The number and length of highways in China far exceed those in other countries. Therefore, to better understand the defects that have occurred in Chinese highways that are currently in service, we collected data on the defects in 90 such tunnels. Using these data, we conducted a systematic study on the causes of such defects. Based on the characteristics thus obtained, the defects could be divided

Transverse passages are ubiquitous in urban subways, and they pose serious mutual threats to the two adjacent tunnels they connect. In this paper, the frequency sweep loads were applied in model tests and the influence mechanism of integral transverse passage (ITP) was studied by using the one-third octave of the frequency response function (FRF). Subsequently, a new assembled transverse passage (ATP)

Due to the widespread use of Tunnel Boring Machines (TBMs) in China, all affected parties involved in related construction of projects have proposed higher requirements for the controllability of TBM construction periods. Consequently, this report proposes a new TBM advance rate prediction method. By mining TBM construction data obtained from a project diverting water from the Songhua River to cities

The plug-holing phenomenon in naturally ventilated tunnel fires with vertical shaft has been receiving considerable attention, however, there is still no simple physical quantity to represent the degree of plug-holing. A series of numerical simulations were conducted to analyze the ventilation performance of vertical shaft in tunnel fires by considering different shaft geometries. Plug-holing height

Failure of rock mass in deep underground excavations could be attributed to a broad range of performance malfunction, from plastic yielding of rock, generation of macro cracks on the boundary of the excavation, gravity driven rockfalls or even complete stress-induced collapse. The failure criteria determine the stress level (or strain level) at which the rock mass loses its load-carrying (or strain-carrying)

Artificial ground freezing (AGF) is a method of paramount importance for underground construction in soft soil area. There were numerous studies concerned on field observations and the theoretical formulations on frost heaves. However, the field observations and validity of the theoretical models from practical points were lack. This paper focused on a more accurate practical prediction method of frost

Short vehicular tunnels (SVT) with heavy traffic are commonly constructed in urban areas of densely populated cities of the Asia-Oceania Region. The introduction of vehicles using clean fuel poses new concerns on the fire safety of existing road tunnels. The explosion of a taxi using Liquefied Petroleum Gas (LPG) occurred in a garage, alarming the need for protecting existing road tunnels against hazards

The vertical tunneling (lifting) method was invented in China to build hydraulic tunnels efficiently, safely, and conveniently. This paper presents a case study of a hydraulic tunnel in Beihai, China. In this study, the jacking force of five standpipes is analyzed and a back analysis principle of the average frictional coefficient is proposed. The jacking force is mainly composed of the face resistance

To investigate the vehicle fire hazard at different locations in inclined tunnels, the effect of longitudinal fire locations on smoke behavior characteristics induced by inclined tunnel fires was proposed by simulation and theoretical analysis. A series of tunnel models with slope of 4% was conducted by Fire Dynamics Simulator (FDS) software for fire simulation, in which three fire scenarios were considered

Suitable rockburst support is critical for the prevention of rockburst disasters. In the present study, rockburst process and mechanism are investigated first in detail based on laboratory tests. It is considered that the splitting and buckling are two stages that precede the occurrence of rockburst, and buckling is the necessary prior step and precondition of rockburst. Therefore, in this study, it

Rock bolts are a crucial part of underground infrastructure support; however, current methods to locate and record their positions are manual, time consuming and generally incomplete. This paper describes an effective method to automatically locate supporting rock bolts from a 3D laser scanned point cloud. The proposed method utilises a machine learning classifier combined with point descriptors based

The studied area is a part of the New Istanbul Airport Metro construction project, which is on the Northwest of the city center towards the Black Sea Coast on the European Side of Istanbul. For this project ten EPB-TBMs were used. Two of them jammed/blocked consecutively within complex weakness zones as loose and open crushed zones. These zones have a complex geometry and structure filling with materials

With the rapid development of subway systems, the related fundamental knowledge is critically needed to benefit their designs and fire hazard assessment. The experimental study was performed in a 1/5th scale subway train model to characterize the fire inside subway train, and the experiment in open space was also conducted as a control group. Results show that in the case where the ceiling flame has

There has been an increasing interest in the study of sinkhole occurrences due to frequent underground activities. Most of the research direction are related to the detection of the underground cavity using geophysics techniques. Very little is done in the area of soil stability. This paper investigates the three-dimensional stability of circular and square trapdoors. The combined effect of surcharge

Tunnels are separated from the ground by structural linings, and are enclosed and unfamiliar for occupants. In tunnel fires, occupants are faced with a dangerous environment and they need to evacuate. Conveying and obtaining information about the evacuation is the key issue for evacuees. Since tunnels typically have low lighting and little connection outside the tunnel, technical installations are

As discontinued segmental joint plays a great important role in the mechanical behavior of shield tunnel lining, design for the joint suffers much from the difficulty in selecting proper parameters i.e., reduction factor η, spring stiffness. The mechanical behavior of longitudinal joint is highly nonlinear and can be classified into four stages. A four stage analytical model for determining the joint

