Hasil untuk "Engineering geology. Rock mechanics. Soil mechanics. Underground construction"

R. Sharafutdinov

Fan Feng, Zhiwei Xie, Shaojie Chen et al.

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 (θ) and the intermediate principal stress (σ2) 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 σ2 for a constant θ. However, when σ2 is constant, the maximum peak strength is obtained at θ of 90°, and the minimum peak strength is obtained at θ of 30° or 45°. 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 σ2, 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 θ, and always exhibit composite tensile-shear failure whatever the σ2 value is. With an increase in σ2 and θ, 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 (φ), and θ in sandstone specimens, we incorporate θ 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.

Mitsu Okamura, Hirotoshi Mori, Masanori Ishihara et al.

Significant sand ejecta repeatedly appeared during the 2018, 2020, and 2021 flooding events at the Gounokawa River levee in the Shimonohara district of Shimane Prefecture, Japan. Detailed site investigations were conducted, including the recording of a local resident’s eyewitness account, soil borings, electric resistivity tomography, and trench excavations. These methods clarified the event timelines, foundation soil profiles, and origins of the sand ejecta. Topographic changes, analyzed using digital elevation models derived from unmanned aerial vehicle photogrammetry, were used to determine whether backward erosion piping (BEP) had occurred. It was confirmed that high water pressure had propagated through the gravel layer and had broken through the overlying layers. Sand volcanoes formed in locations where an underlying gravel layer had existed and ground surface elevations had been low. The water head difference across the levee, when the sand boiling began, was estimated fairly accurately. This provided a valuable opportunity to verify the validity of the methods used to predict the initiation of sand boiling and BEP. The head difference was the highest in the 2018 event and decreased in the subsequent events. Despite the large amount of sand ejecta, no ground surface subsidence was observed. A grain-size distribution analysis revealed that the underlying gravel contained an unstable sand fraction, and thus, was suffusive. Most of the large amount of sand ejecta is considered to have originated from the gravel layer. Detailed trench wall observations facilitated the development of a scenario describing the ground deformation and sand-clod formation during the repeated flooding events.

PENG Xuefeng1 , JI Enyue1, 2 , CHEN Shengshui1, 2, FU Zhongzhi1, 2, ZHANG Yijiang1, 2

The deformation simulation method of core wall dams has always been a hot and difficult topic in the industry. Traditional grid-based methods, such as finite element method, finite volume method and finite difference method, are often applied to deformation analysis. However, when dealing with large deformation problems, the Jacobian matrix becomes abnormal due to mesh distortion, making the calculation impossible. Therefore, within the basic framework of the material point method, this paper constructs the convective particle Gaussian interpolation function and combines it with the particle interpolation function to propose the adaptive interpolation material point method (AIMPM) applicable to fluid-solid coupling problems. Taking the landslide of the Carsington core wall dam as an example, the AIMPM is used to analyze the evolution law of the whole process from the construction period to the instability and landslide of the dam. The results show that: (1) According to the actual construction situation of the dam, the AIMPM can accurately describe the development process of deformation and pore pressure during the construction stage of the dam body; (2) Under the condition of obtaining the initial stress during the construction of the dam body, the Adaptive Interpolation Material Point Method (AIMPM) can simulate the complete evolutionary process of the dam from the formation of the initial sliding surface to the final accumulation body after the dam break; (3) By capturing the running characteristics of particles, the failure process of the dam body can be divided into three stages: rigid body displacement stage, stress equilibrium stage and velocity convergence stage. Through the refined simulation of the classic core wall dam, it is indicated that the adaptive interpolation material point method proposed in this paper can be flexibly applied in both small strain and large deformation fields, providing an effective approach for the deformation and failure analysis of core wall dams.

