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Assessing cutter-rock interaction during TBM tunnelling in granite:Large-scale standing rotary cutting tests and 3D DEM simulations

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Journal of Rock Mechanics and Geotechnical engineering 2024年第9期16卷 3595-3615页

作者： Xin Huang Miaoyuan Tang Shuaifeng Wang Yixin Zhai Qianwei Zhuang Chi Zhang Qinghua Lei Department of Geotechnical engineering College of Civil EngineeringTongji UniversityShanghaiChina College of civil engineering and Architecture Xinjiang UniversityUrumqiChina State Key Laboratory of Geotechnical engineering Ministry of EducationTongji UniversityShanghaiChina China Shipbuilding NDRI engineering Co. Ltd.ShanghaiChina Shanghai Tunnel engineering Co. Ltd.ShanghaiChina Shanghai Shield Design and Experimental Research Center Co. Ltd.ShanghaiChina Department of earth Sciences Uppsala UniversityUppsalaSweden

The widespread utilisation of tunnel boring machines(TBMs)in underground construction engineering requires a detailed investigation of the cutter-rock *** this paper,we conduct a series of largescale standing rotary cutting tests on granite in conjunction with high-fidelity numerical simulations based on a particle-type discrete element method(DEM)to explore the effects of key cutting parameters on the TBM cutter performance and the distribution of cutter-rock contact *** assessment results of cutter performance obtained from the cutting tests and numerical simulations reveal similar dependencies on the key cutting *** specifically,the normal and rolling forces exhibit a positive correlation with penetration but are slightly influenced by the cutting *** contrast,the side force decreases as the cutting radius ***,the side force shows a positive relationship with the penetration for smaller cutting radii but tends to become negative as the cutting radius *** cutter's relative effectiveness in rock breaking is significantly impacted by the penetration but shows little dependency on the cutting ***,an optimal penetration is identified,leading to a low boreability index and specific energy.A combined Hertz-Weibull function is developed to fit the cutter-rock contact stress distribution obtained in DEM simulations,whereby an improved CSM(Colorado School of Mines)model is proposed by replacing the original monotonic cutting force distribution with this combined Hertz-Weibull *** proposed model outperforms the original CSM model as demonstrated by a comparison of the estimated cutting forces with those from the tests/*** findings from this work that advance our understanding of TBM cutter performance have important implications for improving the efficiency and reliability of TBM tunnelling in granite.

关键词： Large-scale standing rotary cutting test Discrete element method(DEM)simulation Cutter-rock interaction Improved CSM(Colorado School of Mines) model Cutting force

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Model Test Study on Response of Weathered Rock Slope to Rainfall Infiltration under Different Conditions

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Journal of earth Science 2024年第4期35卷 1316-1333页

作者： Cong Li Rongtang Zhang Jiebing Zhu Bo Lu Xiaowei Wang Fangling Xu Xiaoke Shen Jiesheng Liu Weizhen Cai School of civil engineering and Architecture Wuhan Polytechnic UniversityWuhan430023China Key Laboratory of Geotechnical Mechanics and engineering of Ministry of Water resources Yangtze River Scientific Research InstituteWuhan430010China Key Laboratory of Ministry of Education for Geomechanics and Embankment engineering Hohai UniversityNanjing210098China

Weathered rock(especially granite)slopes are prone to failure under the action of rainfall,making it necessary to study the response of weathered rock slope to rainfall infiltration for landslide *** this study,a series of model tests of weathered rock slope under different conditions were *** matric suction,volumetric water content,earth pressure and deformation of slope were monitored in real time during *** response of the slope to rainfall infiltration,failure process and failure mode of slope under different conditions were analyzed,and the early warning criterion for the failure of weathered rock slope caused by rainfall was *** results show that the slope deformation evolution process under rainfall condition was closely related to the dissipation of matric *** the distribution of the matrix suction(or water content)of slope met the condition that the resistance to sliding of the slip-mass was overcome,the displacement increased sharply and landslide *** factors including rainfall process,lithologic condition and excavation condition significantly affect the response of weathered rock slope to *** can be found from the test results under different conditions that compared with intermittent rainfall condition,the rainfall intensity and infiltration depth were smaller when the slope entering accelerated deformation stage under the condition of incremental *** accumulated rainfall when weathered clastic landslide occurring was greater than that of weathered granite,which results in greater disaster *** excavation angle and moisture distribution of a slope were the main factors affecting the stability of a *** addition,the evolution processes and critical displacement velocities of slopes were studied by combining the deformation curves and matrix suction curves,which can be used as reference for early warning of rainfall-induced weathered rock landslide.

