Construction of Early Warning Control Platform for Tunnels and Subway Engineering北大核心CSCD

Based on an introduction to the construction and application of the early warning control platform for the tunnel and subway engineering, an overall analysis of the related data during tunnel and subway construction was conducted in order to give a better reference for the site construction, to guarantee safe and rapid qualified construc⁃tion, and to improve management efficiency. Based on red line control, deformation thresholds of surrounding rock, allowances of construction material and advanced geological prediction, a dual early warning system with automatic trigging and manual prejudging was adopted to control the quality of tunnels and subways and to guarantee safe con⁃ struction; through the platform a centralized management is realized, all the construction information and effective data are transmitted instantaneously by internet, decreasing management cost and increasing work efficiency. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

The Updated Concept of Conventional Tunnelling in Soft Surrounding Rocks北大核心CSCD

In a perspective of modern tunnelling philosophy, some problems on conventional tunnelling in soft rock mass were discussed. The development process of rock mechanical behavior and deformation caused by excava⁃ tion is attributed to the change course from yielding to discrete. Some effective control means were presented as well and the effect of advanced support system was evaluated. As to the deformation controlling technology for squeezing ground, the theory and design principle of yielding support system were introduced. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Development of the Software for Calculating Tunnel Portal Structure Based on the Theory of Limit State Method北大核心CSCD

The limit states of railway tunnel portal structure including compression, tensile, anti-overturning, antisliding and bearing capacity of foundation should be considered when portal structure is designed based on the prob⁃ ability limit state method. In order to evaluate the reliability of portal structure, the reliability index and limit state of bearing capacities of different limit states need to be calculated. The traditional methods generally use hand compu⁃ tation combined with MATTLAB, ANSYS, EXCEL and other softwares, which has low computation efficiency and poor practicality. In view of above problems, a calculating software for portal structure was developed based on the probability limit state method and Visual Basic platform, which realizes the function of rapid calculation of reliabili⁃ ty index and limit state of bearing capacities under five limit states of portal structure, offers three methods to calcu⁃ late the reliability index including JC method, fractile method and Monte-Carlo method. Moreover, the calculation results can be written in the EXCEL template file, greatly improving the efficiency of tunnel portal structure calcula⁃ tion. The accuracy of the software is verified by comparing with the results of hand calculation. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Key Techniques for Lean Construction Management of the High Speed Railway Tunnels北大核心CSCD

Improvements of management mode and application level of informationization techniques are the key factors to safe and efficient construction of the high-speed railway tunnels considering the complexity and diversity of construction techniques, unpredictable risk factors and varied geological conditions. In the paper it proposed a management mode for lean construction of high-speed railway tunnels, studied the in-depth integration and applica⁃ tion of key technologies of BIM, advance geological prediction, tunnel surrounding rock measurement, 3D laser scan⁃ ning, etc. in the lean construction management of high-speed railway tunnels, and developed the light portal APP and cloud-based information management system. Through the verification of practical engineering application, it re⁃ alized good monitoring of key risk resources in tunnel construction, redline control for key tasks and effective manage⁃ ment of safety and quality, increased efficiency of collaborative operation of all parties involved and reached the goal of lean construction and management. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

A Preliminary Study on the Law of Ground Settlement Caused by Shield Tunnelling Based on the Stratum Characteristic Value M S北大核心CSCD

Based on an analysis of monitoring data of surface settlement in the construction of a shield running tunnel of Beijing metro, an improved hyperbolic model was proposed to fit the ground subsidence law, and the characteris⁃ tic factor M S was used to evaluate the stratum under the condition of shield construction. The relationship between stratum parameters and surface settlement was studied, with the results indicate that the surface settlement caused by shield construction complies with hyperbolic distribution and it is basically stable at 30 days, the larger the value of M S is, the better the conditions of the stratum is and the smaller the settlement is; a certain correlation exists be⁃ tween the parameters of improved hyperbolic model and the characteristic value M S . © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Estimation Method for Ground Settlements of the Karst Tunnel in Soil Surrounding Rock北大核心CSCD

