Geohazard Mechanics最新文献

China is a mountainous country with highly developed road geologic hazards, which pose a great threat to the construction and operation of highways, bridges, and tunnels and to the safety of people and property. This paper discussed the types, basic features, formation, and prevention conditions of road geologic hazards in China based on field research and study data collected thus far. The study considered an urban area of a city in southwest China as the center and a geological field investigation was performed over a total of 282 ​km on three important lifeline projects. The results show: Types of geologic hazards along the highways are mainly avalanches, debris flows, and landslides, respectively. Among them, the landslips are mainly distributed along the roads, with slip, dumping, and wrong break types as the main ones; the debris flows are widely distributed, mainly concentrated in the river valleys; and the unstable slopes are relatively few in number. Geological disasters are characterized by large-scale and concentrated triggering in time and space, and a single disaster can easily trigger other disasters, thus forming a chain of disasters. Neotectonic movement, seismic activity, topography, climatic conditions, stratigraphic lithology, and human activities are important factors leading to geologic hazards in the study area. This study is of great practical significance for reducing the occurrence of roadbed diseases and prolonging the service life of highways.

Aiming at the deformation control problem of the tunnel entrance crossing the spoil heap at the Xialao junction, this paper adopts the micropile combined with the coupling beams method to treat the spoiled layers. The results show that the excavation of the tunnel after the construction of the micropile and coupling beam will cause vertical deformation of the tunnel and the slope surface. The main reason is that the soil layer structure is loose, and the tunnel excavation causes the whole displacement of the loose body. In addition, the buried depth of the tunnel is shallow, so it cannot form an effective soil arch. The stability process after the construction of the micropile method is the process of stress redistribution, and the rock and soil are gradually compressed and compacted. That is, the construction by the micropile method changes the surrounding rock level of the tunnel and reduces the height of the soil arch. Therefore, it is suggested that the tunnel excavation should be carried out when the micropile is constructed after the soil layers are consolidated completely. The micropile method treats the loose spoiled soil at the tunnel entrance, which saves 73% of the total cost compared with the scheme of directly digging out the accumulation, and the economic benefit is very obvious.

As a widely used rock excavation method in civil and mining construction works, the blasting operations and the induced side effects are always investigated by the existing studies. The occurrence of flyrock is regarded as one of the most important issues induced by blasting operations, since the accurate prediction of which is crucial for delineating safety zone. For this purpose, this study developed a flyrock prediction model based on 234 sets of blasting data collected from Sugun Copper Mine site. A stacked multiple kernel support vector machine (stacked MK-SVM) model was proposed for flyrock prediction. The proposed stacked structure can effectively improve the model performance by addressing the importance level of different features. For comparison purpose, 6 other machine learning models were developed, including SVM, MK-SVM, Lagragian Twin SVM (LTSVM), Artificial Neural Network (ANN), Random Forest (RF) and M5 Tree. This study implemented a 5-fold cross validation process for hyperparameters tuning purpose. According to the evaluation results, the proposed stacked MK-SVM model achieved the best overall performance, with RMSE of 1.73 and 1.74, MAE of 0.58 and 1.08, VAF of 98.95 and 99.25 in training and testing phase, respectively.

With the increasing depth of coal mining each year, rock burst has emerged as one of the most severe dynamic disasters in deep mining. The research status of rock burst prevention and control theory is summarized. Focused on deep coal mining, the major issues encountered in researching the prevention theory of rock bursts are summarized. Subsequently, the scientific connotation theory of stress relief-support reinforcement cooperative prevention and control of rock bursts in deep coal mines is proposed. Then, the mechanisms underlying the major research directions of the theory of stress relief-support reinforcement coordinated prevention and control and present a preliminarily theoretical framework for stress relief-support reinforcement coordinated prevention and control are outlined. To tackle the key scientific problems in the coordinated prevention and control of rock bursts on relief and support in deep mine, the in-depth research based on the synergetic theory is conducted. This involved exploring the principles of near-field coal mass stress relief, near-field roof and floor stress relief, and anchor support. Additionally, the stress-energy evolution processes of the roadway near-field surrounding rock structure under various stress relief and anchor support modes be analyzed. Subsequently, a mechanical model for the optimized matching of stress relief surrounding rock and anchor support is established, with the control of the rock burst energy source at its core. Finally, the principle of collaborative prevention and control of deep mining rock burst stress relief and support from the perspectives of structural synergy, strength synergy, and stiffness synergy is elucidated. This insight is expected to provide theoretical support for the research and development of designs and techniques for deep mining rock burst prevention and control.

