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A modified smoothed particle hydrodynamics method considering residual stress for simulating failure and its application in layered rock mass

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Journal of Mountain Science 2024年第6期21卷 2091-2112页

作者： XIA Chengzhi SHI Zhenming KOU Huanjia department of geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China

Residual strength is an indispensable factor in evaluating rock fracture,yet the current Smoothed Particle Hydrodynamics(SPH)framework rarely considers its influence when simulating *** improved cracking strategy considering residual stress in the base bond SPH method was proposed to simulate failures in layered rocks and slopes and verified by experimental results and other simulation methods(i.e.,the discrete element method).Modified Mohr–Coulomb failure criterion was applied to distinguish the mixed failure of tensile and *** fracture markψwas introduced to improve the kernel function after tensile damage,and the calculation of residual stress after the damage was derived after shear *** simulations were carried out to evaluate its performance under different stress and scale conditions and to verify its effectiveness in realistically reproducing crack initiation and propagation and coalescence,even fracture and *** results indicate that the improved cracking strategy precisely captures the fracture and failure pattern in layered rocks and rock *** residual stress of brittle tock is correctly captured by the improved SPH *** improved SPH method that considers residual strength shows an approximately 13%improvement in accuracy for the safety factor of anti-dip layered slopes compared to the method that does not consider residual strength,as validated against analytical *** infer that the improved SPH method is effective and shows promise for applications to continuous and discontinuous rock masses.

关键词： Smoothed particle hydrodynamics Cracking strategy Residual stress Layered rock Crack propagation

A performance-based hybrid deep learning model for predicting TBM advance rate using Attention-ResNet-LSTM

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Journal of Rock Mechanics and geotechnical Engineering 2024年第1期16卷 65-80页

作者： Sihao Yu Zixin Zhang Shuaifeng Wang Xin Huang Qinghua Lei department of geotechnical Engineering College of Civil EngineeringTongji UniversityShanghaiChina Key Laboratory of geotechnical and Underground Engineering Ministry of EducationTongji UniversityShanghaiChina department of Earth Sciences ETH ZürichZürichSwitzerland department of Earth Sciences Uppsala UniversityUppsalaSweden

The technology of tunnel boring machine(TBM)has been widely applied for underground construction worldwide;however,how to ensure the TBM tunneling process safe and efficient remains a major *** rate is a key parameter of TBM operation and reflects the TBM-ground interaction,for which a reliable prediction helps optimize the TBM ***,we develop a hybrid neural network model,called Attention-ResNet-LSTM,for accurate prediction of the TBM advance rate.A database including geological properties and TBM operational parameters from the Yangtze River Natural Gas Pipeline Project is used to train and test this deep learning *** evolutionary polynomial regression method is adopted to aid the selection of input *** results of numerical exper-iments show that our Attention-ResNet-LSTM model outperforms other commonly-used intelligent models with a lower root mean square error and a lower mean absolute percentage ***,parametric analyses are conducted to explore the effects of the sequence length of historical data and the model architecture on the prediction accuracy.A correlation analysis between the input and output parameters is also implemented to provide guidance for adjusting relevant TBM operational *** performance of our hybrid intelligent model is demonstrated in a case study of TBM tunneling through a complex ground with variable ***,data collected from the Baimang River Tunnel Project in Shenzhen of China are used to further test the generalization of our *** results indicate that,compared to the conventional ResNet-LSTM model,our model has a better predictive capability for scenarios with unknown datasets due to its self-adaptive characteristic.

