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Quick Search     Advanced Search MODERN TUNNELLING TECHNOLOGY   2016 Vol.53 Issue.5 Published 2016-10-25 Article 1 Research and Application of Dust Removal Technology and Standards for Railway Tunnels ZHANG Chong-Dong Excessive dust in railway tunnels could block the driver′s view, do harm to peoples′ health, and cause frequent equipment failure, and tunnel dust removal is therefore very important. In order to ensure smooth dust removal in railway tunnels, typical examples of new railway tunnels and existing railway tunnels should be selected for the establishment of tunnel dust standards, the functional performance definition of tunnel dust-cleaning apparatus and the tunnel dust norm measurement for incorporation into relevant specifications. Test results show that: 1) tunnel dust removal standards in the joint debugging and commissioning can stipulate that dust content in every cubic meter of air is 1~2 mg; and 2) dust removal in the tunnel should be done before railway debugging and commissioning, with a three-step operation method of dust removal adopted for ballastless track tunnels and a four-step operation method adopted for ballasted track tunnels. Dust-cleaning vehicles are usually used during the operational period. 2016 Vol. 53 (5): 1-5 [Abstract] ( 1404 ) [HTML 1KB] [ PDF 1007KB] ( 2063 ) 6 Construction Techniques for Large-Section Loess Tunnels of High-Speed Railways by Bench Method LI Guo-Liang Based on the construction of the Zhengzhou-Xi′an and Baoji-Lanzhou high-speed railways, an experimental study on the practicability of construction methods for large-section loess tunnels was conducted to deter? mine the deformation and stress characteristics of the surrounding rock and bench method supporting system and provide a basis for key construction techniques of large-section loess tunnels. Study results show that the construction of large-section loess tunnels by the bench method is relatively rapid, and the water content in loess is a key influential factor for the deformation and stability of the supporting structure. A technical system is proposed to determine the construction method of large-section loess tunnels by considering different loess water contents. 2016 Vol. 53 (5): 6-16 [Abstract] ( 1338 ) [HTML 1KB] [ PDF 7847KB] ( 1837 ) 17 Research on the Influential Factors of Lining Detection by Non-Contact GPR Vehicle-Based Detection System CAO Rui-Lang- 1 Qi-Fa-Lin- 2, 3 He-Shao-Hui- 2 Based on numerical modeling and field testing, this paper discusses several key technical problems of Ground Penetrating Radar (GPR) regarding the change from traditional contact detection technology to non-contact multi-channel detection technology, especially the influences of detection distance, detection speed and antenna selection of non-contact GPR technology on detection results. The following can be observed from the results: 1) 200 mm is the best detection distance, from which the geological radar signal can form an entire clear radar graph to identify lining quality defects by employing horizontal high-pass filtering, eliminating background and vertical filtering gain. From the radar graph, a tunnel lining defect can be accurately identified, with a lining thickness detection precision of ±3 cm; 2) with a detection speed of 20 km/h, the radar graph is clear and the vehicle-based system performs well in both defect identification and detection efficiency; 3) For defect identification at the bottom of the tunnel, 400 MHz horn antenna can obtain a clearer hierarchy and defect image than the 400 MHz shielded antenna; 4)Most defects can be identified by the GPR graph by applying combined 400 MHz+900 MHZ antennas using mutual rectification. Employing antennas of different frequencies is effective to improving the efficiency and precision of the vehicle-based detection system. This research provides an important technical reference for the development of the non-contact GPR vehicle-based detection system in China. 2016 Vol. 53 (5): 17-24 [Abstract] ( 1389 ) [HTML 1KB] [ PDF 4585KB] ( 2264 ) 25 Analysis of the Long-Term Deformation Law and Longitudinal Distribution Characteristics of Operating Metro Shield Tunnels in Soft Soil LI Ming-Yu- Jiang-Ping-Yuan- Zhao-Ji-Bin- Fan-Ming-Hui- Zhou- Jie- Feng-Gao-Shun- Chen- Hong Using a metro shield tunnel with a continuously jointed segment lining in soft soil as the object of analy? sis, the distribution characteristics and long-term changing law of the longitudinal deformation of a metro tunnel that has been operating for 7 years were systematically studied based on a statistical analysis of the measured elevation and settlement data of the track bed. The study results show that: 1) research on elevation data characteristics is essential to the auxiliary judgment of the longitudinal deformation and force state of the operating tunnel; 2) tunnel settlement occurred quickly at the beginning of operation; 3) as time passes, the average monthly settlement gradually decreases; 4) for the whole line, the average monthly settlement is between -2 mm and 2 mm; 5) it is approximately a linearly