Geological Conditions Research Articles

Stability evaluation of draft tube tunnels of Palamuru Ranga Reddy lift irrigation scheme lift-Ⅲ, Telangana state, India

Geological and geotechnical evaluation for the 7–9 m diameter and 100 m length, 10 numbers of parallel draft tube tunnels were carried out. The draft tubes are constructed to connect the underground pump house and surge pool for lifting the water. Due to adverse geological conditions and the complex geometry of the structure, a sequential excavation method and controlled blasting were adopted, which minimized the risk of instability during the excavation of the draft tubes. To classify the rock masses and recommendation of support, detailed engineering geological investigations were done. The rocks encountered during the excavation of these tunnels are granites/granitic gneiss which are traversed by mafic dykes of Dharwar Craton. Prominent three to four joint sets were recorded during geological mapping and rock mass shows W-I to W-II weathering grade. For the determination of principal stresses, an in-situ hydrofracturing test was conducted in the borehole. Q-values were determined based on the rock joints and their characteristics, 3D mapping of geological units and stress measurement conducted inside the borehole. The Q-system provides a quantitative assessment of rock mass stability in jointed rock for underground tunnel design and construction. Good stability is indicated by high Q-values, while poor stability is shown by low values. Based on the “Q” system, the entire lengths of the tunnels were characterised as poor to fair rock mass categories. Wedge analysis was conducted along the tunnel alignments using RocScience Unwedge software and accordingly, stability was checked. Engineering geological investigations identified potential geotechnical issues, and corresponding engineering solutions were recommended. A support system was designed based on the Q-system and site-specific geological conditions.

Boosting Model Interpretability for Transparent ML in TBM Tunneling

Tunnel boring machines (TBMs) are essential for excavating metro tunnels, reducing disruptions to surrounding rock, and ensuring efficient progress. This study examines how machine learning (ML) models can predict key tunneling outcomes, focusing on making these predictions clearer. Specifically, the models aim to predict surface settlements (ground sinking) and the TBM’s penetration rate (PR) during the Athens Metro Line 2 extension to Hellinikon. For surface settlements, four artificial neural networks (ANNs) were developed, achieving an accuracy of over 79%, on average. For the TBM’s PR, both an XGBoost Regressor (XGBR) and ANNs performed consistently well, offering reliable predictions. This study emphasizes model transparency mostly. Using the SHapley Additive exPlanations (SHAP) library, it is possible to explain how models make decisions, highlighting key factors like geological conditions and TBM operating data. With SHAP’s Tree Explainer and Deep Explainer techniques, the study reveals which parameters matter most, making ML models less of a “black box” and more practical for real-world metro tunnel projects. By showing how decisions are made, these tools give decision-makers confidence to rely on ML in complex tunneling operations.

Study on Development Characteristics and Reservoir Formation Model of Lower Ordovician Reservoirs in Central Sichuan

Sichuan Basin is a large superimposed petroliferous basin, which has experienced multi-stage extension-convergence cycle and has great potential of oil and gas resources. In recent years, the lower combination oil and gas exploration in the middle Sichuan area has made great breakthroughs in the Sinian Dengying Formation and the Lower Cambrian Longwangmiao Formation, but has not achieved good results in the Ordovician. At present, a number of Wells in the middle Sichuan area show varying degrees of oil and gas in the Lower Ordovician strata, suggesting that the Ordovician strata in this area have the basic conditions for the formation of large-scale oil and gas reservoirs. However, no consensus has been reached on the paleogeographic pattern of Ordovician lithofacies and the distribution of favorable facies zones in this area, and the understanding of reservoir types and reservoir properties is quite different. Therefore, the weak basic research on the geological conditions of reservoir formation has severely restricted the hydrocarbon exploration of the Ordovician in this area. In this paper, the Lower Ordovician lithofacies paleogeography reconstruction and reservoir characteristics analysis are carried out by systematically combing the drilling and field profile data in the central Sichuan area, combined with core observation, thin section identification and reservoir analysis, and finally the Ordovician oil and gas accumulation model is established. The results show that the lithofacies paleogeography distribution of the Lower Ordovician Tongzi-Honghuayuanstage in the central Sichuan area is from the paleo-uplift to the east in the order of platform tidal flat to platform shoal to limited platform. The Lower Ordovician reservoir types in the middle Sichuan area include karst reservoir and dolomite reservoir, among which the karst reservoir is heavily filled and the reservoir performance is limited. The Ordovician reservoir-forming model in the middle Sichuan area reveals a new exploration model of dolomite superimposed bedding under karst in the epicontinental platform, which provides important geological basis for the new breakthrough of Ordovician oil and gas exploration.