Application of Artificial Intelligence (AI) in tunnel construction has the potential to transform the industry by improving efficiency, safety, and cost-effectiveness. This paper presents a comprehensive literature review and analysis of hotspots and frontier topics in artificial intelligence-related research in tunnel construction. A total of 554 articles published between 2011 and 2023 were collected from the Web of Science (WOS) core collection database and analyzed using CiteSpace software. The analysis identified three main study areas: Tunnel Boring Machine (TBM) performance, construction optimization, and rock and soil mechanics. The review highlights the advancements made in each area, focusing on design and operation, performance prediction models, and fault detection in TBM performance; computer vision and image processing, neural network algorithms, and optimization and decision-making in construction optimization; and geo-properties and behaviours, tunnel stability and excavation, and risk assessment and safety management in rock and soil mechanics. The paper concludes by discussing future research directions, emphasizing the integration of AI with other advanced technologies, real-time decision-making systems, and the management of environmental impacts in tunnel construction. This comprehensive review provides valuable insights into the current state of AI research in tunnel engineering and serves as a reference for future studies in this rapidly evolving field.

In order to obtain the characteristics of the effects of cyclic impact loading on the damage of coal-rock in the presence of a local static load constraint, the evolution of the damage factor and the fracture rate during the process and incremental cyclic impact on raw coal and briquettes has been studied. Experimental results show that the presence of local static load restraint improves the impact resistance of the coal-rock, and the damage factor of the coal-rock shows obvious zoning characteristics. When the coal-rock is in an elastic state, the partition with a larger static load restraint area has stronger impact resistance, when the coal-rock is in a plastic state, the partition with a larger static load restraint area has a weaker impact resistance. Increasing impulsive cyclic impacts have a higher damage efficiency to coal-rock than constant impulsive cyclic impacts. The difference in rock breaking efficiency between the two cyclic impact methods is mainly reflected in the partition with the largest constrained area. The crack propagation on the coal-rock surface is more consistent with the partition characteristics of the damage factor. When the static load constrained zone is in an elastic state, the static load has an inhibitory effect on the crack growth. When the static load confinement zone is in a plastic state, the cracks mainly propagate in the static load confinement zone, and the constrained zone mainly consists of tensile cracks that grow in the vertical direction, while the cracks in the non-constrained zone mainly grow in an oblique direction. Finally, fracture mechanics was applied to analyze the failure type of the sample.

Comprehensive research methods such as literature research, theoretical analysis, numerical simulations and field monitoring have been used to analyze the disasters and characteristics caused by the linkage failure and instability of the residual coal pillars-rock strata in multi-seam mining. The effective monitoring area and monitoring design method of linkage instability of residual coal pillar-rock strata in multi-seam mining have been identified. The evaluation index and the risk assessment method of disaster risk have been established and the project cases have been applied and validated. The results show that: ①The coal pillar will not only cause disaster in single-seam mining, but also more easily cause disaster in multi-seam mining. The instability of coal pillars can cause not only dynamical disasters such as rock falls and mine earthquakes, but also cause surface subsidence and other disasters. ②When monitoring the linkage instability of residual coal pillar-rock strata, it is not only necessary to consider the monitoring of the apply load body (key block), the transition body (residual coal pillar) and the carrier body (interlayer rock and working face), but also to strengthen the monitoring of the fracture development height (linkage body). ③According to the principles of objectivity, easy access and quantification, combined with investigation, analysis, and production and geological characteristics of this mining area, the main evaluation indexes of the degree of disaster caused by linkage instability of residual coal pillar-rock strata are determined as: microseismic energy, residual coal pillar damage degree, fracture development height. And the evaluation index classification table was also given. ④According to the measured value of the evaluation index, the fuzzy comprehensive evaluation method was used to calculate the disaster risk degree in the studied mine belongs to class III, that is, medium risk level. The corresponding pressure relief technology was adopted on site, which achieved a good control effect, and also verified the accuracy and effectiveness of the risk evaluation results.

