The cracking during the drying process of thickened tailings stack is a critical issue impacting its stability. This study establishes a comprehensive analytical framework that encompasses both mechanism cognition and technical methodologies by systematically integrating multidimensional research findings. Research indicates that cracking results from the coupling effects of environmental parameters and process conditions. The environmental chamber, with its precise control over external conditions, has emerged as essential experimental equipment for simulating actual working environments. From a mechanical perspective, water evaporation induces volume shrinkage, leading to microcrack formation when local tensile stress surpasses the matrix's tensile strength, ultimately resulting in a network of interconnected cracks. This process is governed by the dual parameters of matric suction and tensile strength. In terms of theoretical modeling, the fracture mechanics model analyzes crack propagation laws from an energy dissipation standpoint, while the stress path analysis model emphasizes the consolidation shrinkage coupling effect. The tensile damage model is particularly advantageous for engineering practice due to its parameter measurability. In numerical simulation technology, the finite element method is constrained by the predetermined crack path, whereas the discrete element method can dynamically reconstruct the crack evolution process but encounters the technical challenge of large-scale multi-field coupling calculations. Research suggests that future efforts should focus on optimizing theoretical prediction models that account for the characteristics and cracking behavior of tailings materials. Additionally, it is essential to develop a comprehensive equipment system that integrates real-time monitoring, intelligent regulation, and data analysis. This paper innovatively proposes the establishment of a multi-scale collaborative research paradigm that integrates indoor testing, numerical simulation, and on-site monitoring. By employing data fusion technology, it aims to enhance the accuracy of crack predictions and provide both theoretical support and technical guarantees for the safety prevention and control of thickened tailings stacks throughout their entire life cycle.
Soil desiccation cracks and crack networks significantly influence the mechanical properties of soils. Accurate modeling and prediction of crack development are essential for both laboratory research and practical applications in geotechnical engineering and environmental science. In this study, a Desiccation Crack Simulation Program (DCSP) was developed on the MATLAB platform to simulate the evolution of soil desiccation cracks. Based on comprehensive statistical analyses of crack network images from previous studies and detailed observations of crack propagation, we propose a stochastic crack network generation model informed by geometric parameters and crack development processes. The model encompasses five key steps: (1) selection of crack initiation points, (2) crack propagation and intersection, (3) termination of crack growth, (4) secondary crack generation, and (5) final network formation. Key parameters include crack step size, randomized propagation direction, number of initial development points, and crack attraction distance. The DCSP enables both the rapid generation of random crack networks and the prediction of partially developed networks. The program was validated using two soil types, Xiashu soil and Pukou soil, demonstrating its effectiveness in simulating crack evolution. Prediction accuracy improves as crack network develops, highlighting the model's potential for predicting soil desiccation crack patterns.
This study investigates the underlying causes of pier displacement and cracking in a highway link bridge. The initial geological assessment ruled out slope instability as a contributing factor to pier movement. Subsequently, a comprehensive analysis, integrating in situ soil investigation and finite element modeling, was conducted to evaluate the influence of additional fill loads on the piers. The findings reveal that the additional filled soil loads were the primary driver of pier tilting and lateral displacement, leading to a significant risk of cracking, particularly in the mid- of the piers. Following the removal of the filled soil, visual inspection of the piers confirmed the development of circumferential cracks on the columns of Pier 7, with the crack distribution closely aligning with the high-risk zones predicted by the finite element analysis. To address the observed damage and residual displacement, a reinforcement strategy combining column strengthening and alignment correction was proposed and validated through load-bearing capacity calculations. This study not only provides a scientific basis for analyzing the causes of accidents and bridge reinforcement but, more importantly, it provides a systematic method for analyzing the impact of additional filled soil loads on bridge piers, offering guidance for accident analysis and risk assessment in similar engineering projects.