V. Kaliakin

A. Morgun, Ivan Meth, A. Kolesnyk et al.

The paper addresses the solution of a current spatial contact problem in the behavior of deep foundations, specifically shell piles used for transferring significant loads to soil foundations, utilizing the numerical Boundary Element Method (BEM). One of the main tasks in construction design is assessing the technical and economic feasibility of using specific foundation types, taking into account the particular natural conditions of the construction site. Notably, the estimated cost of the underground part of a building in complex engineering and geological conditions constitutes 40-45% of the total cost. To determine the optimal solution, variant design is applied, based on principles of cost-efficiency, reliability, construction speed, maximum utilization of the bearing capacity of soils and foundations, and the use of modern advancements in soil mechanics and computer technologies. Currently, mathematical modeling is one of the key and most economical tools for theoretical and applied research in foundation engineering. Settlement prediction of foundation soils remains one of the most complex challenges in soil mechanics. A significant potential for gaining an accurate picture of the stress-strain state of the soil foundation lies in the elastic-plastic soil model under load, which is used in this study. Since the overall assessment of soil mass stability is of primary importance in foundation design, reliability and economic calculations of foundation structures determine the success of the construction as a whole. Modern mathematical models for describing soil behavior are systems of partial differential equations, which are too complex for analytical solutions. The behavior of a shell pile under load—a problem in geomechanics—can be solved using numerical methods, one of which is the Boundary Element Method (BEM). The input parameters for the numerical simulation program include values that characterize the physical and mechanical properties of the soil, and describe the geometry and topology of the design scheme. The obtained research results provide answers to a wide range of issues addressed in the design of shell piles. The BEM-based software allows for the determination of coefficients of the BEM influence matrix (the soil compliance matrix). To obtain these, the boundary of the contact area between the foundation structure and the soil is discretized using linear boundary elements, the weighted average soil properties are defined, and the required dimensions of the foundation structure are established. The numerical approach is illustrated through stress-strain state calculations of the pile at each loading step, considering the dilatancy properties of the soil using an elastic-plastic soil model. A comparative analysis of the bearing capacity of shell piles based on calculations and current regulations is provided.

Liangchao Huang, Yanli Fang, Zhengmeng Hou et al.

Abstract Large‐scale underground hydrogen storage (UHS) provides a promising method for increasing the role of hydrogen in the process of carbon neutrality and energy transition. Of all the existing storage deposits, salt caverns are recognized as ideal sites for pure hydrogen storage. Evaluation and optimization of site selection for hydrogen storage facilities in salt caverns have become significant issues. In this article, the software CiteSpace is used to analyze and filter hot topics in published research. Based on a detailed classification and analysis, a “four‐factor” model for the site selection of salt cavern hydrogen storage is proposed, encompassing the dynamic demands of hydrogen energy, geological, hydrological, and ground factors of salt mines. Subsequently, 20 basic indicators for comprehensive suitability grading of the target site were screened using the analytic hierarchy process and expert survey methods were adopted, which provided a preliminary site selection system for salt cavern hydrogen storage. Ultimately, the developed system was applied for the evaluation of salt cavern hydrogen storage sites in the salt mines of Pingdingshan City, Henan Province, thereby confirming its rationality and effectiveness. This research provides a feasible method and theoretical basis for the site selection of UHS in salt caverns in China.

Nilo Cesar Consoli, João Vítor de Azambuja Carvalho, Alexia Cindy Wagner et al.

The disposal of filtered tailings in high dry stacks can induce particle breakage, changing the material's behaviour during the structure's lifetime. The grading changes influence material properties at the critical state, and this is not mature for intermediate artificial soils (tailings) in a broad range of confining pressures. In this paper, it aims to describe the behaviour of iron ore tailings in a spectrum of confining pressures broader than the reported in previous studies. A series of consolidated drained (CD) triaxial tests was carried out with confining pressures ranging from 0.075 MPa to 120 MPa. These results show that the amount of breakage plays an essential role in the response of iron ore tailings. The existence of curved critical state line (CSL) in both specific volume (ν)–logarithm of mean effective stress (p′) and deviatoric stress (q)–mean effective stress (p′) planes, and different responses in the deviatoric stress–axial strain–volumetric strain curves were verified. An inverse S-shaped equation was proposed to represent the silty-sandy tailings' behaviour up to high pressures on ν–lnp′ plane. The proposed equation provides a basis for enhancing constitutive models and considers the evolution of the grading up to severe loading conditions. The adjustment considered three regions with different responses associated with particle breakage at different pressure levels.