Assessment of geomorphological, hydrometeorological and geological trigger conditions of debris flows in northern Patagonia Andes

Assessment of geomorphological, hydrometeorological and geological trigger conditions of debris flows in northern Patagonia Andes

Advancements and Future Prospects in the Hydraulic Fracturing of Geothermal Reservoirs

Reservoir reconstruction is a critical challenge in many significant underground energy projects, such as enhanced geothermal systems, oil shale extraction, and shale gas development. Effectively reconstructing geothermal reservoirs can significantly enhance the exploitation and production capacity of geothermal resources. However, this process requires stringent technical standards and varies with different geological conditions across regions, necessitating tailored reconstruction strategies. This review offers a comprehensive examination of hydraulic fracturing within geothermal reservoirs, covering the geological and physical characteristics inherent to these systems, the effects of injection methods and thermal stimulation on hydraulic fracturing processes, and the assessment and optimization of transformation effects, as well as environmental implications and risk management considerations. We explore the influence of various injection modes on hydraulic fracturing dynamics. Moreover, we compare the differences between hydraulic fracture propagation with and without thermal effects. Additionally, we summarize optimization strategies for reservoir reconstruction. Finally, we discuss several challenges and potential future directions for development, offering insights into possible advancements. This review is of substantial significance for both research and commercial applications related to hydraulic fracturing in geothermal reservoirs.

Nativeness as Gradient: Towards a More Complete Value Assessment of Species in a Rapidly Changing World

Conservation biologists recognize a duty to maintain as much value as possible in ecosystems that are threatened by recent anthropogenic impacts. Until recently the paradigm of contemporary conservation seemed relatively straightforward: the best way to maintain the value of species and ecosystems at a given location was to maintain—or shepherd the system back towards—historical conditions. Among the most difficult theoretical tasks was the determination of “baseline” historical conditions (or trajectories) to return to, recognizing the dynamism of ecosystems over time. However, the rate, scale, and magnitude of contemporary climate change, species introductions, and land-use change make it increasingly impractical to return locations to any kind of historical state. This forces a paradigm shift which is both ongoing and difficult, and necessitates a rigorous evaluation of the scientific and ethical foundations of modern conservation along with a careful reexamination of terminology. Here, I discuss the moral relevance and waning utility of the geographically-based and dichotomous understanding of “native” (or “in situ”) which is an important component of conservation ethics and practice. I then propose a new understanding of nativeness in which a species is native—not to a geographic location—but to a quantifiable set of biotic, climatic, geologic, and topographic conditions (i.e. its niche) that can then map to geographic space. Following this, I demonstrate the unique utility of this concept, which I will refer to as “econativeness,” in thinking through conservation problems—range expansions, range contractions, species introductions, and assisted migration—where the classical understanding of nativeness has become increasingly inadequate for assessing the moral value of species.

