Tunnel Shaft Research Articles

철도차량 통과 시 터널 내부 유동장 해석을 위한 무격자기법의 적용에 관한 연구

We developed a computational fluid analysis program that can perform flow analysis when a high - speed railway vehicle passes through a tunnel by applying meshless computational technology in this study. The program was verified by comparing transonic RAE 2822 airfoil with experimental measurement results and numerical analysis results. From the proven analytical techniques, we propose the behavior of the high - speed trains moving into the tunnel by using the meshless - based computational fluid technique as a dedicated analysis tool that can be easily used even by the novice users. We compared the pressure generated during the passage of a high-speed train using this analysis technique with the results of C-STASUPTM/SUP, which is a conventional program for high-speed train design. In the case of the tunnel without shaft tunnel, it shows the same result as the existing C-STASUPTM/SUP and the result of this development program, showing the possibility of using this program using the meshless technique as a dedicated program for railway vehicles.

Cyber-physical-system-based safety monitoring for blind hoisting with the internet of things: A case study

Abstract This study proposed a cyber-physical-system-based safety monitoring system (CPS-SMS) for blind hoisting in metro and underground constructions. Wuhan Metro's Sanyang road tunnel, which crosses the Yangtze River in China, was selected for this case study. A slurry shield machine with a cutter diameter of 15.76 m was designed to be hoisted for 44 m into the underground tunnel shafts. The major challenges of this hoisting were as follows: 1) complex construction environment for hoisting, 2) limited visibility of crane operator or blind hoisting, and 3) precise control of position and gesture of a giant cutter wheel in real time. To overcome these challenges, the CPS-SMS was proposed to simulate and monitor the hoisting process to avoid the unsafe status of cranes and the hoisted cutter wheel. Internet-of-things technologies, such as wireless sensor-based location and tracking, self-organized Wi-Fi, and bi-directional communication, were used to prevent accidents in the changing and dynamic hoisting process. The implementation of monitoring blind hoist in the Yangtze River, which crosses the metro tunnel construction site, was successful, that is, no collision or injury occurred. The CPS-SMS can be applied by practitioners to various construction projects, such as dams, high-rise buildings, and large-scale infrastructure projects, to decrease the likelihood of safety risks in blind hoisting in complex environments.

Analysis of a new strategy for emergency ventilation and escape scenario in long railway tunnels in the fire mode

The creation of a safe path for evacuating passengers from a tunnel during fire accidents is an important function of a mechanical ventilation system in tunnels. In this work, the operation of emergency ventilation in the fire mode in a long railway tunnel with push–pull ventilation shafts is analyzed using a fire dynamics simulator. As the passenger trains are lengthy – and so is a tunnel – when trains pass through a tunnel, the position of fire on the train becomes an important parameter for rescuing the passengers through a safe path. The novelty of this study is in the design of emergency ventilation scenarios that consider the position of fire on the train in addition to the tunnel ventilation shafts. For this case study, a lengthy (8 km) urban railway tunnel in Tehran with four rail tracks and eight ventilation shafts is considered for designing emergency ventilation scenarios and control of fire products. The fire source is a passenger train wagon with a 25-MW heat release rate. It is shown that, during the rescue operation of the passengers, the location of fire on the train may lead to reverse the ventilation scenario compared with the traditional ones that use only the tunnel shafts. Also, it is observed that there is a region with 50 m radius around each ventilation shaft, i.e. the absolute exhaust zone, where the ventilation system must be set at the exhaust mode due to the presence of fire, to minimize the spreading of fire products downstream. All the logical scenarios of the tunnel ventilation system are designed and demonstrated to create a critical ventilation velocity in the tunnel, which would help in developing a more precise control panel of the tunnel in the fire mode.

Effects of material and drilling uncertainties on artificial ground freezing of cement-admixed soils

The artificial ground freezing method can be used jointly with the deep cement mixing method during break-in and break-out processes of shield machines in a tunnel shaft. The frozen ground can fully cut off groundwater seepage, thus ensuring a watertight working platform. Cement-admixed soils can restrict frost heave and thaw-induced settlement because of the decreased permeability. Both methods can also enhance mechanical strength of the soil to enable construction to proceed. Two main sources of heterogeneity are likely to influence the freezing effect: spatial variability in in situ water content in natural soil and spatial variability in binder concentration in cement-admixed soils. Furthermore, positioning error when installing freeze pipes can also affect freezing efficiency. This study simulates in situ water content and binder concentration as Gaussian random fields, whereby variations in the thermophysical properties are estimated. Positioning error is also assessed by prescribing an incline angle in freeze pipes. The influences of those two sources of spatial variability as well as positioning error are examined with random finite-element analyses and statistical characteristics are estimated based on the results. Results are tabulated to offer practitioners a rule of thumb for estimating additional efforts needed in artificial ground freezing, accounting for variations in the thermophysical properties and positioning errors in installing freeze pipes.

