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Remaining Useful Life for Heavy-Duty Railway Cast Steel Knuckles Based on Crack Growth Behavior with Hypothetical Distributions
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作者 Chao Wang Tao Zhu +2 位作者 Bing Yang Shoune Xiao Guangwu Yang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第4期290-305,共16页
The current research on the integrity of critical structures of rail vehicles mainly focuses on the design stage,which needs an effective method for assessing the service state.This paper proposes a framework for pred... The current research on the integrity of critical structures of rail vehicles mainly focuses on the design stage,which needs an effective method for assessing the service state.This paper proposes a framework for predicting the remaining useful life(RUL)of in-service structures with and without visible cracks.The hypothetical distribution and delay time models were used to apply the equivalent crack growth life data of heavy-duty railway cast steel knuckles,which revealed the evolution characteristics of the crack length and life scores of the knuckle under different fracture failure modes.The results indicate that the method effectively predicts the RUL of service knuckles in different failure modes based on the cumulative failure probability curves for different locations and surface crack lengths.This study proposes an RUL prediction framework that supports the dynamic overhaul and state maintenance of knuckle fatigue cracks. 展开更多
关键词 heavy-duty railway Cast steel knuckle Remaining useful life Fatigue crack growth Hypothetical distribution
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Viscoplastic solutions of time-dependent deformation for tunnels in swelling rock mass considering stress release 被引量:1
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作者 Gengyun Liu Youliang Chen +1 位作者 HyonChol Rim Rafig Azzam 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第8期2053-2071,共19页
Excavation and control of tunneling responses in swelling soft-rock tunnels of Sichuan-Tibet railway under seepage conditions were studied.For this,a fractional viscoplastic(FVP)model for swelling soft rocks was estab... Excavation and control of tunneling responses in swelling soft-rock tunnels of Sichuan-Tibet railway under seepage conditions were studied.For this,a fractional viscoplastic(FVP)model for swelling soft rocks was established by introducing Abel dashpot and unsteady viscosity coefficient,considering additional swelling deformation and damage of rock caused by humidity effect.In view of the FVP model,the viscoplastic deformation solutions for rock mass surrounding tunnel under seepage conditions were derived and long-term mechanical responses of swelling rocks upon tunnel excavation were analyzed.Next,a stress release coefficient considering seepage and creep was proposed,based on which control responses considering stress release and failure mechanism of stress release measures were analyzed.The results showed that:(i)The one-dimensional(1D)FVP model has a good application for swelling rock and the three-dimensional(3D)FVP model could well describe the whole creep process of rock mass despite a much higher creep attenuation rate in the first stage of creep;and(ii)An appropriate stress release and deformation of surrounding rocks could effectively reduce the supporting resistance.However,upon a large stress release,the radius of plastic region could increase significantly,and the strength of the surrounding rock mass decreases greatly.The proposed solution could provide a theoretical framework for capturing the excavation and support responses for tunneling in swelling rock mass in consideration of time effect. 展开更多
关键词 Sichuan-tibet railway Viscoplastic deformation Stress release Fractional model tunneling engineering
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Experimental investigation on the invert stability of operating railway tunnels with different drainage systems using 3D printing technology 被引量:3
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作者 Linyi Li Junsheng Yang +3 位作者 Jinyang Fu Shuying Wang Cong Zhang Maolong Xiang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2022年第5期1470-1485,共16页
In recent years, the invert anomalies of operating railway tunnels in water-rich areas occur frequently,which greatly affect the transportation capacity of the railway lines. Tunnel drainage system is a crucial factor... In recent years, the invert anomalies of operating railway tunnels in water-rich areas occur frequently,which greatly affect the transportation capacity of the railway lines. Tunnel drainage system is a crucial factor to ensure the invert stability by regulating the external water pressure(EWP). By means of a threedimensional(3D) printing model, this paper experimentally investigates the deformation behavior of the invert for the tunnels with the traditional drainage system(TDS) widely used in China and its optimized drainage system(ODS) with bottom drainage function. Six test groups with a total of 110 test conditions were designed to consider the design factors and environmental factors in engineering practice,including layout of the drainage system, blockage of the drainage system and groundwater level fluctuation. It was found that there are