Running Tunnels Research Articles

The Grautschenhof contract – Construction of an intermediate access under complex local conditions

AbstractWith the start of construction on the third tunnelling contract, work has now started on all sections of the Semmering Base Tunnel. The Tunnel Grautschenhof contract is a challenging construction project with numerous unusual problems. Complex ground conditions make extensive grouting necessary. Numerous constraints above‐ground, like high‐pressure gas pipelines require monitoring and protection measures. Since the start in May 2016, two shafts, the first of three caverns and the first metres of the running tunnels have already been driven. In parallel to this, the works above ground to create two site facilities areas are now largely complete.

The Fröschnitzgraben contract – Challenges in shaft sinking, construction logistics and landfill

AbstractContract SBT2.1 Tunnel Fröschnitzgraben is the central and longest construction section of the Semmering Base Tunnel, including 13 km of tunnelling from the intermediate access in Fröschnitzgraben towards Gloggnitz and Mürzzuschlag. The approx. 4 km long section towards Mürzzuschlag is being excavated by drill and blast, and the 9 km section towards Gloggnitz is being driven by two tunnel boring machines. Before the start of the actual construction of the running tunnels, the two shafts about 400 m deep had to be sunk using an innovative concept. Considerable changes are also noticeable above ground: the filling level of the landfill site in Longsgraben is rising constantly.

Development of a novel tunnel dismantling machine for the MTR West Island Line construction

ABSTRACTThe MTR West Island Line (WIL) Contract No. 703 from the Sheung Wan Station (SHW) tunnel to the Sai Ying Pun Station (SYP) tunnel is part of the extension of the existing MTR Island Line (ISL) of Hong Kong Island. The project involved the demolition and backfilling of 132 m of the existing Overrun Tunnel (ORT) through complex geology beneath a densely-populated urban area in order to enable the subsequent excavation of the WIL Down-track (westbound) running tunnel using a tunnel boring machine (TBM). The innovation of a bespoke tunnel dismantling machine (TDM) to tackle this challenge was adopted to minimise construction risks. A concrete bulkhead was built to separate the TDM works area from the operational railway. The TDM worked backwards from the operating railway interface inside the ORT to remove each ring of lining segments under 2.8 bar compressed air pressure, placing a sprayed concrete lining for temporary support and backfill of the remaining void left underground. The crew behind the d...

Parameters and Technology of Experimental Blasts during Drilling of the Left Running Tunnel of the Metro in the City of Dnipro

Parameters and Technology of Experimental Blasts during Drilling of the Left Running Tunnel of the Metro in the City of Dnipro

The Semmering Base Tunnel – Special challenges in construction

AbstractThe Semmering Base Tunnel (SBT) is about 27.3 km long and is being driven from the portal at Gloggnitz and from three intermediate construction accesses in Göstritz, Fröschnitzgraben and Grautschenhof. The main components of the tunnel system are the two single‐track running tunnels, cross passages at a maximum spacing of 500 m and an emergency station in the middle tunnel section, with two shafts about 400 m deep for ventilation and extraction in case of an incident. For organisational, scheduling and topographical reasons, the tunnel is divided into three construction contracts. The eastern contract section SBT1.1 ”Tunnel Gloggnitz“ has been under construction since mid 2015. Construction started on contract section SBT2.1 ”Tunnel Fröschnitzgraben“ at the start of 2014. The western contract section SBT3.1 ”Tunnel Grautschenhof“ has been under construction since May 2016.

Analysis of Effect of Voids behind the Tunnel Lining by the Impact-Echo Method

The voids behind the tunnel lining, as one of the tunnel diseases, can influence the tunnel service life. For existing running tunnels, it is essential to evaluate the effect of the void condition. In this paper, the impact-echo method was employed to check the voids. Firstly, a tunnel-soil coupled finite element model was built. Then, an impact excitation was applied on the tunnel lining. The responses beside the impact locations were compared for the conditions with different sizes of void and without voids behind the tunnel lining. The responses of the conditions with various impact locations were also be contrasted. The signals were analysed in time domain, frequency domain, and time-frequency domain. In addition, the dynamic stiffness of the tunnel-soil structure and fractal box-counting dimensions of the vibration response were calculated as well. By analysing these responses, the results suggest that the existence of void induce a dominant frequency, lower resistivity to deformation and lower attenuate velocity. With the increase of the size of the void, the features of response are more obvious.