A Novel Hybrid Intelligent Approach to Assess Blasting-Induced Overbreak Incorporating Geological Conditions in Different Tunnel Sections

Overbreak induced by tunnel blasting is a harmful phenomenon. Accurate assessment of overbreak can effectively reduce investment and ensure operational safety. In this study, a hybrid intelligent model for assessing blasting-induced overbreak is proposed which can accurately predict overbreak and effectively evaluate the importance of feature parameters. To ensure accurate prediction of overbreak, hyperparameters of four machine learning algorithms are optimized using a whale optimization algorithm. Their performance is compared based on three regression metrics: R2, RMSE, and VAF. Given the limitations of traditional feature importance analysis methods, the Shapley Additive Explanation method is used in conjunction with the random forest algorithm. After accurately predicting overbreak caused by different sections of the tunnel, the impact of each input parameter on overbreak is analyzed, and recommendations for design values of certain significant parameters are provided. The research indicates that the proposed method can accurately predict overbreak caused by actual engineering blasts and provide insights into the selection of design parameter values.

Research Progress on Intelligent Control Heading Machine

Background: With the development of society, the demand for underground works, such as to control road traffic and enhance the development of mineral resources, is increasing. Simple human and mechanical resources can no longer meet people's needs. Therefore, the development of the heading machine has advanced the construction of underground engineering and the development of mineral resources, leading to a significant change in tunneling efficiency. However, the increase in the scale of engineering facilities, changes in geological conditions, the reduction in human resources, and other factors, accompanied by the arrival of the era of big data, have prompted the heading machine to become more and more efficient, advanced, and intelligent. Objective: This article aimed to describe the classification, characteristics, and development of existing heading machines. It also takes into account the impact of changing engineering facilities, geological conditions, and limited human resources. The research and development direction of the equipment in intelligent perception, intelligent construction, and safety management is proposed. Methods: In this study, the working principle and related patents of the heading machine have been summarized. The structural characteristics, differences, and application characteristics of the heading machines in different fields are introduced, and the limitations of previous methods have been analyzed. Results: By analyzing and comparing the existing heading machines and summarizing their typical features, the main problems in the development of heading machines have been analyzed and the development trend of heading machines is predicted. Finally, the current research status and future development trends of heading machines and their patents are discussed. Conclusion: The heading machines are divided into two types based on the operation object: tunnel boring machine and ordinary heading machine. Among these, the full-face heading machine is the most widely used, and heading machines with different working faces are the most typical among ordinary heading machines. Currently, the application of intelligence in heading machines has gained widespread traction both domestically and internationally. The future development direction of heading machines must focus on intelligence, ensuring safety and efficiency, lightweight design, and environmental sustainability.

Prospection of faults on the Southern Erftscholle (Germany) with individually and jointly inverted refraction seismics and electrical resistivity tomography

As part of the Lower Rhein Embayment (LRE), the Southern Erft block is characterized by a complex tectonic setting that influences hydrological and geological conditions on a local as well as regional level. The study area is located in the south of North Rhine-Westphalia and traversed by several NW-SE-oriented fault structures. Since the tectonic structures were located by past studies based on a sparse foundation of geological data, the positions include considerable uncertainties. Therefore, it was decided to re-evaluate and refine the assumed fault locations by conducting geophysical measurements. Seismic Refraction Tomography (SRT) as well as Electrical Resistivity Tomography (ERT) was performed along seven measurement profiles with a length of up to 1.1 km. In addition to compiling individual resistivity and velocity models for all deduced measurements, ERT and SRT datasets were cooperatively inverted using the Structurally Coupled Cooperative Inversion (SCCI). This algorithm strengthens structural similarities between velocity and resistivity by adapting the individual regularizations after each model iteration. Previously assumed locations of the tectonic structures diverge from the new evidence based on ERT and SRT surveys. Especially in the western and eastern parts of the research area, differences between the survey results and formerly assumed locations are in the order of 100 m. Seismic and geoelectric measurements further indicate a fault structure in the southern part of the area, which remained undetected by past studies. The cooperative inversions do not improve the geophysical models qualitatively, since the individually inverted datasets already provide results of good quality and resolution.

