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Quick Search     Advanced Search MODERN TUNNELLING TECHNOLOGY   2020 Vol.57 Issue.1 Published 2020-02-25 1 Discussion on the Key Techniques for Disaster Prevention, Evacuation and Rescue of Large-scale Railway Tunnel Group in High Altitude Area WANG Mingnian1,2 GUO Xiaohan1,2 CUI Peng1,2 YU Li1,2 With an extension of the railway network to the west China, the number of high-altitude railway tunnels has increased significantly. In condition of tunnel fire, the smoke diffusion will speed up and the evacuation capacity will decrease because of the low atmospheric pressure, low temperature, low oxygen content and harsh natural environment condition in high altitude area, endangering the life safety of trapped people. The classification standards for the railway tunnel group are given based on field research, theoretical analysis, numerical simulation and so on,they are defined as the adjacent railway tunnel group if the tunnel portal spacing is less than 250 m, and they are defined as the continuous railway tunnel group if the tunnel spacing is between 250- 400 m. The law of evacuation capacities in high altitude area is understood, and it is found the evacuation capacity decreases by 11.28% for every 1 000 m increase in altitude compared with that of plain area; a comprehensive reduction factor of evacuation capaci? ty, which considers the slope and altitude, is obtained. It is recommended the lengths of isolation areas of rescue emergency station in uphill and downhill directions should be no less than 700 m and 200 m respectively considering the altitude, slope and other factors. In light of the smoke diffusion law and personnel evacuation capacity, the suggestions concerning the designs of civil structures of disaster prevention and rescue like emergency rescue station both inside and outside of tunnel, emergency exit and refuge are proposed, and the rescue mode suitable for the railway tunnel in high altitude area is presented. 2020 Vol. 57 (1): 1-7 [Abstract] ( 856 ) [HTML 1KB] [ PDF 2613KB] ( 1716 ) 8 Research Progress of Hoek-Brown Strength Criterion and Determination of Mechanical Parameters of Rock Mass ZHU Yongsheng1 LI Pengfei2 The determination of mechanical parameters of rock mass is one of the key links during engineering con? struction, the rationality of the method and result is of great importance for the study of surrounding rock stability and support design. Based on the Hoek-Brown strength criterion, the characteristics of this method and determination results as well as the differences from that of empirical method stipulated in standard and the inherent sources are discussed systematically. In general terms, the Hoek-Brown strength criterion based determination method for mechanical parameters comprehensively considers the effects of three key geological factors of lithology, rock quality and stress. Compared with the method stipulated in standard, this method fully considers the diversities of geological factors and the differences of determined mechanical parameters. The engineering practice in deep-buried rock mass shows this method is relatively reasonable compared with the conventional M-C strength theory and the specified parameter determination method based on it. 2020 Vol. 57 (1): 8-17 [Abstract] ( 859 ) [HTML 1KB] [ PDF 3606KB] ( 1777 ) 18 Study on the Stability of Large-Span Tunnel by Distinct Element Based Strength Reduction Method ZHENG Yuchao1 ZHANG Wensheng1 SUN Keguo1 CAI Jialiang1 LI Jie2 LENG Biao1 ZHAO Ruiwen2 As the weak structural surface of rock mass, the joint plane significantly affects the stability of tunnel surrounding rocks, and the chip off-falling at crown, collapse and slippage are more likely to occur for the largespan tunnel with many joints. Taking the Nanyalu No.3 tunnel in Guiyang as the background, it analyzes the safety factors in conditions of different joint angles, joint spacings, set numbers and lining parameters by distinct element based strength reduction method in 3DEC software, and evaluates the effects of various factors on tunnel stability.The results show that the larger the joint angles and the joint set numbers and denser the joints, the more unstable the tunnel; the stability of tunnel is mainly effected by the joint angle for the rock mass with single set of joint;sprayed concrete layer significantly improves the tunnel stability, the safety factor of the tunnel with lining thickness of 10 cm is improved by 17.9% compared with that without any lining structure, and some optimization suggestions for the tunnel lining parameters are proposed in light