proportional relationship between the law of tunnel settlement development and formation compression deformation and groundwater level variations, which means the average monthly settlement of the operating tunnel decreases gradually with the rising of the groundwater level, and vice versa; 6) the longitudinal deformation curve of each running tunnel is distributed as a Gaussian function and its symmetric center is approximately the bypass passage, with the minimum elevation near the bypass and the point of inflection near the entrance and exit of the sta? tion; and 7) the curve of elevation difference per linear meter to estimate the longitudinal distribution characteristics of the staggered hoop joint is asymmetrically distributed and centered approximately around the bypass. 2016 Vol. 53 (5): 25-30 [Abstract] ( 1352 ) [HTML 1KB] [ PDF 2228KB] ( 2384 ) 31 New Solution of Rock Resistant Coefficients Based on the Mogi-Coulomb Failure Criterion ZHANG Chang-Guang- 1 Zeng-Kai-Hua- 2 The rock resistant coefficient is one of the important parameters in the support design of underground structures such as hydraulic tunnels. Based on the ideal elastic-plastic material model and the Mogi-Coulomb failure criterion, which considers the role that intermediate principal stress plays in increasing strength of the surrounding rock, an analytical solution of stress and displacement of the surrounding rock around a deep buried circular tunnel is derived, and a new solution for the rock elastic-plastic resistant coefficient is obtained. Lastly, the effects on rock strength parameters are studied after the comparison and verification of all the solutions. The results show that the new solution for the rock resistant coefficient based on the Mogi-Coulomb failure criterion is between the solutions of Matsuoka-Nakai (SMP) failure criterion and the Lade-Duncan failure criterion, with little differences; as the solution of the Mohr-Coulomb failure criterion is obviously smaller than the other ones, the consideration of intermediate principal stress could give full play to the load sharing capability of the surrounding rock; and the cohe? sion and inner friction angle have great influence on the rock resistant coefficient, and the influence of the inner friction angle is more obvious. 2016 Vol. 53 (5): 31-34 [Abstract] ( 1417 ) [HTML 1KB] [ PDF 787KB] ( 2127 ) 35 Numerical Simulation of the Rheological Damage Mechanism of a Surrounding Rock Mass with High Ground Stress SUN Jin-Shan- 1 Zuo-Chang-Qun- 1 Jiang-Qing-Hui- 2 Xie- Ni- 1 Jiang- Nan With high ground stress, a tunnel′s surrounding rock reveals rheological behaviors and damage—it may even break up. However, the evolution process of internal damage has not yet been directly observed. Taking the marble mass around the JINPING II Hydropower Station diversion tunnel as a research subject, and based on tri-axial strength test results and data from the analysis of a rheological damage experiment, a numerical model is established to reflect the short-term and long-term strength features of the marble specimen by introducing the parallelbonded stress corrosion model (PSC) into the particle flow numerical simulation method. The tri-axial compressive creep numerical experiments show that the cracking type, cracking direction, distribution characteristics and extension process of the micro-cracks in the marble specimen present various patterns under different stress states, and the rheological damage effect of the marble will gradually decrease with an increase of the confined stress. Based on an analysis of the rheological damage characteristics of the marble specimen, a finite element (FEM) numerical model of the Jinping II Hydropower station diversion tunnel was built and the rheological damage evolution mechanism of the surrounding rock during tunnel excavation was elucidated. 2016 Vol. 53 (5): 35-42 [Abstract] ( 1287 ) [HTML 1KB] [ PDF 2167KB] ( 2062 ) 43 Equivalent Plane Frame Method for the Aseismic Design of the Cross Section of Underground Structures AN Jun-Hai- Tao-Lian-Jin- Li-Ji-Dong- Guo- Fei- Bian- Jin The“Linear meter framework model”used in the traditional response displacement method is analyzed and its error sources and application restrictions are presented. Based on the physical concepts and design ideas of an equivalent beam of slab-column structures under the function of lateral loads, an equivalent plane frame method,which is suitable for aseismic calculations for the longitudinal beam-column system of an underground structure, isproposed. In order to verify the effectiveness of the equivalent plane frame method, calculations of the internal force of different structures and soil parameters are carried out and a comparison between the calculated results and the results of the“linear meter frame model”and dynamic time-history method is conducted using a specific engineering case as an example. The calculation results show that the internal force calculation by the equivalent planar frame method is accurate and has fewer calculations; it can be applied to the aseismic design for an opening in the sidewall, which is highly applicable to various structures and soil conditions. 