Numerical Simulation of Critical Velocity in Ventilation

Given the importance of the safety and health of passenger’s in underground tunnels, analysis and simulation of fires in tunnels is to design a ventilation system. Longitudinal ventilation systems are widely used in tunnel ventilation and are one of the most important parameters for fire safety in this type of critical velocity system. Critical velocity of ventilation is minimum longitudinal velocity flow of air that prevents the smoke from the fire to the upstream flow.In this study, the effects of the distance between the fire source of the tunnel, obstacle before and after the fire, several sources of fire in the tunnel and ventilation shaft tunnels will be discussed on the critical velocity. Each effect parameter according to a correlation analysis of numerical results obtained using the solver FLUENT software Airpak and then the relationship between dimensionless critical velocity and dimensionless heat release are stated.

Temperature profile of fire-induced smoke in node area of a full-scale mine shaft tunnel under natural ventilation

This paper investigated ceiling temperature profile of fire-induce smoke in the common node area of tunnels. The experiments were conducted in a full-scale mine shaft tunnel under natural ventilation with the node area consisted of a straight tunnel and two curved tunnels. Maximum ceiling temperature above the fire, transverse ceiling temperature along the elliptic ceiling and longitudinal ceiling temperature along the main and branch tunnels were measured by K-type thermocouples or thermometric cable. Dimensionless expression for predicting transverse and longitudinal ceiling temperature distribution was proposed based on previous models. Normalized expression of longitudinal temperature decay coefficients were correlated as well by taking the heat release rate and transverse fire locations under the elliptic ceiling into account. Then the results calculated by the proposed formula were compared with the experimental measured maximum ceiling temperature along the main tunnel and shows good agreement. Finally, effects of vertical wall and ceiling height on temperature decay trend in branch tunnels were investigated by analyzing the accumulation and descendant of smoke in front of the portals based on measured temperature data.

A radiological comparative study between transtibial & anteromedial portal drilling of femoral tunnel in single bundle anterior cruciate ligament reconstruction: A comparison of four angles

Femoral tunnel drilling for graft insertion is performed by transtibial or transportal technique. AimMain objective of this study was to compare the postoperative anteroposterior and lateral radiographs after arthroscopic ACL reconstruction by transtibial and transportal techniques by measuring four angles. Materials and methodsA retrospective study of 60 patients was conducted, who were further subdivided into two groups containing 30 each. The first group had patients who had undergone arthroscopic ACL reconstruction by transtibial technique and the second group had patients who had undergone ACL reconstruction by transportal technique. Post-operative anteroposterior radiographs (AP) and lateral radiographs of the operated knees were compared. Condylar tunnel (CT) and tunnel screw (TS) angles were measured in AP radiographs and compared. In lateral radiographs, shaft tunnel (ST) and TS angles were measured and compared. ‘Student t-test’ was used in calculating the results. ResultsMean of the angles measured were tabulated and compared. CT angle was noted to be more acute in transportal group (38.4±8.756°) as compared to transtibial group (46.97±12.754°) with a significant ‘p-value’ (0.004). ST angle was noted to be more obtuse in the transportal group (119.57±11.212°) as compared to transtibial group (113.17±12.793°) with a significant ‘p-value’ (0.044).This infers that transportal technique oriented the graft more horizontal as compared to transtibial technique.Tunnel screw angles when compared in AP radiographs showed that transportal technique (5.5±4.644°) had more acute angulation as compared to transtibial group (12.57±8.287°) with a significant ‘p-value’ (<0.001). Same results were obtained when the lateral views were compared between transportal (9.27±8.25°) and transtibial technique (23.73±12.174°) with a significant ‘p-value’ (<0.001). This indicated reduced screw tunnel divergence in transportal technique as compared to transtibial technique. ConclusionTransportal technique results in a more anatomical femoral tunnel placement as compared to transtibial technique.