of this. 2020 Vol. 57 (1): 18-25 [Abstract] ( 812 ) [HTML 1KB] [ PDF 5633KB] ( 1496 ) 26 Study on Health Evaluation Method of Large-Span Highway Tunnel with Fractured Surrounding Rocks LIU Xuezeng1,2 CAI Xin3 DING Maorui3 CHEN Fubin3 DENG Feng3 At present, there are few research on the mechanism of deformation and damage evolution of large-span tunnel structure under loose load, lacking health evaluation system and early warning standard of the tunnel structure in operation, which is not conducive to understand the safety state of tunnel structure. Aiming at these problems, this paper studies the mechanical and deformation characteristics of large-span tunnel structure under loose load in the surrounding rocks of grade Ⅳ and Ⅴ by establishing two-dimensional and three-dimensional numerical analysis models. A 5-grade evaluation system and 3-level early warning standard are established based on the characteristics of deformation and damage. It comes to the following conclusions: (1) the failure process of the large-span tunnel under loose load is divided into four stages, namely elastic stress stage under designed load, elastic stress stage under loose load, plastic working stage after structure cracking and accelerated deformation and failure stage;(2) under designed load, the tunnel deformation obtained by three-dimensional numerical simulation method is basically consistent with that by the calculation method of load code, which verifies the feasibility of numerical calcula? tion. By numerical calculation, it is found that in the surrounding rocks of grade Ⅳ, the ultimate bearing capacity is 734 kPa, the crown settlement is 6.75 cm, the convergence of sidewall is 1.56 cm; in the surrounding rocks of grade V, the ultimate bearing capacity is 812 kPa, the crown settlement is 10.47 cm, the convergence of side-wall is 4.06cm; (3) a health degree evaluation system and early warning standard of large-span tunnels in the surrounding rocks of grade IV and V are established by taking the vault cracking, local buckling, vault and haunch buckling, haunch buckling depth reaching 1/3 of lining thickness and rebar tensile rupture as the key nodes and structure stress,crown settlement and side-wall convergence as the evaluation indexes. 2020 Vol. 57 (1): 26-35 [Abstract] ( 851 ) [HTML 1KB] [ PDF 5423KB] ( 1722 ) 36 Study on the Shear Strength of Surrounding Rocks and Mechanical Behaviors of Supporting Structure of the Shallow-buried Tunnel in Swelling Soil TAO Weiming1 LI Huayun2 ZHANG Zhiqiang2 GUO Yongfa3 Swelling induced by water absorption of swelling soil results in complex swelling stress on tunnel supporting structure. In order to investigate the impact of strength declining and swelling effect of shallow-buried swelling soil on supporting structure, taking the Chenggong tunnel as the background, the relationship of shear strength and initial moisture content is verified by indoor direct shear test; based on the result of laboratory test,ABAQUS 3D finite element software is used to study the effect of soil swelling on tunnel support structure, and the impact of swelling effect on deformation of surrounding rocks and internal force of supporting structure under different buried depths is revealed. The results show that: friction angel and cohe sion decrease with an increase of moisture content, cohesion is significantly affected, the relationship between the shear strength and moisture content of swelling soil can be represented by quadratic parabola; large swelling pressure is produced due to restraint of supporting struc? ture after water absorption of swelling soil and it results in damage of surrounding rocks and increase of invert heaving and horizontal convergence of sidewall; after swelling of surrounding rocks, the axial force of primary supporting structure increases evenly, the bending moment increases slightly at haunch but largely at the foot of sidewall, and the supporting structure is in an unsafe state; swelling is largely affected by buried depth and no further swelling occurs when it reaches certain ultimate buried depth. 