关键词： weathered rock slope model test rainfall early warning unsaturated soil

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Retrieval of high spatial resolution mountainous land surface temperature considering topographic and adjacency effects

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Science China earth Sciences 2024年第11期67卷 3610-3625页

作者： Zhiwei HE Bohui TANG Zhaoliang LI faculty of Land resources engineering Kunming University of Science and Technology Key Laboratory of Plateau Remote Sensing Department of Education of Yunnan Province State Key Lab of resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences Key Laboratory of Agricultural Remote Sensing Ministry of Agriculture and Rural Affairs Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences

Land surface temperature(LST) is a key parameter reflecting the interaction between land and atmosphere. Currently,thermal infrared(TIR) quantitative remote sensing technology is the only means to obtain large-scale, high spatial resolution LST. Accurately retrieving high spatial resolution mountainous LST(MLST) plays an important role in the study of mountain climate change. The complex terrain and strong spatial heterogeneity in mountainous areas change the geometric relationship between the surface and satellite sensors, affecting the radiation received by the sensors, and rendering the assumption of planar parallelism invalid. In this study, considering the influence of complex terrain in mountainous areas on atmospheric downward radiation and the thermal radiation contribution of adjacent pixels, a mountainous TIR radiative transfer model based on the sky view factor was developed. Combining with the atmospheric radiative transfer model MODTRAN 5.2, a nonlinear generalized split-window algorithm suitable for high spatial resolution MLST retrieval was constructed and applied to Landsat-9 TIRS-2satellite TIR remote sensing data. The analysis results indicate that neglecting the topographic and adjacency effects would lead to significant discrepancies in LST retrieval, with simulated data showing LST differences of up to 2.5 K. Furthermore, due to the lack of measured MLST in the field, the MLST accuracy obtained by this retrieval method was indirectly validated using the currently recognized highest-accuracy forward 3D radiative transfer model DART. The MLST and emissivity were input into the DART model to simulate the brightness temperature at the top of the atmosphere(TOA) of Landsat-9 band 10, and compared with the brightness temperature at TOA of Landsat-9 band 10. The RMSE(Root Mean Square Error) for the two subregions was0.50 and 0.61 K, respectively, indicating that the method proposed can retrieve high-precision MLST.

关键词： Mountainous land surface temperature Topographic and adjacency effects Nonlinear generalized split-window algorithm Landsat-9 data DART model

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Intelligent Diagnosis of Highway Bridge Technical Condition Based on Defect Information

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Structural Durability & Health Monitoring 2024年第6期18卷 871-889页

作者： Yanxue Ma Xiaoling Liu Bing Wang Ying Liu faculty of Maritime and Transportation Ningbo UniversityNingbo315211China School of civil&Environmental engineering and Geography Science Ningbo UniversityNingbo315211China

