This study proposes a new approach for analyzing images of the internal structure of soil (microtomograms) and modeling key hydrophysical functions based on the tomographic characteristics of the pore space. The approach is based on constructing a series of closed shells (alpha-shapes) around the studied three-dimensional of the tomogram. These shells are capable of penetrating into the pores of the object with a diameter greater than a specified value. The dependence of the internal volume of the shells on the minimum pore size is analyzed. The algorithm of alpha-shapes construction simulates the process of drying pores connected to the surface and allows for analyzing the anisotropy of pore connectivity by limiting the permeability of a part of the object's surface. The constructed alpha-shapes model the surface of the liquid phase, and the maximum curvature of the surface corresponds to the capillary pressure. The approach is applied to analyze samples of the soil microprofile of a crusty solonetz with a contrasting pore space structure. The microhorizons of the solonetz demonstrate pronounced closed porosity and anisotropy of pore connectivity. The approach allows for the assessment of connectivity and anisotropy of pores, the water retention curve (WRC) without considering soil shrinkage. The results were compared with typical known WRCs of solonetzic soil horizons in soils of Russia. A comparison of WRC models obtained based on 2D and 3D images was conducted. The method was also tested on tomograms of samples of aeolian laminated sandstone, for which both tomograms and direct WRC measurements were simultaneously available.

Sliding damage of canal slopes due to the degradation of shear and compression properties of expansive soils caused by long-term dry-wet-freeze-thaw cycles is frequently encountered in canal projects in cold and arid regions. To address this issue, this paper developed a new reinforcing technique for expansive soil canal slopes with monolithic structural anti-slide piles. The sliding damage mechanism of the canal and the reinforcement schemes were analyzed based on the numerical simulations with the FLAC 3D software. The results showed that force redistribution of double-row piles occurred under the longitudinal connection. The maximum reduction in pile displacement was 20.66% under the X-type connection, and the distribution of internal force of pile body changed. The pile forces were redistributed again under the full connection mode, and the pile displacement increased by 4.38%, 95.14%, and 82.09% under the transverse and longitudinal connection mode, the front and rear full connection mode, and the frame full connection mode, respectively. The stability of the canal slope returned to a steady state (F-S > 1.30) in the full connection mode. The findings in this paper can provide guidance for practical engineering.