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Quick Search     Advanced Search MODERN TUNNELLING TECHNOLOGY   2023 Vol.60 Issue.5 Published 2023-10-25 1 Study on the Influence Law of Structural Design Parameters of the Railway Tunnel on Secondary Lining Cracks ZHU Xingyu LIU Zheng ZHANG Zhiqiang FENG Ying Statistical analysis is conducted on the distribution of cracks in the secondary lining of the Anding Tunnel of the Yuxi-Mohan Railway, and a simulation method closer to the actual load is proposed to study the development law and control factors of cracks in the secondary lining. Orthogonal test is conducted to study the lining cracks under three levels of four factors (concrete strength grade, lining thickness, steel bar diameter, and protective layer thickness).The results indicate that the distribution of cracks in the lining on site shows that the cracks are mainly distributed at the arch foot and arch hance, secondarily at the crown, with fewer cracks at the spandrel, and the longitudinal cracks account for 63% and 18% and 19% for circumferential and slanting cracks, respectively. The occurrence order of damage to various parts of the lining is arch foot, crown, arch hance, and spandrel, while their degrees of crack development are sorted as follows: arch foot>arch hance>crown>spandrel. The influence degrees of secondary lining structural parameters on the width of arch foot crack are sorted as follows: concrete strength grade>protective layer thickness>lining thickness>steel bar diameter. As the factor level increases, the influence of concrete strength grade,lining thickness, and steel bar diameter gradually decreases, while the influence trend of lining thickness is opposite. 2023 Vol. 60 (5): 1-10 [Abstract] ( 340 ) [HTML 1KB] [ PDF 6141KB] ( 857 ) 11 Study on Multi-mode Conversion and Energy Saving of Ventilation in Super-long Highway Tunnel Operation ZENG Yanhua1,2 ZHAO Dongxu1,2 TU Yulong1,2 TAO Lianglinag1,2 To reduce the energy consumption of the ventilation system for complex operation of multi-vertical (in? clined) shafts, the multi-mode conversion system for ventilation is applied to the segmented longitudinal ventilation of super-long highway tunnels. In this study, based on the theory of wind pressure balance of the circuit and ventilation network in the tunnel, the following design process is proposed: preliminary drafting of tunnel ventilation mode,calculation of maximum traffic bearing capacity, selection of dynamic ventilation mode, determination of jet fan number, and comparison and optimization of ventilation energy consumption. In addition, the operation mode of the multi-mode ventilation conversion system is investigated, and the operation energy consumption is compared and analyzed between the conventional segmented longitudinal ventilation mode and the multi-mode conversion ventilation mode. The results show that when the peak hour traffic volume in the long-term design of the tunnel reaches the maximum value of 3,137 veh/h, 29 sets of jet fans need to be started, and at this time, the wind speed in each section of the tunnel is less than 8 m/s. Mode 1 can meet the ventilation requirements in 31.25% of the time in a day, and only Mode 4 can meet the ventilation requirements in 52.08% of a day, and the total power is reduced by 20.71% for the multi-mode conversion ventilation compared with the ventilation relied only on Mode 4. When the traffic volume is less than 1,726 veh/h, the exhaust air volume of the 3# vertical shaft can be reduced to 93 m3/s, and the total power of fans in the tunnel can be reduced by 37.57%. 2023 Vol. 60 (5): 11-19 [Abstract] ( 261 ) [HTML 1KB] [ PDF 4721KB] ( 693 ) 20 Adaptability Evaluation on Gas Drainage of Tunnels in Non-Coal Measure Strata ZHANG Junwei1,2 GAO Xia1 WANG Haoquan1 In order to evaluate whether tunnel gas in the non-coal measure strata can be depressurized and emitted through the gas drainage means, a gas tunnel in the non-coal measure strata is taken as the research caset. Based on the characteristics of the gas tunnel in non-coal measure strata, a comprehensive evaluation method with fuzzy mathematics is used to establish an adaptability evaluation model for tunnel gas drainage in the non-coal measure strata. An adaptability evaluation system is established for gas drainage in non-coal measure strata tunnels from three aspects:gas occurrence control factors, feasibility control factors for gas drainage and drilling stability control factors. Ten basic factors are selected as evaluation indicators. The product scale method based on the Analytic Hierarchy Process is used to calculate the weights of evaluation indicators. A membership function that can quantitatively characterize the membership degree of each evaluation indicator factor is constructed.and Class I and Class Ⅱfuzzy comprehensive evaluation models are establish. This can assign corresponding scores to each remark in the evaluation vector,and achieve uniformization of the evaluation vector, thus determing the gas drainage adaptability in tunnels in the non-coal measure strata, and conducting verification and analysis in combination with instances. The results show that the adaptability of the full-section advance gas drainage in the high gas content section of the Mazui Tunnel on the Nanchuan-Daozhen Expressway is Class B (relatively adaptive), and theoretical and practical response measures are in good agreement. 2023 Vol. 60 (5): 20-29 [Abstract] ( 241 ) [HTML 1KB] [ PDF 2780KB] ( 548 ) 30 Study on Variation of Driver′s Field of View Contrast in Tunnel Light Environment and Its Influence on Driving Safety ZHANG Yue1 HE Shiyong1,2,3 SUN Yuanyi1 WANG Rongbin3 TANG Ransong4 LIANG Bo1,2 In order to reveal the variation law of the driver's field of view contrast under the tunnel lighting environment and its influence on driving safety, 17 drivers are selected for real vehicle test. Eye movement data of the drivers during driving in the tunnel is recorded with eye trackers, and then the luminance data of the tunnel lighting environment along the line are collected using imaging-type luminance meters. The fixed point fusion analysis of the fixation point image position and the distribution parameters of the lighting environment are performed. Finally, a mathematical model is used to further quantify the relationship between field of view contrast and each eye movement indicator, so as to further understand the influence of changes in driver's field of view contrast on driving safety. The results show that in the entrance and exit section of the tunnel, the contrast of the driver's field of view is relatively high, and its dynamic change is more obvious. The corresponding change rate of the driver's pupil diameter will also be greater, and the glance time will be longer. For most tunnel lighting environments, as the contrast of the field of view increases within a specific interval, the change rate of pupil diameter rises and the glance time is extended.When the contrast of the field of view exceeds a certain value, the change rate of pupil diameter and the glance time decrease on the contrary. 