Running Tunnels Research Articles

Effects of train speed and passenger capacity on ground vibration of underground suburban railways

This study aims to explore the optimal driving speed for ground vibration in suburban railway underground sections. We focused on the ground surface of suburban railway underground sections and developed a 3D finite element dynamic coupling model for the tunnel–soil system. Subsequently, considering factors such as train speed and passenger load, we analyzed the propagation characteristics of ground vibration responses in urban railway underground sections. The research results indicate a significant amplification phenomenon in the peak power spectrum of measurement points near the tunnels in underground sections. The high-frequency components of the power spectrum between measurement points are noticeably higher between the two tunnels. Furthermore, as the train speed increases, this amplification phenomenon becomes more pronounced, and the power spectrum of each measurement point mainly concentrates on several frequency bands, with the amplitude of the power spectrum near the prominent frequencies also increasing. However, when the train speed is between 100 and 120 km/h, the impact on the amplitude of the power spectrum at measurement points above the running tunnel is minimal. Additionally, the amplitude of the middle-to-high frequency components in the power spectrum increases with the increase in passenger numbers. The impact on the peak acceleration amplitude at each measurement point is minimal when the train speed is 80 km/h or below. However, once the train speed exceeds 80 km/h, the peak acceleration amplitude above the running tunnel rapidly increases, reaching its maximum value at 113 km/h, and then gradually decreasing.

Southbank Place development: tunnel movement predictions and monitoring performance

The Southbank Place project comprised the redevelopment of the UK headquarters of the Shell Company (formerly known as the Shell Centre) in the Waterloo area of London. The project included the demolition of all structures within the site except for the iconic tower building, local extension of the existing basement and the construction of eight new mixed-use buildings. London Underground's (LU) Bakerloo Line and Northern Line running tunnels pass beneath the site. The excavation of the basement and construction of the Shell Centre in the late 1950s caused movements of the underlying Bakerloo Line tunnels that were much larger than expected. The monitoring of these tunnels between 1958 and 1995 has provided a classic case history for the behaviour of London Clay. The proposed redevelopment offered an opportunity to analyse and monitor the behaviour of LU tunnels over a period of 60 years and two phases of significant construction. This paper presents a back-analysis of the historical monitoring of the Bakerloo Line tunnels and the calibration of a sophisticated finite-element model. The model was subsequently used to predict the impact of the redevelopment on the tunnels as part of the assurance procedure with LU.

Potenential for thermal energy from Tunnels beneath Manchester and Crewe: a case study

potenential for thermal energy from Tunnels beneath Manchester and Crewe: a case study

Ground behaviour and settlements analysis on tunnelling of shallow-buried metro in Tashkent city

This paper proposed a calculation method that reflects the process of deformations of the soil mass and subsidence of the ground's surface around the shallow subway tunnels and their study, taking into account the engineering and geological conditions of the construction site on the third line of Tashkent metro. The vertical ground displacements of soil mass and zone of destruction (instability) around the hole of the running tunnel of the metro located at different depths were determined. As a result of the numerical calculations performed, the settlements of the ground's surface were determined during tunneling by the shield method. It was found that the maximum value of the trough of the ground's surface decreases with an increase in the depth of the tunnel. This is because with deep tunneling, settlements are largely determined by the decrease in the vertical pressure of the soil on the tunnel due to the formation of a limited disturbed zone around the tunnel hole.

Comparative Analysis of the Results of Mine Surveying and Numerical Studies of the Running Tunnel of the Kyiv Metro

Purpose. The article is aimed to perform a comparative analysis of the results of mine surveying and numerical studies of the running tunnel of the Kyiv metro and obtain the reliability of the author’s system of parametric analysis. Methodology. The comparative analysis of the results of research on the displacements of the running tunnel was carried out in two directions. In the first direction, the movement of the lining of the running tunnels between the stations «Slavutych» – «Osokorky», «Osokorky» – «Pozniaky» and «Pozniaky» – «Kharkivska» obtained in the course of mine surveying studies was analyzed. In the second direction, a numerical analysis using the finite element method was performed. For this analysis, models of three lining rings were created. These rings were chosen because the maximum level of vertical movements was observed in them. Their reason is the influence of the engineering and geological conditions of the part of the Syretsko-Pecherska line on the left bank of the Dnipro River. These conditions are characterized by the layering of weak and water-saturated soils (sands of various sizes and densities, sandy loams, light loams and clays). The lining of the real tunnel is a standard structure used for shield tunneling of the Kyiv metro. The models reflect the geometric dimensions of the running tunnels, as well as the deformation characteristics and soil density of the surrounding layered massif. Findings. The authors analyzed the characteristics of the layered massif and the maximum displacements of the running tunnels of the part of the Syretsko-Pecherska line on the left bank of the Dnipro River. In the course of the numerical analysis, the vertical displacements of the models of the three lining rings were obtained. A comparative analysis of the results of mine surveying and numerical studies was carried out. The obtained level of error (up to 15 %) between the results of mine surveying and numerical studies proves that the developed bases of parametric analysis are reliable. Originality. For the first time, the theoretical foundations of parametric analysis for a real underground object were introduced. The author’s developments related to the creation of finite-element models based on the real characteristics of the soils of the layered massif provide a high level of similarity to the results of theoretical developments and instrumental mine surveying measurements. Practical value. It consists in the substantiation of the parameters of the deformed state that occurs in the horizontal working during shield tunneling.