2020 Vol. 57 (1): 36-43 [Abstract] ( 830 ) [HTML 1KB] [ PDF 5789KB] ( 1750 ) 44 On Relationship between Surrounding Rock Deformation and Surrounding Rock Pressure under Large Deformation of Soft Rock MA Shiqiang1，2 In order to understand the relationship between the deformation of surrounding rocks and the surround? ing rock pressure under large deformation of soft rock to provide basis for yielding design of large deformation, the maximum compressive stress of the elastic supporting structure after some deformations of a single-track railway tunnel without support is calculated by FLAC3D numerical simulation software, the surrounding rock pressure is identified indirectly, and the curve of surrounding rock pressures varying with time is obtained. The monitoring data of some similar projects are compared with this relationship curve, and the results show that: the pressure release curve is divided into three parts, i.e. steep drop area, adjustment area and slow dropping area; the large deformation of soft rock can be divided into convergence type and non-convergence type, it is economical and reasonable if the measur? able peripheral deformations can be controlled within 15 cm (3% of tunnel radius) in condition of convergence, and the best effect can be obtained by installing conventional systematic anchor bolts; the pressure release effect of surrounding rocks will be improved further when the measurable peripheral deformation is more than 63 cm（14% of tunnel radius）in condition of non-convergence; it will result in large increase of plastic zone if the pressures of surrounding rocks are reduced by large peripheral deformations, and the systematic anchor bolts play little role at this time. 2020 Vol. 57 (1): 44-50 [Abstract] ( 788 ) [HTML 1KB] [ PDF 2187KB] ( 1292 ) 51 Study on Working Face Stability of the Shallow-buried Tunnel in Soft Surrounding Rocks Based on Strength Reduction Theory DU Jun1,2 MEI Zhirong2 FU Lilei3 CHEN Yongzhao3 The stability of tunnel working face is the prerequisite for safe tunnel construction. Taking the shallowburied tunnel in soft surrounding rocks as the research object, based on the strength reduction theory, a judgment process for working face stability is established and safety factor of stability can be solved; the instability criterion is analyzed, and it is considered that criteria of abrupt change of displacement or plastic strain energy can be adopted for judgment of working face stability; on the basis of the Jiaheyuan underpass, the countermeasures for working face stability are studied, stability safety factor is used to pre-evaluate the reinforcement effect of single and combined pre-reinforcement measures, and the pre-reinforcement method for working face is determined. 2020 Vol. 57 (1): 51-57 [Abstract] ( 746 ) [HTML 1KB] [ PDF 3040KB] ( 1546 ) 58 Hydrogeological Investigation of the Underground River of Karst Tunnel in Carbonate Rock of Red Bed GUO Chenggang1 GUO Yongfa2 ZHU Menglong3 ZHANG Qingwen3 There are abnormal geological structures like karst caves and underground rivers in the contact area be? tween the insoluble rocks (such as sandstone and mudstone) and soluble rocks(such as carbonate rocks) in the red bed area of central Yunnan Province. Taking the Shanchongqing tunnel on Yiliang-Shilin expressway for example,the hydrogeological conditions of the underground river in the typical interspersed contact zone is analyzed by means of geological interpretation, investigation of water outlet at ground surface, apparent resistivity detection with transient electromagnetic method and geological radar scanning inside tunnel. It concludes that the water supply of the karst river is ground surface fissure water without regional connection, and tunnel water inflow is predicted as well as basic treatment methods are proposed. 2020 Vol. 57 (1): 58-64 [Abstract] ( 807 ) [HTML 1KB] [ PDF 4575KB] ( 1562 ) 65 Visualization Analysis of Metro Station Deformation Based on Thermodynamic Diagram ZHAN Xianjun PEI Taotao ZHOU Jibing In order to show the real-time distribution of the overall deformation of metro station during construc? tion, a visualization study on the data of the monitoring points is conducted based on thermodynamic diagram. In light of the deformation monitoring data of certain metro station, a visualization analysis on the deformation is carried out from aspects of ground surface settlement, horizontal displacement of the pile(wall) and the axial force of support. The results show that the real-time deformation distribution can be obtained by a real-time visualization analysis on the monitoring data based on thermodynamic diagram, which can present the macroscopic deformation condition at different positions more vividly, rapidly and visually. 