2023 Vol. 60 (5): 30-39 [Abstract] ( 273 ) [HTML 1KB] [ PDF 5478KB] ( 526 ) 40 Research on Factors Influencing the Resilience of the Tunnel System and Related Evaluation WENG Yuan1 LI Aichun1 ZHAO Ting1 LIU Buwu2 In order to solve the problems of frequently occurred geological hazards, difficulty in rescue and posthazard repair in tunnel engineering, the resilience theory is introduced into the safety system of the tunnel engineering system, and a DEMATEL-BN based tunnel engineering system resilience evaluation model is proposed. Twentytwo influence factors are initially identified from five aspects: human, machine, material, method and environment.Influence factors with low correlation are eliminated through DEMATEL and a Bayesian network topology diagram is constructed; the system resilience value is calculated by forward reasoning in combination with the Bayesian networks and the GeNIe software; key influence chains and sensitive factors are identified by reverse reasoning and sensitivity analysis; finally, an empirical study is conducted using the Bingcaowan Tunnel as an example. The results show that the Bingcaowan Tunnel has a medium to high level of resilience, with a key influence chain of "emergency rescue drills → emergency decision-making and response → recovery ability", and sensitive factors of "complex geological conditions, safe and civilized construction, emergency decision-making and response". Finally, phased improvement suggestions are proposed based on analysis. 2023 Vol. 60 (5): 40-47 [Abstract] ( 287 ) [HTML 1KB] [ PDF 4322KB] ( 625 ) 48 Shield Attitude Optimization and Control Based on Random Forest-NSGA-Ⅲ WU Zhongtan1 WU Xianguo2 LIU Jun2 CHEN Hongyu3 XIAO Hongdi2,4 QIN Yawei2,4 In order to realize attitude control of the shield tunnelling machine and ensure safety and quality of tunnel construction, in this study, a hybrid intelligent framework incorporating random forest (RF) and non-dominant sorting genetic algorithm-Ⅲ(NSGA-Ⅲ) is proposed. Based on the Wuhan Metro project, 17 influencing factors are selected as input variables, and the nonlinear mapping function relationship between input parameters and shield attitude is established by the RF algorithm, which is used as the fitness function of NSGA-Ⅲ, and then the key influencing factors are determined by the RF algorithm. A multi-objective intelligent optimization model of RF-NSGA-Ⅲ is established to minimize the absolute value of shield attitude parameter. Based on the proposed optimization principle, case study is conducted to test the applicability and effectiveness of the proposed method. The results show that the prediction model obtained by training and simulating measured engineering data using the RF algorithm has high accuracy. With the developed RF-NSGA-Ⅲ intelligent algorithm, a remarkable optimization and control effect of shield attitude is obtained. 2023 Vol. 60 (5): 48-57 [Abstract] ( 309 ) [HTML 1KB] [ PDF 4440KB] ( 542 ) 58 Study on Automatic Identification and Real-time Measurement Technology for Tunnel Surrounding Rock Settlement Based on Improved YOLOv5 HAO Yijie1 LI Gang2 SHEN Dan3 DENG Youwei1 LIU Yiyang1 In response to the complex internal environment of the tunnel and the difficulty in monitoring surrounding rock settlement during construction, an improved YOLOv5 algorithm for automatic identification and measurement of tunnel surrounding rock settlement is proposed. The observation targets are installed at key locations of tunnel construction, and industrial cameras are used to shoot the targets in real-time, and then the target detection model is used to automatically identify the targets. The settlement of surrounding rock is indirectly measured by calculating the settlement of the targets. Based on the YOLOv5s network model, an ECA-Net channel attention mechanism is introduced to enable the network to focus on the target to be detected in channel aspect, in order to avoid the channel dimension reduction and enhance its perception ability for the target. The use of an improved α-IoU target regression loss function has improved the learning ability of the model for image features and target detection accuracy on the whole. The experimental results show that the improved target detection model achieves recognition accuracy and recall rate of 98.5% and 98.4% respectively under the industrial camera shooting target dataset, with high detec? tion accuracy. By analyzing the error, it can be seen that the absolute error is within 6 mm when shooting at a distance of 0~10 meters. When shooting at a distance of 15~25 meters from the target to be tested, the absolute error is within 15 mm, which is relatively small. 2023 Vol. 60 (5): 58-66 [Abstract] ( 328 ) [HTML 1KB] [ PDF 4448KB] ( 588 ) 67 Research on Transverse Seismic Resistance of Compound System of Segments and Internal Structure of a Super-large Diameter Double-layer Highway Shield Tunnel XUE Guangqiao1,2 XIAO Mingqing1,2 FENG Kun3 WANG Shaofeng1,2 XUE Haoyun3 GUO Wenqi3 To study the influence of the internal structure of a double-layer highway shield tunnel on the transverse seismic resistance of the tunnel, the three-dimensional refined finite element models of the double-layer highway shield tunnels with and without an upper layer plate applied are established based on a super-large diameter doublelayer highway tunnel project. The implicit dynamic time history method is used to study the transverse seismic resistance of the compound system of segments and internal structure of the shield tunnel. The results show that: (1) the internal structure of a double-layer highway tunnel can increase the transverse stiffness of the tunnel, reduce tunnel deformation, and the internal structure with the upper layer plate applied can cause a more significant increase in transverse stiffness; (2) The internal structure can reduce the local peak bending moment and the peak axial force of the tunnel, with the axial force reduced by 732.16 kN (max.) at the arch foot and with the bending moment reduced by 723.59 kN·m (max.) at the spandrel, arch foot and hance; (3) When the upper layer plate is applied in the internal structure, the damage to the segment decreases slightly, while the damage to the internal structure increases. When the upper layer plate is not applied, new damage appears on the outer side of the segment at the hance. Considering that the internal structure is not the main load-bearing structure, the post-earthquake repairability of the tunnel with the upper layer plate is better than that of the tunnel without the upper layer plate; (4) The application of the upper layer plate in the internal structure is superior to the internal structure without the upper layer plate in reducing deformation, stress and internal force of the tunnel. However, the damage to the internal structure increases after the application of the upper layer plate. It is recommended to take corresponding strengthening measures. 