Safety inspection system and comprehensive evaluation method for concrete structure of gas pipeline tunnel based on fuzzy mathematics

Regular safety inspections are an important guarantee to ensure the high-quality operation of concrete structures of tunnels. The Chinese West-east Gas Pipeline Project is large in scale and complex in construction environment. These tunnels are equipped with gas pipelines, and the concrete structural defects of the tunnels are continuously exacerbated during the long-term operation. There are few studies on the safety evaluation methods of concrete structures of gas tunnels. Based on the characteristics of the operation of the gas tunnels, this paper proposes the establishment of a structural safety comprehensive inspection system from the following seven aspects, that is, the void between the concrete lining and surrounding rock, the strength of the concrete lining, the thickness of the protective layer of the reinforced concrete lining, the carbonization depth of the concrete lining, the deformation of the tunnel section, the cracks in the concrete lining, and the auxiliary concrete structure of the tunnel. In addition, a corresponding quantitative determination method and safety level classification standard are established. Based on the fuzzy mathematics theory and a structural safety comprehensive inspection system, a five-level safety evaluation method for tunnel concrete structures is proposed. Finally, a comprehensive inspection and evaluation were carried out for a tunnel running across the mountain.

Macroscopic and Mesoscopic Characteristics of a Small-Span Metro Tunnel in the Development of a Disaster Under Load

A similarity model with a volumetric similarity ratio of 1:100 and a granular flow model for the tunnel were designed. By comparing macroscopic and mesoscopic information (such as fracture process, strain evolution, stress transfer, crack propagation, and stress distribution) of the tunnel models under load, the failure mechanism of the metro tunnel under load was investigated. The result showed that: 1) under the loading path, the instability area of the tunnel is mainly distributed in the straight wall on both sides. When the load is 1.5 MPa, a large number of cracks on both sides of the straight wall run through, resulting in the initial failure of the rock mass; 2) the surface rock mass of arch bottom is under tensile stress and the deep rock mass is under pressure stress, therefore, the fracture does not develop continuously. The surface of straight wall produces continuous development crack under the action of tensile stress; 3) the arch bottom first responds during the stress redistribution of the small-span tunnel; the top and middle parts of the side walls of the running tunnel with greatest potential for damage respond most; 4) in the process of stress redistribution, the peak stress of the deep measuring points of the straight wall is greater than that of the free surface; 5) at the initial stage of loading, tensile cracks account for a high proportion of all cracks found. When the load is 1.5 MPa, the proportion of shear cracks increases to 28%, and when the load is 1.6 Mpa, the proportion of shear cracks increases to 31%. Finally, the tensile-shear effect triggers the failure of the tunnel.

Automated geotechnical monitoring in construction of running tunnels in subways under operating railroads

The city of Moscow is currently faced with the extremely aggravating problem connected with traffic. Hereupon, majority of transportation systems are being expanded and upgraded. Construction of new running tunnels and subway stations, road spans, crossovers, underground parking lots, etc. is in process. The new construction affects the existing development sites in the time of surplus fallout, which leads to emergency situations. It is required to provide geotechnical monitoring of soil mass in the influence zone of new construction. To this effect, the wireless online monitoring system has been designed and introduced into surveillance of building structures and soil mass. The system is meant for the integrated and continuous observation of a control object. The operation charts and advantages of the wireless monitoring system are presented. The introduction experience of the automated geotechnical monitoring in the process of construction is described. The observation of a railroad overpass used the tilt sensors and crack meters. The deformation monitoring in soil mass was carried out using borehole deviation devices and extensometers. It is demonstrated that the time of the measurement cycles is related with the position of the shield tunneling face relative to the measurement boreholes. The interpreted data analysis proves correlation of the measured and predicted deformations. The deformation propagation in depth of soil mass is characterized. The data analysis made it possible to predict deformations of ground surface and, thereby, to eliminate a potential accident during shield tunneling under the surface railroad.

