Underground Space最新文献

{"title":"Soil conditioning of clay based on interface adhesion mechanism: Microscopic simulation and laboratory experiment","authors":"Yong Fang,&nbsp;Bin Zhuo,&nbsp;Ruyue Zhang,&nbsp;Yubo Wang,&nbsp;Liupan Dou,&nbsp;Yuxiang Yao","doi":"10.1016/j.undsp.2023.12.007","DOIUrl":"https://doi.org/10.1016/j.undsp.2023.12.007","url":null,"abstract":"<div><p>Clogging frequently occurs in the cutter head, excavation chamber or screw conveyor when an earth pressure balance (EPB) shield machine is tunneling in soft or silty clay ground with high clay mineral content. In this paper, montmorillonite, kaolinite, and illite were selected as research objects, and molecular dynamics (MD) simulation and laboratory experiment were adopted. At the microscopic scale, dynamic contact behavior and interfacial mechanical behavior of the interface between clay minerals and water/surfactant solution was simulated and the interfacial adhesion and conditioning mechanism between clay minerals and water/surfactant solution was revealed. Thus, sodium dodecyl benzene sulfonate (SDBS) surfactant was selected as the main composition of the soil conditioner. Then, the adhesion stress before and after soil conditioning and the contact angles between clay minerals and water/surfactant solution were tested and analyzed at the macroscopic scale. The result shows that the contact angle between droplet and clay mineral surface is an important parameter to characterize soil adhesion. The simulation rules of the microscopic contact angle are consistent with the experiment results. Furthermore, the adsorption energy between microscopic substances is dominated by electrostatic force, which can reflect the adhesion stress between macroscopic substances. Soil adhesion stress can be effectively decreased by adding the surfactant to the soil conditioner.</p></div>","PeriodicalId":48505,"journal":{"name":"Underground Space","volume":"18 ","pages":"Pages 239-255"},"PeriodicalIF":6.4,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2467967424000461/pdfft?md5=67caadaba449500a75f0cfe6586321b7&pid=1-s2.0-S2467967424000461-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141263856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Migration time prediction and assessment of toxic fumes under forced ventilation in underground mines","authors":"Jinrui Zhang ,&nbsp;Tingting Zhang ,&nbsp;Chuanqi Li","doi":"10.1016/j.undsp.2024.01.004","DOIUrl":"https://doi.org/10.1016/j.undsp.2024.01.004","url":null,"abstract":"<div><p>This study aims to predict the migration time of toxic fumes induced by excavation blasting in underground mines. To reduce numerical simulation time and optimize ventilation design, several back propagation neural network (BPNN) models optimized by honey badger algorithm (HBA) with four chaos mapping (CM) functions (i.e., Chebyshev (Che) map, Circle (Cir) map, Logistic (Log) map, and Piecewise (Pie) map) are developed to predict the migration time. 125 simulations by the computational fluid dynamics (CFD) method are used to train and test the developed models. The determination coefficient (<em>R</em>²), the variance accounted for (VAF), the Willmott’s index (WI), the root mean square error (RMSE), the mean absolute percentage error (MAPE), and the sum of squares error (SSE) are utilized to evaluate the model performance. The evaluation results indicate that the CirHBA-BPNN model has achieved the most satisfactory performance by reaching the highest values of <em>R</em>² (0.9945), WI (0.9986), VAF (99.4811%), and the lowest values of RMSE (15.7600), MAPE (0.0343) and SSE (6209.4), respectively. The wind velocity in roadway (<em>W</em>_v) is the most important feature for predicting the migration time of toxic fumes. Furthermore, the intrinsic response characteristic of the optimal model is implemented to enhance the model interpretability and provide reference for the relationship between features and migration time of toxic fumes in ventilation design.</p></div>","PeriodicalId":48505,"journal":{"name":"Underground Space","volume":"18 ","pages":"Pages 273-294"},"PeriodicalIF":6.4,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2467967424000448/pdfft?md5=fdbe69eadbfc36a8f4bfb03ecbe3f1db&pid=1-s2.0-S2467967424000448-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141286403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analytical model regarding compression-bending capacity of segmental joint reinforced by steel plate","authors":"Zhen Li ,&nbsp;Xuezeng Liu","doi":"10.1016/j.undsp.2024.01.005","DOIUrl":"10.1016/j.undsp.2024.01.005","url":null,"abstract":"<div><div>The mechanical properties of the steel-plate-reinforced segmental lining are generally determined by the load-bearing capacity of reinforced joints. However, there is a lack of valid calculation methods for compression-bending bearing capacity, and researchers mainly rely on experience and analogy for the design of reinforced joints. This paper proposes an analytical model based on the deformation and stress characteristics of the joint surface to calculate the compression-bending capacity of the steel-plate-reinforced joint. After verifying the applicability of this analytical model through finite element simulations, the evalution rules of the load-bearing capacity of the reinforced joint were attained, followed