Anti-seismic Analysis and Study for the Joint Structure Between Running Tunnel and Tunnel and Subway Station

Based on a subway section in Tianjin city, the MADIS finite element software was used to numerical simulation analyze the subway station joint section. The research results show that the stress of segment joints of shield segment wells are significantly higher than the standard section of the stress; the bending moment and sheer force of the shield shaft end wall in the floor and the negative floor location are large, so measures should be taken to strengthen the structure of this point; axial force of the maximum and minimum values are in the open mouth of the shield, and they all meet the requirements of structural stress. The seismic structural measures during design and construction for Tianjin area are summarized, and the research results can provide reference for the subway station structure and tunnel seismic design.

Numerical simulation and measurement of fire ventilation in river-crossing tunnel

This paper takes the subway train head fire in the upstream section of the river-crossing tunnel as the research object. The ventilation velocity with different patterns was simulated by STESS software. Then the influence of ventilation velocity on the distribution, temperature and visibility of smoke in running tunnel was studied by non-premixed combustion model in CFD software. And the ventilation velocity of recommended pattern was measured and verified. The results show that the opening and closing of the screen door in the direction of personnel escape has a great influence on the ventilation velocity of the tunnel. When the screen door is opened, it is recommended to open the 6 TVF fans in the running tunnel and the two stations. This can effectively inhibit the smoke return and meet standardized requirements.

Development of Tunnel Dismantling Machine (TDM) in an Underground Railway Project

The MTR West Island Line (WIL) project in Hong Kong involved demolishing and backfilling a 132 m section of the existing Overrun Tunnel (ORT) through complex geology beneath densely populated urban area, in order to enable subsequent excavation of the WIL Down-track (westbound) running tunnel by tunnel boring machine (TBM). To tackle the challenge while minimizing construction risks, a bespoke tunnel dismantling machine (TDM) was innovated. The TDM worked backwards from the operational railway interface inside the ORT to remove each lining segment ring under 2.8 bar compressed air pressure, sprayed shotcrete lining for temporary support, and backfilled the remaining void left underground. The crew behind the demolition chamber of TDM worked under atmospheric pressure. Part of the backfilled tunnel was then re-excavated by slurry TBM to form the re-aligned WIL Down-track running tunnel. The TDM was able to accomplish the works safely and led to the successful opening of WIL. This paper explicates the development of the world-wide unprecedented TDM and the construction process of ORT demolition.

The 102 Landslide: human–slope interaction in SE Tibet over a 20-year period

The evolution of large-scale landslides should be studied because, over long periods of time, primary remediation measures may suffer reduced efficiency or have to be adjusted many times. The 102 Landslide in southeast Tibet, which originally formed in 1991 with a volume of 5.1 million m3 and still exhibits post-failure activity, provides a distinctive case study. The landslide evolved from earthquake destruction and unloading, rainfall-triggered sliding, and debris flow to sands sliding slopes. The NE ringed scarp receded by 38.96 m during a five-year period (2003–2008). The total recession was 160 m with a total area of 2500 m2 during a 17-year period (1991–2008). Although several types of remediation measures were applied and were temporarily effective, the normal function of the Sichuan–Tibet Highway was affected by landslide reactivation from time to time. Actual effects of the engineering measures such as retaining walls, prestressed anchor cables, and drainage ditches confirm that hasty governance of this type of large-scale landslide is generally unfeasible over long time periods. Finally, an approach involving a tunnel running backward from the front face has been adopted as a permanent solution to large-scale moraine slope failures: This engineering practice has been in progress since April 2012. This paper describes the evolution of the 102 Landslide, the engineering interventions to mitigate the effects of the landslide on the Sichuan–Tibet Highway, and the choice of tunneling as a final mitigation measure. The present study concludes that approaches that allow escape from developing geo-hazards should always be the initial choice.

Use of a 10.22m diameter EPB shield: a case study in Beijing subway construction.

