The water retention behaviours and pore size distributions of undisturbed and remoulded complete-intense weathering mudstone

Abstract

A series of experiments were performed to explore the difference in the soil water retention curves (SWRCs) and the pore size distributions (PSD) between undisturbed and compacted clays over a wide range of suction. It is showed that the SWRCs of undisturbed and compacted specimens are only significantly different in the transition zone. The SWRC of undisturbed specimens has a typical shape of ‘S’, but the compacted specimens have a ‘horizontal stage’ in transition zone. The data of mercury intrusion porosimetry show that the undisturbed soil has the unimodal pore structure, while the compacted soil with 38 MPa has the bimodal pore structure, which can account for the difference of water retention behaviour. The maximum effective pore diameter of the undisturbed specimens which control air entry value (AEV) is lower than the compacted specimens, which further confirmed that the AEV of the undisturbed soils is relatively higher than the compacted soils. As the suction increases, the undisturbed soil always has a unimodal pore structure, whereas the pore structure of the compacted soil is variable significantly. In addition, the AEV and residual water content can be confirmed from the PSD curve accurately and reliably.

KEYWORDS:

• Soil water retention curve
• undisturbed and compacted soils
• pore size distribution
• the evolution law of pore size distribution
• transient water release and imbibition method

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

National Natural Science Foundation of China [11372078, 51479023].