In the bridge technical condition assessment standards,the evaluation of bridge conditions primarily relies on the defects identified through manual inspections,which are determined using the comprehensive hierarchical analysis ***,the relationship between the defects and the technical condition of the bridges warrants further *** address this situation,this paper proposes a machine learning-based intelligent diagnosis model for the technical condition of highway ***,collect the inspection records of highway bridges in a certain region of China,then standardize the severity of diverse defects in accordance with relevant ***,in order to enhance the independence between the defects,the key defect indicators were screened using Principal Component Analysis(PCA)in combination with the weights of the building *** on this,an enhanced Naive Bayesian Classification(NBC)algorithm is established for the intelligent diagnosis of technical conditions of highway bridges,juxtaposed with four other algorithms for ***,key defect variables that affect changes in bridge grades are *** results showed that the technical condition level of the superstructure had the highest correlation with cracks;the PCA-NBC algorithm achieved an accuracy of 93.50%of the predicted values,which was the highest improvement of 19.43%over other *** purpose of this paper is to provide inspectors with a convenient and predictive information-rich method to intelligently diagnose the technical condition of bridges based on bridge *** results of this research can help bridge inspectors and even non-specialists to better understand the condition of bridge defects.

关键词： Highway bridges defects Naive Bayesian classification principal component analysis machine learning

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Identifying drivers of urban landuse changes in the Wenchuan earthquake- affected area by using night-time light data

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Journal of Mountain Science 2024年第4期21卷 1140-1159页

作者： HUANG Tao DING Mingtao GENG Dongxian GAO Zemin ZHENG Hao School of civil engineering and Architecture Southwest University of Science and TechnologyMianyang 621010China faculty of Geosciences and Environmental engineering Southwest Jiaotong UniversityChengdu 611756China Analysis and Test Center of Sichuan Province Chengdu 610023China

To learn the process of urban land evolution before and after an earthquake is vital to formulate the urban reconstruction control policies and recovery measures in the earthquake-stricken ***,spatiotemporal evolution and its driving factors of urban land in earthquake-prone areas remains limited due to the scarcity of ground observation *** research,leveraging night-time light remote sensing imagery and land cover data,conducted a comprehensive analysis of the long-term evolution characteristics of urban land in earthquake-prone *** introduced methodologies for assessing the socio-economic impact and the primary natural environmental factors driving urban land evolution in these *** validate the proposed methods,the 2008 Wenchuan earthquake-affected area in China was selected as a representative study *** results indicated that the average Digital Number(DN)values in socio-economically impacted areas showed a trend of rising,falling,and then rising again after the *** values in three types of damaged areas including Type Ⅱ,Type Ⅲ,and Type Ⅳ exceeded pre-earthquake *** analysis of determinative factors influencing urban land evolution revealed that slope and elevation were key elements in controlling urban land expansion before the earthquake,whereas factors such as slope,elevation,lithology,and faults had a stronger influence on urban land expansion after the *** can be seen that,in view of the differences in the natural conditions of regions for post-disaster reconstruction,the local government need to actively adjust and adapt to urban spatial planning,so as to leverage the scale effect of large-scale inputs of funds,facilities,human resources and other factors after the disaster,thus enhancing resilience and recovery efficiency in response to disaster impacts.

关键词： Wenchuan earthquake Night-time lights Urban land Post-earthquake reconstruction

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Introducing a new rock abrasivity index using a scaled down disc cutter

Rock Mechanics Bulletin

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Rock Mechanics Bulletin 2024年第3期3卷 24-37页

作者： Maziar Moradi Mohammad Hossein Khosravi Jafar Khademi Hamidi Department of civil and Environmental engineering University of StrathclydeGlasgowG11XQUK Department of Mining engineering Faculty of EngineeringUniversity of BirjandBirjand ***Iran

Rock abrasivity influences wear of cutting tools and consequently,performance of mechanized tunneling *** methods have been proposed to evaluate rock abrasivity in recent decades,each one has its own *** this paper,a new method is introduced to estimate wear of disc cutters based on rock cutting tests using scaled down discs(i.e.54 and 72 mm diameter).The discs are made of H13 steel,which is a common steel type in producing real-scale discs,with hardness of 32 and 54 *** small-scale linear rock cutting machine and a new abrasion test apparatus,namely University of Tehran abrasivity test machine,are utilized to perform the *** width of the worn discs is monitored and presented as the function of the accumulated test run to classify the rock *** tests show that by increasing the uniaxial compressive strength(UCS)of the rock samples,wear rate is doubled gradually that reveals the sensitivity of the test procedure to the main pa-rameters affecting the abrasivity of hard *** the rocks with the highest UCS,the normal wear stops after performing 5 to 10 rounds of the tests,and then,deformation of the disc tip is *** abrasivity indices are defined based on the abrasivity tests results and their correlations with Cerchar Abrasivity Index(CAI)and UCS are *** of the established correlations in this study with previous investigations dem-onstrates the sensitivity of the indices to the parameters affecting wear of the disc cutters and repeatability of the outputs obtained from abrasivity tests using scaled down *** of this study can be used to enhance the accuracy of rock abrasivity classifications.

