Seepage problems in half-space domains are crucial in hydrology, environmental, and civil engineering, involving groundwater flow, pollutant transport, and structural stability. Typical examples include seepage through dam foundations, coastal aquifers, and levees under seepage forces, requiring accurate numerical modeling. However, existing methods face challenges in handling complex geometries, heterogeneous media, and anisotropic properties, particularly in multi-domain half-spaces. This study addresses these challenges by extending the modified scaled boundary finite element method (SBFEM) and using this method to explore steady seepage problems in complex half-space domain. In the modified SBFEM framework, segmented straight lines or curves, parallel to the far-field infinite boundary, are introduced as scaling lines, with a one-dimensional discretization applied to them, thereby reducing computational costs.Then the weighted residual method is applied to obtain the modified SBFEM governing equations and boundary conditions of steady-state seepage problem according to the Laplace diffusion equation and Darcy's law. Furthermore, the steady seepage matrix at infinity is obtained by solving the eigenvalue problem of Schur decomposition and then the 4th-order Runge-Kutta algorithm is used to iteratively solve until the seepage matrix at the boundary lines is reached. Comparisons between the present numerical results and solutions available in the published work have been conducted to demonstrate the efficiency and accuracy of this method. At the same time, the influences of the geometric parameters and complex half-space domain on the seepage flow characteristics in complex half-space domain are investigated in detail.

The long-term disposal of high-level radioactive waste (HLW) in deep geological repositories requires the reliable performance of engineered barrier systems (EBS). Compacted bentonite, widely used for its high swelling capacity, low permeability, and self-sealing properties, plays a critical role in these barriers. However, understanding the complex coupled thermo-hydro-mechanical (THM) behavior governing water infiltration dynamics remains a significant challenge, especially when gap spaces (or technological voids) are present. This study investigates water infiltration dynamics in bentonite-based EBS using a novel laboratory-scale experimental setup. Time-lapse photography was employed to monitor the evolution of hydration and swelling under thermal gradients and varying gap sizes, simulating repository conditions. The experimental program was designed to compare the effects of two gap sizes on infiltration rates, swelling behavior, and desiccation cracking. Results demonstrated that larger void spaces accommodated greater swelling, leading to lower dry density and higher permeability, while smaller gaps restricted desiccation cracking due to mechanical constraints. The correlation between pixel intensity and water content allowed the derivation of a linear calibration model, enabling real-time, non-destructive estimation of moisture distribution in bentonite. Findings in this study highlight the interplay between gap size, water infiltration, and thermal effects, emphasizing the need for optimized EBS designs to balance mechanical integrity and hydraulic performance. It is anticipated that the insights provided by this study contribute to the refinement of predictive models and advancing the safe and effective containment of HLW over geological timescales.

To the aim of this paper is to study the structural and environmental deformation characteristics caused by the excavation of a very large deep foundation pit in the sandy soil area of Beijing. This paper is based on numerical simulation and field monitoring results and these results are compared with the deformation data of a soft soil foundation pit in the Shanghai area. The results show that the influence of the environment surrounding the super-large deep foundation pit project studied in this paper is obviously too great. With the progress of construction, the deformation rate and deformation amount of the column at the side of the foundation pit are obviously higher than that of the column in the middle area. Due to the hysteresis of stress transfer in the sand, the settlement of the roof of the north wall is delayed and the deformation range is smaller than that of the south wall. Compared with the conventional foundation pit, the influence area of the surrounding surface is larger, reaching 4 He (He is the depth of the foundation pit). Delta vmax (the maximum surface settlement) is between 0.2 similar to 2.3% He, and the relationship between delta vmax = 1.43% Vwm. Through orthogonal experiments and numerical simulation, it is concluded that the deformation of foundation pit structure and its surrounding environment is more sensitive to excavation unloading, precipitation amplitude, and column spacing. It is also concluded that the strong, medium, and weak influence areas of the bottom uplift after foundation pit construction are (0 similar to 0.07) x L, (0.07 similar to 0.14) x L, and (0.14 similar to 0.5) x L, respectively (L is the width of foundation pit). When the embedment ratio is between 1.8 similar to 2.4, the displacement mode of the parapet structure is T mode; when the embedment ratio is between 2.4 similar to 3.4, the displacement mode of the parapet structure is RB mode.