Cause identification of damage in tunnel constructed in soil-rock mixture site and effect of suggested reinforcement measures

A running tunnel in Chongqing, China was constructed in a soil-rock mixture (SRM) by the open-cut method. During the construction period, severe cracks occurred on the tunnel lining floor, which will significantly affect the tunnel’s long-term stability. In this study, the numerical investigation was performed to study the development trend of damage zones in the tunnel lining, identifying the causes of damage and further evaluating the effects of suggested reinforcement measures. Firstly, numerical modeling experiments were conducted to obtain the physical and mechanical parameters of SRM. Then, three 3-dimensional (3D) numerical simulation models were established. The settlement, tensile stress, and distribution of damage zones on the tunnel floor were highlighted. Results indicated that the maximum deformation occurs on the roof of the tunnel lining, and the minimum displacement is in the middle part of the tunnel floor. The maximum compressive stress is within the ultimate compressive strength. However, the tensile strength significantly exceeded the ultimate tensile strength, resulting in cracks in the tunnel lining. If no reinforcement measures are taken, about 66% of the tunnel floor will be tensioned to damage, significantly reducing the bearing capacity and long-term stability of tunnel lining. The stiffness difference between SRM and the bored piles is the reason for damage zones in tunnel lining. It is suggested that grouting reinforcement and steel fiber reinforced concrete should be taken on the tunnel floor to improve damage resistance. Finally, it is verified that the suggested reinforcement measures can effectively control uneven settlement and damage zones in the tunnel floor.

BIM Process and Application in Geological Exploration of Rail Transit Engineering in Mountainous Cities

Based on the practical problems in the geological modeling of rail transit engineering in Chongqing, this study conducts a comparative analysis of the commonly use methods of engineering geological modeling. In view of the special geological conditions such as sand-mudstone interbedding and lens in mountainous cities, the problem of unified stratification of complex strata is solved by means of three-dimensional auxiliary layering and a process of three-dimensional modeling suitable for regular underground running tunnels and deep-buried underground running tunnels in mountainous cities is established.

Protective Measures during Construction of Ground Structures over Existing Underground Structures

Today, there is an acute issue of ensuring the safe operation of buildings and structures located in the immediate vicinity of new construction. The process of performing works on the installation of load-bearing structures and their further operation can have a negative impact on already existing facilities. In this regard, the task of developing innovative methods and tools to ensure the safe operation of such structures as subway running tunnels is very urgent. To solve it, a reliable forecast of additional deformation and appointment of a complex of protective measures are required. In addition, much attention should be paid to the numerical modeling of the system “surface structures – protective measures – underground structures”. As an example of assessing the impact of new construction, namely, the erection of surface structures over existing underground ones, one can cite the construction of a transport interchange at the intersection of Nezavisimosty Avenue with Filimonov Street. As protective measures, a protective screen on bored piles has been used here, which made it possible to minimize significantly dynamic and static effects on the lining of tunnels and other underground structures of the subway. Effectiveness of protection application is confirmed by the result of monitoring the stress-strain state of running tunnel structures at all stages of traffic intersection construction. Protective measures and continuous monitoring of the stress-strain state in structures help to avoid accidents during construction and further operation.

Excavation influence of triangular-distribution tunnels for wind pavilion group of a metro station

For the Guanshui Road Station tunnel project of Guiyang Metro Line 2, the wind pavilion group was moved out of the main tunnel to reduce the number of openings in the main tunnel, and the wind pavilion group was excavated in a triangular configuration at the entrance of the main tunnel. Based on the finite element software ABAQUS, a three-dimensional model is established to study the influence of different triangular-distribution tunnels excavation schemes on the surface settlement and tunnel stability. The objective of this study is to reveal the change rules of surface settlement, deformation and force in the support structures and the surrounding rock and identify the best excavation scheme for this tunnel configuration. Results show that to control the surface settlement and the deformation of the support structures, the optimal excavation sequence involves excavating the upper fresh air exhaust tunnel before the lower running tunnel. To control the stress of the support structures, the optimal excavation involves excavating the lower running tunnel before the upper fresh air exhaust tunnel. In this project, the most reasonable excavation sequence of the tunnel is from top to bottom. The most reasonable thickness of tunnel penetration is 5 m.

