate in these regions, such as decomposition and dissolution, are fairly well understood phenomena. However, the effect this weathering has on the physical, mechanical, and dynamic properties of the rock/soil is not fully understood. This paper presents some laboratory test results and correlations that indicate behavioral trends to be caused by the effects that weathering has on a residual soil from the western coast of Puerto Rico. The study focuses on the dynamic shear modulus G and material damping ratio D of both natural (undisturbed) and remolded samples, for low- to mid-level amplitudes of vibration. The understanding of these effects will allow for a better prediction of phenomena such as soil amplification that may trigger landslides in such soil formations. This study was accomplished with the aid of a computerized resonant column device. Correlations and empirical formulations are presented that demonstrate the effects that the degree of weathering has on the dynamic properties of these residual soils for undisturbed andmore » remolded samples.« less