The Response of Runoff to Land Use Change in the Northeastern Black Soil Region, China

With the intensification of climate change and human activities, the impacts of land use shifts on hydrological processes are becoming more pronounced, especially in regions with complex geographic, geological, and climatic conditions such as the Northeast Black Soil Region, China. This study quantitatively examines the variations in various land use types from 1980 to 2020 by means of a land use transfer matrix, and it incorporates the multi-year average runoff value to mitigate the interference of short-term climate fluctuations on the runoff trend, thereby enhancing the representativeness and stability of the simulation outcomes. The SWAT (Soil and Water Assessment Tool) model is employed to simulate land use alterations in different periods. The findings indicate that the area of farmland increased by 5.34% and the area of grassland decreased by 5.36% over 40 years. The areas of forest land and wetland have fluctuated significantly due to policy interventions and population growth. This study discovers that LUCC has resulted in a marginal increase in annual water yield. For instance, the water yield of paddy fields in 2020 amounts to 92.26 mm/year, which is 0.52–9.42% higher than the historical scenario and exhibits a notable upward trend in summer. Spatial analysis discloses regional disparities, with substantial changes in the hydrological behavior of northern watersheds (such as the Huma River) and southeastern regions (such as the Toudao River). The augmentation of wetland and forest coverage has effectively mitigated peak runoff, especially during extreme rainfall events. Wetlands have manifested strong water regulation capabilities and alleviated the impact of floods. This study quantitatively discloses the complex response pattern of LUCC to runoff by introducing a multi-scale analysis approach, which furnishes a scientific basis for flood risk assessment, land use optimization, and water resource management, and demonstrates the potential for extensive application in other countries and regions with similar climatic and topographic conditions.

A Northgrippian sedimentary magnetic enhancement along the western margin of India

Sedimentary magnetic records of shelf region contains complex environmental evolution information, necessitating records from various global regions to accurately interpret its significance. A sediment core (SSD-39/GC-01) retrieved from the eastern Arabian Sea was analyzed to elucidate the geologic and climatic controls on the sediment rock magnetic and grain size properties. We report the first record of high energy sediment deposits linked with intense monsoon phases, sea level variations, and extreme natural events during the Northgrippian period (8.27 ka to 4.20 ka). The compilation of magnetic susceptibility profiles of six sediment cores from the western margin of India revealed the presence of multiple sedimentary intervals of enhanced magnetic susceptibility and most likely reflect periods of high sedimentation events controlled by the regional geologic and climatic processes. We identified two anomalous sedimentary magnetic zones (Z-II, Z-IV) marked by an elevated magnetite content and sediment grain size, which reflect the periods of high-sedimentation events on the shelf off Goa. A shift in the magnetic mineral composition, clastic grain size, calcium carbonate, and organic carbon content at ~1.8 ka (Z-I) indicate a abrupt change in monsoon intensity. The elevated organic content within Z-I indicate efficient preservation of labile organic matter which survived oxidation due to rapid sediment deposition. End-member modeling of rock magnetic and grain size properties enabled us to discriminate and quantify the contributions of terrigenous fluxes and post-depositional mineral phases to the bulk magnetic mineral assemblage. We demonstrate that rapid scanning of magnetic susceptibility of sediment cores has the potential to precisely detect the periods of increased continental (magnetic flux) inputs into the marine shelf system. The proposed magnetic mineralogical approach has wider scope to constrain the understanding of how shelf sedimentation responded to past geological and climatic conditions globally.