Pumped storage power stations usually arrange galleries in the backfill area at the bottom of the reservoir basin. Under the influence of uneven deformation, the galleries may be difficult to adapt to deformation and generate cracking, which can affect dam safety. In this study, the upper reservoir of Hohhot pumped storage power station was taken as a case study. Through a combination of monitoring data and numerical simulation, the deformation characteristics of the galleries on the backfill foundation were analyzed, and the causes and mechanisms of galleries cracking and structural joints damage were revealed. The in situ monitoring records cover the internal settlement of the dam, the deformation and seepage flow of the galleries, and the ambient temperature. Based on actual engineering data, a numerical model considering the structure and filling method of dam, backfill area, and gallery was established, and the calculation parameters of rockfill material constitutive model were inverted by the direct back analysis method. The monitoring data analysis and numerical calculations showed that the long length of the gallery and the sudden drop of the ambient temperature were the main reasons for the longitudinal microcracks in the top arch of the galleries in the backfill area; the strong constraint of bedrock and the uneven settlement of backfill foundation were the root causes for the penetrating cracks in the galleries at the junction of backfill area and bedrock. In addition, the depth of the gallery embedded in the bedrock determines the deformation form (torsional deformation or bending deformation) of the galleries at the junction of the backfill area and bedrock. Based on the monitoring and numerical simulation, the long-term deformation of the galleries and the development of structural joints were also predicted.
Underground mining exploitation causes deformations on the ground surface as a result of the filling of the resulting voids. In certain situations, apart from mild continuous deformations, discontinuous deformations may occur in the form of, e.g., steps in the ground. Unexpectedly occurring discontinuous deformations cause significant damage to buildings protected against the influence of continuous deformations, but do not lead to their complete destruction. For this reason, the aim of this paper is to present a numerical analysis of such an impact case, which, on the one hand, is sufficiently accurate and reflects the behaviour of the real structure, and on the other hand, it will be a guide for experts who will aim to determine the safety of similar structures. In the presented case, the multiple longwall mining of coal ended in the same place resulting in the formation of a step in the ground about 15 cm high under a residential building. Not protected building against such deformations, suffered significant damage. The numerical analysis of the residential building was carried out with the advanced ATENA software package. In order to accurately represent the building and the impacts, the structure and the surrounding ground were modelled. The structure of building and the ground were modelled with tetrahedron- and hexahedral-shaped volumetric elements. On the contact surface of the structure elements and the ground, flat contact elements were used. The loads on the structure were introduced in the form of displacements caused by the appearance of a terrain threshold. The results of numerical calculations are presented in the form of color stress maps. The obtained calculation results are very close to the actual damages, which confirms the correctness of the analysis.
The long-term stability of compacted soil liners in landfill barriers depends on maintaining extremely low water permeability and resisting cracking induced by wet-dry cycles. This study investigated the potential of biochar as an amendment to improve the characteristics of granite residual soil, a commonly used material in barrier construction. Laboratory experiments were conducted on soil-biochar blends at different compaction levels (60% and 80%) and biochar concentrations (0%, 5%, 10%, and 20% by mass). The results showed that biochar addition gradually reduced saturated soil water permeability by up to one order of magnitude. Alterations in pore size distributions indicated a shift towards smaller diameters, suggesting the role of biochar in blocking macropores. The crack experiments demonstrated that biochar lowered surface crack ratios by 75% compared with untreated soil. Moreover, biochar affected the drying behaviour of residual granite soils, prolonging the evaporation period from 10 to 12 days and increasing the residual moisture content from 5% to 8%. In conclusion, biochar exhibited the potential to diminish soil permeability coefficients and alleviate soil cracking, providing valuable insights for enhancing the long-term performance of landfill containment barriers.
Expansive soils are susceptible to cracking due to significant moisture fluctuations, which can potentially lead to structural instability. Although geogrid reinforcement is widely used to control soil swelling and shrinkage, its effects on cracking behavior are not fully understood. This study investigates the influence of geogrid reinforcement on the cracking behavior of expansive soils by comparing soil samples reinforced with two layers of geogrid to unreinforced samples under evaporation conditions. Crack development was monitored using high- resolution imaging and fluorescence tracing to measure crack depth and calculate surface crack ratio. Additionally, moisture content distribution and evaporation rates were assessed. The results show that geogrid reinforcement reduced the total crack ratio by 1.34% and decreased average crack depth by 43.5%, leading to a more uniform crack distribution with smaller openings. Both internal and external cracks facilitated moisture exchange between the soil and atmosphere. The frictional and interlocking effects at the soil-geogrid interface effectively inhibited cracking and reduced moisture migration. The uniaxial geogrid also induced anisotropy crack restraint, with environmental exposure and geogrid orientation playing critical roles in crack control. Overall, these findings demonstrate the effectiveness of geogrids in enhancing the stability of expansive soils and limiting atmospheric influence through crack suppression.