2016 Vol. 53 (5): 43-50 [Abstract] ( 1286 ) [HTML 1KB] [ PDF 1333KB] ( 1975 ) 51 Analysis of the Impact of Interface Contact Friction on the Seismic Effect of Deeply Buried Shield Tunnels ZHANG Yu- 1, 2 Yan-Qi-Xiang- 1 He- Chuan- 1 Geng- Ping- 1 Based on a quasi-static finite-element numerical model, the law of influence of the seismic effect of a shield tunnel is analyzed for four types of interface contact characteristics, e.g. full contact without slipping, slipping with friction Ⅰ, slipping with friction Ⅱ and full slipping, respectively. Meanwhile, the feasibility and rationality of the quasi-static numerical method is verified by the quasi-static analytical method based on the elastic center method and empty complex function based quasi-static analytical method. The results show that: 1) the quasi-static analysis of circular shield tunnels is feasible with the friction elements simulating interface characteristics under proper boundary conditions; 2) full contact without slipping and full slipping are two ultimate states considering interface contact friction characteristics; 3) under the action of horizontal shear waves, the additional seismic bending moment and axial force distribute as an asymmetrical axis on the axis of 45° and -45°, with a distribution pattern of an asymmetricone; and 4) the additional seismic axial force increases with the increase of the interface friction coefficient,while the additional bending moment decreases with the increase of the interface friction coefficient, which means the friction coefficient has more influence on the axial force than on bending moment. 2016 Vol. 53 (5): 51-55 [Abstract] ( 1251 ) [HTML 1KB] [ PDF 1957KB] ( 2113 ) 56 Stability Analysis of the Surrounding Rock of Shallow Bias Tunnels under a Slope Crest Load LUO Wei- 1, 2 Zeng-Run-Zhong- 2 Rong- Yao- 1 Geng-Da-Xin- 2 Shi-Yu-Feng- 2 Based on a typical failure mode of shallow tunnels in sloping areas, the combined limit analysis upper bound method and the nonlinear failure criterion of the tangent method were used to derive the surrounding rock pressure formula of a shallow tunnel in a sloping area with consideration given to the slope crest load. MATLAB software was used to program the optimization solution, which analyzed the impact of the slope- top load and burial depth ratio on the surrounding rock pressure of the shallow tunnel and failure mode. The results show that the surrounding rock pressure of the shallow tunnel increases with an increase of the ground nonlinear coefficient and a decrease of the counter-force ratio of the horizontal-to-vertical support; both the increase of the slope crest load and burial depth ratio will reduce the surrounding rock stability of the shallow tunnel; and with the increase of the slope crest load and burial depth ratio, the failure of the shallow tunnel deflects to the side of the slope, where it is relatively shallow. 2016 Vol. 53 (5): 56-62 [Abstract] ( 1261 ) [HTML 1KB] [ PDF 1375KB] ( 1977 ) 63 Distribution and Simplified Calculation Method of the Frost Heaving Force of Highway Tunnels in Cold Regions HUANG Ji-Hui- 1, 2 Xia-Cai-Chu- 1, 2 Han-Chang-Ling- 3 Li-Zhi-Hou- 4 Considering the uneven frost heaving of surrounding rocks, calculations of frost heaving forces on curved-wall tunnels in different frost regions were carried out by FEM method and the impacts of tunnel depth and lining structure on frost heaving force values were analyzed. The results show that the envelope of frost heaving forces is pearl shaped, with the maximum force occurring at the arch spring and the minimum force at the inverted arch,and the frost heaving force on the lining increases with tunnel depth, while the frost heaving force basically remains unchanged when the depth of the tunnel in a seasonal frost region and permafrost region is more than 50 m or the depth of the tunnel in a permafrost region is more than 100 m. The ratio of frost heaving forces on the curved-wall lining and round lining is a constant regarding the same class surrounding rock in different frost regions. Accordingly, the analytical solution for the frost heaving force on a round-shaped tunnel was modified and the distributions and simplified calculation methods were obtained for the frost heaving force loads of tunnels in different frost regions, as well as the frost heaving force loads on the Qingshashan Tunnel. The difference between the calculated value and the measured value of the maximum frost heaving force is 16% to 33%, and the calculated frost heaving force envelop curve coincides quite well with the in-situ measurements in terms of magnitude and distribution characteristics. In conclusion, this method does not require modeling, is performed more quickly than the FEM method, consid? ers the impacts of depth and lining structure on frost heaving force and makes up the shortfall of analytical solutions,and is therefore very practical and can be used for calculating the frost heaving force on tunnels in cold regions. 