significant differences in the water discharge, EWP and invert stability for the tunnels with the two drainage systems. Even with a dense arrangement of the external blind tubes, TDS was still difficult to eliminate the excessive EWP below the invert, which is the main cause for the invert instability. Blockage of drainage system further increased the invert uplift and aggravated the track irregularity, especially when the blockage degree is more than 50%. However, ODS can prevent these invert anomalies by reasonably controlling the EWP at tunnel bottom. Even when the groundwater level reached 60 m and the blind tubes were fully blocked, the invert stability can still be maintained and the railway track experienced a settlement of only 1.8 mm. Meanwhile, the on-site monitoring under several rainstorms further showed that the average EWP of the invert was controlled within 84 k Pa, while the maximum settlement of the track slab was only 0.92 mm, which also was in good agreement with the results of model test. 展开更多
关键词 Operating railway tunnels Invert stability tunnel drainage system Three-dimensional(3D)printing technology Model test
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Point cloud-based environment reconstruction and ray tracing simulations for railway tunnel channels
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作者 Ziyi Qi Ruisi He +6 位作者 Mi Yang Xuejian Zhang Bo Ai Weiming Li Shaopeng Wang Wenpu Sun Lizhe Li 《High-Speed Railway》 2023年第4期241-247,共7页
Radio propagation environment plays a critical role in the performance of wireless communication systems,and understanding channel characteristics is vital for ensuring reliable communication links and optimizing syst... Radio propagation environment plays a critical role in the performance of wireless communication systems,and understanding channel characteristics is vital for ensuring reliable communication links and optimizing system performance.Ray tracing is an effective method to investigate propagation characteristics in a complex environment,and how to quickly and accurately obtain environmental information needs to be solved.This paper presents dynamic environment reconstruction and ray tracing simulation in railway tunnel environment based on Simultaneous Localization and Mapping(SLAM)algorithm and Poisson reconstruction algorithm.Accurate channel parameters are obtained and analyzed based on ray tracing simulation.Both straight and curved tunnels are considered and investigated,and the results show the channel characteristics in complex railway tunnel environments. 展开更多
关键词 railway communication tunnels Ray tracing Environment reconstruction Wireless channel
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Reasonable compensation coefficient of maximum gradient in long railway tunnels 被引量:1
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作者 Sirong YI Liangtao NIE Yanheng CHEN Fangfang QIN 《Journal of Modern Transportation》 2011年第1期12-18,共7页
This paper deals with the theory and calculation methods for compensation of the gradient in railway tunnels through theoretical analysis, numerical calculation, and statistic regression methods. On the basis of the p... This paper deals with the theory and calculation methods for compensation of the gradient in railway tunnels through theoretical analysis, numerical calculation, and statistic regression methods. On the basis of the principle that the resultant force is zero, the formula of the maximum calculated gradient was derived for the freight and passenger line and high-speed passenger special line. The formula of aerodynamic drag in tunnel is provided using the domestic and foreign relevant experimental investigations, and revised with modem train and engineering parameters. A calculation model of aerodynamic drag when the train goes through a single-tracked tunnel was built. Finally, the concept of maximum calculated gradient was adopted to revise the formula for compensation of the gradient in railway tunnels. 展开更多
关键词 railway tunnel maximum gradient PROFILE gradient compensation
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Deformation characteristics and safety assessment of a high-speed railway induced by undercutting metro tunnel excavation 被引量:20
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作者 Wangping Qian Taiyue Qi +2 位作者 Yunjian Zhao Yizhou Le Haiyang Yi 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2019年第1期88-98,共11页
Stratum deformation(settlement) is a challenging issue in tunnel engineering, especially when construction of metro tunnels has to undercut high-speed railway. For this purpose, we used the FLAC30 software to analyze ... Stratum deformation(settlement) is a challenging issue in tunnel engineering, especially when construction of metro tunnels has to undercut high-speed railway. For this purpose, we used the FLAC30 software to analyze the stratum settlement characteristics of high-speed railway at different crossing angles intersected by metro tunnel, in terms of ground settlement trough, stratum slip line and irregularity of ballastless tracks. According to the evolution of the stratum settlement at different angle regions, an optimized angle is proposed for the actual project design. In order to reduce the influence of stratum settlement on the safety of high-speed railway, an approach of safety assessment is proposed for the shield engineering undercutting high-speed railway, as per Chinese specifications using numerical results and on-site conditions. A case study is conducted for the shield tunnel section crossing the Wuhan-Guangzhou High-speed Railway between the Guangzhou North Railway Station and the Huacheng Road Station, which represents the first metro tunnel project passing below a high-speed railway in China. A series of measures is taken to ensure the safe excavation of the shield tunnel and the operation of the high-speed railway. The results can provide a technical support for performing a safety evaluation between high-speed railways and metro tunnels. 展开更多