Soil desiccation cracking, a natural phenomenon involving the complex interaction of multi-physical fields, significantly weakens the mechanical and hydraulic properties of soil, potentially leading to natural hazards. This study proposes a coupled thermo-hygro-mechanical peridynamic (PD) model to investigate the mechanical responses and fracture behaviors in saturated soils due to moisture evaporation and heat transfer. Specifically, the temperature-dependent moisture diffusion and moisture-dependent heat conduction equations are nonlocally reformulated using peridynamic differential operators (PDDO). The constitutive model incorporates the spatial attenuation of nonlocal interactions and the effects of moisture and temperature in the bond-based peridynamic framework. Utilizing a hybrid explicit-implicit solution strategy, the model can effectively capture soil strip detachment, cracking, and curling. The model is also employed to explore moisture transmission mechanisms, evaluate the effects of temperature and thickness on crack morphology, and reveal the relationship between stress, strain evolution, and crack propagation. Furthermore, the model incorporates the reference evapotranspiration formula, which can account for environmental factors such as solar radiation, ambient temperature, relative humidity, and wind speed. Therefore, this expands the scope of model applicability and enables the simulation of soil desiccation cracking under natural conditions.
The substantial development of desiccation cracks profoundly impacts the mechanical and hydraulic properties of clayey soils, potentially leading to various engineering challenges such as slope failures. Therefore, identifying the soil's cracking potential is crucial for guiding engineering design and construction processes. The aim of this study was to propose a method for cracking potential classification for clayey soils. To this end, standard cyclic wet-dry tests, capable of maximizing the soil's cracking potential, were proposed based on an analysis of the cracking behavior of lateritic soils under different wet-dry conditions. Subsequently, the cracking characteristics of several typical clayey soils (i.e., lateritic soil, kaolinite, bentonite, and attapulgite) were examined by standard cyclic wet-dry tests. Finally, a novel method for cracking potential classification of clayey soils was proposed incorporating the entropy weighting method. The results show that the most significant degree of cracking in lateritic soil is observed under vacuum saturation and 60 degrees C oven-drying, which is identified as the standard wet-dry condition. When the crack development stabilizes after multiple standard wet-dry cycles, the cracking potential of the soil is characterized by parameters such as the total crack length, maximum crack width, surface crack rate and the fractal dimension of the cracks. On this basis, a classification method is proposed to categorize the cracking potential of clayey soils into five levels: extremely weak, weak, medium, strong, and extremely strong. The cracking potential of different clayey soils was evaluated using this method, revealing that bentonite exhibited the highest cracking potential, classified as extremely strong.
A series of true triaxial unloading tests are conducted on sandstone specimens with a single structural plane to investigate their mechanical behaviors and failure characteristics under different in situ stress states. The experimental results indicate that the dip angle of structural plane (B) and the intermediate principal stress (o2) have an important influence on the peak strength, cracking mode, and rockburst severity. The peak strength exhibits a first increase and then decrease as a function of o2 for a constant B. However, when o2 is constant, the maximum peak strength is obtained at B of 90 degrees, and the minimum peak strength is obtained at B of 30 degrees or 45 degrees. For the case of an inclined structural plane, the crack type at the tips of structural plane transforms from a mix of wing and anti-wing cracks to wing cracks with an increase in o2, while the crack type around the tips of structural plane is always anti-wing cracks for the vertical structural plane, accompanied by a series of tensile cracks besides. The specimens with structural plane do not undergo slabbing failure regardless of B, and always exhibit composite tensile-shear failure whatever the o2 value is. With an increase in o2 and B, the intensity of the rockburst is consistent with the tendency of the peak strength. By analyzing the relationship between the cohesion (c), internal friction angle (4), and B in sandstone specimens, we incorporate B into the true triaxial unloading strength criterion, and propose a modified linear Mogi-Coulomb criterion. Moreover, the crack propagation mechanism at the tips of structural plane, and closure degree of the structural plane under true triaxial unloading conditions are also discussed and summarized. This study provides theoretical guidance for stability assessment of surrounding rocks containing geological structures in deep complex stress environments. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).