WANG Fan, XV Bing, CHEN Lunjian et al.

Groundwater pollution induced by Underground Coal Gasification(UCG)seriously hinders its development.Permeable Reactive Barrier(PRB)remediation therefore stands out as a major research focus for in-situ groundwater remediation, where the characteristics of PRB material is crucial to their effective operation.This study thus examines the adsorption properties of sand, organic bentonite, and activated carbon on phenol, a characteristic organic pollutant associated with UCG.A self-constructed permeation experimental system is employed to study the adsorption and permeation characteristics of sand, organic bentonite, activated carbon, mixtures of sand and organic bentonite, as well as sand and activated carbon to investigate their comprehensive impact in purifying contaminated water.The results indicate that: ①Organic bentonite exhibits a rapid adsorption rate for phenol in solution, reaching adsorption equilibrium within 10 minutes, despite a relatively low adsorption capacity(1.98 mg/g). Activated carbon, on the other hand, demonstrates a slower adsorption rate yet a higher adsorption capacity(2.22 mg/g).②The adsorption of phenol by organic bentonite conforms to the Freundlich isotherm model, with parameters kF = 0.040 and n = 1.207.Activated carbon follows the Langmuir isotherm model, with parameters Smax = 2.44 mg/g and kL= 0.125 L/mg.③The permeability coefficients of sand and activated carbon are 1.006×10-3 m/s and 4.761×10-2 m/s, respectively.The mixture of sand with activated carbon or organic bentonite could effectively moderate the permeability of the mixed material.When the mass ratio of sand to organic bentonite increases from 1∶1 to 3∶1, the permeability coefficient of the mixed material increases from 2.624×10-6 to 3.468×10-5 m/s.Conversely, when the ratio of sand to activated carbon increases from 1∶1 to 3∶1, the permeability coefficient of the mixed material decreases from 1.379×10-3 to 1.301×10-4 m/s.

Shuangzhan SHENG, Haifeng PAN, Xiang SHI et al.

Objective The Shengbei Depression is the largest petroliferous depression of the Tuha Basin. With the strong demand for the exploration and development of tight sandstone gas in the Middle Jurassic Sanjianfang Formation, it is urgent to study the sedimentary characteristics and predict favourable exploration zones of the Sanjianfang Formation. Methods Using core, well logging, and seismic data, the high-resolution sequences and sedimentary characteristics of the tight sandstone gas reservoir in the Sanjianfang Formation of the Shengbei Depression were studied. A lacustrine delta system was identified, and favourable exploration zones of tight gas reservoirs were predicted. Results Three long-term sequences (L1, L2, L3) and five medium-term sequences (M1, M2, M3, M4, M5) were developed in the Sanjianfang Formation in the Shengbei Depression; particularly, these medium-term sequences can be regionally identified. The deposition of the M1 to M3 sequences involved a braided river delta in the lake, but the deposition of the M4-M5 sequences involved a meandering river delta in the lake. The favourable tight gas reservoirs of the Sanjianfang Formation in the Shengbei Depression were mainly developed in subfacies of the delta front. On the plane, the Shengbei 5 and Shengshen 3 well areas of the M2 sequence, the Shengbei 5 and Shengbei 6 well areas of the M3 sequence, and the Shengbei 5, Shengbei 6, and Shengtan 1 well areas of the M5 sequence are favorable exploration areas. The favorable reservoir rarely appears in the M4 sequence. Conclusion This research can promote the exploration of tight gas reservoirs in the Sanjianfang Formation of the Shengbei Depression in the Tuha Basin.

مهدیه نیک روش, علیرضا موحدی نایینی, کلثوم عبداللهی et al.