2023 Vol. 60 (5): 67-77 [Abstract] ( 329 ) [HTML 1KB] [ PDF 5989KB] ( 690 ) 78 Improved Integral Response Displacement Method for Shallow-buried Tunnel Portal Section in Highly Seismic Regions SHEN Yusheng1,2 ZHAO Helin1 ZHU Zhengchao1 YI Penghao1 LEI Long3 SU Wei3 In order to improve the seismic performance of the tunnel portal structure under strong earthquakes, based on a pipeline tunnel project in a high-intensity seismic area, the error influencing factors of the integral response displacement method in seismic calculation of the tunnel portal section are studied. The structural displacement amplification coefficient is introduced, and an improved integral response displacement method suitable for structural seismic calculation of the tunnel portal is proposed. Furthermore, the improved calculation method is verified based on case analysis. The results show that the error in the seismic calculation of the tunnel portal section using the integral response displacement method is mainly caused by the relative displacement between the top and the bottom of the tunnel at the tunnel portal section, and it can be corrected by introducing a structural displacement amplification coefficient. The structural displacement amplification coefficient is positively correlated with the front slope angle of the tunnel portal and the seismic intensity, but negatively correlated with the slope height and relative burial depth. The deviation of amplification coefficient in different levels of surrounding rock is less than 10%, and the influence of surrounding rock conditions on it can be ignored. The error of the improved integral response displacement method under 0.6g seismic motion is basically less than 10%, which has higher accuracy than the integral response displacement method and can be applied to seismic calculation of the tunnel portal section. 2023 Vol. 60 (5): 78-87 [Abstract] ( 325 ) [HTML 1KB] [ PDF 4984KB] ( 495 ) 88 Study on Support Characteristics of Super-large Section Tunnels in Unfavorable Geological Condition and Related Engineering Application YAO Zhixiong1, 2 ZHOU Qichuang1 ZHENG Guowen3 WU Bo4 FAN Lanxin1 QIN Haoyu1 Improper support for the construction of super-large section tunnels in weak and fractured ground is very likely to cause collapse and instability. Therefore, a thorough understanding of support characteristics and the selection of reasonable support parameters is the key to ensuring tunnel stability. In this study, based on the actual geological and environmental characteristics of a typical super-large section highway tunnel in Fujian province, four support schemes are designed. Through numerical simulation and on-site test, the mechanical characteristics of the surrounding rock, tunnel face and support structure under single advance support, double-layer advance support and only double-layer initial support are analyzed in depth, and the action mechanism of advance support is discussed, and furthermore a reasonable support scheme is proposed on this basis. The results show that under a single advance support (small pipes or pipe umbrella), the deformation of the surrounding rock can be reduced by 13% to 28%. Under double-layer advance support (pipe umbrella + small pipes or double layers of small pipes), the deformation of surrounding rock can be reduced by 51%~58%, and the stress state of the support can also be significantly improved. With the increasing strength of advance support, the deformation of surrounding rock significantly decreases, the reduction rate even exceeds 50% and a support effect of "1+1>2" is achieved, and the overall support effect of the pipe umbrella is slightly better than that of the small pipes. This conclusion is basically consistent with the on-site test result, verifying the rationality of the calculation method and the support plan. Based on the analysis results, a support plan for the tunnel section under-crossing the highway and other surrounding rock sections has been proposed. Practice has proven that the plan is feasible and has taken into account tunnel safety, economy of the support and rigidity matching 2023 Vol. 60 (5): 88-98 [Abstract] ( 237 ) [HTML 1KB] [ PDF 5874KB] ( 565 ) 99 Study on Vibration Influence of Layered Rock Mass Tunnel Blasting on Support System YU Jianxin LIU Wenjin WANG Jinxing LIU Huanchun ZHOU Zhibin In order to analyze the stability of surrounding rock under drilling and blasting excavation of layered rock mass tunnel, the dynamic response characteristics of the tunnel support system under different bedding angles are studied with the LS-DYNA numerical simulation method. The results show that : (1) When the bedding angle of surrounding rock is 60°, the peak vibration velocity along horizontal tangential direction of the vault at 25 m behind the tunnel face increases by 1.74 times. (2) The asymmetric vibration mechanism of particles is present at left and right hances and side walls under different bedding angles of surrounding rock. (3) The horizontal radial and vertical peak vibration velocities at left and right hances and side walls under different bedding angles show a U-shaped change trend with the increase of the distance from the tunnel face. (4) The asymmetric stress coefficients of lateral and vertical compressive stresses at the hance position show a significant turning point when the bedding angle of the surrounding rock is 60°, showing a trend of rapid increase at first and then rapid decrease. (5) As the bedding angle of surrounding rock layer changes from 0° to 90°, the peak dynamic tensile stress of the bolt shows a trend of increase at first and then decrease. The circumferential distribution of the peak dynamic tensile stress of the bolt shows inconsistency with the change of the bedding angle of surrounding rock. The on-site monitoring results show that the particle vibration law of the anchor support structure caused by tunnel blasting at a 30° bedding angle of surrounding rock is consistent with the research results. 