2020 Vol. 57 (1): 65-69 [Abstract] ( 904 ) [HTML 1KB] [ PDF 1742KB] ( 1491 ) 70 Relevant Standards and Quality Management of the Mould for Reinforced Concrete Segments of Shield Tunnels CAI Yaning1 HUANG Qingjie2 Mould is one of the key factors affecting the quality of finished tunnel segments. Based on an introduc? tion to relevant standards of the moulds for reinforced concrete segments of shield tunnels, the issues concerning mould design and machining as well as operation are summarized, the quality problems related to mould and corresponding reasons are analyzed, treatment measures for the common problems occur during mould operation and maintenance are presented, and the suggestions on after-sales service of the mould manufactory are proposed in order to control the quality in the course of segment manufacturing and serving. 2020 Vol. 57 (1): 70-75 [Abstract] ( 853 ) [HTML 1KB] [ PDF 812KB] ( 1940 ) 76 Calculation Method for the Surrounding Rock Pressure of Mined Lower Tunnel Structure of a Metro Station Built by Combination of Open Cut and Mined Method YAN Tao1 LI Kunjie1 QIN Pengcheng1 CHEN Jingyu1,2 LIN Rui3 ZUO Qiang3 Restricted by the topography, the Qingxiushan metro station of Nanning rail transit line 3 is built by open cut method for the upper part and mined method for the lower part. The lower mined tunnel is classified as the one in the transition zone from the shallow overburden to the deep overburden, and it′s significant for proper equivalent calculation of the upper open-cut excavated station hall to ensure structure safety of mined tunnel regarding structure design. The vertical pressure of surrounding rocks of the lower mined tunnel is 150.69 kN/m and the horizontal pressure of surrounding rock is 95.28 kN/m when the upper station hall structure is equivalent to soil body;the vertical pressure of surrounding rocks of the lower mined tunnel is 439.83 kN/m and the horizontal pressure of surrounding rock is 103.28 kN/m when the upper station hall structure is equivalent to additional load. The numerical calculation shows that the maximum safety factor is 60.29 (at haunch) and the minimum safety factor is 7.39(at bottom) when the upper station hall structure is equivalent to soil body; the maximum safety factor is 21.558 (at arch spring) and the minimum safety factor is 2.529 (at bottom) when the upper station hall structure is equivalent to additional load. It is suggested that it is proper for the upper station hall structure to be equivalent to additional load regarding the pressure calculation of surrounding rocks of the mined tunnel. 2020 Vol. 57 (1): 76-82 [Abstract] ( 813 ) [HTML 1KB] [ PDF 1532KB] ( 1704 ) 83 Study on the Characteristics of Secondary Lining Cracking under the Effect of Rheological Load WANG Jun LIN Guojin Aiming at the increasing cracking of secondary lining of the road tunnel with long time operation, the cal? culation method of discrete element-finite difference coupling is adopted to study the cracking process of secondary lining under the effect of rheological load, and the effect of geo-stress and voids behind the lining on the characteristics of secondary lining cracking is discussed. The results show that: (1) geo-stress has significant effect on the cracking patterns of tunnel lining, cracks mainly occur near the crown and invert when λ=0.5, while cracks congregate near the left and right arch haunches when λ=1 or 2; (2) the cracking processes and final failure patterns of tunnel lining in condition of voids at crown are different from that with no void, however the situation is similar to that with no void if there are voids at spandrel; the situation of cracking process is different from that with no void but the final failure pattern is similar to that with no void if there are voids at haunch; (3) if there are voids at crown and spandrel, the cracking process and final failure pattern of tunnel lining are similar to that only with voids at crown; if there are voids at spandrel and haunch or at crown and haunch, the cracking process and final failure pattern of tunnel lining are different from that with single void; (4) cracking of concrete occurs near the voids in conditions of different voids numbers and combinations. 2020 Vol. 57 (1): 83-90 [Abstract] ( 817 ) [HTML 1KB] [ PDF 3259KB] ( 1380 ) 91 Simulation Study on Foundation Pit Excavation in Soft Soil Considering Effect of Creep and Seepage LIN Zhibin ZHANG Boyang YANG Dafang In order to study the coupling effect of creep and seepage on foundation excavation in soft soil, a study on the water pressure, pile displacement, ground surface settlement and bottom heaving of soft soil foundation pit after piling under different calculation conditions are conducted based on creep and seepage analysis modes of FLAC3D by taking the Qianhaiwan station excavation of Shenzhen metro Line 11 as the background. The results show that：(1) both seepage and creep have significant impact on deformation of foundation pit and the mutual effect must be considered so as to ensure the simulated results comply with the actual results; (2) during foundation pit excavation, the values and positions of maximum pile displacements at both sides of foundation pit are of exponential decay relationship to excavation time, while the values of maximum ground surface settlement are of slow linear growth relationship to excavation time except for rapid increasing in the course of dewatering; (3) with the increase of phreatic water level, the maximum pile displacements and the maximum ground surface settlements at both sides of foundation pit decrease linearly. 