Improving subsurface structural interpretation in complex geological settings through geophysical imaging and machine learning

This study employs seismic refraction tomography (SRT) and electrical resistivity tomography (ERT) to assess subsurface geological conditions along the proposed Porsgrunn Highway in Norway. The primary objective is to analyze SRT and ERT tomograms to identify subsurface geological structures. However, interpreting tomograms is often limited by smoothed boundaries and reduced resolution. To address these challenges, we apply k-means clustering, a machine learning technique that groups data based on similarities in physical properties, to post-process the geophysical tomograms. This study pioneers the use of k-means clustering to interpret tomograms from SRT and ERT data in complex geological settings. We first evaluate the effectiveness of clustering techniques using numerical modeling for two geological scenarios: a horizontally layered case and a layered case with undulation and a fault structure. Utilizing automated methods (Elbow and Silhouette), we objectively determine the optimal number of clusters for each geophysical tomogram. Subsequently, we compare the performance of the k-means clustering algorithm with subjective expert interpretations and the Laplacian edge detection method. Borehole data validate the clustering results and confirm the effectiveness of optimal cluster selection techniques. The findings of this study demonstrate that k-means clustering significantly enhances the detection of geological structures by establishing clearer boundaries and minimizing noise interference, enabling more accurate fault zone delineation. Compared to traditional edge detection and subjective interpretation methods, k-means clustering offers a systematic and objective approach that improves consistency and reliability across diverse geological settings. Moreover, its automated classification of geophysical data into meaningful clusters enables efficient analysis of large datasets. This study underscores the value of integrating machine learning techniques with geophysical methods such as SRT and ERT to improve interpretability and accurately identify subsurface geological structures, particularly in fault zone identification.

Thermal and mechanical impact of artificial ground-freezing on deep excavation stability in Nakdong River Deltaic deposits

This paper presents a case study of deep excavation using the artificial ground freezing (AGF) method for tunnel restoration work in the Nakdong River deltaic deposits. The study involved detailed construction monitoring and data analysis to assess the thermal and mechanical impacts on surrounding ground and underground structures. Factors influencing heat transfer were identified and evaluated for their effect on ground temperature distribution. The excavation and frost expansion of the ground led to unique lateral deformation of the diaphragm wall. However, the frozen soil effectively resisted earth pressure and suppressed deformation of the wall. The axial stress applied to the braced strut was closely related to the deformation of the diaphragm wall and was influenced by both excavation-induced and frost-expansion pressures. Boreholes near the frozen soil functioned as stress-relief holes, enhancing excavation stability. These comprehensive findings enhance the understanding of AGF techniques and their impact on complex deltaic geological conditions and adjacent structures.

Research on transparency of coal mine geological conditions based on distributed fiber‐optic sensing technology

AbstractCoal mining induces changes in the nature of rock and soil bodies, as well as hydrogeological conditions, which can easily trigger the occurrence of geological disasters such as water inrush, movement of the coal seam roof and floor, and rock burst. Transparency in coal mine geological conditions provides technical support for intelligent coal mining and geological disaster prevention. In this sense, it is of great significance to address the requirements for informatizing coal mine geological conditions, dynamically adjust sensing parameters, and accurately identify disaster characteristics so as to prevent and control coal mine geological disasters. This paper examines the various action fields associated with geological disasters in mining faces and scrutinizes the types and sensing parameters of geological disasters resulting from coal seam mining. On this basis, it summarizes a distributed fiber‐optic sensing technology framework for transparent geology in coal mines. Combined with the multi‐field monitoring characteristics of the strain field, the temperature field, and the vibration field of distributed optical fiber sensing technology, parameters such as the strain increment ratio, the aquifer temperature gradient, and the acoustic wave amplitude are extracted as eigenvalues for identifying rock breaking, aquifer water level, and water cut range, and a multi‐field sensing method is established for identifying the characteristics of mining‐induced rock mass disasters. The development direction of transparent geology based on optical fiber sensing technology is proposed in terms of the aspects of sensing optical fiber structure for large deformation monitoring, identification accuracy of optical fiber acoustic signals, multi‐parameter monitoring, and early warning methods.