2023 Vol. 60 (5): 99-110 [Abstract] ( 283 ) [HTML 1KB] [ PDF 8339KB] ( 564 ) 111 Study on Fire Smoke Spreading Characteristics in Asymmetric V-Slope Highway Tunnel LI Xiang1,2 CHEN Xiaofeng1,2，3 BA Weijun4 WANG Xiaofei5 YU Junxiang2 ZHENG Jun1,2 WU Ke1,2,3 Underwater tunnels are often high at both ends and low in the middle, showing the "V" shape, with high fire risk. Therefore, mastering the characteristics of fire smoke spreading is the basis of fire emergency response,evacuation and rescue work. The Fire Dynamics Simulation software (FDS) is used to build the asymmetric V-slope tunnel fire model under the condition of natural ventilation, to study the spreading process of fire smoke under different combination of slopes, and to analyze the changes of smoke pressure and velocity at the tunnel portal on both sides of the tunnel. The results show that: after a fire occurs at the slope change point, the smoke spreading in the asymmetric V-slope tunnel presents the multi-phase spreading characteristics similar to that in the single-slope tunnel,but the smoke spreading velocity on the high slope side is slower than that in the single slope tunnel, while the smoke spreading velocity on the low slope side is faster, and the steady back-flow length of fire smoke is shorter; In the process of smoke spreading in the asymmetric V-slope tunnel, there exist three characteristic stages: flow field remodeling, forward dynamic cycle reconstruction, and maintaining stability; The maximum back-flow length and the steady back-flow length of the tunnel smoke on the low slope side and their corresponding moments are jointly affected by the tunnel slope gradients on both sides and the gradient difference, and there is a critical gradient difference of 4%. When the gradient difference is greater than 4%, the characteristics of fire smoke spreading will no longer be affected by the gradient difference. 2023 Vol. 60 (5): 111-119 [Abstract] ( 264 ) [HTML 1KB] [ PDF 4442KB] ( 468 ) 120 Numerical Simulation of Suction-type Smoke Exhaust Strategy for Super-long Highway Tunnels with Parallel Pilot Tunnel WANG Fangchao1 LIU Hongsen1 CHEN Changkun2 JIAO Weibing2 In order to explore a new suction-type smoke exhaust mode using the parallel pilot tunnel as the smoke exhaust duct, a numerical model of a super-long tunnel with the parallel pilot tunnel is established to study smoke spread characteristics and temperature distribution law in the tunnel during smoke exhaust through the parallel pilot tunnel. The results indicate that the suction-type smoke exhaust using the parallel pilot tunnel can effectively suppress the spread of smoke in the main tunnel. At 100 seconds after the fire, there is basically no smoke in the main tunnel,and at 900 seconds, the smoke reaches a stable state, and it no longer spread to both sides of the main tunnel. As the smoke exhaust volume at both ends of the parallel pilot tunnel increases, the spread distance of smoke in the main tunnel gradually decreases when it becomes stable. When the total smoke exhaust volume at both ends of the parallel pilot tunnel is 600 m3/s, the smoke is completely controlled within the range of the three open smoke discharge ducts.When three cross passages are opened for smoke exhaust, the highest smoke temperature rise of the ceiling drops with the increase of smoke exhaust volume. When two cross passages are symmetrically opened for smoke exhaust,the maximum smoke temperature rise of the tunnel ceiling does not change significantly with the increase of smoke exhaust volume. In suction-type smoke exhaust using parallel pilot tunnel, the smoke temperature below the tunnel ceiling exhibits exponential decay, and the decay rate of smoke temperature is almost independent of the opening mode of the cross passage and the exhaust volume. 2023 Vol. 60 (5): 120-127 [Abstract] ( 270 ) [HTML 1KB] [ PDF 6394KB] ( 482 ) 128 Study on Detection Location of Average Gas Concentration in a Large Section Tunnel Based on Numerical Simulation - multiple Regression MIAO Huigui1 HUANG Fei1,2 LI Shuqing1,2 LUO Yafei1,2 MIAO Dehua1 JIAO Yangyang1 The imprecision of gas concentration detection in the large cross-section tunnel can lead to significant de? viation between the measured absolute gas emission quantity and the actual value, ultimately affecting the division of gas working areas in the tunnel and posing a huge challenge to tunnel construction safety and cost control. In this study, the computational fluid dynamics software Fluent is used to simulate the distribution law of gas inside the tunnel. The influence of section width (A), section height (B), and section wind speed (C) on the average gas concentration in the tunnel section is qualitatively analyzed through the orthogonal test method. Furthermore, multiple linear regression is used to determine the optimal detection location for the average gas concentration. The research has shown that under stable ventilation conditions, the gas inside the gas tunnel exhibits a stable distribution, and there will be obvious layered distribution from top to bottom on the tunnel cross-section. There are differences in primary and secondary sequence of the influence of section width (A), section height (B), and section wind speed (C) on the average gas concentration of tunnel sections under different gas working area conditions. Through quantitative multiple linear regression analysis, a calculation model for the average gas concentration detection location on the crosssection of stable laminar flow areas under different gas working area conditions is obtained. 2023 Vol. 60 (5): 128-135 [Abstract] ( 296 ) [HTML 1KB] [ PDF 3160KB] ( 514 ) 136 Research on Failure Mechanism of Tunnel with Articulated Lining Crossing Strike-slip Fault MA Yalina1,2 CHEN Yaqi1,2 LIU Jiguo1,2 CUI Zhen3 ZHOU Guangxin4 In this paper, the Xianglushan Tunnel for water conveyance is taken as the case, and small-scale physical model test and numerical simulation methods are used to study response characteristics, failure modes, and failure mechanisms of the articulated tunnel lining under the action of strike-slip fault movement. A comparative analysis was conducted on the internal failure characteristics, overall deformation, and detailed failure modes of tunnels with or without articulated design under the strike-slip fault dislocation. Meanwhile, the longitudinal displacement and stress variation trend of the lining structure, as well as the distribution law of longitudinal internal forces including bending moment and axial shear force, were systematically studied.And the failure mechanism of tunnels crossing strike-slip faults was revealed, and the anti-fault mechanism of articulated tunnels was analyzed. The research shows that: (1) under the movement of the strike-slip fault, the lining strain near the fault zone is relatively large,which is prone to yield failure; (2) The effect of fault movement causes longitudinal cracks