2020 Vol. 57 (1): 91-98 [Abstract] ( 782 ) [HTML 1KB] [ PDF 2949KB] ( 1480 ) 99 Influence of Foundation Construction and Additional Load of Transfer Structure on Underneath Metro Tunnel PENG Qi The transfer structure above a metro tunnel will affect the structure of metro tunnel underneath: (1) load relief due to foundation excavation of transfer structure will cause heaving of tunnel structure; (2) the load transmitted from the high-rise building to the transfer structure will result in deflection deformation of large-span transfer structure, and upon the transfer structure contacts with the rock-soil material it will apply additional load on metro tunnel. Taking certain project above metro tunnel as an example, the coupling influence of the load relief due to foundation excavation and dewatering is simulated, and a contrastive analysis is conducted regarding the two cases of transfer structure being laid on cushion and rock and soil. The results show that the transfer structure laid on cushion will effectively reduce the additional load transmitted to metro tunnel, the influence of transfer structure vertical deflection induced additional load on underneath metro tunnel can′t be ignored. 2020 Vol. 57 (1): 99-104 [Abstract] ( 835 ) [HTML 1KB] [ PDF 3410KB] ( 1338 ) 105 Forward and Inversion Simulation of Tunnel Reflection Wave Tomography and a Contrastive Analysis of TRT Inversion PENG Yan1,2 FANG Hui1,2 LV Qinyin1,2 As for the tunnel reflection tomography (TRT), receiving points only within 10 channels can be installed and used for inversion, and due to destruction in installation, the numbers of effective receiving points are often less than 10 channels, which seriously affects the work progress and greatly limits the practicability of the instrument. In view of this, the travel time formulae for the direct wave and reflected wave of observing system on tunnel arch surface are deduced. And the forward and inversion method for the random receiving point and seismic focus point on tunnel arch surface is obtained based on the principles of wavefront diffusion and TRT inversion technology. With this method, the inversion results comply with that of TRT software with no restriction by channel numbers, ensuring enough effective channels involving in inversion in the case of some bad channels. 2020 Vol. 57 (1): 105-114 [Abstract] ( 819 ) [HTML 1KB] [ PDF 7974KB] ( 986 ) 115 Identification of Tunnel Damages Based on Wavelet Packet Transform LIU Chong MAO Cui Timely identification of tunnel damage and rehabilitation will ensure safe tunnel operation since tunnel is an important part of traffic engineering. Based on a two-dimensional tunnel model, taking the pressure generated by high-speed train passing through tunnel as the applied load, the time-history curve of inner lining node is obtained by FEM, the curvature curve corresponding to this time-history curve is factorized by using wavelet packet transform, and the position of damage is identified by taking the standard error of displacement curvature energy as a damage index. The research results show that this method can effectively identify the position of tunnel damage. 2020 Vol. 57 (1): 115-119 [Abstract] ( 720 ) [HTML 1KB] [ PDF 2371KB] ( 1314 ) 120 Quantitative Study on the Discomfort Glare of the Road Tunnel Sunshades XU Yu1 ZHENG Xuan2 LI Xue2 LIU Haoxue1 In order to evaluate the discomfort glare of the light spot which is caused by the tunnel sunshade, the glare influence of the projected sunshade light spot is analyzed, a quantitative method for evaluating the glare comfort of tunnel sunshades is established, the UGR of the projected light spot of sunshades with equal grilling distance is calculated, the relationship among light spot width, luminance and UGR are analyzed using UGR which is to evaluate the glare degree in lighting places. The results show that at the tunnel access zone, the smaller the luminance,the width of the bright area of the sunshade light spot and the UGR, the better the comfort, and vice versa; if the luminance and the width are more than a certain value and UGR is larger than 22, the discomfort glare is large and it affects the driving comfort. Finally a proposal for the design of sunshades is proposed. 