Waterseepageofakarsttunnelsectioninsoilsurroundingrockispronetosurfacesubsidence.Considering the settlement caused by descending of water level due to water leakage, a method of surface settlement estimation under steady seepage of phreatic water was proposed. Based on the seepage and consolidation theory, the changes of dead-weight and seepage effective stress of soil unit in surrounding rock was analyzed in condition of water seepage, and the settlement zone of surrounding rock was divided by taking the funnel curve of precipitation as the boundary line. A two-dimension plane was established based on the excavation cross section and the estimation formula for surface settlement due to seepage effect was deduced by means of double integral. On the basis of Yaozhai tunnel of Liuzhai-Hechi Expressway in Guangxi Zhuang Autonomous Region, the surface settlement of soil surrounding sec⁃ tion was predicted by field measurement and formula estimation respectively. Facts and figures show that the mea⁃ sured values are mainly consistent with the estimation ones, while the measured values are larger than the estima⁃ tion ones within the scope 3 m away from the excavation face along the horizontal radial direction. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Comparative Analysis of Calculation Methods for Jacking Force of Jacking Pipes北大核心CSCD

Jacking force is the most important parameter in jacking pipe engineering, and reasonable calculation of jacking forces plays an important role in safe and smooth pipe jacking construction. There are many calculation methods for pipe jacking force at present, and the calculation results may be affected to some extent by different cal⁃ culation methods. For this reason, calculation methods of jacking force (frictional resistance) were collected and a comparative analysis was conducted with aspects to the advantages, disadvantages and applicabilities. The results show that as for the jacking force calculated by empirical formulae, the soil layer classifications corresponding to giv⁃ en frictional force per unit area and relevant factors to be considered are different, and the values of frictional force per unit area between pipe and soil in the same soil layer are also different; as for the jacking force calculated by theo⁃ retical formulae, the calculation methods for vertical earth pressure at crown are different and much effected by the pipe buried depth; as for the jacking force calculated by numerical simulation, the selected theories for the simula⁃ tion program and the construction factors to be considered during simulation are different. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Flexible Overlap Technology for the Lining Trolley of Single-track Railway Tunnels北大核心CSCD

Falling-off of rock piece at tunnel arch and invert heave are the main potential safety problems affecting normal operation of the railway tunnel. The reasons causing falling-off of rock piece include squeezing by lining trol⁃ ley at construction joint, concrete cutting by cantilever end of water stop at construction joint, construction cold joint at arch, concrete quality deficiency and so on. To eliminate the falling-off of rock piece at tunnel arch caused by rig⁃ id overlap, modification of lining trolley and the flexible overlap technique combining tray with rubber gasket were adopted during the construction of Nuwashan tunnel on China-Laos railway, and the potential quality problem due to rigid overlap at construction joint of tunnel lining were effectively solved. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Distribution Laws of Earth Pressure Acting on a Shield Tunnel Based on Measured Data北大核心CSCD