关键词 METRO tunnel EXCAVATION High-speed railway SETTLEMENT characteristics Safety assessment Numerical simulation Case application
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Model test on dynamic characteristics of invert and foundation soils of high-speed railway tunnel 被引量:13
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作者 Huang Juan Yuan Tieying +2 位作者 Peng Limin Yu Jun Ding Zude 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2015年第3期549-559,共11页
A dynamic model test(CL = 4) at different velocities of train,namely different loading frequencies,is carried out to study the dynamic characteristics of a high-speed railway tunnel invert and its foundation soils.Not... A dynamic model test(CL = 4) at different velocities of train,namely different loading frequencies,is carried out to study the dynamic characteristics of a high-speed railway tunnel invert and its foundation soils.Not only are the accelerations,dynamic coefficients,dynamic stresses of the invert and foundation soils emphatically analyzed,their relationship with the velocity of the train are discussed in detail.Through laboratory testing,the attenuation of vibration propagating from up the rails is obtained and the calculation formula of the speed influence coefficient of the tunnel invert is preliminarily established.The depth of the foundation soils influenced by vibration is also determined in this study.It is shown that the responses of the tunnel invert and foundation soils to vibration are slightly increased with the velocity of the train;circumferential stresses in the bottom of the invert are tensile stresses and maximum stresses appear under the foot of the rails;the dynamic soil pressures of the foundation decrease quickly with the distance away from the tunnel invert and an exponential relationship exists between them. 展开更多
关键词 high speed railway tunnel dynamic characteristic M
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Deterioration of concrete in railway tunnel suffering from sulfate attack 被引量:10
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作者 龙广成 谢友均 +1 位作者 邓德华 李小坤 《Journal of Central South University》 SCIE EI CAS 2011年第3期881-888,共8页
For the sake of understanding the deterioration behavior of concrete in actual railway tunnel structures subjected to aggressive sulfate medium in practice,detailed field investigations and tested analysis on sprayed ... For the sake of understanding the deterioration behavior of concrete in actual railway tunnel structures subjected to aggressive sulfate medium in practice,detailed field investigations and tested analysis on sprayed concrete linings of approximately 40-year-old railway tunnels in environments containing sulfate ion were carried out,respectively.The results show that the deterioration of concretes in the investigated area is serious,which involves complicated physicochemical process between the sulfate salt and concrete.Among them,the secondary sulfateminerals such as gypsum formation under very high concentration sulfate ion condition by accumulating and evaporation process dominate,followed by the crystallization of sulfate salt and formation of thaumasite. 展开更多
关键词 sulfate attack CONCRETE railway tunnel secondary sulfate minerals salt crystallization
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Railway tunnel concrete lining damaged by formation of gypsum,thaumasite and sulfate crystallization products in southwest of China 被引量:7
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作者 马昆林 龙广成 谢友均 《Journal of Central South University》 SCIE EI CAS 2012年第8期2340-2347,共8页
The railway tunnel concrete lining exposed to sulfate-bearing groundwater beyond 40 years in southwest of China was investigated. Field investigation, sulfate ions content and corroded products analysis, macro/microsc... The railway tunnel concrete lining exposed to sulfate-bearing groundwater beyond 40 years in southwest of China was investigated. Field investigation, sulfate ions content and corroded products analysis, macro/microscopic test were carried out. Results show that under the tunnel concrete lining structure and its served environmental conditions, sulfate solutions permeate concrete lining and accumulate on windward-side of concrete lining, resulting in the increase of sulfate ions content on windward-side and the diffusion of sulfate ions from windward-side to waterward-side, which cause the concrete lining of windward-side damaged seriously but the waterward-side of concrete lining is still in perfect condition. It is confirmed that structural characteristic of tunnel and environmental conditions lead to physical attack with the leaching of concrete and sodium sulfate crystallization as well as chemical corrosion with formation of gypsum in high sulfate concentration and formation of thaumasite in proper temperature rather than formation of ettringite. These achievements can provide academic and technical supports for understanding the deterioration mechanism of concrete lining as well as constructing railway tunnel under sulfate attack. 展开更多