A LabVIEW Based Optimization and Integration of Supersonic Wind Tunnel Instrumentation System

Indonesian National Institute of Aeronautics and Space have a supersonic wind tunnel for research in high speed object . The condition of LAPAN's supersonic wind tunnel can only be used for shockwave observation by using schlieren apparatus. The data acquisition system can not collect data from sting balance, some of the control panels are either not operational or it need calibration. Based from these conditions, this research is done to develop a new integrated control system and data acquisition so that the effectiveness of operation in terms of time and better data quality can be achieved. For angle of attack (AoA) control from manual operation, have been optimized to a digital control using PID control method. With the new system, the AoA control has been automated and a new testing option for moving the AoA while the wind tunnel running can be done. In terms of data acquisition, after the optimization it can collect better data, (noise / interference becomes smaller), and now it can record data from the balance, the pressure data, AoA position and block position can be recorded. The system was created using PXIe from National Instrument and LabVIEW graphical programming as user interface.

A LabVIEW Based Optimization and Integration of Supersonic Wind Tunnel Instrumentation System

Indonesian National Institute of Aeronautics and Space have a supersonic wind tunnel for research in high speed object . The condition of LAPAN's supersonic wind tunnel can only be used for shockwave observation by using schlieren apparatus. The data acquisition system can not collect data from sting balance, some of the control panels are either not operational or it need calibration. Based from these conditions, this research is done to develop a new integrated control system and data acquisition so that the effectiveness of operation in terms of time and better data quality can be achieved. For angle of attack (AoA) control from manual operation, have been optimized to a digital control using PID control method. With the new system, the AoA control has been automated and a new testing option for moving the AoA while the wind tunnel running can be done. In terms of data acquisition, after the optimization it can collect better data, (noise / interference becomes smaller), and now it can record data from the balance, the pressure data, AoA position and block position can be recorded. The system was created using PXIe from National Instrument and LabVIEW graphical programming as user interface.

GEOPHYSICAL STUDIES AND STRENGTHENING A LAYERED AND WATER-SATURATED SOIL MASS IN THE KYIV METRO CONDITIONS

Purpose. An urgent issue for shallow underground tunnels in difficult engineering and geological conditions is the determination of the physical and mechanical properties of soils not only during engineering surveys, but also when they are studied using geophysical methods for studying ground conditions. In addition, it is important to choose ways to improve the properties of soils by strengthening, especially in areas where their strength characteristics are reduced. This ensures the efficient operation of tunnels with the elimination of hazardous phenomena such as vibration creep of soils and deformations of the track and lining. Methodology. Using the existing provisions on geophysical research, in order to identify the weaknesses of the layered and water-saturated massif and justify ways to strengthen it, the basics of a comprehensive study and production implementation have been developed to increase the level of safe operation of metro tunnels. Findings. Geophysical studies were carried out to identify weaknesses in the soil stratum along the route of the running tunnels of the Syretsko-Pechersk line of the Kyiv metro (the left bank of the Dnipro) and it was established that in present conditions, to strengthen weak water-saturated and layered soils, it is necessary to use methods of mixing soils with binders that are injected under pressure. Originality. Based on the performed analytical studies, the dependence of the porosity of weak water-saturated soils on the ratio of the acceleration of vibrations to the acceleration of gravity at certain frequencies of the path vibration caused by the movement of metro trains was obtained, and the parameters of soil strengthening on the sides and the bottom of the rim of the running tunnels were determined. Practical value. The use of geophysical methods for determining weak spots in the soil massif allowed them to be strengthened in the existing shallow underground tunnels and reduce the risk of their dangerous operation.

Numercial analysis on the thermal performance of capillary heat exchange system in metro running tunnel

Abstract During the operation of the capillary heat exchange system in the metro tunnel, the pipe length, pipe spacing and air velocity have different effects on the heat transfer effect and show certain rules. Taking Kunming as an example, a single-factor analysis method was used to establish multiple-capillary model, and the variation of different influencing factors in the heat transfer process was obtained. On this basis, a single-capillary model was established to analyze the thermal interference variation of the pipe spacing between the two models. Under the condition of ensuring the capillary outlet water temperature and heat flux, the relevant parameters of the capillary heat exchanger were optimized. The results show that the pipe length of the capillary heat exchanger should be kept within 3–5 m, the pipe spacing is maintained at 20–30 mm, and the capillary heat exchanger of each set can be operated in parallel to ensure that heat exchanger have better heat transfer performance. During the system stop running, the air velocity in winter and summer has different effects on the recovery of surrounding rock.

