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Evaluation of crustal deformation and associated strong motions induced by the 2022 Paktika earthquake, Afghanistan

Earthquake Science 2024年第6期37卷 546-557页

作者： Jahed A.B. Aydan Ö. Ito T. Iwata N. University of Ryukyus Okinawa 903-0213 Japan chuden engineering consultants Hiroshima 734-8510 Japan

The 2022 Paktika earthquake (moment magnitude: 6.2) occurred on June 22, 2022, near the border between the Khost and Paktika Provinces of Afghanistan, causing heavy damage and casualties in Paktika Province. This study evaluated the crustal deformation and associated strong motions induced by the Paktika earthquake. Crustal deformations were determined using the Differential Interferometric Synthetic Aperture Radar (DInSAR) technique and three-dimensional finite element method (3D-FEM) and the results were compared. The permanent ground displacements obtained from the DInSAR and 3D-FEM analyses were similar in terms of amplitude and areal distribution. Strong motions were estimated using the 3D-FEM with and without considering regional topography. The estimations of maximum ground acceleration, velocity, and permanent ground deformations were compared among each other as well as with those inferred from failures of some simple structures in the Spera and Gayan districts. The inferred maximum ground acceleration and velocity from the failed adobe structures were more than 300 Gal and 50 cm/s, respectively, nearly consistent with the estimates obtained using empirical methods. The empirical method yielded a maximum ground acceleration of 347 Gal, whereas the maximum ground velocity was approximately 50 cm/s. In light of these findings, some surface expressions of crustal deformations and strong ground motions, such as failures of soil and rock slopes and rockfalls, have been presented. The rock slope failures in the epicentral area were consistent with those observed during various earthquakes in Afghanistan and worldwide. © 2024 The Authors

关键词： Afghanistan fault rupture FEM Paktika earthquake rockfall SAR slope surface deformation

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Surrounding rock pressure in the tunnel portal section through moraine under freeze-thaw action

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Journal of Mountain Science 2024年第7期21卷 2480-2493页

作者： CHEN Zhimin LIU Baoli LIU Yaohui XU Jiangtao School of Civil engineering Lanzhou Jiaotong UniversityLanzhou 730070China CSCEC AECOM consultants Co. ltdLanzhou 730000China National and Local Joint engineering Laboratory of Road and Bridge engineering Disaster Prevention Technology Lanzhou Jiaotong UniversityLanzhou 730070China

Moraines,characterized by the accumulation of rock and soil debris transported by glacial activity,present unique challenges for tunnel construction,particularly in portal sections,due to prevailing geographical and climatic conditions that facilitate freeze-thaw *** these challenges,there is a dearth of studies investigating the influence of freeze-thaw action and water content on the mechanical properties of moraines,and no research on calculating surrounding rock pressure in moraine tunnels subjected to freeze-thaw *** this study,direct shear tests under freeze-thaw cycles were conducted to examine the effects of freeze-thaw cycles and water content on the mechanical properties of frozen moraine.A comprehensive parameter K,integrating the number of freeze-thaws and water content,was introduced to model cohesion *** on Terzaghi Theory,we propose an improved algorithm for calculating surrounding rock pressure at the portal section of moraine *** a tunnel as a case study,surrounding rock pressure was calculated under various conditions to validate the Improved Algorithm's *** results show that:(1)Strength loss exhibits a linear trend with the number of freeze-thaw cycles at water content levels of 4%and 8%,while at 12%water content,previous freeze-thaw cycles induce more significant damage to the soil.(2)Moraine saturation peaks between 8%and 12%water *** repeated freeze-thaw cycles,moraine shear strength initially increases before decreasing with varying water content.(3)The internal friction angle of moraine experiences slight reductions with prolonged freeze-thaw cycles,but both freeze-thaw cycles and water content significantly influence cohesion.(4)Vertical surrounding rock pressure increases after the initial freeze-thaw cycle,particularly with higher water content,although freeze-thaw cycles have minimal effect on it.(5)Freeze-thaw cycles lead to a substantial increase in lateral surrounding rock pre

关键词： Moraines Freeze-thaw cycles Direct shear test Surrounding rock pressure

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Formation of the Tibetan Plateau during the India-Eurasia Convergence:Insight from 3-D Multi-Terrane Thermomechanical Modeling

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Journal of Earth Science 2024年第1期35卷 112-130页

作者： Jile Chen Peimin Zhu Yuefeng Yuan Guifan Chen School of Geophysics and Geomatics China University of GeosciencesWuhan 430074China Geothermal engineering Research Center Three Gorges Geotechnical Consultants Co.Ltd.Wuhan 430074China

