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Quick Search     Advanced Search MODERN TUNNELLING TECHNOLOGY   2024 Vol.61 Issue.4 Published 2024-08-25 1 Review of Research on Embodied Carbon Emissions in Urban Rail Transit Infrastructure CHEN Xiangsheng 1,2,3 CHEN Kunyang1,2,3 QIU Tong1,2,3 WANG Lei 1,2,3 HE Qiufeng1,2,3 LAI Yani1,2,3CHEN Wuxiong4 FU Yanbin1,2,3 Quantitative research on carbon emissions of urban rail transit infrastructure has become a focal point in the field of low-carbon construction in transportation. This study provides a systematic review and analysis of the quantitative research on carbon emissions of urban rail transit infrastructure, based on the Web of Science (WOS) core database and the China National Knowledge Infrastructure (CNKI) database. This literature review delves into research methods and influencing factors, covering four types of infrastructure: subway systems (including tunnels and stations), light rail systems, urban rapid transit systems, and tram systems. Firstly, the research methods, objectives and scope definition, functional units and inventory data of the literature on carbon emission calculation are compared, the scope of application of the research methods is determined, and the data sources are classified. Secondly,the key factors affecting the embodied carbon emissions of urban rail transit infrastructure are identified and analyzed.Finally, discuss the shortcomings of existing research. The research results provide reference for the standardization of carbon emission accounting for urban rail transit infrastructure. 2024 Vol. 61 (4): 1-13 [Abstract] ( 157 ) [HTML 1KB] [ PDF 4559KB] ( 1007 ) 14 Information Perception Mechanism and Evaluation Method of Highway Tunnel Lighting Environment LIANG Bo1NIU Jia'an1 QIN Can1 HE Shiyong2 RAN Yifeng3 ZHU Shuangkai? Current tunnel lighting standards are primarily based on physical evaluation indicators such as luminance in photopic vision, which do not fully consider the actual spatiotemporal variations of the dynamic visual environment during driving in tunnel, and also do not adequately reflect the psychological and physiological perceptions as well as the behavioral responses of drivers. In light of this, a systematic study on tunnel lighting environment and information perception is conducted to reveal the variation trends and relationships between physical information and physiological perception. Consequently, a series of tunnel lighting environment evaluation methods based on information perception are proposed, and validated through extensive static and dynamic information perception tests.The results show that the tunnel lighting environment consists of material information, which is represented by physical quantity information. As a human-vehicle-road coupling environment, information perception involves both the physical quantity information of the tunnel lighting environment and the psychological and physiological responses of humans, i.e., biological perception. By comprehensively analyzing the relationship between physical quantity in? formation and biological perception, the mechanism of information perception is formed, and evaluation methods based on information perception are established. These methods can provide theoretical basis and reference indicators for the design and improvement of tunnel lighting environments. 2024 Vol. 61 (4): 14-27 [Abstract] ( 197 ) [HTML 1KB] [ PDF 6868KB] ( 587 ) 28 Research Status and Progress of Linkage Theory and Technology of Ventilation and Lighting in Extra-long Highway Tunnels HE Shiyong1,2 TANG Huanhuan2 LIANG Bo1,2 SHI Lingna3 LI Jie2 LIU Hao2 WANG Xiaoyu2 With the increasing number and types of extra-long highway tunnels in China, issues regarding the safe? ty, energy-saving, and comfort related to operational ventilation and lighting have gradually become prominent. To address the problems in the theory and technology of ventilation and lighting in extra-long highway tunnels, this paper first systematically reviews relevant literatures from the China National Knowledge Infrastructure (CNKI) and Web of Science (SCI) databases over the past 20 years, analyzing the number of publications, research trends, and hotspots. Then, the paper elaborates on the problems in the linkage theory and technology of ventilation and lighting in extra-long highway tunnels, focusing on research hotspots. Finally, it summarizes and reviews the research status in terms of three aspects: the accurate prediction of the impact of natural wind and natural light in the tunnel site area on ventilation and lighting, the impact of dynamic changes in traffic flow on driving safety, and the construction of a smart ventilation and lighting linkage digital twin model considering tunnel operation characteristics. The aim is to provide ideas for the safe, comfortable, and energy-saving operation of extra-long highway tunnels. 2024 Vol. 61 (4): 28-40 [Abstract] ( 142 ) [HTML 1KB] [ PDF 5043KB] ( 561 ) 41 Study on the Generation Mechanism of Non-exhaust Emissions from New Energy Vehicles and Its Impact on Air Demands in Tunnels LIU Yuan1,2,3 YU Li1,2,3 WANG Xue1,2,3 GUO Xiaohan1,2,3 LU Ming1,2,3 With the widespread adoption of new energy vehicles (NEVs) in China, the composition ratio of pollutants in tunnels has been changing. To clarify the impact of NEVs on air demand in tunnels, the research methods including data investigation and theoretical analysis were employed to quantify the pollutant generation characteristics of NEVs and distinguish them from internal combustion engine vehicles. The impact of different mix ratios of large, medium, and small-sized NEVs on the air demand during tunnel operation was explored under influence of the gradient and vehicle speed. The tunnel air demand calculation formula in PIARC2019 was revised, and a calculation method for the correction factor was proposed. Detailed ventilation design method was provided based on a project case. The results are as follows: (1) Based on the generation mechanisms of non-exhaust particulate matter (PM) from four sources, the calculation formulae for the relationship between non-exhaust PM emissions and vehicle weight were provided; (2) The correction factors for baseline emissions of non-exhaust PM for large, medium, and small-sized NEVs are 1.127, 1.093, and 1.088, respectively; (3) Considering the impact of tunnel gradient, vehicle speed, and mix ratio, a correction factor calculation method for the air demand in temporary construction transport tunnels and ordinary road tunnels was provided; (4) The discrimination formulae for three applicability conditions—no correction, correction, and setting dust removal machine—were established for calculating the air demand during tunnel operation. 