Introduction Beijing subway line 14 includes four stations and approximately 2.8 km of tunnels between the Dongfengbeiqiao and Jingshunlu areas of the city. Due to the surface and underground space limitations of this section, a double-track running tunnel instead of two single-track running tunnels was adopted to connect the two stations. The double-track tunnels were excavated by a 10.22 m diameter earth pressure balance (EPB) shield. It was the first time that an EPB shield more than 10 m in diameter was used in Beijing subway construction.Case description The shield, which passes underneath densely built-up areas of the city and is equipped with a spoke-type cutterhead, with balance between the ground pressure and the earth chamber pressure at the tunnel face, is of great importance. Referring to experiences gained in the EPB shield tunneling, attention was paid to the function of soil conditioning and simultaneous backfilling grouting of the shield, and some special designs were considered in manufacturing the machine.Discussion and EvaluationIn addition to the agitating rods welded to the cutterhead, two independently driven agitators were added to fully mix everything in the earth chamber. Independent pipelines were arranged for injecting different conditioning agents. Indoor tests in combination with field tests were conducted to find suitable additives and injection ratios of the additives, and determine the mix ratio of the two-component grout for simultaneous backfilling grouting. A scheme was employed for simultaneously injecting the bentonite slurry at 8% concentration and the foam liquid at 5% concentration to condition the excavated soil. The cement–sodium silicate grout was adopted to fill the tail void and the injection volume per ring was 14.1–15.3 m3.ConclusionsThe performance of the shield and evaluation of the corresponding tunneling technologies are introduced in terms of the shield tunneling induced ground surface settlements. The success of the project is of great significance to Beijing subway construction and underground space utilization. The findings serve as a useful reference for similar projects.

An observational approach to railway tunnel voids grouting

Water and fine sand ingressed into a section of running tunnels on the Jubilee line of the UK's London Underground railway in 2010. Concern arose that voids around the tunnel would lead to tunnel instability due to a reduction of lateral confining pressure from the soil. Ground investigation works identified that the running tunnel passed through a very large buried sand channel in the Lambeth Group. Initial attempts to arrest the ingress using an expanding grout were unsuccessful, and manual monitoring showed a slow but continuing deformation of the tunnel. A detailed tunnel investigation revealed that intermittent voiding was present over a wide area. A more comprehensive tunnel investigation and grouting solution was procured and carried out successfully by a group of specialists working together with London Underground. An important aspect of the design was the use of an observational approach, a key component of which was an innovative wireless monitoring system with trigger levels linked to the grouting injection system.

Numerical Analysis of Tunnel Running through Bridge Pile Foundation

Based on the background of Dalian subway running through bridge pile foundation, a 3d numerical model is built by the finite element software MIDAS/GTS in order to research the laws of the internal force and the displacement of the pile and soil during the Construction process. The outcome reflects that the sedimentation value of the top of the pile is bigger than others. Because the bigger thrust about the shield machine, the horizontal displacement of the pile is increasing at first and decreasing at last from a positive into a negative. Because of the loss of the soil, the soil beside the pile collapses and causes strong friction force. The surface sedimentation value which is near the central line of the tunnel is bigger than other place. This paper is of good reference roles in the similar underground engineering in Dalian.

Design of a continuously variable Mach-number nozzle

A design method was developed to specify the profile of the continuously variable Mach-number nozzle for the supersonic wind tunnel. The controllable contour design technique was applied to obtaining the original nozzle profile, while other Mach-numbers were derived from the transformation of the original profile. A design scheme, covering a Mach-number range of 3.0<Ma<4.0, was shown to illustrate the present design technique. To fully validate the present design method, computational fluid dynamics (CFD) analyses were carried out to study the flow quality in the test area of the nozzle. The computed results indicate that exit uniform flow is obtained with 1.19% of the maximal Mach-number deviation at the nozzle exit. The present design method achieves the continuously variable Mach-number flow during a wind tunnel running.

Settlement Impact Analysis and Countermeasure Research of the Down Traversing Formed by the Double-Arch Subway Tunnels through the Existing Railways in Loess Area