Earthquake Iso‐Nuisance and Iso‐Damage Mapping for Alberta: Applications for Choosing Magnitude Thresholds to Manage Induced Seismicity

AbstractWe generate earthquake iso‐nuisance and iso‐damage maps for Alberta. These maps show the spatial distribution of earthquake magnitude required to reach a specific level of nuisance and damage, considering human exposure and surficial geological conditions. We rely on population distribution for the human exposure factor while utilizing Vs30 derived from surficial geological modeling to approximate site amplification effects. By including the trailing seismicity factor, the iso‐nuisance and iso‐damage maps provide the base for the Magnitude Threshold for Acceptable Seismicity maps, which can set a guideline for the upper magnitude boundary, or largest magnitude event permissible, related to industrial activities causing seismicity. The trailing seismicity factor refers to the subsequent seismicity after a substantial change or end of the seismogenic operations; for instance, the cessation of seismogenic hydraulic fracturing activities under a traffic light protocol after a magnitude threshold event (red‐light event). Considering variations in the trailing seismicity factor, we derive different Magnitude Threshold for Acceptable Seismicity maps for various injection‐induced activities, including hydraulic fracturing and fluid disposal activities. Extended versions of the Magnitude Threshold for Acceptable Seismicity maps could allow for safety factors pertinent to critical infrastructure in a particular area, incorporating other factors beyond the population distribution and warranting a different tolerance level. These maps help to define the magnitude threshold from induced seismicity, maintaining the same tolerance levels throughout a region. Thus, they can be highly beneficial in managing current and future cases of induced seismicity related to the energy sector.

Innovation and Application of Cluster Edge Buttons of DTH Hammer Drill Bit in Large-Diameter Geothermal Well with High-Strength Rock

Down-the-hole (DTH) hammer drilling has high rock-breaking efficiency and a decisive advantage in hard rock drilling, which can reduce the cost of geothermal drilling. However, when the drill bit rotation speed and the DTH percussion frequency do not match properly, especially when the drill bit diameter is large and the ball button diameter is small, while drilling a high-strength formation, the edge buttons of the drill bit are prone to fracture and break, leading to the failure of the drill bit and a significant reduction in its lifespan. This paper investigates the failure modes firstly, then analyzes the failure mechanism of the large-diameter DTH bit, and finally proposes a novel method of cluster edge buttons of the DTH hammer drill bit in a large-diameter geothermal well with high-strength rock. The drill bit has been tested in a high-compressive-strength formation, and we will continue to do more testing and research in various geological conditions. Field application shows that this technology significantly improves the bit life and drilling efficiency and reduces the drilling costs.

Deformation failure mechanism and stability-control technology of deep layered clastic-rock roadway under dynamic disturbance

The deep layered clastic-rock roadways (LCRRs) of the gold mines in southwestern Guizhou, China, are adversely affected by dynamic disturbances such as blasting and mechanical operations, yielding poor roadway stability and unsatisfactory control effectiveness. This study investigates the deformation failure mechanism of a deep LCRR under dynamic disturbance and proposes and validates an optimised roadway stability-control scheme. Through on-site investigation and theoretical analysis, the main roadway stability-control factors are determined; that is, the mudstone-layer thickness, roadway buried depth, and dynamic-load amplitude. Similar simulation experiments reveal the deformation failure characteristics and strain-field evolution laws of similar models. Numerical analysis shows that increasing buried depth most severely affects the two sides of the roadway, whereas the dynamic-load amplitude determines the disturbance duration. Moreover, with increasing mudstone-layer thickness, the overall impact of the dynamic disturbance on the surrounding rock first intensifies and then diminishes. The results of the similar simulation experiment and numerical analyses are highly consistent, indicating a danger zone on the roadway roof. The roadway deformation and failure mechanisms are revealed, and a more rational technical solution for roadway stability control is proposed and implemented on-site. Analysis and monitoring results reveal a relative reduction in roadway surface displacement exceeding 30 %, and improvement of the overall roadway stability. The findings constitute a valuable reference and guide for roadway stability control under such geological conditions.