to occur in the lining of the active side tunnel. As the movement size increases, the longitudinal cracks gradually evolve into annular cracks,causing upheaval failure of the lining, and at the same time the shape of the lining cross-section becomes elliptical;(3) The failure of articulated lining is mainly concentrated near the fault movement surface, manifested as large angle rotation between lining segments and compression-shear failure of deformation joints within the fault zone. 2023 Vol. 60 (5): 136-147 [Abstract] ( 285 ) [HTML 1KB] [ PDF 9752KB] ( 615 ) 148 Field Measurement and Analysis of Forces on Shield Tunnel Structure at Great Depth CHEN Long FENG Kun WU Baihan GUO Fukang WANG Wei In this study, based on the Dayuan Station - Taihe Station project of the East Ring Tunnel of the Guangfo Ring Line, field test of internal forces on the shield tunnel structure at great depth is performed to explore the change law of the internal forces on the segments during different phases of actual construction. By combining with numerical simulation, a comparative study is conducted on the error between the on-site measured values and simulated values of internal forces on the segments, and the main areas of segments where the internal forces are influenced by construction factors and the related causes are analyzed. The results show that during shield tunnelling, the maximum internal force of the segment occurs during the filling phase behind the wall after the detachment of 4-8 lining rings,and the minimum value occurs during the completion phase of segment assembly. After the detachment of 12 lining rings at the shield tail, the forces on the segment become basically stable. The measured values of internal forces in the segment are greater than the simulated values, and the distribution laws of measured and simulated bending moments are similar. There are certain differences in the distribution of their axial forces, and filling with bean gravel can make the actual axial force more evenly distributed along the circumferential direction. The maximum relative error between the measured value and the simulated value is about 40%, which occurs in the tunnel crown and bottom areas, while the relative error at the arch waist is relatively small. In construction of shield tunnel at great depth,main influencing factors on internal forces of the segment in filling behind the wall and during stabilization phase are filling of bean gravel and creep of surrounding rock. 2023 Vol. 60 (5): 148-157 [Abstract] ( 285 ) [HTML 1KB] [ PDF 7013KB] ( 560 ) 158 Monitoring Method for Multi-phase Crown Deformation of Highway Tunnels Based on Fixed-station Laser Scanning Data LUO Chao1 LI Zeyu1 LIU Rufei1 LI Yanyan1 LI Ming2 The laser point cloud data are characterized by high precision, high density and good adaptability. In this study, the laser point cloud technology is applied to the deformation monitoring for highway tunnels, and the study is conducted on the methods of continuous extraction, filtering and multi-phase deformation monitoring for highway tunnel cross sections based on fixed station laser scanning data. In order to ensure that observed cross sections with multi-phase deformation are in the same position, the scanner with fixed position is installed in the tunnel, and the 3D central axis and the registration algorithm are used to ensure the identity of multi-phase cross sections. A twostep iterative elliptic curve fitting method is proposed. In the first iteration, the point cloud of the sub-crown section of the tunnel crown is filtered based on the elliptical shape constraint, and in the second iteration, the filtered crown section is fitted with the elliptic curve using the iterative least square fitting algorithm. The multi-phase deformation of the section is monitored based on the fitting elliptic curve and the polar coordinate method. Compared with the traditional RANSAC method, the two two-step iterative elliptic curve fitting method shows better filtering effect and higher accuracy in extracting the tunnel elliptic curve. In this study, the tunnel model is built for deformation simulation and monitoring test, and the extracted multi-phase data are analyzed. The test results show that the proposed method is feasible in multi-phase deformation monitoring for highway tunnels, and the mean square error is less than 2 mm, which high accuracy. 2023 Vol. 60 (5): 158-166 [Abstract] ( 305 ) [HTML 1KB] [ PDF 4197KB] ( 509 ) 167 Test and Analysis in Support Application of Scalable Steel Arch Frame in Super-long Donggang Highway Tunnel ZHAO Jun1 DU Shiming2 WANG Yun3 XIA Lifeng2 WEI Xinjiang4 HAN Tongchun5 In response to the problems existing in conventional steel arches, the use of a steel arch with scalable joints is proposed, that is, adding scalable joints and supporting arms to the ordinary steel arch. The application test of scalable steel arch frame is conducted in the Donggangshan Super-Long Tunnel, and a comparative analysis is performed on deep displacement of surrounding rock, internal force of steel arch, surrounding rock pressure, and crown settlement of the scalable steel arch support section and the ordinary steel arch support section. The results show that the scalable joint steel arch frame provides timely support for the surrounding rock. Compared with the ordinary steel arch frame, it can more effectively constrain the deformation of surrounding rock. For the surrounding rock with large deformation, it can effectively limit the early development of the loose area of surrounding rock, and is suitable for support in weak and fractured surrounding rock areas. 2023 Vol. 60 (5): 167-176 [Abstract] ( 282 ) [HTML 1KB] [ PDF 7248KB] ( 505 ) 177 Study on Collaborative Fusion Method for Urban Tunnel Environmental Monitoring Data Based on Multi-sensor MI Chun LI Siying MOU Jiayi YUAN Xiaolong LI Tao In this study, in view of the problems existing in environmental monitoring of urban tunnels, such as im? perfect monitoring schemes, large amount of monitoring data and many factors affecting the data, a collaborative fusion method for tunnel environmental monitoring data based on multi-sensor is proposed to improve the accuracy of environmental monitoring. Firstly, the box plot method is used to detect the abnormal values in the environmental data, and the abnormal values are corrected with the mean substitution method, improving the accuracy of the data;Secondly, data fusion of homogeneous sensors is realized with the adaptive weighted average algorithm, reducing the system redundancy effectively; Finally, data fusion of heterogeneous sensors is realized based on the PSO-BP neural network algorithm. The results show that the accuracy of the BP neural network fusion model optimized by the PSO algorithm in judging the environmental grade of a tunnel is more than 80%, which is better than the traditional BP neural network. It is confirmed that the overall environmental quality of the tunnel can be evaluated more reliably with this method, which provides important decision information for the intelligent control of electromechanical facilities in the tunnel. 