2016 Vol. 53 (5): 63-70 [Abstract] ( 1467 ) [HTML 1KB] [ PDF 2123KB] ( 2350 ) 71 Back-Analysis on the Retaining Structure Deformation/Internal Force of a Subway Deep Foundation Pit WANG Ye-Sheng- Chen-Wen-Hua- Wu- Yong- Huang-Jiang-Hua Considering the inclination monitoring data of retaining structures, a comparative analysis on the com? monly used curve-fitting based multiple back analysis methods was carried out for retaining structure deformation/internal force (bending moment) and their effects. Furthermore, a back-analysis of shear force is put forward. The research results show that it is reliable to obtain the results of internal force (bending moment, shear force) by means of back analysis of the retaining structure based on fitting deformation curves by the smooth spline and least square method. Meanwhile, the feasibility, range of application, suggested values of the fitting parameters and serviceability of those two methods are discussed according to the actual measurement data of a foundation pit project in Ningbo. It is possible to accurately control the internal force state of the retaining structure by comparing the back-analysis results of internal force with the ultimate bearing capacity of the retaining structure, which provides technical support for the dynamic safety risk assessment of subway deep foundation pit engineering. 2016 Vol. 53 (5): 71-77 [Abstract] ( 1340 ) [HTML 1KB] [ PDF 2520KB] ( 2098 ) 78 Study on the Temperature Field and Insulation Layer Thickness of the Yuximolegai Tunnel FENG Qiang- 1 Liu-Wei-Wei- 1 Jiang-Bin-Song- 2 The Yuximolegai tunnel on the G217 national highway in Xinjiang is located in a high-altitude seasonal frozen-ground region. In order to ensure its safe operation, it is necessary to study its temperature field and determine a proper insulation layer thickness. An automatic temperature monitor was used to obtain temperature variations at different radial depths of the Yuximolegai tunnel. Based on the calculating parameters determined by laboratory tests, the model boundary conditions were determined by fitting the analytical results of field temperature monitoring. The temperatures obtained by field monitoring were compared with those determined by the temperature field calculation without an insulating layer, and their changing tendencies are basically in agreement. Further analysis was conducted on the reliability of the 5 cm-thick insulating layer used in the field, and the calculations show that there is a freeze scope of 0.4 m behind the lining wall. The expanding law of the freezing front was analyzed and results indicate that the freezing front expands fastest and for the farthest distance on the spandrel and bottom, where the most dangerous positions on the whole cross section are. Ultimately, the required thickness of the insulating lay? er was calculated according to the criteria of whether or not the temperature outside the spandrel and bottom lining layer is 0℃. 2016 Vol. 53 (5): 78-84 [Abstract] ( 1404 ) [HTML 1KB] [ PDF 2543KB] ( 1895 ) 85 Experimental Study on the Mechanical Characteristics of the Xujiachuan Loess Tunnel on the Baoji—Lanzhou PDL ZHANG Tang-Jie- 1, 2 , 3 Liang-Qing-Guo- 1, 2 Wu-Xu-Yang- 1, 2 Wang-Xin-Dong The Xujiachuan loess tunnel on the Baoji-Lanzhou PDL was constructed by the three-bench and sev? en-step assembly-line construction method, and being characterized by its large deformation of surrounding rock, it was very difficult to construct. In this paper, the time-dependent change rules and distribution tendencies of the surrounding rock pressure, steel arch stress, contact pressure between the primary lining and secondary lining, and the xial force of the secondary lining reinforcement and concrete strain are studied by in- situ monitoring measurements and the safety of practical engineering is assessed. The general rule and characteristics of the tunnel’ s construction are concluded through in-situ monitoring measurements and data analysis, which can provide a reference for the construction of similar loess tunnels in the future. 2016 Vol. 53 (5): 85-91 [Abstract] ( 1380 ) [HTML 1KB] [ PDF 3592KB] ( 2114 ) 92 Stochastic Medium Prediction for Ground Settlement Induced by Double-Line Parallel Shield Tunnelling WEI Gang- Zhou-Yang-Kan According to the calculation method of ground settlement induced by double-line parallel shield tunnel? ling (DLPST), a simplified method of stochastic medium theory is modified in this paper that: calculates the ground settlements induced by both prior and later shield tunnelling, respectively; considers different parameter values and the shifting of maximum ground settlement induced by later shield tunnelling; and eventually obtains the total ground settlement induced by double- line parallel shield tunnelling. Research findings show that the proposed method can be used to calculate the ground settlement and horizontal displacement; its calculated values mostly coincide with the measured values of ground settlement, and it therefore has a wide application. Because of the impacts of prior shield tunnelling, the surrounding soil mass is disturbed during later shield tunnelling and the radius convergence of the second shield tunnelling is larger than that of the prior shield, while the main influential