关键词 railway tunnel concrete lining sulfate attack deterioration mechanism
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In Situ Experiments on Supporting Load Effect of Large-span Deep Tunnels in Hard Rock 被引量:4
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作者 HE Ben-guo ZHU Yong-quan +2 位作者 SUN Ming-lei LIU Hong-yan ZHANG Zhi-qiang 《Journal of Mountain Science》 SCIE CSCD 2013年第6期1125-1136,共12页
A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for... A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for the tunnel was300 m2and is classified as the largest cross section for railway tunnels in China. Through in situ experimental studies, mechanistic properties of the tunnel were identified, including the surrounding rock pressure, convergences along tunnel perimeter and safety of primary support and lining structure.Based on the field measured data, the surrounding rock pressure demand for large-span deep tunnel in hard rock is recommended as double peak type in the vertical direction and fold line type was recommended for horizontal pressure. The results suggested that Promojiyfakonov's theory was most close to the monitored value. Specific recommendations were also generated for the use of bolts in tunnel structures.Numerical simulation was used to evaluate the safety of the tunnel and it confirmed that the current design can satisfy the requirement of the current code. 展开更多
关键词 Large-span tunnel railway tunnel Surrounding rock pressure Load distribution In situ experiment
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Aerodynamic effects on a railway tunnel with partially changed cross-sectional area 被引量:4
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作者 LI Wen-hui LIU Tang-hong +3 位作者 MARTINEZ-VAZQUEZ Pedro XIA Yu-tao CHEN Zheng-wei GUO Zi-jian 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第8期2589-2604,共16页
The present study numerically explored the aerodynamic performance of a novel railway tunnel with a partially reduced cross-section.The impact of the reduction rate of the tunnel cross-section on wave transmissions wa... The present study numerically explored the aerodynamic performance of a novel railway tunnel with a partially reduced cross-section.The impact of the reduction rate of the tunnel cross-section on wave transmissions was analyzed based on the three-dimensional,unsteady,compressible,and RNG k-εturbulence model.The results highlight that the reduction rate(S)most affects pressure configurations at the middle tunnel segment,followed by the enlarged segments near access,and finally the exit.The strength of the newly generated compression wave at the tunnel junction where the cross-section abruptly changes increases exponentially with the decrease of the cross-sectional area.The maximum peak-to-peak pressureΔP on the tunnel and train surface for non-uniform tunnels is reduced by 10.7%and 13.8%,respectively,compared with those of equivalent uniform tunnels.Overall,the economic analysis suggests that the aerodynamic performance of the developed tunnel prototype surpasses those conventional tunnels based on the same excavated volume. 展开更多
关键词 high-speed train railway tunnel CROSS-SECTION transient pressure blockage ratio
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Finite-State Markov Wireless Channel Modeling for Railway Tunnel Environments 被引量:3
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作者 Cuiran Li Ling Liu Jianli Xie 《China Communications》 SCIE CSCD 2020年第2期30-39,共10页
In recent years,high-speed railways(HSRs)have developed rapidly with a high transportation capacity and high comfort level.A tunnel is a complex high-speed rail terrain environment.It is very important to establish an... In recent years,high-speed railways(HSRs)have developed rapidly with a high transportation capacity and high comfort level.A tunnel is a complex high-speed rail terrain environment.It is very important to establish an accurate channel propagation model for a railway tunnel environment to improve the safety of HSR operation.In this paper,a method for finite-state Markov chain(FSMC)channel modeling with least squares fitting based on non-uniform interval division is proposed.First,a path loss model is obtained according to measured data.The communication distance between the transmitter and receiver in the tunnel is non-uniformly divided into several large non-overlapping intervals based on the path loss model.Then,the Lloyd-Max quantization method is used to determine the threshold of the signal-to-noise ratio(SNR)and the channel state quantization value and obtain the FSMC state transition probability matrix.Simulation experiments show that the proposed wireless channel model has a low mean square error(MSE)and can accurately predict the received signal power in a railway tunnel environment. 展开更多
关键词 railway tunnel FSMC channel model SNR path loss