2023 Vol. 60 (5): 177-185 [Abstract] ( 344 ) [HTML 1KB] [ PDF 4220KB] ( 702 ) 186 Research on Ventilation Design for Construction of Super-large Diameter Slurry Shield Tunnel HU Weidong1,2 In this study, based on the ventilation design of a large diameter slurry shield tunnel under construction, the computational fluid dynamics software (ANSYS Fluent) is used to simulate and analyze the ventilation effect of tunnel construction. The accuracy of calculation results of the numerical simulation model is verified through onsite measurements, and the flow field distribution and the airflow movement law under ventilation conditions are summarized. A comparative study is conducted on the influence of three different ventilation parameters such as wind speed at the air duct outlet, air duct diameter, and position of air duct outlet, and an optimization plan for ventilation parameters is proposed. The results show that the wind speed distribution in the ventilation flow field of the tunnel exhibits the following characteristics: the wind speed on the return air side is generally larger than that on the inlet air side, and the wind speed on the upper part of the tunnel is generally less than that on the lower part. Increasing the wind speed at the outlet of the air duct is the most significant in improving the ventilation effect of tunnel construction; After adopting the optimized plan, the average wind speed at the tunnel center can be increased by about 59.3%, and the velocity of airflow in each working area can reach the construction ventilation standard of 0.15 m/s or above, which can economically and efficiently improve the ventilation effect in the working area of the shield section of the tunnel. 2023 Vol. 60 (5): 186-194 [Abstract] ( 286 ) [HTML 1KB] [ PDF 5100KB] ( 606 ) 195 Study on Precise Geophysical Prospecting and Processing Technique for Large-diameter Shield Tunnelling Through Coastal Boulder Strata LU Shaozhuang ZHAO Lu GUO Zhifeng In this study, based on the shield tunnel project underpassing the boulder section from Hengli Station to Wanqingsha Station along the southern line of Guangzhou Metro Line 18, the boulder prospecting and the preprocessing technology are studied. In this paper, a set of precise location and prospecting technologies are proposed, in which the HSP horizontal acoustic wave/seismic wave profile method and the virtual source method are jointly used to quickly detect the development range of boulder body, and the geological drilling method is used to determine vertical and transverse boundaries of the boulder. This reduces the geological drilling and prospecting work, and then the blasting of the boulder revealed by geological drilling is allowed. The results show that the proposed boulder prospecting method is advanced and reliable, and it is allowed to detect boulders in time, reduce the prospecting cost, and shorten the construction period; in this method, the design of blasting parameters are designed reasonably,and the boulder section is processed well; the average tunnelling speed in the boulder section after blasting along left and right lines is 34.63 mm/min, which is close to the average tunnelling speed in the conventional strata. 2023 Vol. 60 (5): 195-204 [Abstract] ( 263 ) [HTML 1KB] [ PDF 7534KB] ( 633 ) 205 Study on Influence of Shield Cabin Opening at Ordinary Pressure on Deformation of Existing Tunnel Structures in Mudstone Strata ZHOU Zhou1 ZHONG Changping2 XIE Wenda1 In order to study the influence of shield cabin opening at ordinary pressure on the structural deformation of the existing line when the slurry balance shield is under-passing the existing subway tunnel in the full-section weathered mudstone layer, the shield tunnel of Guangzhou Metro Line 14 underpassing the existing Line 3 subway tunnel is taken as a study case. The fluid-solid coupling calculation is carried out using the finite difference analysis software (FLAC 3D), and on-site monitoring data are combined to study the influence of underpassing process and shield cabin opening at atmospheric pressure on the deformation of existing line structures. The results indicate that the slurry balance shield is prone to the problem of mud cake forming on the cutterhead during tunneling in the full-section mudstone strata. Based on the simulation, both settlement and section deformation of the existing line,which are caused by shield cabin opening at ordinary pressure and cleaning of mud cakes after tunneling every day as per the construction plan, meet the control requirements. In actual construction, the method of shield cabin opening at ordinary pressure for cleaning mud cakes after daily tunneling has increased the average advancing speed by 41% compared to the method of continuously tunneling for multiple days and then cleaning mud cakes, greatly shortening the construction period. The shield cabin opening method at ordinary pressure can be used in the full-section weathered mudstone, and the settlement of the existing line structure caused by shield cabin opening process can be controlled at around -5 mm. 2023 Vol. 60 (5): 205-212 [Abstract] ( 269 ) [HTML 1KB] [ PDF 5537KB] ( 550 ) 213 Instability of Large Diameter Slurry Shield Tunnelling Attitude in Highly Viscous Clay Strata and Treatment Measures WANG Yanhui1 ZHOU Tianshun1 HU Junshan1 CHEN Haiyong2，3 SHI Chenghua2 PENG Yu1 WANG Zuxian2 In order to solve the problems of low tunnelling efficiency and difficulty in control of the shield attitude that may occur when the shield tunnelling machine operates in highly viscous clay strata, in this study, based on a cross-river tunnel project with a large diameter slurry shield tunneling machine and focused on the problems of abnormal excavation and attitude instability, the causes for attitude instability during tunnelling in highly viscous clay strata are discussed in combination with the tunnelling parameters and the changes of the strata within the tunnelling section, and corresponding treatment measures are proposed and implemented. The results show that: (1) the abnormal section of shield tunnelling coincides with the distribution of highly viscous clay strata, and the change in geological conditions is the fundamental cause for the attitude instability of shield tunnelling; (2) The actual frontal resistance of the cutterhead when the shield tunnelling machine operates