Palsas and peat plateaus occur in various environmental conditions, but their driving environmental factors have not been examined across the Northern Hemisphere with harmonized datasets. Such comparisons can deepen our understanding of these landforms and their response to climate change. We conducted a comparative study between four regions: Hudson Bay, Iceland, Northern Fennoscandia, and Western Siberia by integrating landform observations and geospatial data into a MaxEnt model. Climate and hydrological conditions were identified as primary, yet regionally divergent, factors affecting palsa and peat plateau occurrence. Suitable conditions for these landforms entail specific temperature ranges (500-1500 thawing degree days, 500-4000 freezing degree days), around 300 mm of rainfall, and high soil moisture accumulation potential. Iceland's conditions, in particular, differ due to higher precipitation, a narrower temperature range, and the significance of soil organic carbon content. The annual thermal balance is a critical factor in understanding the occurrence of permafrost peatlands and should be considered when comparing different regions. We conclude that palsas and peat plateaus share similar topographic conditions but occupy varying soil conditions and climatic niches across the Northern Hemisphere. These findings have implications for understanding the climatic sensitivity of permafrost peatlands and identifying potential greenhouse gas emitters.

In-Situ Resource Utilisation (ISRU) is increasingly being seen as a viable and essential approach to constructing infrastructure for human habitation on the moon. Transporting materials and resources, from Earth to the Moon, is prohibitively expensive and not sustainable for long-term, large-scale development. Various fabrication technologies have been investigated in recent years, designed for extra-terrestrial exploration and settlement. This review presents a comprehensive study on the development of several sintering techniques of lunar regolith simulant to demonstrate its feasibility for ISRU on the moon. Various critical processing parameters are evaluated in pursuit of creating a structural material that can withstand the extreme lunar environment. Key outcomes are summarised and assessed to provide insight into their viability. Finally, current challenges are addressed and potential improvements, and avenues for further research, suggested.

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.

The massive utilization of fossil energy by humans has promoted socio-economic development. However, it has also generated severe regional eco-environmental problems, including water shortage, soil erosion, and land desertification. An optimal ecological-network-based regulation of eco-environmentally damaged areas is necessary to balance economic development with rigid eco-environmental constraints in pursuit of sustainable regional development. Using remote-sensing, meteorology, land use, and soil data of energy and chemical industrial areas in the mid-upper reaches of the Yellow River, we quantitatively evaluated the related ecosystem services (ESs) by applying InVEST, CASA, and RWEQ models. Additionally, we constructed ecological conservation networks comprising ecological source areas, resistance surface, corridors, and nodes. The results are as follows. First, from 2000 to 2020, the areas of cultivated and unused land decreased, but those of forest, grassland, water bodies, and construction land increased. Regarding spatial distribution, the proportion of grassland was the highest, followed by unused land, and other types of land accounting for a relatively low proportion. Second, from 2000 to 2020, all ESs and the overall ecosystem improved. However, ESs demonstrated a clear spatial heterogeneity (i.e., better in the southeast than in the northwest). Third, comparing the two ecological networks constructed by minimum cumulative resistance (MCR) and circuit models, the MCR-based ecological network was considered better because of its higher epsilon, theta, and sigma values. Robustness analysis also showed that the MCR-based ecological network was more stable. Finally, ecological source areas of 110,300 km(2) were obtained, accounting for 21.69 % of the study region. Ecological resistance was relatively high in desert areas, which are to the northwest of the study region, and relatively low in the southeast. Fifty-nine ecological corridors (including 31 important ones) and 22 ecological nodes were extracted. The finalized ecological network was diamond-shaped, with the ecological source areas in four directions (i.e., east, south, west, and north) of the study region being closely connected. To promote the spatial optimization of the study region, appropriate measures (e.g., afforestation and soil improvement) must be taken to reduce regional imbalance in ecological condition, improve ecosystem functions and landscape connectivity, reduce various resistance, and ultimately promote conservation outcomes.