2024 Vol. 61 (4): 41-50 [Abstract] ( 143 ) [HTML 1KB] [ PDF 3924KB] ( 590 ) 51 Study on Ventilation Energy Efficiency in High-altitude Tunnels Based on Traffic Flow Characteristics REN Rui1,2 XIAO Zhenzhi,1,2 WANG Yaqiong1,2 SHI Peilong1 WANG Lizhi3 To study the vehicle pollutant emission characteristics and the ventilation efficiency of mechanical venti? lation system in high-altitude road tunnels, an on-site smoke emission test was conducted on three types of diesel vehicles in the Tianshan Shengli Tunnel on the Urumqi-Yuli Highway. A random forest model was established to predict the smoke emission of single diesel vehicle based on parameters such as vehicle model, longitudinal gradient,speed, and altitude. The correlation between the measured values of single-vehicle smoke emission and the calculated values from the Guidelines for Design of Ventilation of Highway Tunnels was analyzed. The Monte Carlo method was used to study the impact of tunnel traffic flow characteristic parameters on traffic wind-induced boosting efficiency and mechanical ventilation pressure. The results show that the random forest model has good predictive accuracy for single-vehicle smoke emissions, with a root mean square error of 0.251 3 in the test set. The measured single-vehicle smoke emissions are lower than the calculated values from the "Guidelines," and they are highly linearly correlated when the speed is less than 70 km/h. The required mechanical ventilation boost pressure in the tunnel increases linearly with the increase in mixed vehicle traffic flow, while the traffic wind boost efficiency decreases exponentially with the increase in traffic flow and decreases with the increase in single-vehicle smoke emissions. The primary influencing factors of single-vehicle smoke emissions in descending order are the longitudinal gradient, vehicle model,speed, and altitude. Therefore, the longitudinal gradient should be appropriately controlled in the design of high-altitude road tunnels. 2024 Vol. 61 (4): 51-59 [Abstract] ( 148 ) [HTML 1KB] [ PDF 4118KB] ( 620 ) 60 Experimental Study on the Impact of Sunshades at Urban Tunnel Entrances on Driver′s Visual Load SHEN Di1，2 DU Zhigang1，2 ZHANG Xing1，2 JIAO Zhigang3 XU Wenguang1，2 To study the visual load characteristics of drivers at tunnel entrances and the impact of sunshades on visual load, real vehicle experiments were conducted at Xiang′an Tunnel (with the sunshade) and Jiaozhou Bay Tunnel (without the sunshade). Parameters such as pupil area, fixation duration, saccade amplitude, and blink frequency were collected for comparative analysis. A visual load intensity evaluation model for drivers at tunnel entrances was established based on the factor analysis to determine the visual load intensities at the entrances of the two tunnels.The study shows that, compared to tunnels without sunshades, the pupil area, the mean change rate of pupil area, the fixation duration, and the mean saccade amplitude of drivers in tunnels with sunshades are all smaller. As drivers enter the tunnel, the pupil areas gradually increase. The increase in blink frequency fluctuates significantly in tunnels without sunshades, while it changes more smoothly in tunnels with sunshades. Sunshades can reduce the visual load value by 51.85%, which is beneficial for improving the visual load of drivers in the tunnel entrance area (including the adjacent section of the sunshade, the sunshade section, and the tunnel entrance section). 2024 Vol. 61 (4): 60-69 [Abstract] ( 144 ) [HTML 1KB] [ PDF 4078KB] ( 608 ) 70 Study of Driving Safety on Colored Pavement at Tunnel Entrance Section Based on Real Vehicle Measurements LIN Zhi1 LIU Chaoming1 WANG Jianghua2 ZHAO Yao2 HUANG Kexin1 LI Jiaqi1 When drivers enter a tunnel, the sudden change in luminance environment can cause visual dark adapta? tion, leading to the so-called "black hole effect," which severely reduces drivers' visual recognition ability and easily causes traffic accidents. In view of this, this paper proposes laying brightly colored pavement at the tunnel entrance to increase the brightness in the tunnel, thereby mitigating the adverse effects of the "black hole effect." Real vehicle tests were conducted to quantitatively evaluate drivers' visual recognition ability under colored pavement conditions. The results show that the obstacle detection distances for drivers under original, green, red, and yellow pavement conditions distance are obtained through distance measurement tests, revealing that all three colored pavements improved drivers' visual recognition ability to varying degrees, with the yellow pavement showing the greatest improvement. 2024 Vol. 61 (4): 70-76 [Abstract] ( 125 ) [HTML 1KB] [ PDF 2866KB] ( 507 ) 77 Measurement and Analysis of Dust Concentration in Service Tunnel during Construction of Tianshan Shengli Tunnel with "TBM Method + Drill and Blast Method" HUANG Dengxia1 LUO Yanbin2 ZHAO Zhiqiang2 CHEN Jianxun2 LIU Weiwei2 FENG Rubing1 WU Teligen1 To explore the spatiotemporal distribution patterns of meteorological parameters and dust concentrations in a high-altitude super-long tunnel during the construction combined with the "TBM method + drill and blast method", this study is based on the Tianshan Shengli Tunnel on the Urumqi-Yuli Highway. On-site monitoring was conducted to analyze the time-varying patterns of meteorological parameters such as wind speed, wind direction, air pressure, temperature, and humidity, as well as the spatiotemporal characteristics of dust concentration. The distribution characteristics of dust concentration in the service tunnel and the connection passage under different working conditions (blasting and non-blasting periods) were compared and analyzed. The study revealed the distribution patterns of dust along the service tunnel under multiple working face conditions and explored the impact of blasting at different working face locations on the dust concentration in the service tunnel and connection