2020 Vol. 57 (1): 120-124 [Abstract] ( 803 ) [HTML 1KB] [ PDF 1195KB] ( 1366 ) 125 Application of Radar Chart Method to the Karst Tunnel in Complex Geology YANG Runxia The factors inducing karst tunnel risks are complex and diverse. Aiming at the subjectivity, unicity and one-sidedness of objective weight of risk assessment of the karst tunnel in complex geology, a concept combining qualitative with quantitative analysis is adopted, a risk evaluation system for the karst tunnel is established by selecting the main influencing factors, the indexe weights are determined and normalization processing is conducted by entropy method. A risk assessment model combining numerical values and graphics is set up by utilizing the radar chart method, four reference samples corresponding to four risk levels are introduced, and the comprehensive evaluation range of each risk level is obtained quantitatively and intuitively. 2020 Vol. 57 (1): 125-129 [Abstract] ( 692 ) [HTML 1KB] [ PDF 1031KB] ( 1257 ) 130 Experimental Study on Rockburst of Jinping Marble Based on an Analysis of Acoustic Emission Waveform DU Shuai1 WANG Yang2 Rockburst is a very complicated nonlinear mechanical behavior due to many influencing factors. Through two whole-range failure tests and one non- whole-range failure test, the parameters of stress and acoustic emission are acquisited, the key points are determined based on the stress curve and cumulative energy curve of acoustic emission, and the waveform of acoustic emission in the course of rockburst is analyzed, and the rockburst rules of Jinping marble is obtained. The results show the distribution of waveform numbers of acoustic emission in unit time is closely related to the key points, most of the waveforms are single wave, and the waveforms of doublewave, three-wave and four-wave are concentrated at the key points, multiple wave only occurs during rockburst; compared with the situation in loading stage, the rockburst wave with countless waveform numbers in unit time may occur during rockburst of Jinping marble, which is the unique characteristic in rockburst stage. 2020 Vol. 57 (1): 130-135 [Abstract] ( 790 ) [HTML 1KB] [ PDF 2057KB] ( 1195 ) 136 Research on Bearing Modes of Compound Middle-wall of Multi-arch Tunnels with Large Spans YANG Guolin1 HU Min1 SHEN Zongqiu2 YANG Jie2 In order to study the bearing characteristics of the compound curved middle-wall of the multi-arch tun? nel during dynamic tunnel excavation, based on the Hejiadaling tunnel on the Yuelushan-Ningxiang highway, the axial force of main reinforcement and strain of concrete at the shoulder of middle-wall are monitored by embedded components. According to the data from the site monitoring, the development process of axial force of main reinforcement is divided into several stages, the law of axial force development of main reinforcement is analyzed, 3 typical bearing modes of middle-wall and the development process are summarized, and the instability types of middlewall under different bearing modes are concluded. The relationship between principal strain of concrete at shoulder of middle-wall and time is interpreted by the bearing modes of middle-wall and the development process, and the rationality is verified thereof. 2020 Vol. 57 (1): 136-141 [Abstract] ( 697 ) [HTML 1KB] [ PDF 2581KB] ( 1204 ) 142 Statistical Analysis of Monitoring Data and Reserved Deformation Based on Interval Estimation Method LIU Qingfeng1 LIU Qingzhi2 Aiming at the distribution scope of deformation magnitudes and reserved deformations of the YuxiChuxiong expressway tunnel, a statistical analysis on the laws in condition of surrounding rocks with different classifications and overburdens is conducted by selecting the monitoring data of 471 sections of 14 tunnels based on interval estimation method. The results show that tunnel deformation increases with an increase of tunnel overburden, the deformation of surrounding rocks of grade Ⅳ is larger than that of grade Ⅴ and attention should be paid to the deformation and deformation control; the deformations of surrounding rocks of grade Ⅳ and Ⅴ tend to be stable around 40 days after excavation, and it is suggested lining should be installed after this time. As for the surrounding rocks of grade Ⅳ, it is suggested the reserved deformation should be 17 cm if the overburden is less 50 m and the reserved deformation should be 50 cm in condition of enhancing the primary support strength if the overburden