سابقه و هدف: آلودگی‌های زیست‌محیطی ناشی از کاربرد آفت‌کش‌ها یکی از مهم‌ترین عوامل تهدیدکننده سلامت زیست‌بوم‌ها و بشر هستند، از این‌رو، بررسی سرنوشت علف‌کش‌های مصرف شده در خاک برای به حداقل رساندن تحرک آنها در خاک و کنترل آلودگی آب‌های زیرزمینی ضروری می‌باشد.از علف‌کش کلوپیرالید در محصولات کشاورزی منطقه خلیج گرگان به‌صورت گسترده استفاده می‌شود و در ارتباط با سرنوشت این علف‌کش در خاک، مطالعه اندکی در کشور انجام شده است. به‌دلیل نگرانی از خطر آبشویی زیاد این علف‌کش در خاک و نفوذ به آب‌های زیرزمینی، این مطالعه با هدف ارزیابی میزان عمق آبشویی و نیمه‌عمر علف‌کش کلوپیرالید در خاک و حضور آن در آب‌های زیرزمینی منطقه در شرایط مزرعه‌ای انجام شد.مواد و روش‎ها: این مطالعه در بخشی از مزارع شهرستان بندرگز انجام شد. به‌ این‌منظور دو مزرعه کلزا واقع در غرب و شرق منطقه مورد بررسی، در نظر گرفته شد. پس از مصرف این علف‌کش در اواخر آذر1400 در زمان‌های 1، 14، 28، 56، 86 و 116 روز بعد از سمپاشی، از اعماق 17-0، 34-17، 51-34 و 67-51 سانتی‌متر با سه تکرار در هر مزرعه نمونه‌برداری گردید. همچنین، برای بررسی وضعیت آلودگی آب چاههای منطقه، از 4 حلقه چاه در پنج دوره نمونه‌برداری شد. برای استخراج باقیمانده کلوپیرالید از خاک و آب از روش کروماتوگرافی مایع با کارایی بالا در فاز معکوس که مجهز به آشکارساز UV-Vis بود، استفاده شد.یافته‏ ها: مدل سینتیکی مرتبه اول تغییرات غلظت علف‌کش کلوپیرالید را با زمان به خوبی پیش‌بینی کرد. 56 روز بعد از سمپاشی، مقدار نفوذ عمقی این علف‌کش در خاک هر دو مزرعه، حداکثر تا عمق 34 سانتی‌متری بود. نتایج نشان داد که خاک زیرسطحی بخش شرقی (لوم‌شنی) نسبت به بخش غربی (لوم)، درشت بافت‌تر بود. مقادیر ثابت سرعت تجزیه (k) در مزرعه غربی در بخش سطحی و زیرسطحی، به‌ترتیب 06/0 و 04/0 و در مزرعه شرقی در بخش سطحی و زیرسطحی بترتیب 05/0 و 03/0 بود. نیمه‌عمر کلوپیرالید (DT50) در مزرعه غربی در بخش سطحی و زیر‌سطحی، به‌ترتیب 12 و 18 روز و در مزرعه شرقی در بخش سطحی و زیر‌سطحی به‌ترتیب 13 و 26 روز به دست آمد. مقدار شاخص GUS نیز در هر دو مزرعه بزرگ‌تر از 8/2 بدست آمد که بیانگر خطر آبشویی این علف‌کش می‌باشد. نتایج آنالیز باقیمانده کلوپیرالید در نمونه‌های آب چاه، حاکی از عدم وجود علف‌کش در آنها بود.نتیجه‏ گیری: در شرایط مزرعه‌ای، آبشویی علف‌کش نقش مهمی در پیش‌بینی بقایای آن در خاک دارد. همچنین، مواد آلی، روند تجزیه کلوپیرالید را تسریع و نیمه‌عمر آن را کاهش می‌دهد. ارزیابی خطر آلودگی کلوپیرالید با مدل جوری نیز نشان داد که کاربرد آن در مناطقی که میزان مواد آلی خاک کمتر از یک درصد، بافت خاک سبک و ظرفیت نگهداشت آب پایین است باید با احتیاط صورت گیرد.