passage. The results indicate that the time-varying patterns of temperature, air pressure, humidity, and dust concentration in the service tunnel and connection passage are consistent, but the wind speed and wind direction vary due to differences in cross-sectional ventilation area and construction impact. The wind speed in the connection passage fluctuates more than in the service tunnel. Impacted by close-range blasting in the right tunnel, the wind direction in the connection passage temporarily reverses from exhausting air to the connection passage to supplying air to the service tunnel.Dust concentration in the service tunnel increases in three gradients from the portal to the inside, with a significant natural ventilation effect from the shaft. During non-blasting periods in the main tunnel, dust concentrations in the service tunnel are stable, with PM2.5, PM10, and PM100 concentrations maintained at 0.8 mg/m3, 3.7 mg/m3, and 9.5mg/m3, respectively, meeting the dust concentration thresholds for tunnel construction. During blasting periods in the main tunnel, dust concentrations in the service tunnel increase sharply, peaking at 1.4 mg/m3 for PM2.5, 6.9 mg/m3 for PM10, and 21.3 mg/m3 for PM100. Except for PM2.5, concentrations of PM10 and PM100 exceed their allowable levels by 38% and 113%, respectively. And so the ventilation volume in the service tunnel should be increased to 128.5 m3/s.Before the main tunnel connects with the connection passage, airflow must be exhausted through the service tunnel,synchronously driving dust concentration changes in both the service tunnel and connection passage during main tunnel blasting. Once the main tunnel working face connects directly to the connection passage, the blasting in the main tunnel will significantly affect dust concentration in the connection passage but has a smaller impact on the service tunnel 2024 Vol. 61 (4): 77-85 [Abstract] ( 132 ) [HTML 1KB] [ PDF 5179KB] ( 819 ) 86 Experimental Study on the Impact of Reboundable Traffic Cylinders at Highway Tunnel Entrances on Traffic Safety YU Liang1 DENG Wenti1 DU Zhigang2,3 YANG Yongzheng2,3 To explore the effectiveness of reboundable traffic cylinders in improving traffic safety at highway tunnel entrances, four scenarios were constructed using fluorescent reboundable traffic cylinders with heights of 100 cm, 90cm, and 75 cm, as well as without reboundable traffic cylinders. Experiments were conducted using a driving simulation platform to collect driving data. Based on the human characteristics of drivers at highway tunnel entrances, the impact of different scenarios with/without reboundable traffic cylinders and different reboundable traffic cylinder schemes on lane keeping and speed control of drivers was analyzed. The study shows that fluorescent reboundable traffic cylinders can result in smaller and more stable lateral deviations of vehicle trajectory. Compared to the scenario without reboundable traffic cylinders, driver's lane-keeping ability can be improved by 44.93%, 36.38%, and 14.62% under the 100 cm, 90 cm, and 75 cm reboundable traffic cylinders schemes, respectively. Using the reboundable traffic cylinders can effectively control vehicle speed, warning drivers to decelerate in advance in the approach section. The vehicle speeds can be maintained near 85% of the maximum limit and were stable. Compared to the scenario without reboundable traffic cylinders, the speed control ability improved by 38.38%, 30.40%, and 13.36% under the 100 cm, 90 cm, and 75 cm reboundable traffic cylinder schemes, respectively. The reboundable traffic cylinders can enhance the continuity, consistency, and symmetry of the sight guidance in the tunnel entrance area, with the height of the reboundable traffic cylinders being positively correlated with the improvement effect.The 90 cm and 100 cm reboundable traffic cylinders can significantly improve traffic safety. 2024 Vol. 61 (4): 86-94 [Abstract] ( 130 ) [HTML 1KB] [ PDF 4596KB] ( 606 ) 95 Calculation Method for Underlying Tunnel Deformation Induced by Foundation Pit Excavation Based on Layered Mindlin Solution LV Linhai1,2,3 JIANG Mingjie1,2 XIE Zhongming1,2 HUANG Zhonghui4 WANG Binghua3 MEI Guoxiong5 Foundation pit excavation inevitably causes rebound of the soils within a certain depth range at the pit bottom, leading to the uplift deformation of underlying tunnels, which will pose a threat to tunnel safety if the deformation is significant. To further explore the impact of foundation pit excavation on the deformation of underlying tunnels, based on the elastic theory of layered materials, and considering the influence of the soils on both sides of the pit on the soils at the pit bottom, the vertical additional stress of the soils under internal action of axisymmetric loads in the multi-layered soils is derived using integral transformation and matrix recursion methods. On this basis, the tunnel is simplified as an Euler-Bernoulli long beam placed in a Lifking foundation model that considers the continuity of soils, and the differential equations for controlling the longitudinal deformation of the tunnel under unloading of pit excavation are derived. The finite difference method is used to solve the longitudinal displacement matrix expression of the tunnel. Through comparative analysis of engineering cases, it is found that the results by proposed method are closer to the measured data than the Winkler foundation model, verifying its good prediction effect. 2024 Vol. 61 (4): 95-104 [Abstract] ( 154 ) [HTML 1KB] [ PDF 3673KB] ( 551 ) 105 Viscoelastic-plastic Solution for Circular Tunnels Based on the Three-stage Creep Model with the D-P Criterion The rheological properties of surrounding rock significantly influence the long-term deformation of tunnel structures. To better describe the viscoelastic-plastic mechanical behaviors of the surrounding rock after circular tunnel excavation, a fractional-order creep model is used to characterize the rheological properties, and the DruckerPrager criterion is used to represent the plastic characteristics of the surrounding rock. The theoretical solution of the stress-displacement of the surrounding rock, considering the support effect after circular tunnel excavation, is derived. Through specific examples, the influence of rheological parameters on viscoelastic-plastic deformation of the surrounding rock is analyzed. The results show that: (1) The creep displacement curve of the surrounding rock obtained analytically matches well with the average curve of field measured results, proving the correctness of the theoretical derivation; (2) When the dilatancy effect of the surrounding rock in the viscoplastic zone is considered,the deformation value of the surrounding rock increases. The more pronounced the dilatancy effect, the greater the increase in the deformation value of the surrounding rock; (3) When the viscosity of the viscoelastic or viscoplastic body increases, the creep displacement value and rate of the surrounding rock also increase accordingly. 