is between 50-300 m. As for the surrounding rocks of grade Ⅴ, it is suggested the reserved deformation should be 18 cm if the overburden is less than 50 m and the reserved deformation should be 32 cm if the overburden is between 50-300 m 2020 Vol. 57 (1): 142-147 [Abstract] ( 725 ) [HTML 1KB] [ PDF 1913KB] ( 1482 ) 148 Penetration Test of Cutter in Mixed Stratum with Different Rock Strengths LI Kejin1 ZHANG Dewen1 LI Wen1,2 WEI Qingwen1 XIA Enhu1 ZHANG Daqing3 Mixed stratum has significant influence on the efficiency of rock breaking and driving parameters of cut? ters. Aiming at the shield running tunnel section of lot 1 of Jinan urban rail transit R1 line in mixed stratum, penetration tests of the cutter in condition of rock samples with different strengths are conducted, and the effects of different penetration rates on rock breaking of cutter are studied. The test results show that: the larger the rock strength, the larger the invading-resistance coefficient and the impact load acting on disc cutter and more obvious of brittle failure; the effect of penetration rate on rock breaking of cutter is similar to that of rock strength, but the penetration load, load drop, critical penetration at jumping point are all in a logarithmical function relationship with penetration rate; the rock breaking process can be divided into four stages, namely compaction stage, dense core formation and development stage, crack cut-through stage and residual strength stage. 2020 Vol. 57 (1): 148-155 [Abstract] ( 632 ) [HTML 1KB] [ PDF 3299KB] ( 1419 ) 156 Experimental Research on Image Acquisition Method of Tunnel Lining Cracks Based on Line-scanning Digital Camera LENG Biao1 CUI Zhaodong1 YANG Hui1 HOU Gaopeng1 ZHU Yongbiao2 It′s significant to detect the cracks of tunnel lining for tunnel disease detection. Aiming at the low auto? maticity, inefficiency, poor accuracy and likely missing of record in traditional tunnel lining crack detection technology, an experimental study on image acquisition method of tunnel lining is conducted based on line-scanning digital camera. The basic principle of line-scanning imaging under experimental conditions is introduced, a theoretical analysis and equipment selection of the experimental equipments and system integration are carried out, a test is conducted under experimental conditions, and image data acquisition of cracks of tunnel lining model is completed.The results show that the proposed image acquisition method can be applied to the image acquisition of tunnel lining cracks. 2020 Vol. 57 (1): 156-161 [Abstract] ( 629 ) [HTML 1KB] [ PDF 2505KB] ( 1297 ) 162 Application of 3D Transient Electromagnetic Advance Detection Technology in Tunnel Water Exploration XING Xiuju WU Zhengfei ZHANG Yirui JIANG Qiping Working face might suffer from water and mud inrush during excavation of a water-rich tunnel, which poses a great threat to construction safety. By physical modeling of the water-bearing structure in front of the working face, the transient electromagnetic response law is summarized. The test and practice show that the positions of abnormal bodies at different distances can be captured accurately by using multi-turn small-coil transient electromagnetic method; by using the multi-directional and multi-angle three-dimensional transient electromagnetic data acquisition technique, the results will be displayed in three-dimensional way, which overcomes the shortcomings of the traditional transient electromagnetic detection that the spatial scope of abnormal body can′t be displayed and effectively improves the visualization and intuition of results interpretation. 2020 Vol. 57 (1): 162-167 [Abstract] ( 623 ) [HTML 1KB] [ PDF 4530KB] ( 1632 ) 168 On Cutter Wearing Control Technology of the Shield Passing through Mixed Strata LI Qiang1 GAN Penglu2 Taking the Hangfa Factory station-Renmin Road station of shield tunnel of Hangzhou metro line 2 as the background, an analysis on the cutter wearing during shield construction in the upper soft and lower hard mixed stratum is conducted, a series of abnormities caused by severe cutter wearing are revealed, including abnormal driving parameters, abnormal shield mucking, severe ground surface settlement and so on; in light of the unexpected severe cutter wearing, a treatment method combining foundation reinforcement and cutter replacement in atmospheric pressure and the countermeasures of soil conditioning, equipment configuration optimization and parameter control are proposed. The results show that the cutter wearing can be controlled within allowed range by optimizing the countermeasures of shield construction in mixed stratum. 