Vulnerability of floating tunnel shafts for increasing earthquake loading

Fragility curves constitute the cornerstone in seismic risk evaluations and performance-based earthquake engineering. They describe the probability of a structure to experience a certain damage level for a given earthquake intensity measure, providing a relationship between seismic hazard and vulnerability. In this paper a numerical approach is applied to derive fragility curves for tunnel shafts built in clays, a component that is found in several critical infrastructure such as urban metro networks, airport facilities or water and waste water projects. The seismic response of a representative tunnel shaft is assessed using tridimensional finite difference non-linear analyses carried out with the program FLAC3D, under increasing levels of seismic intensity. A hysteretic model is used to simulate the soil non-linear behavior during the seismic event. The effect of soil conditions and ground motion characteristics on the soil-structure system response is accounted for in the analyses. The damage is defined based on the exceedance of the concrete wall shaft capacity due to the developed seismic forces. The fragility curves are estimated in terms of peak ground acceleration at a rock or stiff soil outcrop, based on the evolution of damage with increasing earthquake intensity. The proposed fragility models allows the characterization of the seismic risk of a representative tunnel shaft typology and soil conditions considering the associated uncertainties, and partially fill the gap of data required in performing a risk analysis assessment of tunnels shafts.

Research on Permeability Coefficient about Tertiary System Sandstone of Humaling Tunnel

Constant flow pumping test is finished in the 7th shaft tunnel of Humaling,based on the measured data,permeability coefficient of tertiary system sandstone is calculated by using Boulton formula wiring method,lining method and water level recovery method.The value is 0.14～0.23 m/d,Providing a reliable basis for further engineering application.Compared this data with that permeability coefficient calculated by J.Dupuit method when pumping stability.The conclusion is that there have a critical value,the latter numerical value greater than the former when the distance of observation well and pumping well less than critical value,and gradually become smaller than the former with the distance of observation well and pumping well increase and greater than critical value.

터널 굴착 및 가물막이 시공에 따른 주변 지하수계 유동분석

본 연구는 A호와 B호를 연결하는 도수로터널 굴착 및 가물막이 공사가 주변 지하수계에 미치는 영향을 정량적으로 평가하고자 수행하였으며, 이를 통해 인근 지하수 환경 변화 예측 및 터널의 라이닝 타설에 대한 효과를 검토하였다. 그 결과 터널 굴착 및 가물막이 공사기간 동안 터널 갱구부에서 최대 3.58 m의 지하수위 강하가 나타났으며, 터널 완공 및 라이닝 타설 시공 후 약 2년 경과 시점에서 자연상태 지하수위의 최대 90 %까지 회복하는 것으로 모사되었다. 터널 굴착에 따른 터널 내 지하수 유입량은 주향이동단층과 접하는 구간에서 터널의 배수설계기준을 초과하는 것으로 분석되었다. 이후 터널의 라이닝 타설이 완료된 후 지하수 유입량은 최대 <TEX>$0.006m^3/min/km$</TEX>로 감소하여, 라이닝 타설에 의한 효과는 93 % 이상으로 평가되었다. 또한 공사로 인한 인근 지역의 지하수 환경에 대한 분석 결과 민가, 사찰 및 견사 등에서 약 0.04~0.31 m의 수위강하가 발생하였으며, 이는 연구지역 인근에 위치한 국가지하수관측소의 연간 수위 변동량(1.3 m)의 24 %에 해당하는 수치로 분석되었다. This study is to quantitatively evaluate the impact on surrounding groundwater of waterway tunnel excavation and cofferdam construction in which A-dam and B-dam, so prediction of groundwater fluctuation and tunnel lining installation was studied. As a result, drawdown of groundwater level during tunnel excavation and cofferdam construction occurred about 3.58 m in the tunnel shaft. The initial condition of groundwater level recovered by up to 90 % was simulated after the completed the construction of the tunnel and lining installation. Groundwater inflow in the tunnel evaluated was analyzed to have exceeding water design criteria of the tunnel. The groundwater inflow is reduced to maximum <TEX>$0.006m^3/min/km$</TEX> after lining installation done in the tunnel, so effect of lining installation was evaluated as 93 % or more. Drawdown of about 0.04~0.31 m occurs in the houses and temples analysis of groundwater system of the surrounding area from construction. Drawdown has occurred nearly by considering annual groundwater level fluctuation of National Groundwater Observation Network.