关键词： Tunnel boring machine(TBM) Advance rate Deep learning Attention-ResNet-LSTM Evolutionary polynomial regression

Bayesian partial pooling to reduce uncertainty in overcoring rock stress estimation

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Journal of Rock Mechanics and geotechnical Engineering 2024年第4期16卷 1192-1201页

作者： Yu Feng Ke Gao Suzanne Lacasse Norwegian geotechnical Institute OsloNorway department of Earth and Space Sciences Southern University of Science and TechnologyShenzhenChina

The state of in situ stress is a crucial parameter in subsurface engineering,especially for critical projects like nuclear waste *** one of the two ISRM suggested methods,the overcoring(OC)method is widely used to estimate the full stress tensors in rocks by independent regression analysis of the data from each OC ***,such customary independent analysis of individual OC tests,known as no pooling,is liable to yield unreliable test-specific stress estimates due to various uncertainty sources involved in the OC *** address this problem,a practical and no-cost solution is considered by incorporating into OC data analysis additional information implied within adjacent OC tests,which are usually available in OC measurement ***,this paper presents a Bayesian partial pooling(hierarchical)model for combined analysis of adjacent OC *** performed five case studies using OC test data made at a nuclear waste repository research site of *** results demonstrate that partial pooling of adjacent OC tests indeed allows borrowing of information across adjacent tests,and yields improved stress tensor estimates with reduced uncertainties simultaneously for all individual tests than they are independently analysed as no pooling,particularly for those unreliable no pooling stress estimates.A further model comparison shows that the partial pooling model also gives better predictive performance,and thus confirms that the information borrowed across adjacent OC tests is relevant and effective.

关键词： Overcoring stress measurement Uncertainty reduction Partial pooling Bayesian hierarchical model Nuclear waste repository

Probabilistic analysis of tunnel face seismic stability in layered rock masses using Polynomial Chaos Kriging metamodel

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Journal of Rock Mechanics and geotechnical Engineering 2024年第7期16卷 2678-2693页

作者： Jianhong Man Tingting Zhang Hongwei Huang Daniel Dias department of geotechnical Engineering Key Laboratory of Geotechnical and Underground Engineering of Ministry of EducationCollege of Civil EngineeringTongji UniversityShanghai200092China Grenoble Alpes 3SR LabCNRS UMR 5521Grenoble38000France

Face stability is an essential issue in tunnel design and *** rock masses are typical and ubiquitous;uncertainties in rock properties always *** view of this,a comprehensive method,which combines the Upper bound Limit analysis of Tunnel face stability,the Polynomial Chaos Kriging,the Monte-Carlo Simulation and Analysis of Covariance method(ULT-PCK-MA),is proposed to investigate the seismic stability of tunnel faces.A two-dimensional analytical model of ULT is developed to evaluate the virtual support force based on the upper bound limit *** efficient probabilistic analysis method PCK-MA based on the adaptive Polynomial Chaos Kriging metamodel is then implemented to investigate the parameter uncertainty *** input parameters,including geological strength indices,uniaxial compressive strengths and constants for three rock formations,and the horizontal seismic coefficients,are treated as random *** effects of these parameter uncertainties on the failure probability and sensitivity indices are *** addition,the effects of weak layer position,the middle layer thickness and quality,the tunnel diameter,the parameters correlation,and the seismic loadings are investigated,*** results show that the layer distributions significantly influence the tunnel face probabilistic stability,particularly when the weak rock is present in the bottom *** efficiency of the proposed ULT-PCK-MA is validated,which is expected to facilitate the engineering design and construction.

关键词： Tunnel face stability Layered rock masses Polynomial Chaos Kriging(PCK) Sensitivity index Seismic loadings

Roof collapse mechanism of weak surrounding rock for deep-buried tunnels under high geostress conditions

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Journal of Mountain Science 2024年第7期21卷 2408-2426页

作者： ZHANG Qi GUO Xiaokang YAN Zhiguo LEI Zhongdai SHEN Yixin School of Civil Engineering Southeast UniversityNanjing 211189China department of geotechnical Engineering Tongji UniversityShanghai 200092China