angle becomes smaller and the maximum ground settlement is shifted to the direction of the central axis. 2016 Vol. 53 (5): 92-99 [Abstract] ( 1327 ) [HTML 1KB] [ PDF 2321KB] ( 1954 ) 100 Analysis of Ground Settlement Induced by Small-Space Twin-Tube Tunnel Excavation Underneath a Mined-Out Area ZHANG Xue-Jin- 1 Fang- Yong- 2 Yang- Bin- 3 Liu-Shu-Bin- 2 During the construction of a small-space twin-tube tunnel underneath a mined-out area, the distur? bance from an adjacent tunnel excavation will be superimposed and the stability of the mined-out area is seriously affected. An indoor similar model test of a small-space twin-tube tunnel underneath the mined-out area was carried out and the settlement of the rock mass and around the mined-out area during excavation was monitored. Considering the two cases of formation dip angles of 15 ° and 25° in the mined-out area, the simulation of formation discreteness in the mined-out area and the similarity of the model to prototype was achieved by controlling the rock compressive strength and porosity in the mined-out area. Test results show that: 1) there are three extreme ground settlement points located in the left tunnel, right tunnel and middle rock wall of the mined-out area, respectively, with the maximum ground settlement occuring above the pilot tunnel; 2) the greater the dip angle is, the larger the settlement is and the wider the range of settlement is; 3) the maximum settlement induced by the small-space twintube tunnel excavation is about 35% to 74% higher than that of single-tube tunnel excavation, and the impact of pilot tunnel excavation on the settlement above the subsequent tunnel is less than that of the following tunnel excavation on the settlement above the pilot tunnel in the mined-out area; and 4) the settlement process of the mined-out area can be divided into six stages, and the settlement develops quickly during excavation of the left and right tunnel underneath the mined-out area. In order to avoid the extension of the disturbance range during the following tunnel excavation, excavation of the following tunnel should be performed after stabilization of the mined-out area settlement induced by the pilot tunnel excavation or installation of the secondary lining of the pilot tunnel. 2016 Vol. 53 (5): 100-107 [Abstract] ( 1306 ) [HTML 1KB] [ PDF 2833KB] ( 1980 ) 108 Composite Beam Model for the Force Calculation of a Tunnel Lining with Double-Layer Molded Concrete LI De-Wu- 1, 2 Yang-Jin-Jing- 1 Based on the load structure model and the elastic linkage finite element method, the force applied on a double-layer tunnel lining with molded concrete was simulated using a composite beam model. As the contact pressure between the two lining layers is transferred by the radial spring, which can only be compressed, the double-layer molded concrete lining can share the load, whose ratio can be distributed automatically. The calculation results show that the composite beam model has advantages over the traditional methods in terms of the analysis of safety and stability of the double-layer lining with molded concrete and can serve as a new approach for the design and calculation of complex tunnel linings. It is suggested that an elastic coefficient of 500 MPa/m below the haunch and 300 MPa/m between the crown and haunch should be used when the force on the double-layer lining is calculated based on a composite beam model. 2016 Vol. 53 (5): 108-113 [Abstract] ( 1272 ) [HTML 1KB] [ PDF 936KB] ( 2062 ) 114 Analysis of the Influence of Basis Conditions on the Dynamic Response of a Bottom Structure of a Heavy Haul Railway Tunnel and Its Service Life LIU Ning- Peng-Li-Min- Shi-Cheng-Hua- Yan-Wei-Guang Bottom softening and voids in a railway tunnel often occur over long-term operation, which has a great impact on the service life of the tunnel structure. Based on the train vibration load represented by the superposition of sine functions with different frequencies, a numerical model is established of a tunnel rock mass with consideration given to the interactions between the tunnel bottom structure and foundation rock mass. The influence law is discussed based on the changing characteristics of the dynamic response of the tunnel bottom structure, and the influence of the basis condition on the service life of the heavy haul railway tunnel is analyzed based on the Miner linear cumulative damage law. The results show that in different softening and void conditions, the dynamic stress response regularities of the tunnel bottom structures are similar; average stress and stress amplification on each part of the tunnel bottom structure increases, and its fatigue life decreases; the maximum value of tensile stress occurs at the center of the invert at the tunnel bottom; and fatigue failure first occurs at the invert under the tunnel track. 