2024 Vol. 61 (4): 105-111 [Abstract] ( 168 ) [HTML 1KB] [ PDF 2765KB] ( 586 ) 112 Study on Mechanical Model for Longitudinal Deformation of Existing Shield Tunnel Caused by New Tunnel Over-crossing Construction LIU Bo1,2 ZHENG Jinlei1,3,4 ZHANG Zhao1 MA Jianfei4 Based on the pressure arch theory, the construction of a new tunnel crossing over an existing shield tunnel is divided into three modes according to the relative position of the new tunnel and the pressure arch. Corresponding mechanical calculation models are established, and the applicable deformation control equations and solution methods for the models are provided. The models are then validated using measured data from the new Caoqiao Station of the Beijing Daxing Airport Line, which crosses over the existing shield tunnel of Line 10. The results show that the proposed models have high accuracy, with the calculated maximum vertical displacement of the shield tunnel being closer to the measured values compared to traditional models, thereby improving the accuracy of longitudinal deformation prediction for shield tunnels. 2024 Vol. 61 (4): 112-118 [Abstract] ( 148 ) [HTML 1KB] [ PDF 3456KB] ( 578 ) 119 Technical and Economic Comparative Study of TBM Belt Conveyor Mucking YANG Yinwei1 WANG Baoyou1 WANG Lichuan1,2 WANG Zhengzheng3 GENG Qi4 ZHANG Huijian2 JI Guodong1 An efficient mucking system is crucial for the project schedule and cost planning. Based on TBM con? struction practices, this paper analyzes the advantages of belt conveyor mucking technology, summarizes five commonly used types of belt conveyors in tunnel construction and analyzes their characteristics and application scopes.On this basis, a TBM tunnel construction model was established to compare the economics of belt conveyor mucking with rail mucking. Recommendations are proposed for TBM belt conveyor mucking: (1) The belt conveyor should be the preferred equipment for TBM mucking; (2) Energy saving and environmental protection should be key aspects of the belt conveyor design; (3) the level of intelligent operation and maintenance management of belt conveyors should be enhanced; (4) The reliability of key components of belt conveyors should be improved; (5) The adaptability of belt conveyor structures to engineering should be enhanced through considering special structural design. 2024 Vol. 61 (4): 119-125 [Abstract] ( 143 ) [HTML 1KB] [ PDF 3418KB] ( 514 ) 126 Study on Calculation Method and Influencing Factors of Carbon Emission during Construction of Rectangular Pipe-jacking Tunnels CUI Guangyao1 DAI Aimeng1 MA Jianfei2 NING Maoquan3 Based on the rectangular pipe jacking project at the square in front of Putian Railway Station and using the life cycle theory framework combined with the emission coefficient method, this study investigates the calculation method and influencing factors of carbon emissions during the construction of rectangular pipe-jacking tunnels.The research indicates that cement, steel, and electricity are the primary sources of carbon emissions during the construction of rectangular pipe-jacking tunnels. The jacking length of the tunnel is directly proportional to the total carbon emissions of the project, but inversely proportional to the carbon emissions per meter. When the jacking length increases from 224 m to 424 m, the carbon emissions per meter decrease the most, with a reduction of over 26%. When the segment width increases from 1.2 m to 2.4 m, the carbon emissions in terms of segment waterproofing decrease by up to 72%. For the same excavation length, increasing the segment width from 1.2 m to 1.5 m provides the best carbon emission reduction benefits, with a maximum reduction of 4.3%. When the segment width exceeds 1.5 m, the reduction in carbon emissions per meter is no longer significant. 2024 Vol. 61 (4): 126-134 [Abstract] ( 145 ) [HTML 1KB] [ PDF 3369KB] ( 483 ) 135 Research and Development of the LoRa-based Data Transmission Technology for Long and Large Tunnels (Groups) XU Minjian1 LING Rui2 GUO Hongyan1 WANG Qingling3 Addressing the issue of obstructed transmission of monitoring data during the construction and operation of long and large tunnels (groups), a data transmission method is proposed based on LoRa and the data relay technology. By analyzing the communication distance, anti-interference capability, and low-power characteristics in the special environment of tunnels, a data transmission communication network scheme for long and large tunnels (groups) was designed. Corresponding wireless relay and wireless gateway devices were developed, enabling reliable data transmission between remote servers and on-site tunnel sensors. Experimental and testing results show that the proposed LoRa-based data transmission technology for long and large tunnels (groups) can achieve interconnection between remote servers and on-site sensors, meeting the requirements for long-distance communication and low-power operation during the construction and operation of long and large tunnels. 