Shirui Zhang, Shili Qiu, Quan Jiang et al.

Jing Wang, Honghu Zhu, Daoyuan Tan et al.

Defects in cast-in-situ piles have an adverse impact on load transfer at the pile‒soil interface and pile bearing capacity. In recent years, thermal integrity profiling (TIP) has been developed to measure temperature profiles of cast-in-situ piles, enabling the detection of structural defects or anomalies at the early stage of construction. However, using this integrity testing method to evaluate potential defects in cast-in-situ piles requires a comprehensive understanding of the mechanism of hydration heat transfer from piles to surrounding soils. In this study, small-scale model tests were conducted in laboratory to investigate the performance of TIP in detecting pile integrity. Fiber-optic distributed temperature sensing (DTS) technology was used to monitor detailed temperature variations along model piles in sand. Additionally, sensors were installed in sand to measure water content and matric suction. An interpretation method against available DTS-based thermal profiles was proposed to reveal the potential defective regions. It shows that the temperature difference between normal and defective piles is more obvious in wet sand. In addition, there is a critical zone of water migration in sand due to the water absorption behavior of cement and temperature transfer-induced water migration in the early-age concrete setting. These findings could provide important insight into the improvement of the TIP testing method for field applications.

Sanjay Mate, Vikas Somani, Prashant Dahiwale

Agriculture has a good stake in the world’s GDP. In many countries, agriculture and allied sectors have a good stake in national GDP. This paper covers details related to livestock since 1960s. The workforce has managed livestock for many decades. The workforce increases as the number of animals increases; it is an energy, time-consuming, and economically costly approach. Apart from it, there is no assurance about animal welfare in case of diseases, breeding, and feed intake issues. In the 21st century of digitalization, technology has a key role in improving overall monitoring, controlling, and processing in livestock management. This paper has gone thoroughly into the manual and automated livestock farm management, aiming welfare of animals, livestock products, consumers’ benefit, and sustainable environmental approaches.

Lihua Hu, Liyuan Yu, Minghe Ju et al.

The effect of intermediate stress (in situ tunnel axial) on a strainburst is studied with a three-dimensional (3D) bonded block distinct element method (DEM). A series of simulations of strainbursts under true triaxial in situ stress conditions (i.e. high tangential stress, moderate intermediate stress and low radial stress) of near-boundary rock masses are performed. Compared with the experimental results, the DEM model is able to capture the stress-strain response, failure pattern and energy balance of strainbursts. The fracturing processes of strainbursts are also numerically reproduced. Numerical results show that, as the intermediate stress increases: (1) The peak strain of strainbursts increases, the yield stress increases, the rock strength increases linearly, and the ratio of yield stress to rock strength decreases, indicating that the precursory information on strainbursts is enhanced; (2) Tensile and shear cracks increase significantly, and slabbing and bending of rock plates are more pronounced; and (3) The stored elastic strain energy and dissipated energy increase linearly, whereas the kinetic energy of the ejected rock fragments increases approximately exponentially, implying an increase in strainburst intensity. By comparing the experimental and numerical results, the effect of intermediate stress on the rock strength of strainbursts is discussed in order to address three key issues. Then, the Mogi criterion is applied to construct new strength criteria for strainbursts by converting the one-face free true triaxial stress state of a strainburst to its equivalent true triaxial stress state. In summary, the effect of intermediate stress on strainbursts is a double-edged sword that can enhance the rock strength and the precursory information of a strainburst, but also increase its intensity.