Pipe Length Limit Analysis to Tunnel Vertical Well of Natural Gas Pipeline

In practical applications, often using natural gas pipeline through the pipe shaft way, so conditions for shaft pipe stress analysis has a very important practical significance and economic value, and limit the tube length calculation is one of the key issues. Take advantage of this stress analysis software, combined with program design, the shaft condition of the pipeline depth simulation. The results show that: gas pipeline tunnel shaft limit pipe length and pipe material, wall thickness and operating conditions are closely related, the greater the steel yield strength and wall thickness, the smaller the operating pressure, the longer the tube length limit. In the actual design pipeline crossing, it should fully take into account the limits of the tube length limit, the limit calculated under different conditions, to ensure the normal operation of gas pipelines provide pipeline reliability and economic benefits.

The interplay between RPGR, PDEδ and Arl2/3 regulate the ciliary targeting of farnesylated cargo

Defects in primary cilia result in human diseases known as ciliopathies. The retinitis pigmentosa GTPase regulator (RPGR), mutated in the most severe form of the eye disease, is located at the transition zone of the ciliary organelle. The RPGR-interacting partner PDEδ is involved in trafficking of farnesylated ciliary cargo, but the significance of this interaction is unknown. The crystal structure of the propeller domain of RPGR shows the location of patient mutations and how they perturb the structure. The RPGR·PDEδ complex structure shows PDEδ on a highly conserved surface patch of RPGR. Biochemical experiments and structural considerations show that RPGR can bind with high affinity to cargo-loaded PDEδ and exposes the Arl2/Arl3-binding site on PDEδ. On the basis of these results, we propose a model where RPGR is acting as a scaffold protein recruiting cargo-loaded PDEδ and Arl3 to release lipidated cargo into cilia.

A new damage criteria norm for blast-induced ground vibrations in Turkey

Environmental problems such as vibration and air blast are often faced and discussed in mining, quarrying, civil construction, shaft tunnel, pipeline, and dam operations, where blasting is inevitable. It is necessary to establish national standards in order to minimize environmental problems induced by blasting and judicial matters in our country as it is in the USA, European Union (EU) countries, and other developed countries. This necessity and the obligation of Turkey, which has started the procedure of joining the EU, to accept EU criteria emphasize the importance of this study. In other words, the establishment of a particular national standard related with this subject is inevitable for Turkey. This will be possible only by studying and applying scientific methods and techniques by experts. This paper presents a new damage criterion norm for blast-induced ground vibrations in Turkey. In this study, first, numerous vibration records were taken in blasting operations performed at different sites and rock units. For these rock units, particle velocity predictions and frequency analysis were done. At the same time, structures in the neighborhoods of these blasts were also observed and investigated. Finally, a damage criterion norm based on risk analysis was established and proposed by using these collected data. In light of the norm to be obtained from the data that were collected in the research, it will lead the excavation work in our country to be performed in such way that they are more effective and will cause minimum environmental problems.

Field Measurements and Finite-Element Method Simulation of a Tunnel Shaft Constructed by Pneumatic Caisson Method in Shanghai Soft Ground

Characterized by unmanned excavation and remote controlling, the new pneumatic caisson (NPC) method has advantages in deep excavation such as deep shield tunnel shafts and some underground construction close to the existing structures or facilities. When adopted in urban areas, it is very important to control the ground deformation during a caisson construction. For this purpose, field measurements of ground deformation were conducted during a tunnel shaft construction in Shanghai soft ground, in which the NPC method was used. On the basis of the particular construction procedure of a pneumatic caisson, one kinematic mechanical model was proposed for evaluating the influence of NPC construction on the surrounding strata. This model was incorporated into a finite-element (FE) program. By comparing the FE-predicted results of the proposed model and the field measurements, the accuracy and reliability of this model were verified.

Construction of deep tunnel shafts in Mexico city soft clays by the flotation method

The drainage system of Mexico City, one of the largest metropolitan areas in the world, is formed by a large network of interceptors and collectors leading to the main outlet: a 49.3-km-long tunnel with a 6.5 m diameter. To build the access shafts to the tunnels of the system and the deep sumps of the pumping stations in the very soft clays of the lacustrine area of Mexico valley, a technique known as “flotation method” has been commonly used since 1969. The paper presents the main construction steps followed and some aspects of the analysis and design of shafts constructed by this technique. The experience gained obtained after more than 30 shafts have been constructed by this method, and the actual trends in its application are also discussed.