2024 Vol. 61 (4): 135-141 [Abstract] ( 145 ) [HTML 1KB] [ PDF 4029KB] ( 458 ) 142 Mechanical Behavior Analysis and Construction Optimization for Inclined Shaft Transitioning to Main Tunnel in Extreme-highly Stressed and Fractured Strata ZHOU Song1 PAN Yue1，2 LIU Yongsheng1，2 XIE Tao1 Aiming at the safety issues caused by multiple disturbances and tunnel group effects during the drill and blast construction of large-section tunnel group in highly stressed and fractured strata in the course of the inclined shaft transitioning the main tunnel, this study investigates the mechanical state and degradation process of surrounding rock during tunnel group construction. Taking the construction of the inclined shaft transitioning to the main tunnel of a deeply buried large-section twin-tube TBM tunnel project as an example, the mechanical mechanism and influencing factors of the tunnel group effect in highly stressed and fractured strata are revealed through theoretical analysis of tunnel mechanics. A three-dimensional numerical model of the tunnel group is established to analyze the stress-strain state of the surrounding rock during the excavation process of tunnel group. The results indicate that strengthening the support structure and constructing the advanced support can both reduce the deformation of the surrounding rock, with the advanced support providing better control effect. By optimizing the construction sequences and using the large pipe roof for pre-supporting, the deformation of the surrounding rock can be effectively controlled without changing the support structure parameters, ensuring construction safety. 2024 Vol. 61 (4): 142-150 [Abstract] ( 114 ) [HTML 1KB] [ PDF 5617KB] ( 626 ) 151 Study on the Influence of Construction Methods of Internal Structures on Longitudinal Mechanical Characteristics of Shield Tunnels LIU Xiaohui1 FENG Kun1 GUO Wenqi1 LU Xuanyi1 PENG Changsheng2 LI Jiaoyang2 To study the longitudinal mechanical properties of shield tunnels with prefabricated assembly + cast-inplace internal structures and fully cast-in-place internal structures under overloading conditions, the Jinan Jiluo Road Yellow River Crossing Tunnel and Wuhan Sanyang Road Tunnel were taken as engineering backgrounds. A three-dimensional numerical model of the surrounding rock-segment-internal structure was established using ABAQUS finite element software, and the rationalityof the numerical model was verified through similar model tests.Comparative analysis of the deformation and mechanical characteristics of the segments and internal structures under different construction methods was conducted. Based on the damage distribution of the internal structures, optimization ideas for connections between components were proposed. The results show that the internal forces borne by the prefabricated assembly+ cast-in-place internal structure are smaller than those of the fully cast-in-place structure. The bending moment and shear force borne by the segments are greater, resulting in larger openings and dislocations compared to the fully cast-in-place structure, with the difference in openings being particularly significant, 10.02%~21.64% higher than the fully cast-in-place structure. Furthermore, the prefabricated assembly +cast-in-place internal structure is more prone to local damage due to stress concentration. When the internal structure experiences large-scale damage, the positive bending moment borne by the loading area decreases, while the negative bending moment borne by the undamaged area at both ends increases, reducing the bending stiffness of the structure and increasing the bending moments and inter-ring openings of the segments. 2024 Vol. 61 (4): 151-160 [Abstract] ( 178 ) [HTML 1KB] [ PDF 6432KB] ( 478 ) 161 Study on the Deformation Law of Large-diameter Fully Prefabricated Assembled Shield Tunnels under Ground Surcharge ZHU Meiheng1 CHEN Sirui2 HUANG Zhongkai2 LI Yongbo1 ZHANG Wuyu3 ZHANG Dongmei2 To meet structural design requirements, a certain deformation space is reserved between the mid-parti? tion wall and the segment lining in large-diameter fully prefabricated assembled shield tunnels. However, during the operation period, the segments and mid-partition wall of the tunnel may come into contact under the ground surcharge conditions, changing the stress modes of the tunnel structure and posing significant challenges to the safe operation and maintenance of the tunnel structure. In view of this, based on the Shanghai Airport Link Line Tunnel project,a three-dimensional refined finite element analysis model of a large-diameter fully prefabricated assembled shield tunnel was established to analyze the cooperative load bearing and deformation law of the segments and mid-partition wall under the ground surcharge conditions. The study shows that under the ground surcharge conditions, the segments and mid-partition wall of the large-diameter fully prefabricated assembled shield tunnel will come into contact, which will improve the stiffness and bearing capacity of the tunnel structure, but the surcharge can cause damage to the segments and internal components of the tunnel. The bottom of the plate of the arc component, the top of the column cap of the arc component, the outer side of column cap of the arc component, and the bottom of the mid-partition wall are all in a tensile state and are the vulnerable nodes. The damage and failure modes of the tunnel structure are affected by the reserved gap at the top of the mid-partition wall. To improve the bearing capacity of the tunnel, it is recommended to control the gap at the top of the mid-partition wall at about 90 mm. 2024 Vol. 61 (4): 161-171 [Abstract] ( 174 ) [HTML 1KB] [ PDF 6693KB] ( 580 ) 172 Analysis of the Impact of Connecting Bolts on the Vibration Response of Shield Tunnels WANG Zhiyuan1 YANG Hao2 LIN Gang1 LIAN Zhengzhou2 YU Bo1 To study the impact of bolt failure on the dynamic response of a shield tunnel to train loads and to clarify the action of linings under bolt failure, a three-dimensional refined numerical model was established based on a domestic shield tunnel project. The explicit dynamic time-history method was used to calculate and analyze the tunnel's dynamic response. The results show that: (1) Under train vibration load, the failure of segment bolts increases the peak acceleration of the tunnel's internal structure by 29.4% and the segment peak acceleration by 64.8%, indicating that bolt failure reduces the stiffness of the tunnel lining structure, thereby exacerbating the tunnel structure's dynamic response. (2) When bolts fail, the peak acceleration of the internal structure of a double-layer lining tunnel is 13.3% lower than that of a single-layer lining tunnel, and the peak acceleration of the segments is 54.1% lower, indicating that the double-layer lining shield tunnel has a weaker dynamic response under train vibration load. This shows that secondary lining can buffer the impact force of trains on the tunnel structure. (3) Under train load, the maximum peak acceleration of segments is 17.2% of the peak acceleration of the internal structure, indicating that the train load is mainly borne by the internal structure. (4) Bolt failure has almost no impact on the peak stress and displacement at the connection between segments and the internal structure, suggesting that stress and displacement at the connection point under train load are not sensitive to bolt failure. (5) The application of secondary lining reduces the peak acceleration at the connection between segments and the internal structure by 57.1%, displacement by 22.2%, and maximum principal stress by 21.4%, indicating that secondary lining can reduce the dynamic response at the connection under train load, protecting the tunnel structure. 