High geostress,a typical attribute of tunnels located at significant depths,is crucial in causing stress-induced failure and influencing the stability of the tunnel *** study developed an analytical method for the failure mechanism that occurs in deep-buried tunnel roofs,taking into account the influence of *** limit analysis theory was utilized for deriving analytical solutions about the geometry of the collapsing surface and the limit supporting *** collapsing surface obtained by the analytical solution was validated by the findings of the physical model test,which shows a high level of agreement with the actual *** extensive investigation was done to explore the effects of the lateral pressure coefficients,the tunnel buried depth,the geological conditions of the surrounding rock,the long-short axis ratio,and the size of the tunnel *** findings indicate that an increase in the lateral pressure coefficient from 0.5 to 1.5 results in a reduction in the height of the collapsing zone by 2.08 m and the width of the collapsing zone by 1.15 m,while simultaneously increases the limit supporting pressure by 18.9%.The proposed upper bound method accurately determines the limit supporting pressure and the geometry of the collapsing surface,which aligns well with the results acquired through numerical modelling and on-site monitoring in actual engineering *** proposed analytical method can serve as a reference for similar crown failure issues of deep-buried tunnels.

关键词： Geostress Deep-buried tunnels Collapse mechanism Pressure arch Limit analysis HoekBrown criterion

Fatigue properties and damage constitutive model of salt rock based on CT scanning

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International Journal of Mining Science and Technology 2024年第2期34卷 245-259页

作者： Junbao Wang Xiao Liu Qiang Zhang Xinrong Liu Zhanping Song Shijin Feng College of Civil Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Shaanxi Key Lab of geotechnical and Underground Space Engineering Xi’an 710055China School of Civil Engineering Chongqing UniversityChongqing 400045China department of geotechnical Engineering Tongji UniversityShanghai 200092China

To investigate the macroscopic fatigue properties and the mesoscopic pore evolution characteristics of salt rock under cyclic loading,fatigue tests under different upper-limit stresses were carried out on salt rock,and the mesoscopic pore structures of salt rock before and after fatigue tests and under different cycle numbers were measured using CT scanning *** on the test results,the effects of the cycle number and the upper-limit stress on the evolution of cracks,pore morphology,pore number,pore volume,pore size,plane porosity,and volume porosity of salt rock were *** failure path of salt rock specimens under cyclic loading was analyzed using the distribution law of plane *** damage variable of salt rock under cyclic loading was defined on basis of the variation of volume porosity with cycle *** order to describe the fatigue deformation behavior of salt rock under cyclic loading,the nonlinear Burgers damage constitutive model was further *** results show that the model established can better reflect the whole development process of fatigue deformation of salt rock under cyclic loading.

关键词： Salt rock Cyclic loading CT scanning Mesoscopic pore evolution Constitutive model

Thermo-hydro-mechanical (THM) coupled simulation of the land subsidence due to aquifer thermal energy storage (ATES) system in soft soils

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Journal of Rock Mechanics and geotechnical Engineering 2024年第6期16卷 1952-1966页

作者： Yang Wang Fengshou Zhang Fang Liu department of geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai200092China Key Laboratory of geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai200092China Shanghai Engineering and Technology Research Center of Shallow Geothermal Energy Shanghai200072China

Aquifer thermal energy storage(ATES)system has received attention for heating or cooling ***,it is well known that land subsidence becomes a major environmental concern for ATES ***,the effect of temperature on land subsidence has received practically no attention in the *** paper presents a thermo-hydro-mechanical(THM)coupled numerical study on an ATES system in Shanghai,*** water wells were installed for seasonal heating and cooling of an agriculture *** target aquifer at a depth of 74e104.5 m consisted of alternating layers of sand and silty sand and was covered with *** level,temperature,and land subsidence data from 2015 to 2017 were collected using field monitoring *** by data,we constructed a field scale three-dimensional(3D)model using TOUGH(Transport of Unsaturated Groundwater and Heat)and FLAC3D(Fast Lagrangian Analysis of Continua)equipped with a thermo-elastoplastic constitutive *** effectiveness of the numerical model was validated by field *** model was used to reproduce groundwater flow,heat transfer,and mechanical responses in porous media over three years and capture the thermo-and pressure-induced land *** results show that the maximum thermoinduced land subsidence accounts for about 60%of the total *** thermo-induced subsidence is slightly greater in winter than that in summer,and more pronounced near the cold well area than the hot well *** study provides some valuable guidelines for controlling land subsidence caused by ATES systems installed in soft soils.