Y. Gui, Zhiqiang Yin, Kun Du

With the development of the social economy, the depth of underground excavation has seen a significant increase in the fields of mining, tunnelling, hydropower, nuclear waste deep geological storage, and underground protection engineering. In mining engineering, for instance, nearly 200 metal mines have mining depth of more than 1 km, and the deepest one has reached more than 4 km below the ground surface (Li et al., 2017). The excavation of rocks in deep ground is subjected to the state of complicated circumferential loadings, for example, the high in situ stress, the high ground temperature, the high hydraulic pressure (high gas pressure), in addition to the dynamic disturbance caused by blasting and mechanical excavation (Zhang and Zhao 2014; Huang et al.). Therefore, the excavation process may cause rockburst, coal and gas outburst, sudden fracture of rock mass and other dynamic phenomena, and cause severe engineering disasters. Therefore, in deep rock excavation engineering, the description of dynamic disaster response induced by excavation, the exploration of hidden disaster sources, and disaster forecasting and control have become the key technologies. Within this context, continuous progress needs to be done to improve the safety performance of deep rock excavation. To meet the demand of engineering and academic communities in this topic, a Research Topic “Deep Rock Mass Engineering: Excavation, Monitoring, and Control” was proposed to the renowned journal Frontiers in Earth Science. The aim of this topic was to call for the state-of-the-art research in deep rock mass excavation, particularly in mining engineering, tunnelling, petroleum (gas) engineering and general rock mechanics, and to pulse the research trend in deep rock engineering. It was a great honour to be invited to serve as a Guest Editor for this Research Topic. Upon the open of this topic, it was even more privileged to receive so great response from relevant academic communities. In total 21 papers collected and published in this Topic. A wide range of research was presented from novel laboratory testing (e.g., Liu et al.; Zhao OPEN ACCESS

XIE Yi-fan 1, 2, XIE Zhen-ze 1, 2, WU Ji-chun 3, ZHANG Wei 4, XIE Chun-hong 5, LU Chun-hui 1, 2, 6

The traditional finite element method often requires fine element grids to describle the heterogeneity of medium to ensure the accuracy for numerical modeling of groundwater, which leads to a large amount of calculation consumption. The multiscale finite element method can alleviate this problem, but it still needs a high cost to formulate the basis function when dealing with high computational complexity. A multiscale finite element method-triple grid model (MSFEM-T) is proposed for the simulation of groundwater flows. The MSFEM-T introduces an intermediate grid between the coarse grid and the fine grid, so that the basis function in the coarse grid can be established using the MSFEM instead of the FEM based on the intermediate and fine grids, therefore reducing the construction consumption of the basis function and improving the overall calculation efficiency. Moreover, the MSFEM-T uses an over-sampling method based on the coarse, intermediate and fine grids, which can further improve its calculation accuracy. The results show that the accuracy of the MSFEM-T is similar to that of the MSFEM and the finite element method of fine elements (LFEM-F), but the computational efficiency is much higher.

Isam Shahrour, Hanbing Bian, Xiongyao Xie et al.

This study centers on the use of smart technology to improve the lifecycle management of underground facilities. It presents a comprehensive digital solution that addresses the challenges of underground facilities, particularly those related to the extensive use of underground space, as well as the requirements for safety, sustainability, and quality of services. The proposed solution emerged from discussions with experts, companies, and cities involved in the design, construction, and management of underground facilities. In this paper, we first discuss the major challenges of underground facilities, then, we present the development of a smart solution to address these challenges. This study demonstrates a promising perspective for the use of smart technology in the optimal management of underground facilities, and paves the way for its implementation.

Erhan Gülyüz

The Beypazarı Granitoid is an arc-related intrusion in the Central Pontides, Turkey. This study presents apatite fission track (AFT) ages of the intrusion to shed some light on collision-related cooling/exhumation history of the central Pontides. The AFT ages from different altitudes (506–805-1110 metres above sea level) of the Beypazarı Granitoid yield around 65 ± 3 Ma. This indicates a rapid cooling/exhumation for the intrusion around 65 Ma, which is attributed to the commencement of the collision event in the region. Integration of these ages and low-temperature thermochronology literature suggests a progressive collision propagation towards the margins of the collision system.

Dong-Jie Ren, S. Shen, W. Cheng et al.