As terrestrial resources and energy become increasingly scarce and advancements in deep space exploration technology progress, numerous countries have initiated plans for deep space missions targeting celestial bodies such as the Moon, Mars, and asteroids. Securing a leading position in deep space exploration technology is critical, and ensuring the successful completion of these missions is of paramount importance. This paper reviews the timelines, objectives, and associated geotechnical and engineering challenges of recent deep space exploration missions from various countries. Extraterrestrial geotechnical materials exist in unique environments characterized by special gravity, temperature, radiation, and atmospheric conditions, and are subject to disturbances such as meteoroid impacts. These factors contribute to significant differences from terrestrial geotechnical materials. Based on a thorough literature review, this paper investigates the transformation of geomechanical properties of extraterrestrial geological materials due to the distinctive environmental conditions, referred to as the four unique characteristics and one disturbance, and their distinct formation processes. Considering current deep space mission plans, the paper summarizes the geotechnical challenges and research advancements addressing specific mission requirements. These include unmanned exploration and in-situ mechanical testing, construction of extreme environment test platforms, the mechanical properties of geotechnical materials under extreme conditions, the interaction between engineering equipment and geotechnical materials, and the in-situ utilization of extraterrestrial geotechnical resources. The goal is to support the successful execution of China's deep space exploration missions and to promote the development of geomechanics towards extraterrestrial geomechanics.

This review explores the development and potential applications of space concrete, a critical material for future extraterrestrial construction. Space concrete, adapted to withstand the harsh conditions of outer space, such as extreme temperatures, vacuum, microgravity, and radiation, offers a sustainable solution for building habitats and infrastructure on celestial bodies like the Moon and Mars. Emphasizing the innovative approaches in formulating space concrete, including the use of lunar and Martian soil as aggregates and the exploration of alternative binders to traditional water-based cement, this review highlights the significance of in-situ resource utilization (ISRU) and 3D printing technologies in advancing extraterrestrial construction. Additionally, the current designs and applications of space concrete structures are discussed. By providing a detailed analysis of the challenges faced in space construction and the latest advancements in material and structural research, the review underlines the pivotal role of space concrete in supporting space exploration and long-term habitat.

全球气候变暖导致冰-岩崩及其灾害链成为研究热点，然而由于此类灾害多发于高寒地区，监测和模拟手段不足，研究困难且成果有限。我国西藏东南部雅鲁藏布江流域是冰-岩崩灾害高发区，也是水电建设重要区域，其冰/岩体稳定性对水利工程建设、运营及人民安全构成严重威胁。在全面梳理国内外研究现状的基础上，汇编了雅江流域近70年来有相关记载的冰-岩崩事件；通过深入调查分析，对冰-岩崩灾害进行了重新界定，并探究了该地区冰-岩崩灾害的时空分布规律；进一步，结合雅江流域独特的地理特征，初步揭示了冰-岩崩的形成机制，并将冰-岩崩灾害划分为冰-岩崩泥石流灾害、冰-岩崩堵江溃坝型灾害、冰-岩崩冰湖溃决型灾害和冰-岩崩库坝失效型灾害四种。在此基础上，基于CiteSpace可视化分析软件和WoS核心合集数据库，定量分析了最近25年(1999—2023年)国内外对于冰-岩崩灾害的研究现状，指出了不同时间段的研究热点和发展趋势。上述成果为雅江流域冰-岩崩灾害的深入研究及重大水利工程防灾减灾提供参考价植。