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New technologies for high-risk tunnel construction in GuiyangGuangzhou high-speed railway 被引量:2
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作者 Yubao Zhao Shougen Chen +1 位作者 Xinrong Tan Ma Hui 《Journal of Modern Transportation》 2013年第4期258-265,共8页
Based on the construction of high risk tunnels in Guiguang-Guangzhou high-speed railway, several new technologies were developed for high-risk tunnel con- struction. First, an integrated advanced geological predic- ti... Based on the construction of high risk tunnels in Guiguang-Guangzhou high-speed railway, several new technologies were developed for high-risk tunnel con- struction. First, an integrated advanced geological predic- tion was developed for tunneling in karst area. Then, a new system of ventilation by involving the dedusting technol- ogy was proposed and used in the field, which received a good air quality. Finally, a method to minimize the dis- tance between the working face and the invert installation was proposed by optimizing the invert installation and adopting the micro bench method. Applying the method to the project obtained an excellent result. The achievement obtained for this study would be able to provide a valuable reference to similar projects in the future. 展开更多
关键词 tunneling engineering High-speed railway New technologies High-risk tunnel
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Prototype test study on mechanical characteristics of segmental lining structure of underwater railway shield tunnel 被引量:4
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作者 He Chuan Feng Kun Yan Qixiang 《Engineering Sciences》 EI 2014年第2期65-74,共10页
Based on the first unde rwater railway shield tunnel, the Shiziyang shield tunnel of Guangzhou Zhu- jiang River, the prototype test was carried out against its segmental lining structure by using "multi-function shie... Based on the first unde rwater railway shield tunnel, the Shiziyang shield tunnel of Guangzhou Zhu- jiang River, the prototype test was carried out against its segmental lining structure by using "multi-function shield tunnel structure test system". And the mechanical characteristics of segmental lining structure using straight assembling and staggered assembling were studied deeply. The results showed that, the mechanical characteristics of segmental lining structure varied with the water pressures; especially after cracking, the high water pressure played a significant role in slowing down the growing inner force and deformation. It also testi- fied that the failure characteristics varied with straight assembling structure and staggered assembling structure. Shear thilurc often occurred near longitudinal seam when using straight assembling. 展开更多
关键词 underwater railway shield tunnel segmental lining structure prototype test tenon joint failure characteristics
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Structural mechanism and construction method of mud and water inrush in Xiangyun tunnel of Guangtong-Dali railway
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作者 WANG Yawei 《Global Geology》 2019年第3期167-178,共12页
Mud and water inrush in tunnel is a common problem in the construction process. Nowadays, the research and classification on this are mostly focused on karst situations. According to the characteristics of the surroun... Mud and water inrush in tunnel is a common problem in the construction process. Nowadays, the research and classification on this are mostly focused on karst situations. According to the characteristics of the surrounding rock and damage forms of the tunnel in the studied area, the author analyzed the geological and structural characteristics of mud and water inrush in tunnel and obtained their construction type. Meanwhile, the advanced water detection under the complex geological conditions was studied by using induced polarization method, transient electromagnetic method and three-dimensional seismic method, it can be concluded that the water-rich fracture zone exists within the detection range with a risk of large mud and water inrush disaster. The concrete construction treatment measures are put forward:①cement-water glass binary slurry is selected as the material for ground and hole grouting, its advantage is that the gel time can be controlled, and it has certain grout ability in the strata with large permeability coeffcient, which is conducive to excavate construction immediately after grouting.②applying the mature retrograde grouting construction can reduce grouting time and improve the excavation efficiency. 展开更多
关键词 MUD and water inrush geological model Xiangyun tunnel Guangtong-Dali railway STRUCTURAL mechanism construction method
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Distribution characteristics and the evolution law of excavation damage zone in the large-span transition section of high-speed railway tunnel based on microseismic monitoring
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作者 Ao Li Dingli Zhang +2 位作者 Zhenyu Sun Jun Huang Fei Dong 《Railway Sciences》 2022年第1期56-75,共20页