Positive pressure effect is the result of rapid urban development in recent years, which leads to over-exploitation of karst groundwater, coupled with the emergence of extreme weather (such as heavy rainfall, the increase in the duration of heavy rainfall), leading to the sharp rise of karst water level, the gas in the karst cavity can not be discharged in time to form a high positive pressure in the soil cavity and promote the destruction of the soil layer, which then induces a series of phenomena, such as karst subsidence. As a new collapse mechanism, the positive pressure effect causes geological disasters that seriously affect the safety of people's lives and properties in karst regions. In order to study the damage characteristics and evolution characteristics of karst soil cavities under positive pressure effect, this study is based on the ASCII text provided by FLAC itself, and the orthotropic simulation computation compilation program, which realizes the finite element analysis in FLAC3D, and focuses on the inhomogeneous change of soil displacement, redistribution of stresses, and plastic damage of karst soil cavities in different evolution stages under the action of positive pressure, and summarizes the characteristics and laws of stress, strain and damage in plastic zone of karst soil cave at different stages of evolution. The results will play a positive role in further investigating the potential mechanical effects, development mechanism and critical warning conditions during the evolution of covered karst soil caves, and also have important scientific research value in deepening the theory of prevention and control of collapse disasters in covered karst soil caves.

In order to study the mechanism of the dual side roof cutting technology on the composite disaster of gas and coal spontaneous combustion in goaf, a model for the evolution of porosity and permeability in the dual side roof cutting working face was constructed. The location of the occurrence of the compound disaster of gas explosion and coal spontaneous combustion under the double-sided roof cutting mode was studied, and the sensitivity of the evolution pattern of the compound disaster area to the amount of air supply and gas gush was summarized. The results indicate that the top cutting pressure relief technology significantly reduces the permeability of porous media, and the sensitivity of the goaf on the intake side to airflow disturbances is significantly reduced. As the volume of air supply increases, the distance between the gas explosion risk area and the coal spontaneous combustion risk area gradually decreases, and the probability of composite disaster areas is 0. The increase of air supply and gas emission makes the gas concentration in the middle and deep goaf increase in an exponential function, and the width of the gas explosion risk area increases gradually. When the outflow reaches 40 ​m³/min, there is no composite disaster zone, indicating that the rapid increase in outflow inhibits the occurrence of composite disasters.

The stability of inclined shaft lining structure (ISLS) in complex water-rich strata is affected by many factors, such as water pressure, joint, soft rock, lining corrosion and so on. The instability of the ISLS will affect the safe and efficient coal mine production. Bathe sed on the geological conditions of the Xiaobaodang coal mine, this paper tested the evolution characteristics of concrete composition in long-term water seepage areas and revealed the influence mechanism of corrosion weakening of shaft lining (SL) in water-rich strata. Meanwhile, transient electromagnetic, ground penetrating radar, and infrared monitoring are used to detect the water-rich zones, and damage zones of surrounding rock and lining water seepage zones, and a three-level safety evaluation model for the instability risk of ISLS is constructed. Water abundance of the surrounding rock, surrounding rock deterioration, and shaft lining seepage were the specific indicators in the model. The main inclined shaft (MIS) in the studied coal mine is divided into three levels: non instability risk zone, potential instability risk zone, and high instability risk zone. According to the evaluation results, comprehensive prevention and control measures of “hydrophobic hole drainage” and “back-lining grouting” are adopted for the water inrush source and the surrounding rock micro-crack water channel. The precise prevention and control of ISLS is realized. The research results also provide a reference for the stability evaluation of ISLS and the accurate prevention and control under similar conditions.