关键词： Mechanized tunneling Rock cutting Rock abrasivity classification University of Tehran abrasivity test Wear

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Numerical manifold method for thermo-mechanical coupling simulation of fractured rock mass

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Journal of Rock Mechanics and Geotechnical engineering 2024年第6期16卷 1977-1992页

作者： Jiawei Liang Defu Tong Fei Tan Xiongwei Yi Junpeng Zou Jiahe Lv faculty of engineering China University of GeosciencesWuhan430074China Department of civil engineering Monash UniversityClaytonVIC3800Australia Badong National Observation and Research Station of Geohazards China University of GeoscienceWuhan430074China

As a calculation method based on the Galerkin variation,the numerical manifold method(NMM)adopts a double covering system,which can easily deal with discontinuous deformation problems and has a high calculation *** at the thermo-mechanical(TM)coupling problem of fractured rock masses,this study uses the NMM to simulate the processes of crack initiation and propagation in a rock mass under the influence of temperature field,deduces related system equations,and proposes a penalty function method to deal with boundary *** examples are employed to confirm the effectiveness and high accuracy of this *** the thermal stress analysis of a thick-walled cylinder(TWC),the simulation of cracking in the TWC under heating and cooling conditions,and the simulation of thermal cracking of the SwedishÄspöPillar Stability Experiment(APSE)rock column,the thermal stress,and TM coupling are *** numerical simulation results are in good agreement with the test data and other numerical results,thus verifying the effectiveness of the NMM in dealing with thermal stress and crack propagation problems of fractured rock masses.

关键词： Heat conduction Fractured rock mass Crack propagation Galerkin variation Numerical manifold method(NMM)

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A Comprehensive Study on the Consequences of Gap-Graded Sands Considering the Loss of Fine Particles

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Journal of earth Science 2024年第2期35卷 597-612页

作者： Weiping Liu Yu Gan Yunwei Cui Faming Huang Lina Hu School of civil engineering and Architecture Nanchang UniversityNanchang330031China

Water and sand leakage disasters are likely to occur during construction in water-rich sand layer areas,resulting in ground *** stress-strain action characteristics of discontinuous graded sand under different internal erosion degrees,and the evolution mechanism of water and sand leakage disasters caused by the internal erosion need to be further ***,this paper takes the discontinuous graded sand in a water rich sand layer area in Nanchang City of China as the research *** the influence of different fine particle losses(0,10%,20%and 30%)under the internal erosion of sand,the salt solution method is used to realize the specified loss of fine particles in the internal *** stress-strain behavior after the loss of fine particles due to internal erosion is studied by triaxial shear ***,the physical model test and PFC-CFD method are both used to study the evolution rules of water and sand leakage disaster considered the influence of internal erosion *** show that:(1)under the same confining pressure,the peak failure strength of sand samples decreases along with the increase of fine particle loss.(2)In the water and sand leakage test of saturated sand,a natural filter channel is formed above the observed soil *** greater the loss of fine particles,the steeper and wider the collapse settlement area.(3)The relationship between the cumulative amount of water and sand leakage and time is *** total mass loss of sand increases along with the increase of internal erosion degree.(4)After the soil arch is formed around the damaged opening,the sand continues to converge above the soil arch under the action of water flow,resulting in the dense convergence of contact force chains.

