Abstract: In this paper, the Nuclear Magnetic Resonance (NMR) studies were conducted on the cohesive soils samples with the same moisture content but different dry density as well as the same dry density and different moisture contents. The influence of different soil states on the microstructure of the cohesive soil are investigated. The results show that the saturated cohesive soil samples with lower density have more large sized pores. The dry density has a great influence on the largesized pore structure of the cohesive soils. The initial moisture content will affect the smallsized pore structure of the saturated clay. In addition, by comparing the results of the NMR tests with the mercury intrusion porosimetry tests, it is concluded that, two different approaches lead to the similar results. Both approaches can adequately reflect the micro pore structure of the cohesive soils.

Key words: Cohesive Soils, Nuclear Magnetic Resonance (NMR), Mercury Intrusion Porosimetry, Pore Structures, Pore Size Distribution