Various models exist to explain the formation of the Tibetan Plateau,including“tectonic escape”,“pure shear thickening”,“convective removal of the lithospheric mantle”,and“lower crustal flow”*** first two models are primarily constructed on pure mechanical models but are unable to reasonably explain the tension and shear phenomena inside the *** latter two are rheological dynamic models based on deep geophysical ***,the spatial range of the lower crustal flow and its role in the plateau formation/uplift remain *** multi-terrane viscoplastic thermomechanical models were constructed to simulate the uplift and lithospheric structure change of the Tibetan Plateau during the post-collision stage(since 35 Ma)under the convergence of the Indian *** show that the plateau's formation begins with crustal thickening,blocked by strong terranes at the northern plateau,and expanded laterally to the *** lithosphere thickens gradually and experiences delamination at its base,elevating temperature within the crust and forming partial melting layers in the central *** convergence persists on the southern side,the northern plateau's lithosphere bends downward and undergoes delamination,further heating the crust and promoting the northward and eastward flow of partial melting layers,leading to secondary uplift around the plateau.

关键词： 3-D thermomechanical modeling Tibetan Plateau plateau uplift crustal flow

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Stability analysis of loose accumulation slopes under rainfall:case study of a high‑speed railway in Southwest China

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Railway engineering Science 2024年第1期32卷 95-106页

作者： Xin Wang Qian Su Zongyu Zhang Feihu Huang Chenfang He School of Civil engineering Southwest Jiaotong UniversityChengdu 610031China Key Laboratory of High‑Speed Railway engineering Ministry of Education School of Civil EngineeringSouthwest Jiaotong UniversityChengdu 610031China CCCC Second Highway consultants Co. Ltd.Wuhan 430056China

The high and steep slopes along a high-speed railway in the mountainous area of Southwest China are mostly composed of loose accumulations of debris with large internal pores and poor stability,which can easily induce adverse geological disasters under rainfall *** ensure the smooth construction of the high-speed railway and the subsequent safe operation,it is necessary to master the stability evolution process of the loose accumulation slope under *** article simulates rainfall using the finite element analysis software’s hydromechanical coupling *** slope stability under various rainfall situations is calculated and analysed based on the strength reduction *** validate the simulation results,a field monitoring system is established to study the deformation characteristics of the slope under *** results show that rainfall duration is the key factor affecting slope *** a constant amount of rainfall,the stability of the slope decreases with increasing duration of ***,when the amount and duration of rainfall are constant,continuous rainfall has a greater impact on slope stability than intermittent *** setting of the field retaining structures has a significant role in improving slope *** field monitoring data show that the slope is in the initial deformation stage and has good stability,which verifies the rationality of the numerical simulation *** research results can provide some references for understanding the influence of rainfall on the stability of loose accumulation slopes along high-speed railways and establishing a monitoring system.

关键词： High-speed railway Loose accumulation slope Slope stability analysis Rainfall effect Strength reduction

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Centrifuge modeling of a large-scale surcharge on adjacent foundation

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Journal of Rock Mechanics and Geotechnical engineering 2024年第8期16卷 3181-3191页

作者： Jinzhang Zhang Zhenwei Ye Dongming Zhang Hongwei Huang Shijie Han Tong Zou Le Zhang Key Laboratory of Geotechnical and Underground engineering of Ministry of Education and Department of Geotechnical engineering Tongji UniversityShanghai200092China CCCC Third Harbor consultants Co LtdShanghai200032China Qingdao Conson Jiaozhou Bay Second Subsea Tunnel Co. LtdQingdao266000China

This study investigates the ground and structural response of adjacent raft foundations induced by largescale surcharge by ore in soft soil areas through a 130g centrifuge modeling test with an innovative layered loading *** prototype of the test is a coastal iron ore yard with a natural foundation of deep soft ***,it is necessary to adopt some measures to reduce the influence of the large-scale surcharge on the adjacent raft foundation,such as installing stone columns for foundation *** an acceleration of 130 g,the model conducts similar simulations of iron ore,stone columns,and raft foundation *** tested soil mass has dimensions of 900 mm×700 mm×300 mm(lengthwidthdepth),which is remodeled from the soil extracted from the drilling *** test conditions are consistent with the actual engineering conditions and the effects of four-level loading conditions on the composite foundation of stone columns,unreinforced zone,and raft foundations are *** automatic layer-by-layer loading device was innovatively developed to simulate the loading process of actual engineering more *** composite foundation of stone columns had a large settlement after the loading,forming an obvious settlement trough and causing the surface of the unreinforced zone to *** 12 m surcharge loading causes a horizontal displacement of 13.19 cm and a vertical settlement of 1.37 m in the raft *** stone columns located on both sides of the unreinforced zone suffered significant shear damage at the sand-mud *** to the reinforcement effect of stone columns,the sand layer below the top of the stone columns moves ***,the horizontal earth pressure in the raft foundation zone increases *** stone columns will form new drainage channels and accelerate the dissipation of excess pore pressure.