in highly viscous strata is similar to the theoretical calculation results, while the actual frictional resistance between the shield housing and the strata is far higher than the theoretical value, and no guniting and water seepage occurs after opening the radial grouting holes on the shield housing, so it is inferred that the direct cause of the abnormal shield tunnelling and attitude instability of the shield machine is the continuous adhesion and accumulation of highly viscous clay particles on the outer surface of the shield housing to form dense clay inclusions, which changes the interaction state between the shield housing and the strata; (3) By drawing inspiration from the disposal measures of dispersant mud cake, the protocol that a dispersant is injected into the radial grouting holes on the shield housing is used to remove the clay inclusions outside the shield housing. The dispersant solution is selected through indoor clay dispersion tests; (4) After continuous in? jection of dispersant outside the shield housing for a period of time, the total thrust of the shield machine quickly decreases by about 30,000 kN with the continuous growth of the burial depth of the tunnel. As the shield tunnelling slows down, the shield attitude is continuously adjusted. After reopening the radial grouting holes on the shield housing, guniting occurs, indicating that the dispersant can effectively peel off the clay coverings on the outer surface of the shield housing. 2023 Vol. 60 (5): 213-223 [Abstract] ( 265 ) [HTML 1KB] [ PDF 8166KB] ( 595 ) 224 Key Technologies for Treating Large-scale Water and Mud Inrush in Inclined Shaft Work Area of Super-long Tunnels LANG Zhijun LI Mangyuan QIAO Haiyang When the construction of the 2# inclined shaft work area of the super-long tunnel of Yingpanshan on the Huaping-Lijiang Expressway in Yunnan Province is tunnelled to ZK26+188, a large-scale continuous water and mud inrush occurred at the tunnel face. In response to shaft flooding and long-term water inflow at the inclined shaft mouth caused by water and mud inrush at ZK26+188, the mechanism of water inrush is analyzed and studied. Three treatment plans are comprehensively compared, and a water discharge treatment plan of "temporarily put aside the inclined shaft, discharge high-pressure water from main tunnel work area, implement the plan in phases, and steadily approach the head of the inclined shaft" is proposed. The water discharge problem is successfully overcome, and the water in the inclined shaft is safely discharged. The treatment plan has significant comprehensive benefits such as safety and economy, and can provide guidance and reference for the treatment of geological disasters in similar super-long, high-pressure, water-bearing karst tunnels. 2023 Vol. 60 (5): 224-233 [Abstract] ( 266 ) [HTML 1KB] [ PDF 6099KB] ( 578 ) 234 Study on Engineering Geological Characteristics of Saline Rock in a Tunnel on China-Laos Railway CHEN Wei1,2 ZHANG Minghong2 ZHANG Ying2 LIN Ling2 Saline rock is extremely unfavorable to tunnel engineering. In this study, based on a tunnel passing through thick chloride saline rock on the China-Laos Railway, its engineering geological characteristics are studied.Firstly, the saline rock engineering section is divided into the low salt content section and the high salt content section based on salt content. Then, the sections with different salt contents are tested using thin section identification,X-ray diffraction, strength test, water quality analysis, corrosion and expansibility tests to quantitatively study their physical, mechanical, hydrochemical, corrosion and expansibility and other engineering geological characteristics.The results indicate that the mineral components of the saline rock in this section is mainly rock salt (NaCl). The compressive strength of saline rock in the high salt content section is significantly lower than that of saline rock in the low salt content section. The main anions and cations in the groundwater come from the dissolution of salt, and as the salt content increases, the environmental action level of the groundwater gradually increases. Saline rock is corrosive, and the maximum upper corrosion rate in the high salt content section is 8.846~10.540 mm/h, with an average of 9.527 mm/h. Saline rock is also expandable, and in the saturated environment, the expansion indicator of saline rock in the high salt content section is generally higher than the indicator in the non-saline section and low salt content section. In tunnel construction, targeted prevention and control measures should be taken to avoid the occurrence of engineering defects. 2023 Vol. 60 (5): 234-242 [Abstract] ( 299 ) [HTML 1KB] [ PDF 5085KB] ( 558 ) 243 Study on DERU Testing and Evaluation Technology for Civil Structures of Highway Tunnels in Karst Areas LUO Ziqing1 ZHOU Rui2 LUO Junhui1 JIANG Yajun2 WU Chunwei1 YANG Yonghua1 The inspection and maintenance of the civil structure of operating highway tunnels in karst areas is of great significance for ensuring the safe operation of tunnels. By conducting investigation and statistical research on the defect characteristics of a group of tunnel cases in karst areas of Guangxi, and analyzing the needs of tunnel maintenance work, a highway tunnel civil structure inspection and evaluation system was constructed based on the DERU method. The lining, pavement, and drainage system are regarded as evaluation indicators for tunnel components, and the technical condition index values of tunnel structures are calculated by using D, E, R, and U values.On this basis, a suitable detection system was developed and applied in conjunction with practical engineering cases. 2023 Vol. 60 (5): 243-253 [Abstract] ( 325 ) [HTML 1KB] [ PDF 3963KB] ( 595 ) 254 Analysis of Rapid Scaling Causes in Tunnel Drainage System and Relevant Inhibition Technologies PU Chunping1 LU Jiayue2,3 MU Song2,3 XIE Deqing2,3 ZHOU Ying2,3 Rapid scaling and blockage of the tunnel drainage system will increase the water pressure behind the support, leading to secondary defects such as water seepage, deformation and collapse of lining. In this study, a tunnel in Guangdong province is used as a study case, which experienced severe leakage and crystallization of initial support, and scaling blockage in the drainage system during construction. The causes of rapid scaling of calcium carbonate in the drainage pipe are studied by analyzing the flow direction of surrounding rock water, spatio-temporal changes in ion concentration in water quality analysis, and the composition of scaling minerals. It is clarified that the initial support concrete plays a key role in scaling blockage in the drainage system. Further research is conducted on the effects of