The earth pressure acting on a shield tunnel is intrinsically related to synchronous grouting, the position of the shield machines, the rigidity of the segment and stratum, etc. Existing theoretical formulas and empirical methods couldn′t exactly reflect the actual state of the segment of a shield tunnel during construction due to the com⁃plexities mentioned above. Based on earth pressure data measured at 52 monitoring sections in 35 tunnels, the distri⁃bution laws and influential factors are analyzed. The results show that: 1) the earth pressure scope is 0 to 400 kPa for over 90% of the total samples, but is recommended to be 0.3 to 0.4 MPa for the empirical grouting pressure; 2)the earth pressure on the segment and the buried depth approximately have an exponential relationship, with the dif⁃ference between the max. earth pressure and the stable earth pressure decreasing with an increase of the buried depth; 3) the lateral pressure coefficient range is 0.5 to 2.3, which is partially out of the scope of recommended values(0.5 to 1.0) of surrounding rock of grade Ⅵ, so it is not appropriate to follow the recommended values in the specifi⁃cation; 4) the relationship of the earth pressure and the segment/soil stiffness ratio presents a quadratic function, and the most reasonable value for the stiffness ratio of the segment/soil is 1.0; and 5) there are four typical stages of the spatial distribution of earth pressure on a segment in clay stratum—the erection stage, the grouting influence stage,the consolidation contraction stage and the recovery stage, with the distribution of the circumferential earth pressure being asymmetrical. The distribution curves of the earth and water pressure in sand and soil layers are classified as a“weak decay pulse fluctuation”and“double hump,”respectively. After stabilizing, the circumferential earth pressure is notably in a symmetrical distribution, and the water pressure exhibits a light bulb shaped distribution (large at the lower part and small at the upper part). These conclusions provide a reference for studying the mechanism of earth pressure functions and perfecting the design of segments for shield tunnelling. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Application of Vertical Freezing Technique in the Deep-buried Mountain Railway Tunnel北大核心CSCD

The strata of Chengershan tunnel is mainly consist of the slightly cemented tertiary sandstone, the tun⁃ nel body passes through F 2 fault core zone. Geological disasters of mud outburst, sand gushing and extrusion of work face occurred several times during tunnel construction, so the risks are very high. In view of the core zone of F 2 fault with high pressure and abundant water, a variety of construction schemes were compared and analyzed in terms of technology, feasibility and safety, and vertical freezing technique was used for stratum reinforcement in the railway tunnel for the first time, furthermore the freezing scheme and tunnel support measures were studied, providing refer⁃ ence and guidance for similar tunnel construction.Mountain railway tunnel; Fault zone; Tertiary sandstone; Vertical freezing technique; Application © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Contrastive Analysis of Working Face Stability in Cases of Climbing Excavation and Horizontal Excavation北大核心CSCD

Restricted by site and construction period of ancillary structure of metro project, climbing excavation is often adopted. In order to determine tunnel face’s stability, the stabilities of working face in the cases of climbing ex- cavation and horizontal excavation were analyzed by theoretical analysis and numerical simulation. With upperbound limit analysis, the affected scope and positions of failure zone were compared; the position of equivalent strain zone and the law of horizontal displacement changes were studied by simulation analysis. The results show that the scope of failure zone caused by climbing excavation was slightly larger than that by horizontal excavation and the po- sition of affected zone is slightly lower than that by horizontal excavation; the horizontal displacement caused by climbing excavation within a scope of 0-1/3 height of tunnel face is slightly larger than that by horizontal excavation while it is slightly smaller beyond the scope of 0-1/3 height of tunnel face; the maximum horizontal displacements in the cases of climbing and horizontal excavation both occur at the place where is 1/3 height of work face and the de- formation of work face in the case of climbing excavation is not larger than that of horizontal excavation; the work face stabilities are mostly the same in the cases of climbing and horizontal excavation without regard to advanced support, and the work face stability is to be guaranteed with proper advanced support. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Analysis and Research on the Tunnelling Technology of Compound EPB Shield Machine in High-strength Hard Rocks北大核心CSCD

It's really challenging for shield driving when hard rock partially intrudes into the excavation section of metro tunnels. Abnormal cutter wear is excessive during shield excavation in hard rock and comprehensive perfor⁃ mance of excavation system decreases greatly, resulting in abnormal advancing parameter, small penetration rate and low advance rate. Taking Shenzhen Metro line 9 project as the background, the main difficulties encountered for the compound EPB shield during driving in high-strength granite and the reasons were analyzed, the corresponding countermeasures were presented. EPB shield drove through the hard rock section safely and smoothly attributed to reasonable cutter configuration, in-time cutter replacement and proper advancing parameters. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