关键词： Centrifuge modeling Stone column Composite foundation Ground movement Raft foundation

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Safety analysis of temporary anchorage system for immersed tube in Shenzhen-Zhongshan Link

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Journal of Traffic and Transportation engineering(English Edition) 2024年第4期11卷 797-813页

作者： Lei Yan Jinning Yan Guoping Xu Shuanhai He Zechen Zhang School of Highway Chang'an University Key Laboratory of Transport Industry of Bridge Detection Reinforcement Technology Chang'an University CCCC Highway consultants Co.Ltd.

In the construction of the Shenzhen-Zhongshan Link, a temporary anchorage system,distributed uniformly along the pipe wall, has been employed. To assess the safety and reliability of this system, a combined method utilizing numerical analysis and model experiments was applied to study the safety of the temporary anchorage system and the reliability of the tension rods. Firstly, an overall model of the caisson segment based on GINA rebound force was established to analyze the stress state of the entire system. Secondly, a comprehensive numerical analysis and model experiment verification were conducted for the single tensioning system, revealing its failure mode and safety margin. The results indicate that the tension rod systems are uniformly stressed at an average of 444 k N during underwater jointing, with a safety factor of 1.94. At this point, the maximum von Mises stresses appearing at the front plate corners and the lower edge of the U-groove, with stress values of 181.8 MPa and 172.4 MPa, and safety factors of 1.54 and 1.71, *** the tension rod force reaches 940 k N, the tensioning system reaches its bearing limit,with initial yielding occurring at the front plate corners. Model experiments were conducted to verify the theoretical analysis results, under a test load of 444 k N, the stresses at the front plate corners and the lower edge of the U-groove were 159.6 and 195.9 MPa,respectively. As the test load increased to 940 k N, these stresses reached 390 and 389 MPa,exhibiting good agreement with the numerical analysis. Considering the uncertainty of loads and materials, a reliability analysis of the tension rods was conducted, yielding a reliability index of 4.34, meeting the secondary safety standard. Based on the comprehensive analysis, it can be concluded that the temporary anchorage system in the caisson segments of the Shenzhen-Zhongshan Link exhibits excellent safety margins.

关键词： Tunnel engineering Immersed tube structure Anchorage system Full-scale model test Load bearing performance Safety assessment.

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Mechanical behaviors of warm and ice-rich frozen soil stabilized with sulphoaluminate cement

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Journal of Mountain Science 2024年第1期21卷 335-345页

作者： WANG Honglei ZHANG Hu ZHANG Jianming ZHANG Qi YIN Zhenhua State Key Laboratory of Frozen Soil engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China School of Civil engineering and Transportation Northeast Forestry UniversityHarbin 150040China National Key Laboratory of Green and Long-Life Road engineering in Extreme Environment CCCC First Highway Consultants Co.LtdXi'an 710065China Railway engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China

The warm and ice-rich frozen soil is characterized by high unfrozen water content, low shear strength and large compressibility, which is unreliable to meet the stability requirements of engineering infrastructures and foundations in permafrost regions. In this study, a novel approach for stabilizing the warm and ice-rich frozen soil with sulphoaluminate cement was proposed based on chemical stabilization. The mechanical behaviors of the stabilized soil, such as strength and stress-strain relationship, were investigated through a series of triaxial compression tests conducted at -1.0℃, and the mechanism of strength variations of the stabilized soil was also explained based on scanning electron microscope test. The investigations indicated that the strength of stabilized soil to resist failure has been improved, and the linear Mohr-Coulomb criteria can accurately reflect the shear strength of stabilized soil under various applied confining pressure. The increase in both curing age and cement mixing ratio were favorable to the growth of cohesion and internal friction angle. More importantly, the strength improvement mechanism of the stabilized soil is attributed to the formation of structural skeleton and the generation of cementitious hydration products within itself. Therefore, the investigations conducted in this study provide valuable references for chemical stabilization of warm and ice-rich frozen ground, thereby providing a basis for in-situ ground improvement for reinforcing warm and ice-rich permafrost foundations by soil-cement column installation.

