Hydraulic conductivity and prediction models for clays in Tailan River Irrigation District

This study examines the permeability mechanism of cohesive soils using the Tailan River Irrigation District in Xinjiang as a case. Laboratory hydraulic conductivity tests and scanning electron microscopy were conducted to analyse the effect of dry density on hydraulic conductivity from both macro and micro perspectives, leading to improved hydraulic conductivity calculations. The results show that: Hydraulic conductivity decreases with increasing dry density, and the strongest correlation is found between porosity and hydraulic conductivity. Four commonly used empirical hydraulic conductivity formulas are modified by incorporating the concept of effective porosity ratio. The modified Kozeny–Carman formula performs the best with an average relative error of 28.16%, which is significantly lower than that of the other modified formulas. Further validation with independent test data from arid cold irrigation districts shows that the error of the modified formula is stably below 35%, indicating sound cross-regional applicability. It can provide reference for the calculation of clayey soil hydraulic conductivity in similar groundwater level regulation projects in arid cold irrigation districts.