2024 Vol. 61 (4): 172-179 [Abstract] ( 144 ) [HTML 1KB] [ PDF 4639KB] ( 563 ) 180 Study on Multi-factors Affecting Construction Ventilation in Hydraulic Tunnels with Gas in Tingzikou Irrigation Area SU Peidong LU Xinghao LI Yougui QIU Peng AN Xingling Based on the typical tunnels with gas in the Tingzikou irrigation area, the ventilation effect in tunnels with gas was simulated based on CFD software, obtaining the ventilation flow field and gas concentration distribution field. By controlling the distance between the air pipe outlet and the working face, the diameter of the air pipe, the air velocity at the outlet, the distance from the wall, and the angle of air pipe arrangement, the gas distribution law inside the tunnel was studied. The results show that: (1) Both the increase in the diameter of the air pipe and the air velocity at outlet can effectively dilute the gas accumulated at the working face, reducing the maximum gas concentration in the tunnel. However, if the air velocity is too high, the improvement in the dilution effect is limited. (2) As the distance between the air pipe outlet and the working face increases, the maximum gas mass fraction in the tunnel decreases first and then increases. As the distance from the wall increases, the maximum gas mass fraction in the tunnel shows an overall upward increase trend. (3) At a 75°angle between the air pipe and the horizontal plane it is most conducive to gas dilution, while a horizontal installation of air pipe is least favorable. The angle of the air pipe arrangement has the relative smallest impact on the gas concentration in the tunnel. (4) Considering the composite influence of multiple factors, under the factors and levels of this orthogonal test, the distance from the wall has the greatest impact on the ventilation effect in the tunnel, followed by the distance between the outlet and the working face, and the least is the air velocity at the outlet. 2024 Vol. 61 (4): 180-191 [Abstract] ( 146 ) [HTML 1KB] [ PDF 6214KB] ( 437 ) 192 Study on the Influence of Slurry and Rock Muck Characteristics on Rock Muck Discharge from the Air Cushion Chamber of Slurry Balance Shield Machine YU Wenduan1 DING Wantao2 WANG Chengzhen1 SUN Tengyun1 GUO Chentao1 WANG Zhicheng1 The rapid discharge of rock mucks from the air cushion chamber of a slurry balance shield machine is crucial for ensuring construction safety and improving tunneling efficiency. To explore the impact of different slurry and rock muck characteristics on rock muck discharge, a numerical calculation model that can fully reflect the discharge of rock mucks form the air cushion chamber was established based on the CFD-DEM coupling method and actual project. The study investigates the discharge patterns of rock mucks with varying bentonite content in the slurry,rock muck diameter (d), and shape factor (Sf), and analyzes the degrees of influence of these factors. The results show that as the bentonite content in the slurry increases from 8% to 16%, the rock muck discharge rate increases from 10.0% to 21.9%. Larger diameter rock mucks are more difficult to discharge; as the diameter increases from20 mm to 40 mm, the discharge rate decreases from 14.4% to 7.9%, attributed to the higher slurry flow velocity required to start movement of larger rock mucks. The rolling tendency of rock mucks decreases as the shape factor decreases, thus rock mucks with smaller shape factors cannot be directly discharged by rolling mode. When the shape factor decreases from 1 to 0.6, the discharge rate drops by about 59.5%. The research results can provide guidance for assessing the discharge efficiency of rock mucks during slurry shield construction. 2024 Vol. 61 (4): 192-201 [Abstract] ( 139 ) [HTML 1KB] [ PDF 6813KB] ( 537 ) 202 Study on Configuration Method and Physical-mechanical Properties of Similar Materials for Visual Soft Soil Tunnel Model Test HE Shengya1 LI Liang1 LI Hengyi1 ZHANG Jianjing2 YE Liang1 WEN Haijia3 DUAN Huchen? XIE Peng? Visual model tests are an effective means to clarify the triggering mechanisms of chain accidents induced by soft soil tunnel excavation, and reasonably proportioned similar materials are key to ensuring the reliability of model tests. Transparent similar materials of soft soil were configured using n-dodecane, 15# white oil, fused silica sand, and nano-scale white carbon black. Through density and oil content tests, standard consolidation tests, and consolidated quick shear tests, the mechanical and deformation characteristics of the configured materials were analyzed.The results show that the density of similar materials ranges between 1.30 g/cm3 and 1.59 g/cm3, the oil content between 36.13% and 124.71%, the initial void ratio between 0.70 and 2.34, the compression coefficient between 0.09MPa-1 and 1.04 MPa-1 , the compression modulus between 0.96 MPa and 20.11 MPa, the cohesion between 2.3 kPa and 31 kPa, and the internal friction angle between 14.82° and 27.07°, being similar to natural soft soil. The e-p curves of the samples exhibit a clear "concave upward" shape, and the e-lgp curves show an approximately linear downward trend. The consolidation coefficients of samples for each mix group range between 7.87×10-4 cm2/s and 2.02×10-2 cm2/s, being consistent with the value ranges for natural soft soil. The normalized shear stress-shear displacement curves of the transparent soft soils are identical to those of natural soft soil, both showing the strain hardening characteristics. 