2020 Vol. 57 (1): 168-174 [Abstract] ( 754 ) [HTML 1KB] [ PDF 3695KB] ( 1570 ) 175 Discussion on the Construction Method for the Extra-long Shengli Road Tunnel in Tianshan ZHU Heqing Shengli tunnel in Tianshan is an extra-long road tunnel in an extremely cold area with high altitude and geostress, thus it is critical for the whole railway line and difficult to meet the requirements of construction safety, period and environment protection by traditional drill and blast method. Based on a contrastive analysis of the four construction schemes in terms of construction period, economy, safety and quality control, a three-tube scheme, in which the main tunnel tubes use drill and blast method and the parallel pilot tunnel uses TBM, is determined,achieving the goal of being economic, reasonable, safe, reliable, and shortening of construction period. 2020 Vol. 57 (1): 175-179 [Abstract] ( 812 ) [HTML 1KB] [ PDF 2108KB] ( 1520 ) 180 Application of Grouting Technology in Tunnelling with Mixed Sliding Masses WANG Chunming1 YANG Xiuquan2 The accumulation body of landslide of Wuyuan tunnel on Menghua railway is mixed up with sandy new loess, cohesive new loess, fine round gravel, silty clay and so on, excavation of the inclined shaft reveals that working face is rich in water and the deformation of primary support is large. Ground surface reinforcement by sleeve valve pipe grouting is adopted to guarantee the tunnel safety. This paper describes the construction technology of sleeve valve pipe, assessment method for grouting reinforcement effect and principles of grouting reinforcement for various strata. The practical application effect shows that the grouting by sleeve valve pipe embodies the advantages of penetration grouting, compaction grouting and splitting grouting, which can increase the stratum integrity and stability of main tunnel and guarantee the construction safety of tunnels with mixed sliding masses. 2020 Vol. 57 (1): 180-185 [Abstract] ( 672 ) [HTML 1KB] [ PDF 5142KB] ( 1392 ) 186 Design and Application of the Manual Excavated Shield Inspection Shaft TAN Xingen As for the maintenance of shield cutterhead, it is characterized by long construction period and high cost to replace cutters by conventional shaft under atmospheric pressure. Taking a shield tunnel in Shenyang as an example, a design of the manual excavated small shaft for shield cutterhead maintenance is proposed and the construction procedures and cautions are presented. The practical effect shows this method is safe, reliable and economic, realizing rapid construction of shield inspection shaft. 2020 Vol. 57 (1): 186-189 [Abstract] ( 679 ) [HTML 1KB] [ PDF 2383KB] ( 1571 ) 190 Development of a Virtual Assembly System for Cutterhead of Composite EPB Shield CAI Bao ZHU Wenhua WANG Fang The modeling of cutterhead of composite EPB shield machine usually takes a great deal of time, which not only affects the efficiency of cutterhead design, but also reduces the reliability of cutterhead assembly. A system is developed for the common cutterheads (four spokes and four plates, six spokes and six plates), a model library of two common cutterheads is established by dividing the function modules of the system, and a visual interface of cutterhead system is designed, realizing the drive of main parameters of the cutterhead model. The general method of interference checking for cutterhead model is expounded, and XML technology is adopted to manage the system data. 2020 Vol. 57 (1): 190-196 [Abstract] ( 675 ) [HTML 1KB] [ PDF 4077KB] ( 1442 ) 197 Study on the Labview-based Measuring System of Visual Shield Tail Gap LU Yati XU Zhiliang Shield tail gap is critical for segment selection. It will cause disturbance between shield tail and seg? ment and lower the driving speed if the gap is too small. While grout is likely to break through the grease of shield tail and result in grout leakage if the gap is too large. In order to improve the measurement precision of shield tail gap to ensure the tail gap variations keep within the allowed range, a measuring system for shield tail gap is studied based on visual processing. A design for the whole system is described, the Labview-based image processing algorithm and the two-dimensional convolution-based edge detection algorithm are mainly introduced, and the communication system and data transmission between Labview and PLC are presented. The research results show that this measuring system is easy to operate and good in accuracy. 2020 Vol. 57 (1): 197-202 [Abstract] ( 629 ) [HTML 1KB] [ PDF 2450KB] ( 1487 )

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