*Editorial* **Special Issue on Advances in Soil Pollution and the Geotechnical Environment**

**Bing Bai**

School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China; bbai@bjtu.edu.cn

Soil pollution and disposal technology is currently a hot topic in geo-environmental engineering that involves the interaction mechanisms, migration processes, and treatment measures of various types of pollutants (e.g., heavy metals, organic pollutants, acid or alkali substances, and radioactive materials) with geotechnical media, as well as heat flow processes and thermal damage. Application areas include industrial pollutant treatment in shallow seepage, groundwater exploitation, geothermal resource development, thermal energy storage, waste disposal in metal mining, and landfill leachate barriers.

This Special Issue on *Advances in Soil Pollution and the Geotechnical Environment* addresses the most recent developments in soil pollution and restoration, contaminant hydrology, and ground disturbance to stimulate fruitful technical and scientific interactions between professionals.

A total of thirteen papers in various fields of soil pollution and the geotechnical environment, including soil pollution, soil restoration, and heat transfer in soils, are presented in this Special Issue. To comprehend the effect of tidal actions on the nitrogen cycle in siltyclay riparian hyporheic zones, Cai et al. [1] carried out the synchronous monitoring of water level and water quality along a test transect during a spring tidal period and measured the permeability and chemical composition of soil samples from drilled holes. Wang et al. [2] presented a systemic laboratory experimental investigation on the liquid–plastic limit, moisture retention, hydraulic conductivity, and gas diffusion barrier properties of compacted clay amended with attapulgite and diatomite to control desiccation cracks and the migration of water and volatile organic compounds. Tian et al. [3] proposed a calculation method for thermal pore water pressure while considering the overconsolidation effect of saturated clay, which was verified by the relevant experimental data. Zhang et al. [4] explored the effect and mechanism of xanthan gum treatment on the water retention and shear strength characteristics of silt during the wetting process. Wu et al. [5] proposed a novel subgrade using a capillary barrier to reduce the different settlements and stabilities based on seepage theory for unsaturated soils. Qu et al. [6] investigated the migration, adsorption, and desorption characteristics of Pb2+ on fine, medium, and coarse sand in a water table fluctuation zone using several laboratory methods, including the kinetic aspects of Pb2+ adsorption/desorption and water table fluctuation experiments. Li et al. [7] carried out physical experiments on the nitrogen migration and transformation processes in a groundwater level fluctuation zone and constructed a numerical model for nitrogen migration in a vadose zone and a saturated zone using the software HydrUS-1D. Yang et al. [8] conducted a long-term F–T study of S/S Pb–Zn–Cd composite HM-contaminated soil under six conditions (0, 3, 7, 14, 30, and 90 cycles), with each F–T cycle process lasting 24 h. Kuang et al. [9] simulated the nanoscale elastic properties of hydrated Na-, Cs-, and Ca-MMT with unconstrained system atoms using a molecular dynamics (MD) method. Yu et al. [10] discussed the soil–water characteristic curve and microstructure evolution of unsaturated expansive soil improved by microorganisms in Nanning, Guangxi by means of a filter paper method and scanning electron microscope imaging (SEM). Liu et al. [11] investigated the removal effect of nitrobenzene in an aquifer through a series of two-dimensional sandbox experiments with different stratigraphic structures. Wu et al. [12] proposed a

**Citation:** Bai, B. Special Issue on Advances in Soil Pollution and the Geotechnical Environment. *Appl. Sci.* **2022**, *12*, 12000. https://doi.org/ 10.3390/app122312000

Received: 19 November 2022 Accepted: 23 November 2022 Published: 24 November 2022

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sedimentation ratio calculation method through the analysis of the settlement load ratio to calculate the roadbed replacement thickness. Chen et al. [13] investigated a contaminated site in Xinxiang City, Henan Province and collected 92 groundwater samples from the site to identify the groundwater chemical characteristics of the sites and their control mechanisms for the remediation of pollutants.

Although the submissions for this Special Issue have been closed, more in-depth research in the field of soil pollution and the geotechnical environment continues to address the challenges we face today, such as soil pollution mechanisms, pollutant migration, and the remediation efficiency of pollutants [14].

**Funding:** This research received no external funding.

**Acknowledgments:** Thanks to all the authors and peer reviewers for their valuable contributions to this the Special Issue Advances in Soil Pollution and the Geotechnical Environment. I would also like to express my gratitude to all the staff and people involved with this Special Issue.

**Conflicts of Interest:** The author declares no conflict of interest.