2024 Vol. 61 (4): 202-209 [Abstract] ( 136 ) [HTML 1KB] [ PDF 3740KB] ( 504 ) 210 Study on Response Characteristics of the Tunnel Structure under Dislocation of Strike-slip Faults with Multiple Fracture Surfaces PAN Xiaohai1 SHEN Yusheng1 WANG Haokang1 WANG Yanyan1 ZHANG Xinyang1 ZHANG Xi1 ZUO Leibin2 The rock mass dislocation in the large active strike-slip fault fracture zone exhibits significant nonlinear characteristics, resulting in varying failure features of rock and soil masses in different areas of the fault zone. This makes the deformation and stress of tunnel structure crossing fault zones increasingly complex. This paper, based on a tunnel project crossing a large strike-slip fault, uses model tests and numerical simulations to obtain the longitudinal distribution patterns of tunnel structure responses when crossing faults with multiple fracture surfaces. The results show that with the increase in fault dislocation, the horizontal displacement of the tunnel continuously increases,showing an S-shaped deformation pattern, with dislocation-induced deformation mainly occurring in the fault zone. Under strike-slip fault dislocation, the compression is more pronounced between the reverse bending concave section of longitudinal deformation curve of the tunnel arch waist and the surrounding rock, while the convex section has a tendency to detach from the surrounding rock. The stress-induced failure of the tunnel structure is mainly concentrated near the two fault dislocation surfaces, with the tunnel structure in the upper wall being more prone to failure compared to the lower wall. 2024 Vol. 61 (4): 210-220 [Abstract] ( 142 ) [HTML 1KB] [ PDF 7564KB] ( 602 ) 221 Analysis of the Composition and Concentration of Particulate Matters in Chengdu Operational Metro Running Tunnels ZHAO Shulei1,2 ZHANG Ke3 DONG Chen? CHEN Zheng1,2 GUO Chun1,2 During metro train operation, the pollutants generated in the running tunnels will be emitted into the at? mosphere through ventilation pavilions. To understand the concentration distribution, composition, and morphological characteristics of particulate matters in metro running tunnels, a study was conducted based on four typical metro stations in Chengdu, Sichuan Province. The laser dust detector was used for on-site testing of particulate matter concentrations at the piston wind pavilions of the four stations. Particulate matter samples were collected for scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis to determine their sources. Pearson correlation coefficients were used to analyze the relationship between the running tunnel and ambient environmental conditions. The results show that the particulate matters generated by the train passing through metro running tunnels are mostly spherical or angular and so on, with elemental contents mainly consisting of metals such as Fe, Al, Ba, and Zn. These particles primarily originate from mechanical wear and friction at the interfaces between tracks and wheels, brakes, and the contact points between the pantograph and catenary during metro train operation. The concentration of PM10 is much higher than that of PM1 and PM2.5, with no significant correlation between the concentrations of particulate matters with different particle sizes. The particulate matter concentration in metro running tunnels is significantly influenced by the season, with PM2.5 and PM10 levels higher in winter than in other seasons,and PM10 emissions exceeding the standard limits. The Pearson correlation coefficients r for PM indicators at the four stations are all greater than 0.8, indicating a high linear correlation between the pollutant concentrations at the ventilation pavilions and the air pollution levels in surrounding environment. 2024 Vol. 61 (4): 221-231 [Abstract] ( 146 ) [HTML 1KB] [ PDF 6732KB] ( 496 ) 232 On Segmenting Design Method of Prefabricated Assembled Secondary Lining for High-speed Railway Tunnels Based on Cross-section Geometric Parameters ZHOU Xiaojun Based on the technical indicators of the construction clearance and inner lining profile for single-tube double-track high-speed railway tunnels with design speeds of 300-350 km/h, a design method for segmenting prefabricated assembled secondary lining blocks in drill and blast tunnels is analyzed and proposed. Calculation formulas for determining the geometric parameters of prefabricated assembled secondary lining blocks are presented and verified with examples. Additionally, the assembly methods of prefabricated secondary lining blocks with straight joint and staggered joint high-speed railway tunnels are proposed. 2024 Vol. 61 (4): 232-243 [Abstract] ( 158 ) [HTML 1KB] [ PDF 6102KB] ( 411 ) 244 Construction Challenges and Key Construction Technologies for Large-diameter River-crossing Shield Tunnels in Complex Strata: A Case Study of the Running Tunnel Section between Guobo Center South Station and Lingwu Village Station of the Wuhan Metro Line 12 CHEN Haiyong1,2 ZHENG Xiaoyue1 SHI Chenghua1 SHI Yuan3 SUN Yingjie1 HU Junshan3 WANG Zuxian1 Addressing the construction challenges of large-diameter slurry balance shield tunnels passing through complex strata such as highly cohesive soil, breccia, and gravel, this paper presents targeted solutions in terms of shield equipment selection, equipment modification, and excavation control based on the river-crossing running tunnel between Guobo Center South Station and Lingwu Village Station of the Wuhan Metro Line 12. Field application results demonstrate that through increasing the cutterhead opening ratio, designing an inverted cone shaped central cutterhead area, and implementing multiple combined high-flow flushing, it can effectively solve the issue of cutterhead mud-caking in highly cohesive strata. And through multi measures, such as the targeted cutting tool configuration, lengthening of the mixing arm in the slurry chamber, and the addition of wear detection system, the slurry balance shield smoothly passed through breccia strata, improving the average penetration rate in this strata by approximately 247% after equipment modification. Furthermore, through adding a quarry box and an interactive duplex screening pipeline system, it effectively addressed the problem of pump blocking by large gravel blocks, ensuring continuous excavation in gravel strata. These targeted equipment modifications and construction measures significantly improved tunnelling efficiency, geological adaptability, and project safety during the construction of the running tunnel section between Guobo Central South Station and Lingwu Village Station of Wuhan Metro Line 12. 