Purpose–The microseismic monitoring technique has great advantages on identifying the location,extent and the mechanism of damage process occurring in rock mass.This study aims to analyze distribution characteristics... Purpose–The microseismic monitoring technique has great advantages on identifying the location,extent and the mechanism of damage process occurring in rock mass.This study aims to analyze distribution characteristics and the evolution law of excavation damage zone of surrounding rock based on microseismic monitoring data.Design/methodology/approach–In situ test using microseismic monitoring technique is carried out in the large-span transition tunnel of Badaling Great Wall Station of Beijing-Zhangjiakou high-speed railway.An intelligent microseismic monitoring system is built with symmetry monitoring point layout both on the mountain surface and inside the tunnel to achieve three-dimensional and all-round monitoring results.Findings–Microseismic events can be divided into high density area,medium density area and low density area according to the density distribution of microseismic events.The positions where the cumulative distribution frequencies of microseismic events are 60 and 80%are identified as the boundaries between high and medium density areas and between medium and low density areas,respectively.The high density area of microseismic events is regarded as the high excavation damage zone of surrounding rock,which is affected by the grade of surrounding rock and the span of tunnel.The prediction formulas for the depth of high excavation damage zone of surrounding rock at different tunnel positions are given considering these two parameters.The scale of the average moment magnitude parameters of microseismic events is adopted to describe the damage degree of surrounding rock.The strong positive correlation and multistage characteristics between the depth of excavation damage zone and deformation of surrounding rock are revealed.Based on the depth of high excavation damage zone of surrounding rock,the prestressed anchor cable(rod)is designed,and the safety of anchor cable(rod)design parameters is verified by the deformation results of surrounding rock.Originality/value–The research provides a new method to predict the surrounding rock damage zone of large-span tunnel and also provides a reference basis for design parameters of prestressed anchor cable(rod). 展开更多
关键词 High-speed railway Large-span tunnel Excavation damage zone Microseismic monitoring
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Heterogeneity identification method for surrounding rock of large-section rock tunnel faces based on support vector machine
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作者 Wenhao Yi Mingnian Wang +4 位作者 Jianjun Tong Siguang Zhao Jiawang Li Dengbin Gui Xiao Zhang 《Railway Sciences》 2023年第1期48-67,共20页
Purpose–The purpose of the study is to quickly identify significant heterogeneity of surrounding rock of tunnel face that generally occurs during the construction of large-section rock tunnels of high-speed railways.... Purpose–The purpose of the study is to quickly identify significant heterogeneity of surrounding rock of tunnel face that generally occurs during the construction of large-section rock tunnels of high-speed railways.Design/methodology/approach–Relying on the support vector machine(SVM)-based classification model,the nominal classification of blastholes and nominal zoning and classification terms were used to demonstrate the heterogeneity identification method for the surrounding rock of tunnel face,and the identification calculation was carried out for the five test tunnels.Then,the suggestions for local optimization of the support structures of large-section rock tunnels were put forward.Findings–The results show that compared with the two classification models based on neural networks,the SVM-based classification model has a higher classification accuracy when the sample size is small,and the average accuracy can reach 87.9%.After the samples are replaced,the SVM-based classification model can still reach the same accuracy,whose generalization ability is stronger.Originality/value–By applying the identification method described in this paper,the significant heterogeneity characteristics of the surrounding rock in the process of two times of blasting were identified,and the identification results are basically consistent with the actual situation of the tunnel face at the end of blasting,and can provide a basis for local optimization of support parameters. 展开更多
关键词 Rock tunnel Surrounding rock HETEROGENEITY Support vector machine High-speed railway
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Rapid profiling rock mass quality underneath tunnel face for Sichuan-Xizang Railway
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作者 Siyuan Wu Min Qiu +2 位作者 Zhao Yang Fuquan Ji Zhongqi Quentin Yue 《Underground Space》 SCIE EI CSCD 2024年第6期138-152,共15页