Wechselwirkungen zwischen tiefliegendem Tunnelvortrieb und bestehendem Tunnel im Bereich von Störzonen – Modellierung versus Realität

AbstractThe influence of a tunnel drive on an existing tunnel is primarily the result of the tunnel geometries, the relative location of the two tunnels, the geological‐geomechanical conditions and the associated primary stress state. During construction of the Brenner Base Tunnel, there are constructionally relevant interactions in some places between the running tunnels and the exploratory tunnel (EKS) running centrally and 12 m deeper. The rock mass stress as a result of driving the running tunnels here leads to deformations of the previously driven exploratory tunnel. Due to the high loading on the outer linings of deep tunnels and the high stiffness of the already hardened shotcrete support, slight deformation can cause local cracking in the support layer. This article compares the observed deformations in a fault zone intersecting at a flat angle with numerical simulations, which enables investigation of the geomechanical problems. Comparison of the calculation results with the real deformation behaviour permits the validation of the numerical simulations and the reliability and limits of such analyses.

Whisker exploration behaviours in the 5xFAD mouse are affected by sex and retinal degeneration.

Active whisking in mice and rats is one of the fastest behaviours known in mammals and is used to guide complex behaviours such as exploration and navigation. During object contact, whisker movements are actively controlled and undergo robust changes in timing, speed and position. This study quantifies whisker movements in 6- to 7-month old male and female 5xFAD mice, and their C57/SJL F1 wild-type (WT) controls. As well as genotype, we examined sex differences and the effects of retinal degeneration (rd). Mice were filmed using a high-speed video camera at 500 frames per second (fps), under infrared light while behaving freely in three tasks: object exploration, sequential object exploration and tunnel running. Measures of whisker position, amplitude, speed and asymmetry were extracted and analysed for each task. The 5xFAD mice had significantly altered whisker angular positions, amplitude and asymmetry during object contacts and female 5xFAD mice with rd had lower mean angular positions during object contact. There were no significant effects of genotype on sequential object exploration or on tunnel running but differences due to sex and rd were found in both tasks, with female mice making larger and faster whisker movements overall, and mice with rd making larger and faster whisker movements during object contact. There were sex differences in whisker movements during sequential object exploration and females with rd had higher whisker retraction speeds in tunnel running. These data show that measuring whisker movements can quantify genotype and sex differences and the effects of rd during exploratory behaviour in these mice.

Engineering geological considerations for the ‘Old’ Beacon Hill Railway Tunnel, Hong Kong Special Administrative Region

Abstract The ‘Old’ Beacon Hill Tunnel was constructed through granite from 1906 to 1910 as part of the Kowloon Canton Railway in the then British colony of Hong Kong. It was the first railway tunnel to be constructed in this region and, at 2.2 km long, longer than any Chinese railway tunnel. Prior to Japanese occupation in December 1941, the British detonated charges to collapse the tunnel to deny its use as an invasion route. Following Japanese defeat in 1945 and return to British government, the tunnel was re-excavated and the damaged sections were supported using steel arches based on Terzaghi's rock mass classification system, which uses geological descriptions to classify loading onto arched tunnel supports. The railway was subsequently realigned during the 1980s and placed in a new tunnel running alongside and west of the ‘Old’ Beacon Hill Tunnel, which was converted to accommodate a pipeline connecting gas supplies. Ground investigations implemented after return of the territory to Chinese sovereignty in July 1997 established that groundwater flow and tunnel stability were influenced by a dyke within the granite, joint set orientation, faulting and weathering as well as the wartime detonations.

An analytical method for estimating leakage from a hydraulic pressure tunnel

An analytical method has been proposed to estimate the leakage from a water-filling tunnel between two reservoirs, based on Darcy’s law and the position of the water table, for a phreatic aquifer. The variable water-fill level in the tunnel and an arbitrary intersection angle between the tunnel and horizontal plane were considered. The reliability of this method was validated by numerical analysis and the measured leakage during two water-filling tests in the Heimifeng Pumped Storage Power Station in China. The calculated leakage can represent both the measured value and numerical result due to the small differences between them. Also, the effect of some parameters on the leakage was analysed. Results indicated that leakage increased with decreasing intersection angle, the increase of hydraulic conductivity of the reinforced concrete lining, and the increase of water-fill level in the tunnel. Other parameters exerted little effect on the leakage. Furthermore, the total leakage was estimated under the simultaneous running of two tunnels. When one tunnel was running, the other tunnel was emptying. The calculated leakage was 4.48–8.85 L/s for both tunnels running, which was about 0.5 L/s less than that with one tunnel running and other tunnel emptying. This revealed that the running tunnel had little effect on the leakage from the other (emptying) tunnel.