关键词： Permafrost regions Frozen soil Mechanical behavior Chemical stabilization Ground improvement Ground modification

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A Comparative Study of Machine Learning Models for Traffic Accident Severity Prediction on Rural Highways

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Journal of Traffic and Transportation engineering(English Edition) 2024年

作者： Fengxiang Guo Jingyang Li Feng Zhu Bijiang Tian Wenchen Yang School of Transportation Science and engineering， Harbin Institute of Technology Yunnan Key Laboratory of Digital Communications National engineering Research Center for Efficient Maintenance， Safety and Durability of Roads and Bridges，Broadvision engineering consultants Co.， Ltd Kunming Faculty of Transportation engineering， Kunming University of Science and Technology School of Civil and Environmental engineering， Nanyang Technological University

The use of machine learning models for analyzing Traffic Accident Severity (TAS) is increasingly common in safety assessment and traffic accident prevention. However， many existing studies have not fully considered the importance of feature engineering， model hyperparameter optimization， and training set proportions， all of which significantly affect the performance of these models. This study addresses the research gap by developing a TAS model using the Light Gradient Boosting Machine (LightGBM) and integrating two feature engineering methods (Random Forest (RF) and Principal Component Analysis (PCA)). Additionally， we compared the LightGBM with three other machine learning models: Support Vector Machine (SVM)， Binary Logistic Regression (BL)， and Deep Neural Network (DNN). This comparison evaluates the effectiveness of different machine learning approaches in classifying TAS， taking into account variations in feature engineering techniques and training set proportions. The case study examines rural highway accidents in Yunnan Province， China， focusing on three categories of factors influencing TAS: accident characteristics， traffic flow， and highway conditions. Moreover， the SHAP (SHapley Additive exPlanations) values were employed to identify the primary factors contributing to the accident severity. The results show that with the training set size of 80%， all four models achieve the highest predictive accuracy for severe accidents. Notably， the PCA+lightGBM combination model outperforms others in overall accident prediction accuracy and has the highest recall rate and F1 score for severe accidents. Comparing the four models under different feature inputs， the impact of feature selection on model performance is less significant than reducing the data heterogeneity. LightGBM and DNN are more susceptible to data heterogeneity， and improving data homogeneity markedly boosts the model’s performance. Through SHAP analysis， it is evident that the modes of transportati

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Small-scale fire tests in the underwater tunnel section model with new sidewall smoke extraction

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Deep Underground Science and engineering 2024年第2期3卷 247-254页

作者： Shunyu Yue Ruifeng Miao Huihang Cheng Maohua Zhong Xiujun Yang Department of engineering Physics Institute of Public Safety ResearchTsinghua UniversityBeijingChina Shanxi Province Expressway Group Limited Liability Company Shanxi Expressway Group Shuoshen Co. LtdShuozhouChina Research Institute of Highway Ministry of Transport RIOH Transport ConsultantsLtdBeijingChina

The Shenzhen–Zhongshan Bridge is a 24‐km‐long bridge and tunnel system,including a 6.8-km-long super cross section subsea *** solve the smoke exhaust problem of a super large cross-section subsea tunnel,the tunnel has a new smoke exhaust system that combines a horizontal smoke exhaust cross section at the top and sidewall smoke exhaust *** order to evaluate the potential fire hazards of this type of tunnel,a 1:30 tunnel model was established and 140 smallscale experiments on underwater tunnel fires were *** changing the fire power,fire location,and fan operation mode,different scenarios of submarine immersed tunnel fire were simulated and the related key parameters such as fire smoke diffusion behavior and smoke temperature distribution were *** this basis,the optimal smoke control strategy was proposed for different fire *** research results indicate that the new smoke exhaust system can fully utilize the smoke flow characteristics,significantly improve smoke exhaust efficiency,and increase available evacuation time,thus further enhancing the fire safety of super large cross-section subsea tunnels.

关键词： sidewall smoke extraction system small‐scale fire tests smoke control

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Flow resistance of gravel bed channels

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International Journal of Sediment Research 2014年第1期29卷 126-132页

作者： Wen C.WANG David R.DAWDY Multech engineering consultants

Existing resistance formulas produce a wide range of friction-factor estimates for gravel bed *** purpose of this paper is to develop a reliable resistance formula in terms of the Darcy-Weisbach friction factor/ Published data were screened and used to establish the *** existing formulas have considered that/is a function of relative roughness D84/R only,where R is the hydraulic radius and D84is the particle size referred to the intermediate diameter that equals or exceeds that of 84 percent of bed *** this paper,/is considered as a function of Froude number in addition to the relative roughness./for D84/R>1 displays a different trend than that for D84/R***/formula for D84/R<1 has been established.

关键词： Flow resistance Darcy-Weisbach friction factor Relative roughness Relative submergence Gravel bed channels Open channels

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