The Sichuan-Xizang Railway is a global challenge,surpassing other known railway projects in terms of geological and topographical complexity.This paper presents an approach for rapidly profiling rock mass quality unde... The Sichuan-Xizang Railway is a global challenge,surpassing other known railway projects in terms of geological and topographical complexity.This paper presents an approach for rapidly profiling rock mass quality underneath tunnel face for the ongoing construction of the Sichuan-Xizang Railway.It adopts the time-series method and carries out the quantitative analysis of the rock mass quality using the depth-series measurement-while-drilling(MWD)data associated with drilling of blastholes.A tunnel face with 15 blastholes is examined for illustration.The results include identification of the boundary of homogeneous geomaterial by plotting the blasthole depth against the net drilling time,as well as quantification of rock mass quality through the recalculation of the new specific energy.The new specific energy profile is compared and highly consistent with laboratory test,manual logging and tunnel seismic prediction results.This consistency can enhance the blasthole pattern design and facilitate the dynamic determination of charge placement and amount.This paper highlights the importance of digital monitoring during blasthole drilling for rapidly profiling rock mass quality underneath and ahead of tunnel face.It upgrades the MWD technique for rapid profiling rock mass quality in drilling and blasting tunnels. 展开更多
关键词 Measurement-while-drilling Drilling and blasting Rock mass quality New specific energy Constant penetration rate Sichuan-Xizang railway tunnelLING
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Influence of Golmud-Lhasa Section of Qinghai-Tibet Railway on Blown Sand Transport 被引量:7
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作者 XIAO Jianhua YAO Zhengyi QU Jianjun 《Chinese Geographical Science》 SCIE CSCD 2015年第1期39-50,共12页
The Qinghai-Tibet Railway(QTR) passes through 281 km of sandy land, 11.07 km of which causes serious sand damage to the railway and thus, the control of blown sand is important for the safe operation of the railway. C... The Qinghai-Tibet Railway(QTR) passes through 281 km of sandy land, 11.07 km of which causes serious sand damage to the railway and thus, the control of blown sand is important for the safe operation of the railway. Construction of the railway and sand prevention system greatly changed the blown sand transport of the primary surface. Effective and feasible sand-control measures include stone checkerboard barriers(SCBs), sand fences(SFs), and gravel coverings. This study simulated the embankments, SCBs and SFs of the QTR in a wind tunnel, and analyzed their respective wind profile, sand deposition, and sand-blocking rate(SBR) in conjunction with field data, aiming at studying the influence of Golmud-Lhasa section of the QTR and sand prevention system on blown sand transport. The results of wind tunnel experiments showed that wind speed increased by 67.7%–77.3% at the upwind shoulder of the embankment and decreased by 50.0%–83.3% at upwind foot of embankment. Wind speed decreased by 50.0%–100.0% after passing through the first SF, and 72.2%–100.0% after the first row of stones within the first SCB grid. In the experiment of sand deposition, the higher the wind speed, the lower the SBR of SCB and SF. From field investigation, the amount of sand blocked by the four SFs decreased exponentially and its SBR was about 50.0%. By contrast, SCB could only block lower amounts of sand, but had a higher SBR(96.7%) than SF. Although, results show that SFs and SCBs along the Golmud-Lhasa section of the QTR provide an obvious sand blocking effect, they lead to the deposition of a large amount of sand, which forms artificial dunes and becomes a new source of sand damage. 展开更多
关键词 Qinghai-Tibet railway(QTR) wind profile blown sand transport sand damage wind tunnel
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A Study of the Suitable Measurement Location and Metrics for Assessing the Vibration Source Strength Based on the Field-Testing Data of Nanchang Underground Railway 被引量:4
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作者 Ling Zhang Xiaoyan Lei +1 位作者 Jian Jiang Qingsong Feng 《Sound & Vibration》 2018年第5期22-27,共6页
Underground railway vibration source strength is one of the key values used for environmental impact assessment and the evaluation of mitigation measure’s performance.However,currently there is no international stand... Underground railway vibration source strength is one of the key values used for environmental impact assessment and the evaluation of mitigation measure’s performance.However,currently there is no international standard of measuring the underground railway vibration source strength for such purposes.The available local standards and industrial guidelines do not agree on measurement locations as well as the metrics for presenting the source strength.This has caused many confusions.This paper aims to study the suitable measurement location and metrics using the data from a large scale field-testing carried out at the Nanchang underground railway(Metro Line 1,China)in 2017.200 passing trains were recorded during the test at two different sections of the railway line,one with the spring floating slab installed and the other without.Three locations were chosen at each section,including one in the middle of the track and two on the tunnel wall at different heights.Based on the results of statistical analysis,the maximum of z-weighted vertical vibration level(VLzmax)obtained at a lower measurement location on the tunnel wall is the best for representing the underground railway vibration source strength,which is 76.66 dB obtained from this study. 展开更多
关键词 Underground railway tunnel vibration source strength floating slab statistics analysis
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