by a quantitative investigation into the influence of joint parameters on it. The results show that: (1) the bearing capacity curve of the reinforced joint under different axial forces can be separated into two parts, with the maximum ultimate bending moment found at the demarcation point, where the steel plate yielding and joint failure occur simultaneously; (2) the steel plate strength and cross-sectional area have a strong influence on the bearing capacity of the reinforced joint when the axial force is under 0.15RFF, where RFF is the axial force at pure-compression failure); (3) the concrete strength and segment width have a prominent influence on the curve when the axial force is over 0.30RFF; (4) the impact of the fictitious strain, bolt strength, bolt diameter, and bolt location on the bearing capacity is minimal in range and amplitude.</div></div>","PeriodicalId":48505,"journal":{"name":"Underground Space","volume":"20 ","pages":"Pages 157-173"},"PeriodicalIF":8.2,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disc-cutter induced rock breakage mechanism for TBM excavation in rock masses with different joint shear strengths","authors":"Bolong Liu ,&nbsp;Bo Li ,&nbsp;Liang Zhang ,&nbsp;Rui Huang ,&nbsp;Huicai Gao ,&nbsp;Shilin Luo ,&nbsp;Tao Wang","doi":"10.1016/j.undsp.2023.12.006","DOIUrl":"10.1016/j.undsp.2023.12.006","url":null,"abstract":"<div><p>When tunnel boring machines (TBMs) excavate through jointed rock masses, the cutting efficiency is strongly affected by the shear strength of joints, the mechanism of which, however, remains poorly understood. In this study, a series of disc-cutter indentation tests were conducted on granite rock mass specimens with different joint shear strengths. During the indentation, the cracking process was recorded by a digital image correlation (DIC) system. The deformation and strength of specimens, cracking behavior, rock breakage mode and cutting efficiency were quantitatively investigated. In addition, to investigate the combined effects of joint shear strength, orientation and spacing on the rock breakage mechanism, numerical rock mass models were established based on a particle flow code PFC2D. Experimental results reveal that the cracking of primary and secondary cracks changes from the mixed shear-tensile to tensile mode in the initial stage, while the joint shear strength does not affect the cracking mode in the subsequent propagation process. The rock breakage mode is classified to an internal block breakage mode, a cross-joint breakage mode and a cutters-dependent breakage mode. The cross-joint breakage mode is optimal for improving the cutting efficiency. Numerical simulation results reveal that the increase in the joint shear strength changes the internal block breakage mode to cross-joint breakage mode for rock masses of particular ranges of joint orientation and spacing. These findings provide basis for improving the TBM cutting efficiency through jointed rock masses.</p></div>","PeriodicalId":48505,"journal":{"name":"Underground Space","volume":"19 ","pages":"Pages 119-137"},"PeriodicalIF":8.2,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2467967424000436/pdfft?md5=dbf65fcbce77b037e7679c24b5051bf6&pid=1-s2.0-S2467967424000436-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140790426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MCS-based quantile value approach for reliability-based design of tunnel face support pressure","authors":"Bin Li,&nbsp;Changxing Wang,&nbsp;Hong Li","doi":"10.1016/j.undsp.2024.01.003","DOIUrl":"10.1016/j.undsp.2024.01.003","url":null,"abstract":"<div><p>This paper develops a new approach for reliability-based design (RBD) of tunnel face support pressure from a quantile value perspective. A surrogate model is constructed to calculate the collapse pressures of the random samples generated by a single run of Monte Carlo simulation (MCS). The cumulative distribution function (CDF) of the collapse pressure is then obtained and the support pressure aiming at a target failure probability is chosen as the upper quantile value of the collapse pressures. The proposed approach does not require repetitive reliability analyses compared to the existing methods. Moreover, a direct relationship between the target failure probability and the required support pressure is established. An illustrative example is used to demonstrate the implementation procedure. The accuracy of the reliability-based support pressures is verified by direct MCS incorporating with three-dimensional numerical simulations. Finally, the influencing factors, including the sample size of MCS, the correlation coefficient between random variables, the choice of experimental points, and the surrogate model, are investigated. This method can play a complementary role to available approaches due to its advantages of simplicity and efficiency.