2024 Vol. 61 (4): 244-254 [Abstract] ( 145 ) [HTML 1KB] [ PDF 6139KB] ( 679 ) 255 Study on Grouting Technology for Water Gushing in Sandy Dolomite Stratum with High Water Level YANG Fan1 HE Fusheng1 YAN Qixiang3 LI Weidong2 CHEN Jian2 ZHAO Zechang3 Sandy dolomite is characterized by developed joints and fractures. When the groundwater level is above the tunnel crown and the fractures and joints are densely developed, abundant groundwater can change its flow direction under the influence of hydraulic head, accumulating towards the tunnel excavation face and causing water gushing. To reduce construction risks and address the issue of unsatisfied grouting reinforcement quality, the study,based on the Central Yunnan Water Diversion Project, employs field analysis, numerical simulation, and engineering practice methods to investigate grouting parameters such as grouting pressure, grout mix ratio, and grouting thickness suitable for moderately sandy dolomite, as well as the corresponding construction techniques. The results indicate that in sandy dolomite stratum the grouting length should be controlled within 20 m, the reinforcement range outside the excavation profile should be around 4 m, the final grouting pressure should be controlled within 12 MPa,the grout diffusion radius should be within 1.5 m, and the mix ratio of single-component grout and double-component grout should be 1∶1. As for the grouting process, it should use long and short pipe combined grouting technology to avoid grout backflow, increase grouting pressure, extend the length of grouting sections, accelerate construction progress, and improve grouting reinforcement quality. 2024 Vol. 61 (4): 255-265 [Abstract] ( 151 ) [HTML 1KB] [ PDF 6921KB] ( 1097 ) 266 Analysis of Cracking Characteristics and Causes of Tunnel Secondary Lining in Interbedded Soft and Hard Rocks DENG Feng1 ZHANG Yonghui2 SUN Zhiyuan1 HU Zhiping2 XIAO Jiyong1 WANG Yongliang1 Cracking in the secondary lining are frequently observed during construction of tunnels in interbedded soft and hard rocks. Based on the Yongfeng Tunnel on G544 line under construction, this study analyzes the characteristics and causes of secondary lining cracks through on-site testing, mechanical tests, and theoretical analysis.The research results indicate that the secondary lining of the previously excavated tunnel (right tunnel tube) has more cracks than the subsequently excavated tunnel (left tunnel tube), with an asymmetrical distribution mainly concentrated in the right sidewall and part of the arch waist, predominantly presenting as circumferential cracks. The main reason for secondary lining cracks is the uncoordinated deformation between tilted soft and hard rock layers caused by tunnel excavation under high geostress conditions, resulting in the support structure bearing significant surrounding rock pressure and causing cracks in the secondary lining with design defects. The anisotropy of surrounding rock strength and the uneven distribution of groundwater lead to an uneven distribution of secondary lining cracks. The different excavation sequences of the left and right tunnel tubes result in varying degrees of cracking in each tunnel tube. 2024 Vol. 61 (4): 266-274 [Abstract] ( 136 ) [HTML 1KB] [ PDF 7190KB] ( 571 ) 275 Research and Development of Intelligent Assembly Equipment for Prefabricated Mid-partition Walls with Large Slenderness Ratios CAI Guangyuan1 TANG Zeren2 CHEN Chen3 ZHU Yuanchang2 YU Pengchen3 LIU Xian2 Addressing the technical challenges in the assembly construction of prefabricated mid-partition walls with large slenderness ratios for the Shanghai Airport Link Line shield tunnel, this paper first elucidates the structural characteristics of the prefabricated mid-partition walls and proposes the development concept of intelligent assembly equipment for the prefabricated mid-partition walls. The detailed structures of the assembly equipment are thoroughly introduced. Subsequently, the paper analyzes the posture control of the mid-partition walls and proposes posture control indicators. Finally, the developed equipment is used for the assembly construction of the prefabricated walls,and the corresponding construction methods are summarized. The results indicate that the developed assembly equipment can realize functions such as grabbing, flipping, and fine-tuning of the mid-partition walls, meeting assembly requirements under extreme conditions with good construction results, providing a reference for future similar projects. 2024 Vol. 61 (4): 275-282 [Abstract] ( 123 ) [HTML 1KB] [ PDF 6793KB] ( 502 ) 283 Study on the Influence of Mineral Compositions of Weathered Rock Mucks on the Performance of Backfill Grouting in Shield Tunnelling ZHAO Xiaopeng1 LI Zhen2,3 YUAN Rui2,3 LI Pengfei2,3 MIN Fanlu2,3 ZHANG Lei1 The mineral compositions of rock mucks generated in shield tunnelling in weathered rocks are complex, and its impact on grout performance is not well understood. Based on the Nanjing Heyan Road River Crossing Project,different mineral powders were used to replace fine particles (<75 μm) in the rock mucks. The basic performance of rock muck-hard grout, prepared by replacing commercial sand with weathered rock muck, was tested. Microscopic tests such as XRD and SEM were conducted to explore the mechanism by which the mineral compositions of fine particles in rock muck affects grout performance. The results show that the quartz has almost no impact on grout fluidity and consistency. The addition of kaolinite significantly reduces grout fluidity and consistency. When commercial sand is completely replaced by kaolinite-rock muck, the initial fluidity loss of the grout is about 31%, and the consistency decreases by 48%. The kaolinite content is the main factor affecting grout fluidity. Kaolinite can promote the formation of C-S-H gel and ettringite, shorten the grout setting time by an average of 23.6%. The produced C-S-H gel intertwines and bonds, fills into pores and increases grout strength. However, excessive kaolinite content will result in the formation of excess ettringite, which will cover the cement surface and prevent further hydration, thereby reducing grout compressive strength. 2024 Vol. 61 (4): 283-290 [Abstract] ( 168 ) [HTML 1KB] [ PDF 4538KB] ( 553 )

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