关键词： sandy soil internal erosion stress and strain water and sand leakage PFC3D engineering geology

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Deep Learning and Network Analysis:Classifying and Visualizing Geologic Hazard Reports

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Journal of earth Science 2024年第4期35卷 1289-1303页

作者： Wenjia Li Liang Wu Xinde Xu Zhong Xie Qinjun Qiu Hao Liu Zhen Huang Jianguo Chen School of Geography and Information engineering China University of GeosciencesWuhan430078China Key Laboratory of Geological Survey and Evaluation of Ministry of Education China University of GeosciencesWuhan430078China School of Computer Science China University of GeosciencesWuhan430078China Key Laboratory of Urban Land resources Monitoring and Simulation Ministry of Natural ResourcesShenzhen518034China Hubei Key Laboratory of Intelligent Vision Based Monitoring for Hydroelectric engineering China Three Gorges UniversityYichang443002China Wuhan Geomatics Institute Wuhan430074China faculty of earth resources China University of GeosciencesWuhan430074China

If progress is to be made toward improving geohazard management and emergency decision-making,then lessons need to be learned from past geohazard information.A geologic hazard report provides a useful and reliable source of information about the occurrence of an event,along with detailed information about the condition or factors of the *** such reports,however,can be a challenging process because these texts are often presented in unstructured long text formats,and contain rich specialized and detailed *** text classification is commonly used to mine disaster text data in open domains(e.g.,news and microblogs).But it has limitations to performing contextual long-distance dependencies and is insensitive to discourse *** deficiencies are most obviously exposed in long text ***,this paper uses the bidirectional encoder representations from Transformers(BERT),to model long ***,utilizing a softmax layer to automatically extract text features and classify geohazards without manual *** latent Dirichlet allocation(LDA)model is used to examine the interdependencies that exist between causal variables to visualize *** proposed method is useful in enabling the machine-assisted interpretation of text-based ***,it can help users visualize causes,processes,and other geohazards and assist decision-makers in emergency responses.

关键词： geologic hazard network analysis latent dirichlet allocation text classification deep learning

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Retrospective and prospective review of the generalized nonlinear strength theory for geomaterials

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1767-1787页

作者： Shunchuan Wu Jiaxin Wang Shihuai Zhang Shigui Huang Lei Xia Qianping Zhao faculty of Land Resource engineering Kunming University of Science and TechnologyKunming 650093China Key Laboratory of Geohazard Forecast and Geoecological Restoration in Plateau Mountainous Area MNRKunming 650093China Yunnan Key Laboratory of Geohazard Forecast and Geoecological Restoration in Plateau Mountainous Area Kunming 650093China School of earth and Space Sciences University of Science and Technology of ChinaHefei 230026China School of civil and Resource engineering University of Science and Technology BeijingBeijing 100083China

Strength theory is the basic theory for calculating and designing the strength of engineering materials in civil,hydraulic,mechanical,aerospace,military,and other engineering ***,the comprehensive study of the generalized nonlinear strength theory(GNST)of geomaterials has significance for the construction of engineering rock *** paper reviews the GNST of geomaterials to demonstrate the research status of nonlinear strength characteristics of geomaterials under complex stress ***,it systematically summarizes the research progress of GNST(classical and empirical criteria).Then,the latest research the authors conducted over the past five years on the GNST is introduced,and a generalized three-dimensional(3D)nonlinear Hoek‒Brown(HB)criterion(NGHB criterion)is proposed for practical *** criterion can be degenerated into the existing three modified HB criteria and has a better prediction *** strength prediction errors for six rocks and two in-situ rock masses are 2.0724%-3.5091%and 1.0144%-3.2321%,***,the development and outlook of the GNST are expounded,and a new topic about the building strength index of rock mass and determining the strength of in-situ engineering rock mass is *** summarization of the GNST provides theoretical traceability and optimization for constructing in-situ engineering rock mass strength.

关键词： rock mechanics rock mass strength strength theory failure criterion Hoek-Brown criterion intermediate principal stress deviatoric plane smoothness and convexity

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