With the large-scale construction of city subways, the down traversing formed by subway running tunnels through the existing railways or railway yards are increasing day by day. Down traversing in shield method becomes common; however, the engineering cases which can be referable in the down traversing formed by the shallow-buried excavation of double-arch tunnels through the existing railways are very little. The ability to effectively control the excavation of shallow-buried subway tunnels can directly affect the safety of railway operation. According to the engineering characteristics of the down traversing formed by the shallow-buried excavation of double-arch tunnels in loessial layer, this paper proposed the standards for railway bed and track settlement control, and offers underground water treatment measures with assistant steps implemented on the ground surface during construction, so as to ensure the railway operation safety during the construction of the tunnel. Moreover, this paper applied MIDAS-GTS finite element software to make numerical simulation analysis of the down traversing formed by the double-arch tunnel through the railway and obtained the deformation laws during down traversing. The calculations suggest the railway track deformation caused by the down traversing construction of the double-arch tunnel in this project can meet related control standard requirements. There’s certain reference value contained in the deformation laws for the point locations of monitoring measurement. The research conclusions can provide scientific proof and technical guidance for the design and construction of this running tunnel project in order to offer reference for similar projects in the future.

Analysis on Construction Influence of the Underpass of Oblique Crossing Subway Tunnel

With the rapid development of the city, the construction of underpass of adjacent subway tunnel will have influence on the safety of subway operation. Base on underground pedestrian passage engineering, the complex construction conditions of oblique crossing-over subway running tunnel for A section channel is considered, plane strain finite element simulation analysis for the excavation and support and secondary lining construction of A section channel are conducted, and two kinds of construction conditions of adjacent and crossing subway tunnel for A section channel are simulated, the influence of the construction of A section channel on adjacent subway running tunnel is also analyzed. The results were shown that the maximum floating upward value is within 1mm and almost no lateral displacement during the construction of A section channel. which meet the requirements of urban rail transit safety operation, and the basis for advanced control of underpass construction is provided.

Analysis of Tunnel Running through Bridge Pile Foundation Based on the MIDAS/GTS

Based on the problem of tunnel running through bridge pile foundation, a 3d numerical model is built by the finite element software MIDAS/GTS in order to research the internal force and the displacement of the pile and soil during the Construction process. The sedimentation value of the top of the pile is bigger than others. Because the bigger thrust about the Shield machine, the horizontal displacement of the pile is increasing at first and decreasing at last from a positive into a negative. Because of the loss of the soil, the soil beside the pile collapses and causes strong friction force. The surface sedimentation value which is near the central line of the tunnel is bigger than other place. This paper is of good reference roles in the similar underground engineering in Dalian.

Prediction of Deformation of Adjacent Existing Running Tunnel due to beneath Shield Tunneling

With the rapid development of metro engineering construction in China, the impact of shield tunneling on adjacent existing building has been paid more and more attention in recent years. Taken the Jiulongshan-Dawanglu running tunnel of Beijing Subway No.14 built by shield method as engineering background, a three-dimensional numerical model based on the soil-structure interaction theory is established by using the finite element software ANSYS to simulate the shield tunneling beneath the adjacent existing running tunnel of Beijing Subway No.1. The displacement of the adjacent existing running tunnel is predicted. During the shield tunneling, the vertical deformation of the adjacent existing running tunnel can reach up 2.8 mm, and the horizontal deformation value is about 0.5 mm, which can satisfy the project need and the requirements of relevant standard. The numerical results can be regarded as a valuable reference for the construction.

A Study on Optimization of Middle Vent Shaft in Subway Tunnel Ventilation System

The air flow and temperature variation in the subway tunnel are different in the railway tunnel. Its necessary to study the middle vent shaft in subway tunnel ventilation system. According to the primary design documents of one subway line in Chengdu, the paper sets up the metros geometric model which is used in the SES program and also does the simulation analysis of the biggest transportation capacity in the line. The simulation mainly analyzes the adoption of the middle vent shaft which is located in the running tunnel between the station A and B. Meanwhile it also analyzes the influence of middle vent shaft on the nearby piston vent shaft, the wall surface temperature and the air temperature in the tunnel. Finally it takes temperature as the estimated index, analyzes the advantages and disadvantages of the middle vent shaft and makes the theoretic accounts for the design. The comprehensive analysis is that this middle vent shaft could be canceled.

The Study on Analog Module of Underground Cables Environmental Monitoring System Based on CAN Bus

In order to online real-time monitor of underground cable tunnel environment and running state, the timely discover and preclude troubleshooting that may occur, and to ensure the safety and reliability of the cable running. This article describes the underground cable environment online monitoring system platform based on CAN bus technology, and which is in its application layer using a common international CANopen protocol. This paper focuses on the realization of analog modules. It provides timely and effective monitoring method for real-time monitoring of the underground cable environment.