Burrows of a gopher-like rodent, possibly Gregorymys (Geomyoidea: Geomyidae: Entoptychtinae), from the early Miocene Harrison Formation, Nebraska

This study describes the architectural and surface morphology of small, 5.6−6.7 cm diameter burrows that occur in close proximity to the Daemonelix burrows of palaeocastorin beavers in the early Miocene upper Harrison Formation, Nebraska. The small-diameter burrows are sinuous and rambling or weakly helical in morphology. Distinctive paired grooves from rodent incisors, measuring 4.1−4.3 mm wide, occur on the ceiling and sides of the burrows, whereas ridge-like claw marks of 4.1 mm width occur low on walls and floors. Scratched-out, chamber-like areas on the sides of tunnel shafts are covered on all sides with claw marks, whereas tooth marks are mostly confined to main tunnel shafts. Both types of marks are abundant, indicating a mixed tooth-and-claw digging strategy that appears to have evolved in palaeocastorin beavers as well. Similar digging methods in two unrelated Harrison rodents indicates the relative hardness of the volcanic ash-rich soils, which necessitated digging with teeth in addition to less resistant keratin claws. The new ichnotaxon Alezichnos trogodont is erected to describe these ichnofossils. A possible excavator is Gregorymys sp., an extinct, gopher-like entoptychine rodent that occurs in these and correlative Miocene units in the Great Plains. The width of Gregorymys incisors matches the width of incisor marks on A. trogodont. These burrows may represent the first recorded evidence of subterranean habitat and digging behavior in an otherwise common fossil rodent. The excavator of A. trogodont had a different burrow system, and possibly different foraging behavior, than the contemporaneous beavers, providing new evidence for diversity in a subterranean Miocene ecosystem.

Construction of shaft tunnel by slurry pipe jacking through sedimentary ground under high water pressure

Pipe jacking technology has been developed rapidly in recent years to satisfy demand for distances of more than 1 km or curves of less than 10 m radius. A shaft tunnel driven by pipe jacking, another type of development, was adopted in order to provide ventilation to the Imaigawa underground reservoir tunnel under the national highway in Yokohama, Japan, which has been temporarily in service since 2001. Downward excavation of the 2000 mm ID ventilation tunnel starts from ground surface and reaches to the crown of the existing 10,800 mm ID reservoir tunnel, which is located 87.8 m deep, through the stiff clay layer. Depression angle of the tunnel is set as 75.6 degrees since the ventilation building is constructed in the existing park along the highway. Pore water pressure at the arrival is 0.66 MPa. This project is one of the largest in this type of tunnels in Japan. This paper focuses on equipment and facilities adopted on the project and construction methodology of the inclined pipe jacking. Specially-designed equipment and facilities were planned and employed to overcome anticipated difficulties; namely shield machine, jacks and reaction frame, lift-preventer, inclined elevator, and survey system. Slurry shield machine was specially designed considering the high water pressure, stiff clay excavation, accurate directional control, connection work to the existing reservoir, and simple dismantling. It shall be noted that the machine can not access the existing reservoir tunnel and the dismantled motors of the machine had to be removed through the tunnel driven. The thrust jacks and reaction frame were designed to facilitate easier setting of pipes and ground anchors were used against the reaction force of up to 8000 kN. To prevent the lift due to buoyancy to the shield machine and pipes during excavation, which was significant when the thrust jacks are released, the lift-preventer with power casing jack and ground anchors were developed. Inclined elevator, which is used for pipe connection and maintenance, was designed in such a way that it moves to give space to the pipe setting. Since accuracy was vital for the tunnel drive, survey system with laser theodolite and non-prism laser distancemeter (with automatic target recognition), which enables constant monitoring, was adopted. Relatively complicated construction sequence was developed bearing smooth operation and safety in mind. It was however completed successfully due to the well-prepared sequence. This method is considered effective for inclined shaft construction, such as ventilation shafts or access tunnels. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

Construction of shaft tunnel by slurry pipe jacking through sedimentary ground under high water pressure

Construction of shaft tunnel by slurry pipe jacking through sedimentary ground under high water pressure

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London water ring main tunnel shafts as pumping stations : Kerslake, J C Proc Conference on Shaft Engineering, Harrogate, 5–7 June 1989P249–252. Publ London: IMM, 1989

London water ring main tunnel shafts as pumping stations : Kerslake, J C Proc Conference on Shaft Engineering, Harrogate, 5–7 June 1989P249–252. Publ London: IMM, 1989