A Study of Prevention Techniques for Tunnel Lining Defects北大核心CSCD

Defects of tunnel lining, such as inadequate thickness, voids, cracks, rock falling and water leakage etc., endanger the safety of railway tunnel operation. Based on the site construction, an analysis of the reasons for lining defects was conducted; technical measures against lining defects were proposed and tests were carried out at site. The results show that these measures are reliable and effective, and the purposes of prevention and treatment are re⁃ alized. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Study on Reinforcing Technology System for the Overlapped Running Shield Tunnels underneath the Track Group of High Speed Railways北大核心CSCD

The large settlements of tracks will emerge due to multiple disturbances in the construction of over- lapped shield tunnels, which affects the running safety of trains. Based on the overlapped Sungang station-Honghu station shield running tunnels of Shenzhen Metro line 7 passing underneath 26 tracks of high speed railways, a rein- forcement technology system consisting of”track support + subgrade reinforcement + interlayer soil consolidation + internal support of the lower tunnel”was developed. The settlements of tracks were mainly monitored automatically with manual monitoring as an auxiliary one. The results show that the maximum settlement of main track caused by constructing overlapped shield tunnels is -5.9 mm which is less than the control value of 10 mm, ensuring the opera- tion safety and verifying the reliability and practicability of the reinforcement technology system. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Dynamic Evaluation of Reliability and Stability of the Primary Support of a Tunnel北大核心CSCD

The evaluation of the stability of a tunnel’s primary support is a crucial component of ensuring the safety of subsequent construction. In light of the measured clearance displacements of the Wushishan Tunnel, the reliabili-ty of the primary support is evaluated dynamically and the design of the support structure is optimized. The research results show that full displacement and ultimate displacement are two main parameters for tunnel reliability analy-sis: the former can be obtained by positive and negative analysis, and the latter can be acquired by simulating a field measurement of displacement. It is not sufficient to apply the data specified in the code for railway tunnel design re-liability regarding determination of the reliability of a road tunnel structure using reliability theory, and it is neces-sary to use reliability theory to amend the standard of allowable empirical displacement in the Code of Road Tunnel Design. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Scope Affected by Metro Tunnel Construction Blasting in Qingdao北大核心CSCD

Based on the blasting construction of a Qingdao metro tunnel, a linear regression analysis of Sodev’s em-pirical formula mentioned in the GB6722-2014 Safety Regulations for Blasting is conducted considering the geologi-cal conditions of Qingdao and collected blasting vibration monitoring data. An empirical formula to predict the am-plitude of the vibration intensity of Qingdao metro tunnel blasting is deduced, while the allowed vibration velocity,single-hole charging load and scope affected by the construction vibration are determined. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Numerical Simulation of Shield Tunnelling Under a Historic Building Based on the Local Stiffness Correction Method (DMSM)北大核心CSCD

The district modified stiffness method (DMSM) considers the effect of joints and hand holes on the stiff-ness of the lining ring, assuming the stiffness around the joint and hand hole is to be reduced and the stiffness else-where is not changed. Considering the stiffness reduction of the lining ring caused by the segment’s circumferential joint, the internal force of the lining structure, the ground surface settlement and the displacement response of the surrounding soil body induced by shield driving are analyzed by an HS small strain constitutive model, and a 3D FEM model is established to analyze the interactions among the tunnel, soil body and building to apply to the dou-ble-line running tunnel of Shanghai Metro Line 11, which crosses under a historic building. In contrast, a 3D numeri-cal model based on the routine method (RMM) is set up and a comparison with the site measured data is conducted,with results indicating that they agree very well. The simulation results show that the existing building not only changes the surface settlement trough but also largely reduces horizontal displacement at the corresponding measuring points of the settlement trough; the distortion values of the existing building are related to the positions of the tunnel face and the location of the building; and the final distortion doesn’t decrease after completion of tunnel construction, but major residual distortion remains. This simulation method provides a reference for the control of disturbances during shield construction in soft rock. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Influence of Light Distribution and Installation Style of Luminaires on Power Consumption and Lighting Effect of Tunnel Lighting北大核心CSCD