alkali accelerator, alkali-free accelerator, and densifying hydrophobic material on corrosion resistance of initial support concrete. The results show that the precipitation of Ga2+ and OH- from the initial support con? crete raises the pH value of the surrounding rock water from approximately 7.5 to 10.5, accelerating the generation of calcium carbonate scaling products; Compared to the initial support concrete mixed with only alkali accelerator, the initial support concrete mixed with combined alkali-free accelerator and hydrophobic material shows a 35.3% increase in 28 d compressive strength, a 26.6% decrease in RCM, and a 68.1% decrease in water absorption. By utilizing the densifying and hydrophobic collaborative technology for the matrix, dissolution and precipitation of internal calcium hydroxide are significantly inhibited; The engineering application directly proves that the densifying and hydrophobic technology for initial support concrete matrix can effectively alleviate scaling and blockage in the drainage system. 2023 Vol. 60 (5): 254-261 [Abstract] ( 242 ) [HTML 1KB] [ PDF 4264KB] ( 555 ) 262 Experimental and Numerical Study on Flexural Mechanical Properties of New Stainless Steel Corrugated Plate GUO Yingjie1,2 DING Wenqi1,2 LI Xiaoran1,2 MA Chang1,2 ZHANG Qingzhao1,2 In order to explore the advantages of new S32001 duplex stainless steel corrugated plate structure in the field of tunnel reinforcement, pure bending loading tests are conducted on a new type of stainless steel corrugated plate and the Q235 carbon steel corrugated plate. The mechanical responses of the two plates are compared and analyzed, and a 3D refined finite element model corresponding to the test is established to verify the rationality of the model and carry out sensitivity analysis. The results show that: (1) The maximum mid-span bending moment of the Q235 corrugated plate is 11.8 kN·m, and the maximum mid-span bending moment of the new stainless steel corrugated plate is 15 kN·m. The bending and load-bearing performance of the new stainless steel corrugated plate is better than that of the carbon structural steel corrugated plate, with higher stiffness and stronger ductility. (2) The section strain during the elastic deformation phase of the Q235 corrugated steel plate in the process of loading consorms to the plane cross-section assumption, but after entering the plastic phase, it no longer conforms due to the large plastic strain generated by the trough of the corrugated plate. The strain distribution along the height on the mid-span section of the new stainless steel corrugated plate basically conforms to the plane cross-section assumption. (3) The mid-span bending stiffness and the ultimate bearing capacity of the new stainless steel corrugated plate increase with the rise of axial force. When N=100 kN, the mid-span ultimate bending moment of the new stainless steel corrugated plate is 28.6% higher than that when N=0 kN. 2023 Vol. 60 (5): 262-268 [Abstract] ( 294 ) [HTML 1KB] [ PDF 4813KB] ( 487 ) 269 Experimental Study on the Preparation of Non-fired Building Materials by Recycling Shield Muck in Silty Clay Stratum TIAN Yang1 CHEN Yan1 FANG Ruoquan2 LIU Jie3 SU Ang2 YOU Shaoqiang4 FANG Yong1 To address issues such as the difficulty of disposing of and environmental pollution caused by the waste slurry in shield tunnelling, as well as the difficulty of recycling, the muck from the pressure filtration treatment of the shield tunnel waste slurry in clayey soil layers was taken as the research object to propose a scheme for preparing non-fired building materials using the muck. The study investigated the influence of different solidifying agent systems on the uniaxial compressive strength of non-fired sample and obtained the optimal solidifying agent type, mixing ratio, and reasonable amount of river sand addition. The results of the study show that (1) the technology of preparing non-fired building materials using muck from shield tunnel waste slurry pressure filtration treatment is feasible and practical, and the strength of the produced non-fired sample meets the requirements of product grade MU15 in"JC/T422-2007"; (2) the strength of non-fired sample using cement as the solidifying agent is significantly higher than that of using lime, and the optimal strength is achieved when the cement content is between 20% and 30%; (3) the ratio of cement to lime in the composite curing agent should be 3∶1 to achieve the best curing effect; (4) when the muck to river sand mixing ratio is 3∶1, the waste residue can be utilized to the greatest extent, and the strength and durability of the non-fired sample meet the strength and durability indicators required by the specifications. 2023 Vol. 60 (5): 269-276 [Abstract] ( 307 ) [HTML 1KB] [ PDF 2933KB] ( 604 ) 277 Experimental Study on Mechanical Properties of High-Foot-Bolt &Mould-Package Concrete Fixed Support Ends for Steel Support in Foundation Pit Works GUO Caixia1,2 LIU Wenjie2 ZHANG Mingju2 LI Pengfei 2 GAO Yunhao2 SHAN Yuhan2 In the open excavation works of foundation pit in urban area, a large number of internal support structures are used, among which the steel support end nodes are the key to controlling deformation and stability of the foundation pit. In order to improve the load-carrying mode of the support end, a high-foot-bolt & mould-package concrete fixed support end is developed. Its structural composition and characteristics are explained, and four sets of specimens are processed for indoor test. The mechanical properties of the specimens under axial and eccentric loads are studied. Failure mode, load-displacement curve, and load-strain curve of the specimens are obtained, and the elastic bearing capacity and the stiffness of the fixed support end are obtained. The test results indicate that: (1) the designed bearing capacity of the fixed support end is higher than 4 000 kN, exceeding the designed axial bearing capacity of ?609 steel support and meeting the requirements of strong node design. After yielding of the fixed support end, it has good plastic deformation capacity, with an ultimate bearing capacity larger than 6 500 kN; (2) The final failure modes of the specimen include buckling of the short connecting section of steel pipe, cracking of the mouldpackage concrete, and bending of the high-foot bolt. Increasing the compressive pre-stress and the strength of the mould-package concrete can improve the bearing capacity of the fixed support end; (3) The developed fixed support end has a simple structure and stable performance, which helps to improve the safety of foundation pit construction. 2023 Vol. 60 (5): 277- [Abstract] ( 263 ) [HTML 1KB] [ PDF 6061KB] ( 462 )

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