2016 Vol. 53 (5): 114-122 [Abstract] ( 1402 ) [HTML 1KB] [ PDF 4282KB] ( 2075 ) 123 Study on Burning Failure Mechanism of Friction Couples of the InfinitiveStage-Clutch in a Shield Machine′s Cutterhead CHEN Ning- 1 Derek Chen 2 Qiu-Min-Xiu- 3 Weng-Wei-Bing- 1 Xu- Xing The thermal load field between the friction couples of the 300 kW infinitive-stage-clutch used in a shield machine′s cutterhead, which is composed of copper-based powder metallurgy friction plates and 22MnB5 steel dual-discs, were calculated according to the heat conduction theory combined with the engineering thermodynamics method. The temperature field distribution T(r) along the friction couple′s surfaces was obtained, as well as the week thermal stress σ θ distribution and the radial thermal stress σr distribution along the radial direction of the dual-steel-disc′s surface. Two conclusions were drawn from those distribution curves: that T(r) , σθ and σr are clearly heterogeneous in the radial direction, and that σθ , being larger than σr in an order of magnitude, should be contributed to the deformation of the dual-steel-disc. It can theoretically be concluded from further analyses that the friction couple would be under the critical sliding friction condition if the speed difference Δω falls to 1.37 π rad /s; the material layer of the powder metallurgy friction plate might be burned or damaged because of T(r) when the friction couple repeatedly runs or works for a long time under the critical sliding friction condition, and the dual-steel-disc might be converted from a plane into a shallow dish in the axial direction as a result of σθ . By the experiments, the failure mechanisms and modes of the powder metallurgy friction plate and it′s dual-steel-disc are proved and the recommended values, complying with the quantitative definition indicators under the actual critical sliding friction condition during design and operation of the infinitive-stage-clutch in the shield machine′s cutterhead, are proposed. 2016 Vol. 53 (5): 123-130 [Abstract] ( 1242 ) [HTML 1KB] [ PDF 2118KB] ( 1884 ) 131 Breaking Force Derivation and Wear Rate Forecast of Shield Disc Cutters ZHU He-Yi- 1 Yang-Yan-Dong- 2 Chen- Kui In order to ensure accurate key parameter configuration of a shield machine and seize the opportunity for disc cutter replacement, a visualized breaking force forecast model for disc cutters was established through a mathematical deduction by CSM model and a wear rate forecast model of the disc cutter was set up by analyzing the disc cutter wear mechanism based on the abrasive wear mechanism. Since there are some approximate calculations in the process of model derivation and great changes to parameters in the operation of a disc cutter, an error analysis of the derived models was carried out. Finally, the correctness of the two models was determined through field measured data. 2016 Vol. 53 (5): 131-136 [Abstract] ( 1315 ) [HTML 1KB] [ PDF 1878KB] ( 2495 ) 137 Safety Assessment of Trackless Transportation Systems in Shield Tunnels Based on Fuzzy Comprehensive Evaluation FENG Kun- 1 Cheng-Tian-Jian- 1 Dai-Zhi-Cheng- 1 He- Chuan- 1 Wang-Shou-Qiang- 2 Zhang-Zhi-Bo- 2 Trackless transportation adopted in shield tunnel construction accelerates the advance rate and reduces the influence upon the environment while also increasing transportation risks. By analyzing the relative influential factors of a trackless transportation system, a secondary fuzzy comprehensive evaluation model was established,which includes transportation staff, the environment inside the tunnel, transportation conditions and safety management. Considering the qualitative and quantitative factors, a triangular fuzzy distribution and expert scoring method were used to obtain their membership degrees, respectively. To eliminate the decision maker’ s subjective preference, an analytic hierarchy process was used based on group decision making to establish the weight vector and conduct a fuzzy comprehensive calculation using the weighted average method. This evaluation model was applied to the safety assessment of the trackless transportation system in the shield tunnel of Nanjing metro line 10, and the results show that it is basically safe. No safety accidents occurred during construction after improving this transporta? tion system, which verifies the effectiveness of the evaluation model. 2016 Vol. 53 (5): 137-144 [Abstract] ( 1292 ) [HTML 1KB] [ PDF 1401KB] ( 1910 ) 145 Study on Excavation Schemes for the Redevelopment Construction of Highway Tunnels with Large Sections HUANG Lun-Hai- 1, 3 Qian-Qi-Hu- 1, 2 A redevelopment scheme for highway tunnels with large cross sections is presented using analog simula? tions and numerical calculations to study the law of surrounding rock deformation and stress variation during in-situ reconstruction of a large cross section tunnel in weak surrounding rock based on the first domestic in-situ reconstruction of a highway tunnel expanded from a twin-tube, four-lane highway tunnel into a four-tube, eight-lane tunnel. A combined construction scheme is set forth in which new construction goes before expansion, providing a reference for highway tunnels and similar underground works. 