</p></div>","PeriodicalId":48505,"journal":{"name":"Underground Space","volume":"18 ","pages":"Pages 187-198"},"PeriodicalIF":6.4,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2467967424000424/pdfft?md5=cce4e3a8da26ece1e85330c1360abb86&pid=1-s2.0-S2467967424000424-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140785579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Editorial for Machine learning and AI for underground metaverse","authors":"Kok-Kwang Phoon,&nbsp;Qiujing Pan,&nbsp;Chong Tang","doi":"10.1016/j.undsp.2024.03.002","DOIUrl":"10.1016/j.undsp.2024.03.002","url":null,"abstract":"","PeriodicalId":48505,"journal":{"name":"Underground Space","volume":"19 ","pages":"Pages 1-3"},"PeriodicalIF":6.4,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2467967424000412/pdfft?md5=a5e02d0792c31b0709d89572fb9e5c10&pid=1-s2.0-S2467967424000412-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140787017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance and environmental impacts of deep foundation excavation in soft soils: A field and modeling-based case study in Nanjing, China","authors":"Chenhe Ge ,&nbsp;Meng Yang ,&nbsp;Pengfei Li ,&nbsp;Mingju Zhang ,&nbsp;Zhonghao Zhang","doi":"10.1016/j.undsp.2024.01.002","DOIUrl":"10.1016/j.undsp.2024.01.002","url":null,"abstract":"<div><p>This paper focuses on the performance of a braced deep excavation in soft soil based on field monitoring and numerical modeling. Laboratory tests were conducted to determine the soil parameters used in the modified Cam–Clay (MCC) model. Intelligent field monitoring means were adopted and a three-dimensional model was established. Spatial and temporal effects induced by the excavation are investigated for the deep-large foundation pit in soft soil. Deformation characteristics of the enclosure structure and the surrounding environment throughout the excavation process are presented. The behaviors of diaphragm walls, columns, the maximum wall deflection rate, ground surface settlement, and utility pipelines were focused on and investigated during the whole excavation process. Besides, the axial forces of the internal supports are analyzed. Based on the measured and simulated data, the following main conclusions were obtained: the numerical simulation results are in good agreement with the measured values, which proves the accuracy of the model parameters; the wall and the ground surface showed the maximum displacement increment at stage 9, which was a coupled product of the “creep effect” of the soft soil in Nanjing, China and the “depth effect” of the excavation; as the excavation progressed, the ground settlement changed from a “rising” to a “spoon-shaped” trend, <em>δ</em>_vm was measured between <em>δ</em>_vm = 0.0686%<em>H</em> and <em>δ</em>_vm = 0.1488%<em>H</em>; the rebound deformation curve of the pit bottom was corrugated, and the depth of disturbance of the pit bottom after the completion of soil unloading was 2–3 times the excavation depth; the closer the pipeline is to the corner of the pit, the less the excavation process will affect the settlement of the pipeline and the less the obvious pit corner effect will occur; the support strength of the buttress and the longest corner brace should be strengthened during the actual construction process to ensure the stability of the foundation deformation.</p></div>","PeriodicalId":48505,"journal":{"name":"Underground Space","volume":"18 ","pages":"Pages 218-238"},"PeriodicalIF":6.4,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2467967424000321/pdfft?md5=c6f5bd122f50852365862fdb3606c53d&pid=1-s2.0-S2467967424000321-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140789190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large post-liquefaction deformation of sand: Mechanisms and modeling considering water absorption in shearing and seismic wave conditions","authors":"Jian-Min Zhang,&nbsp;Rui Wang","doi":"10.1016/j.undsp.2024.03.001","DOIUrl":"https://doi.org/10.1016/j.undsp.2024.03.001","url":null,"abstract":"<div><p>Large deformation of sand due to soil liquefaction is a major cause for seismic damage. In this study, the mechanisms and modeling of large post-liquefaction deformation of sand considering the significant influence of water absorption in shearing and seismic wave conditions. Assessment of case histories from past earthquakes and review of existing studies highlight the importance of the two factors. Based on the micro and macro scale mechanisms for post-liquefaction shear deformation, the mechanism for water absorption in shearing after initial liquefaction is revealed. This is aided by novel designed constant water-absorption-rate shear tests. Water absorption in shearing can be classified into three types, including partial water absorption, complete water absorption, and compulsory water absorption. Under the influence of water absorption in shearing, even a strongly dilative sand under naturally drained conditions could experience instability and large shear deformation. The mechanism for amplification of post-liquefaction deformation under surface wave load is also explained via element tests and theoretical analysis. This shows that surface wave–shear wave coupling can induce asymmetrical force and resistance in sand, resulting in asymmetrical accumulation of deformation, which is amplified by liquefaction. A constitutive model, referred to as CycLiq, is formulated to capture the large deformation of sand considering water absorption in shearing and seismic wave conditions, along with its numerical implementation algorithm. The model is comprehensively calibrated based on various types of element tests and validated against centrifuge shaking table tests in the liquefaction experiments and analysis projects (LEAP). The model, along with various numerical analysis methods, is adopted in the successful simulation of water absorption in shearing and Rayleigh wave-shear wave coupling induced large liquefaction deformation. Furthermore, the model is applied to high-performance simulation for large-scale soil-structure interaction in liquefiable ground, including underground structures, dams, quay walls, and offshore wind turbines.