Feasibility Evaluation of I–Shaped Horizontal Salt Cavern for Underground Natural Gas Storage

Underground salt cavern gas storage has been widely applied due to its numerous advantages. Most of China’s salt resources are derived from lacustrine deposits. As high–quality resources in the central sedimentary area are gradually exploited, exploring the utilization of thin salt layers at the edges of sedimentary centers is the future development trend. However, the use of thin salt layers faces challenges such as low resource utilization, small cavern volumes, and poor economic feasibility, which limit its engineering applications. Therefore, a comprehensive assessment of constructing gas storage in thin salt layers is necessary. This paper first analyzes the necessity of building gas storage in thin salt layers and surveys cavern construction methods and their applicability. Based on geological seismic data, the feasibility of constructing gas storage in the Pingdingshan thin salt layer is proposed. A novel I–shaped cavern design is introduced, which, according to engineering economic evaluations, reduces investment by 9.6% compared to traditional single–well vertical cavern construction methods. Finally, rock mechanics tests were conducted to study the impact of mudstone interlayers and cyclic operation modes on the stability of the I–shaped cavern under three different injection and production conditions. The analysis shows that multi–cycle injection and production can effectively suppress cavern shrinkage and the development of the rock–relative plastic zone. The safety factor (SF) for different conditions is greater than 1, indicating that the I–shaped cavern has good stability and can adapt to various operational conditions. This study provides valuable insights into the geological conditions and rock mechanics characteristics for the future construction of gas storage in thin salt layers in China.

High-Resolution 3D Geological Modeling of Three-Phase Zone Coexisting Hydrate, Gas, and Brine

Three-dimensional geological modeling is essential for simulating natural gas hydrate (NGH) productivity and formulating development strategies. Current approaches primarily concentrate on the single-phase modeling of either hydrate or free gas layers. However, an increasing number of instances suggest that the three-phase coexistence zone, which includes hydrate, gas, and water, is common and has become a focal point of international research, as this type of reservoir may present the most viable opportunities for exploitation. At present, there exists a significant gap in the research regarding modeling techniques for such reservoirs. This study undertakes a comprehensive modeling investigation of the three-phase zone reservoir situated in the sand layer of the Qiongdongnan Basin. By employing deterministic complex geological modeling techniques and integrating existing seismic and logging data, we have developed a three-phase coexistence zone model that precisely characterizes the interactions between geological structures and utilizes them as auxiliary constraints. This approach effectively mitigates the potential impact of complex geological conditions on model accuracy. Through a comprehensive analysis of 105 seismic profiles, we enhanced the model’s accuracy, resulting in the creation of a three-phase coexistence zone model comprising 350,000 grids. A comparison between the modeling results and well data indicates a relatively small error margin, offering valuable insights for future development efforts. Furthermore, this method serves as a reference for modeling hydrates in marine environments characterized by three-phase coexistence on a global scale.

Natural Creation of Large Rock Cavern: Can We Construct Them? Jenolan Caves as a Case Study

The Jenolan Caves are the most spectacular limestone caves in Australia. Within this cave system, the Grand Arch, which is 24 m high, 55 m wide, and 127 m long, is the largest open cave in the country. A cave of this size could potentially accommodate small city streets, buildings, and other facilities. This paper examines a stability simulation of the Grand Arch, using numerical models to deduce foundational insights into rock openings under different geological and rock mass conditions. Following this, using numerical analysis, we investigate the creation of a man-made rock opening with the same span, height, and ground conditions of the Grand Arch but formed in two different arch shapes (i.e., with and without rock reinforcement as a stabilization measure). With all stability simulations conducted in this study, a clear explanation to describe the relationship and interaction between various parameters, such as rock mass structure and quality, rock mass strength, and in situ stress field, as well as different arch roofs shapes of the rock opening, is provided. Through its comparisons between natural rock cave and man-made rock openings, this study provides some findings and deep insight, as well as further questioning on creating a large size rock-reinforced cavern in different shapes to be opened in a range of rock conditions.