2016 Vol. 53 (5): 145-153 [Abstract] ( 1329 ) [HTML 1KB] [ PDF 4690KB] ( 2169 ) 154 Study on the Excavation Scheme for the Deep Foundation Pit of a Subway Station Approaching an Existing Railway SONG Lin- Li-Chang-Ning- Fan-Heng-Xiu The appropriate selection of an excavation scheme is important for controlling the deformation of the deep foundation pit of a subway station approaching an existing railway. Using the foundation pit engineering of the Qianhaiwan station of Shenzhen Metro line 11 as a background, and considering the interaction of the soil mass, retaining structure and support system, a 3D numerical model is established by finite element software to carry on a dynamic study of the two excavation schemes, i.e., the open-cut bottom-up method and the cover-and-cut topdown method. The results show that the latter is more effective for controlling the deformation of the retaining structure while the bending moment and shearing force produced by the retaining structure is larger. This research provides essential theoretical data support for excavation schemes of deep foundation pit construction. 2016 Vol. 53 (5): 154-160 [Abstract] ( 1392 ) [HTML 1KB] [ PDF 3118KB] ( 2149 ) 161 Practical Calculation Method for the Construction of Parallel Shield Tunnels with Small Spacing LI Xiao-Lin- 1, 2 Tao-Lian-Jin- 1 Guo- Ting- 2 Hui-Li-Ping The interaction between two parallel shield tunnels with small spacing is obvious in construction, and the space between two tunnels is a controlling factor. Considering the lack of reliable computation and analysis methods and inexperience regarding the design and construction of shield tunnels with small spacing, a calculation method is presented to describe the whole process of construction interactions between two shield tunnels with small spacing based on a combination of the modified routine method and the incremental method, which are the typical structure design methods used in shield tunnels. As the presented method has been successfully applied in practice,it can be used as a general design method for shield tunnels with small spacing and long distances. 2016 Vol. 53 (5): 161-167 [Abstract] ( 1322 ) [HTML 1KB] [ PDF 2755KB] ( 2032 ) 168 On the Effects of Horizontal Jet Grouting Pile Pre-Reinforcement of Tunnels in a Strong Weathered Granite Stratum WANG Ke- 1 Lai-Jin-Xing- 2 Qiu-Jun-Ling- 2, 4 Huang- Hao- 3 Li-Xiao-Hong- 4 In Fuzhou, the bored section of the Hudongdonglu tunnel passes through a sandy strong weathered granite stratum and therefore requires strict control of surface deformation. Horizontal jet grouting piles pre-reinforcement technology was adopted in its design. In order to guide construction and identify the key points for tunnel construction monitoring, a study on the pre-reinforcement effect of horizontal jet grouting piles and the law of tunnel structure displacement was performed using the 3D elasto-plastic finite element method. Study results show that with reinforcement with horizontal jet grouting piles, compared to construction with no horizontal jet grouting piles,the final settlement of the arch crown was reduced by 63.45%, the longitudinal displacement of the tunnel face was decreased by 69.6% and the plastic strain area of the tunnel face was reduced dramatically. The pre-reinforcement by horizontal jet grouting piles effectively controls the deformation and has a remarkable reinforcement effect. 2016 Vol. 53 (5): 168-175 [Abstract] ( 1266 ) [HTML 1KB] [ PDF 2754KB] ( 1978 ) 176 Landscape Design of a Tunnel Portal Integrating the Regional Culture of Bai Nationality BAI Guo-Quan People of Bai nationality live mostly in Dali in the Yunnan province, and the special Bai national cul? ture and architectural art are captured by their residence there. As the Dali-Lijiang expressway is a cultural tourism route, how to embody the regional culture of Bai nationality in the design of highway structures is a problem worth being discussed in-depth. Focusing on the Huajiaoqing tunnel as a background, the following were studied and analyzed: common architectural and decorative features of Bai residences, the pattern development of the tunnel portal,the landscape design principles and the present status of the tunnel portal. The landscape design overview of the Huajiaoqing tunnel portal is described, and recommendations are put forth in order to address regional cultural inheritance through structures like tunnels. 2016 Vol. 53 (5): 176-182 [Abstract] ( 1436 ) [HTML 1KB] [ PDF 3455KB] ( 2299 ) 183 Optimized Design for the Construction of a Double-Arch Tunnel with a Concealed Mid-Partition LI Hai-Jun- 1 Zhang-Wan-Bin- 1 Wang-Ming-Nian- 2 During the construction of a long and shallow double-arch tunnel with a concealed mid-partition, some technical difficulties are encountered, such as the complicated construction procedure of pipe-roof advance support,stress concentrations at both the haunch and side wall while excavating the pilot tunnel and poor stability of sandwiched rock on top of the mid-partition, etc. Using a specific project as an example, pipe-roof technology without a chamber was adopted to decrease the influence on construction efficiency of the double-arch tunnel. The optimized design and calculation analysis of a double-arch tunnel with a concealed mid-partition was carried out with the three aspects of installing long, meshy non-isoparametric system bolts at the top of mid-partition; utilizing a smooth transition between the mid-partition and preliminary lining of the pilot tunnel; and installing suspended self-drilling rock bolts on both sides of the temporary mid-partition. Analysis results show that the construction safety of a double-arch tunnel with a concealed mid-partition is greatly improved by the above-mentioned optimizations; for a double-arch tunnel with a concealed mid-partition, using optimized structures and pipe-roof technology without a chamber enables rapid and safe construction, indicating a positive prospect for engineering application. 