</p></div>","PeriodicalId":48505,"journal":{"name":"Underground Space","volume":"18 ","pages":"Pages 3-64"},"PeriodicalIF":6.4,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2467967424000333/pdfft?md5=4a365bcb9c7c2846f243e42a67044e01&pid=1-s2.0-S2467967424000333-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141078217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting the strut forces of the steel supporting structure of deep excavation considering various factors by machine learning methods","authors":"Haibo Hu,&nbsp;Xunjian Hu,&nbsp;Xiaonan Gong","doi":"10.1016/j.undsp.2023.12.005","DOIUrl":"10.1016/j.undsp.2023.12.005","url":null,"abstract":"<div><p>The application of steel strut force servo systems in deep excavation engineering is not widespread, and there is a notable scarcity of in-situ measured datasets. This presents a significant research gap in the field. Addressing this, our study introduces a valuable dataset and application scenarios, serving as a reference point for future research. The main objective of this study is to use machine learning (ML) methods for accurately predicting strut forces in steel supporting structures, a crucial aspect for the safety and stability of deep excavation projects. We employed five different ML methods: radial basis function neural network (RBFNN), back propagation neural network (BPNN), <em>K</em>-Nearest Neighbor (KNN), support vector machine (SVM), and random forest (RF), utilizing a dataset of 2208 measured points. These points included one output parameter (strut forces) and seven input parameters (vertical position of strut, plane position of strut, time, temperature, unit weight, cohesion, and internal frictional angle). The effectiveness of these methods was assessed using root mean square error (RMSE), correlation coefficient (<em>R</em>), and mean absolute error (MAE). Our findings indicate that the BPNN method outperforms others, with RMSE, <em>R</em>, and MAE values of 72.1 kN, 0.9931, and 57.4 kN, respectively, on the testing dataset. This study underscores the potential of ML methods in precisely predicting strut forces in deep excavation engineering, contributing to enhanced safety measures and project planning.</p></div>","PeriodicalId":48505,"journal":{"name":"Underground Space","volume":"18 ","pages":"Pages 114-129"},"PeriodicalIF":6.4,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2467967424000308/pdfft?md5=c487b2f4422e9875ea2ee5760ffafcba&pid=1-s2.0-S2467967424000308-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140777439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics of the crack tip field in high-speed railway tunnel linings under train-induced aerodynamic shockwaves","authors":"Yi-Kang Liu ,&nbsp;Yu-Ling Wang ,&nbsp;E Deng ,&nbsp;Yi-Qing Ni ,&nbsp;Wei-Chao Yang ,&nbsp;Wai-Kei Ao","doi":"10.1016/j.undsp.2024.01.001","DOIUrl":"https://doi.org/10.1016/j.undsp.2024.01.001","url":null,"abstract":"<div><p>High-speed railway tunnels in various countries have continuously reported accidents of vault falling concrete blocks. Once the concrete block falling occurs, serious consequences follow, and traffic safety may be endangered. The aerodynamic shockwave evolves from the initial compression wave may be an important inducement causing the tunnel lining cracks to grow and form falling concrete blocks. A joint calculation framework is established based on ANSYS Fluent, ABAQUS, and FRANC3D for calculating the crack tip field under the aerodynamic shockwave. The intensification effect of aerodynamic shockwaves in the crack is revealed, and the evolution characteristics of the crack tip field and the influence factors of stress intensity factor (SIF) are analyzed. Results show that (1) the aerodynamic shockwave intensifies after entering the crack, resulting in more significant pressure in the crack than the input pressure. The maximum pressure of the inclined and longitudinal cracks is higher than the corresponding values of the circumferential crack, respectively. (2) The maximum SIF of the circumferential, inclined, and longitudinal crack appears at 0.5, 0.68, and 0.78 times the crack front length. The maximum SIF of the circumferential crack is higher than that of the inclined and longitudinal crack. The possibility of crack growth of the circumferential crack is the highest under aerodynamic shockwaves. (3) The influence of train speed on the SIF of the circumferential crack is more than 40%. When the train speed, crack depth, and crack length change, the change of pressure in the crack is the direct cause of the change of SIF.</p></div>","PeriodicalId":48505,"journal":{"name":"Underground Space","volume":"18 ","pages":"Pages 199-217"},"PeriodicalIF":6.4,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S246796742400031X/pdfft?md5=b6569802d355b629db8c0cc90e906fb8&pid=1-s2.0-S246796742400031X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141239886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}