Light distribution (LD) and installation style of luminaires affect the utilization factor (UF) of luminaires, and the UF affects the luminaire power and road pavement illuminance and further the power consumption of illu- minating system and the luminous effect of road pavement. An UF model of tunnel lighting was established based on the luminaire LD data and installation parameters, in which four LD styles were adopted. For each LD the parame- ters optimization and simulation were conducted regarding four installation styles, e.g. central style, offset-of-vault style, symmetric style and staggered style. The energy-saving and the lighting effects of each LD and luminaire in- stallation style at the tunnel middle zone were studied. The results show that symmetric luminaire installation is the most energy-saving style and has the best lighting effect than the other three luminaire installation styles; the lighting effect of central luminaire installation is the second best; staggered luminaire installation is the most energy-intensive style and has the worst lighting effect except for some special-shaped LD; waterdrop-shaped LD is the most suitable one along transverse direction of tunnel and applicable to the central, offset-of-vault and symmetric luminaire instal- lation styles; symmetric butterfly-shaped LD is the most suitable one along longitudinal direction of tunnel and appli- cable to the central, offset-of-vault, staggered and symmetric luminaire installation styles; with waterdrop-shaped LD along transverse direction and symmetric butterfly-shaped LD along longitudinal direction, they are suitable for the above four luminaire installation styles, and have better energy-saving and lighting effect; as for the LD with symmetric and oblique curve, it’s better for the profile of oblique luminaire distribution to be comply with that along tunnel transverse direction, and it is suitable for the symmetric and offset-of-vault luminaire installation styles. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Model Test Study on’Lost’Deformation and Corresponding Control Measures in Soft Rock Tunnels with Extremely High Ground Stress北大核心CSCD

In order to study the laws of core rock deformation and’lost’rock deformation in soft rock tunnels with high ground stress, the deformations of core rocks in front of the working face and surrounding rocks are monitored by model test method, and the tunnel excavation process is simulated in detail under different high ground stress levels and working conditions with/without lining. The results show that: (1) the ground stress plays a key role in determining the installation time of soft rock tunnel support; (2) the advance deformation within 0.5D in front of the face accounts for about 2/3 of the total advance deformation; (3) the’lost’deformation behind the tunnel face has a great impact on the monitoring and measurement. With a certain high ground stress, there is a power function relationship between the’lost’deformation and the distance from the tunnel face. With the high ground stress greater than 20 MPa, it has little impact on the’lost’deformation; (4) in order to effectively control the advance deformation in soft rock tunnels with high ground stress, it is necessary to reinforce the core rock mass within 0.5D in front of the tunnel face. For the core rock mass within 0.5D~1D in front of the tunnel face, the reinforcement depends on the actual situation. © 2022, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Optimization of the Construction Scheme for a PBA Metro Station Adjacent to an Existing Metro Tunnel北大核心CSCD

The Olympic Park Station crossing the existing Datun-Road tunnel covers a long distance and closely approaches an existing metro tunnel. Initially, the PBA construction method was adopted with eight pilot tunnels. In light of the tunnel group cavern effect and the surrounding soft silty clay with abundant water, the construction risks were very. Optimization of the metro station construction scheme was conducted, and the four pilot tunnels at the downside were cancelled and replaced with long drill hole grouting piles. Construction technology for a large-diame-ter pile for a bored pilot tunnel was adopted based on the engineering characters of the PBA method using four pilot tunnels. Monitoring on the Datunlu tunnel structure was performed during metro station construction and the results indicate that the construction scheme for the station’s main structure was rational; the new construction technology ensures construction safety for the existing tunnel and metro structure. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.