2016 Vol. 53 (5): 183-187 [Abstract] ( 1426 ) [HTML 1KB] [ PDF 941KB] ( 1968 ) 188 Risks and Countermeasures during Shield Construction of the Xiamen Metro Under Complicated Geological Conditions YANG Shu-Jiang The geological conditions encountered during construction of the Xiamen metro are extremely complicated and the shield construction has been confronted with enormous risks. Taking the Xiamen Metro Line 1 as an example, the potential risks were analyzed in terms of geological surveys, shield selection, shield driving in special geological conditions and shield construction management, etc. Relevant countermeasures based on practical experience are discussed, which offers a reference for shield construction in similar strata. 2016 Vol. 53 (5): 188-193 [Abstract] ( 1367 ) [HTML 1KB] [ PDF 1422KB] ( 2636 ) 194 Key Techniques for Construction of the Taiyue Mountain Tunnel SONG Li The Taiyue Mountain tunnel, with a total length of 16 km, passes through multiple faults in water-rich sections characterized by large water inflow, high water pressure and fractured zones, and is characterized by a surrounding rock formation that is mainly horizontal sand shale interbed with certain expansibility. Considering the complicated geological conditions and construction difficulties encountered at the Taiyue Mountain, relevant key techniques for tunnel construction were optimized and improved with respect to the bench method, the drill&blast method, ventilation and drainage, and these improvements accelerated the construction speed and ensured highquality and efficient tunnel construction. 2016 Vol. 53 (5): 194-199 [Abstract] ( 1502 ) [HTML 1KB] [ PDF 1511KB] ( 2195 ) 200 Optimization of Wave Velocity Parameters for TRT Forecast and Its plication in the Advanced Geological Forecast of a Karst Tunnel in Guizhou TIAN Gang- 1, 2 Bai-Ming-Zhou- 1, 2 Wang-Cheng-Liang- 1, 2 Shi- Hai- 1 Nie-Yi-Cong- 1 The basic principles of TRT technology are analyzed and discussed, and the advantages and disadvan?tages of TRT technology in tunnel geological forecasts are listed. Considering that the selection of TRT background wave velocity is greatly influenced by human factors and lacks objectivity, a calculation mode for the direct velocity confidence interval under a normal distribution is put forward. The upper and lower thresholds of the confidence interval were used as the background wave velocity parameters put into the TRT system for calculation and analysis,and to some extent this method avoids the limitations of a single background wave velocity selected manually for geological disaster forecasts in Karst tunnels. For analysis of the resulting TRT images, the map would be divided into three pairs of chromatographic bands to be interpreted and analyzed, and thereby the interpretation of the TRT images shall be more targeted. Based on the segmented wave velocity information and the geological field data of a certain Karst tunnel, a comprehensive geological forecast was conducted and the accuracy of this method was verified 2016 Vol. 53 (5): 200-207 [Abstract] ( 1309 ) [HTML 1KB] [ PDF 3792KB] ( 2155 ) 208 Application of Combined Clapboard and Vent-Pipe Ventilation Techniques in the Construction of Extra-Long Tunnels on a Plateau HAN Xian-Min- Sun-Ming-Lei- Zhu-Yong-Quan Ventilation is always a challenge that tunnel technicians have to face in the construction of long-dis? tance tunnels by the drill-blasting method, especially in the hypoxic plateau. The 32.6 km-long Guanjiao tunnel is characterized by its high altitude, long distance, multiple working faces and ventilation difficulties; therefore, a combined separated inclined shaft and vent-pipe ventilation system is put forward for the first time to solve the tunnel′s ventilation problem during construction. After the selection of a fan and the design of the tunnel ventilation system,a numerical simulation and field measurements were carried out to test the ventilation effects and obtain a reasonable distance from the nozzle of the air pipe to the working face and its relationship to the air speed on the working face when the working face is under construction by the combined ventilation scheme. The measurements show that the poisonous gases (CO, SO2) have a lot to do with the construction situation of the working face, and the ventilation effect is good and meets the current requirements of tunnel specifications for general working conditions. 2016 Vol. 53 (5): 208-215 [Abstract] ( 1384 ) [HTML 1KB] [ PDF 2165KB] ( 2015 )

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