关键词： Aquifer thermal energy storage(ATES) Land subsidence TOUGH-FLAC3D Thermo-elastoplastic constitutive model

Interaction Mechanisms between Natural Debris Flow and Rigid Barrier Deflectors:A New Perspective for Rational Design and Optimal Arrangement

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1679-1699页

作者： Yu Huang Beilei Liu Dianlei Feng Hao Shi department of geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai200092China department of Hydraulic Engineering College of Civil EngineeringTongji UniversityShanghai200092China

Rigid barrier deflectors can effectively prevent overspilling landslides,and can satisfy disaster prevention ***,the mechanisms of interaction between natural granular flow and rigid barrier deflectors require further *** date,few studies have investigated the impact of deflectors on controlling viscous debris flows for geological disaster *** investigate the effect of rigid barrier deflectors on impact mechanisms,a numerical model using the smoothed particle hydrodynamics(SPH)method with the Herschel–Bulkley model is proposed to simulate the interaction between natural viscous flow and single/dual barriers with and without *** model was validated using laboratory flume test data from the ***,the model was used to investigate the influence of the deflector angle and multi-barrier *** optimal configuration of multi-barriers was analyzed with consideration to the barrier height and distance between the barriers,because these metrics have a significant impact on the viscous flow pile-up,run-up,and overflow *** investigation considered the energy dissipation process,retention efficiency,and dead-zone *** with bare barriers with similar geometric characteristics and spatial distribution,rigid barriers with deflectors exhibit superior effectiveness in preventing the overflow and overspilling of viscous debris *** for the rational design of deflectors and the optimal arrangement of multi-barriers are provided to mitigate geological disasters.

关键词： Rigid barrier deflectors deflector angle single-barrier dual-barrier arrangements viscous debris flow over-spilling delta-plus-SPH

Rock mass quality prediction on tunnel faces with incomplete multi-source dataset via tree-augmented naive Bayesian network

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International Journal of Mining Science and Technology 2024年第3期34卷 323-337页

作者： Hongwei Huang Chen Wu Mingliang Zhou Jiayao Chen Tianze Han Le Zhang Key Laboratory of geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China department of geotechnical Engineering Tongji UniversityShanghai 200092China School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China Qingdao Guoxin Second Jiaozhou Bay Subsea Tunnel Co. Ltd.Qingdao 266071China

Rock mass quality serves as a vital index for predicting the stability and safety status of rock tunnel *** tunneling practice,the rock mass quality is often assessed via a combination of qualitative and quantitative ***,due to the harsh on-site construction conditions,it is rather difficult to obtain some of the evaluation parameters which are essential for the rock mass quality *** this study,a novel improved Swin Transformer is proposed to detect,segment,and quantify rock mass characteristic parameters such as water leakage,fractures,weak *** site experiment results demonstrate that the improved Swin Transformer achieves optimal segmentation results and achieving accuracies of 92%,81%,and 86%for water leakage,fractures,and weak interlayers,respectively.A multisource rock tunnel face characteristic(RTFC)dataset includes 11 parameters for predicting rock mass quality is *** the limitations in predictive performance of incomplete evaluation parameters exist in this dataset,a novel tree-augmented naive Bayesian network(BN)is proposed to address the challenge of the incomplete dataset and achieved a prediction accuracy of 88%.In comparison with other commonly used Machine Learning models the proposed BN-based approach proved an improved performance on predicting the rock mass quality with the incomplete *** utilizing the established BN,a further sensitivity analysis is conducted to quantitatively evaluate the importance of the various parameters,results indicate that the rock strength and fractures parameter exert the most significant influence on rock mass quality.

关键词： Rock mass quality Tunnel faces Incomplete multi-source dataset Improved Swin Transformer Bayesian networks