An investigation on the dynamic interactions existing in a system consisting of multiple above-ground buildings, soil and a subway station when subjected to ground motions, normally named surface structures–soil–underground structure interaction (SSSI), is presented in this paper. Based on a series of shaking table tests on the seismic response of a system comprising a building, a tunnel and soil,

The interaction between a shield machine and the ground is a complicated problem involving numerous extrinsic and intrinsic factors. Machine learning (ML) algorithms have been recently employed to predict tunnel-soil interactions. This study introduces a more powerful algorithm termed the deep learning (DL) long short-term memory (LSTM) neural network, to identify the interaction between a shield machine

The use of fiber-reinforced polymer (FRP)-reinforced concrete (RC) soft-eyes in tunnel constructions has been gaining noticeable popularity as a successful and practical application of the non-corrosive FRP reinforcement. This unique use of FRP bars takes advantage of their anisotropic property, meaning they are strong along the main axis but can be machined, abraded away, or consumed by tunnel boring

The infrastructure types such as bridge-tunnel connection have become increasingly common along the high-speed railway lines in rugged terrains. The deterioration of traffic safety is inevitable when evoking the sudden variation of aerodynamic load when a train is running at the junction of two infrastructure scenarios (bridge to tunnel or tunnel to bridge) in a windy environment. This study is dedicated

Smoke is one of the important causes of tunnel fire casualties. The critical velocity and smoke back-layering length are important parameters of smoke control in the tunnel. This paper focused on experimentally studying the characteristics of the critical control parameter (such as, critical velocity, transition velocity) and smoke back-layering length induced by carriage fire in the longitudinal ventilated

Tunnels in urban areas typically have complex geological conditions, and sufficient support pressure is necessary to guarantee the safety of tunnel excavations and prevent damage to adjacent structures. In this study, the slip line method is employed to obtain the limit support pressure on the tunnel face and analyze the effects of the internal friction angle, cohesion of the soil, interface friction

In order to study the maximum temperature beneath tunnel ceiling of double fire sources, experiments were carried out in a model tunnel (1:10) with different heat release rates, longitudinal ventilation velocities and fire source pitches considered. Results showed that under the condition without wind effect, two flames merging phenomenon gradually disappeared as the increase of fire source pitch.

While pending full standardisation, the application of BIM in tunnel projects still requires customised solutions for many aspects of the design and construction phases. During construction of the tunnel, the position and orientation of segmented lining rings follows the actual path of the TBM, which is prone to steering tolerances. Hence, the final location of the lining segments is not fully determined

In this study, the dynamic interaction between a surficial alluvial valley and an underground tunnel embedded in it under plane shear horizontal (SH) waves is investigated. Within the framework of classical elastodynamics, an analytical solution to the wave propagation and scattering around a circular lined tunnel embedded in a semi–circular alluvial valley in an elastic half space is proposed. Using

Increasing the popularity of using fibres in precast structures has brought questions about their usability in segmental tunnel linings as an alternative to the conventional reinforced lining. Most prior studies have already revealed that the replacement of conventional steel reinforcement is possible with steel fibres. However, the usability of macro-synthetic fibres (MSFs) as reinforcements in precast

Transient pressure changes induced by trains passing through tunnels have a significant influence on the structural safety of tunnels. A verified numerical method was employed in this study to explore the influence of the tunnel cross-sectional shapes with the same blockage ratio on the change in surface pressure of the tunnel. The results show that the difference mainly appears in the region affected

Direct shear tests have been commonly used to study the frictional stresses during pipe-jacking. Particle angularity and mineralogy will influence the shear strength with apparent cohesion contributing to the arching effect during soil-structure interaction via pipe-jacking. Past researchers found it challenging to physically study particle behavior along the shear band during shearing due to the opaque

Dependency of urban life and modern industries on civil infrastructure and lifelines urges the stake-holders and authorities to consider the resilience of lifeline systems as a crucial decision-making factor. In this paper, the performance of a complex urban gas distribution network, under the effects of wave propagation, in a city with more than 12 million residents is assessed. In the first phase

The purpose of this work is to highlight the impact of input parameters uncertainty in discrete fracture network (DFN) models and their engineering applications. We show how the error of an input parameter, here the volumetric discontinuity intensity P32, impacts the DFN model and two important rock mechanics engineering applications: the in-situ fragmentation size distribution and the potential of

With the rapid urbanization and development of China, urban utility tunnels (UUTs) that combine various city lifelines are developing quickly. However, along with the convenience brought by UUTs, these concentrated lifelines also create more potential hazards. To overcome the shortage of traditional hazard identifications and match the characteristics of UUTs, the EPE model (Energy transfer theory

In recent years, with the rapid growth of traffic flow in highway tunnels, the in-tunnel environmental pollution problem has aroused widespread concern in China. Previous studies mainly focused on the emission factors in tunnels dominated by passenger cars (PCs) and light commercial vehicles (LCVs). However, this study concentrated on the characteristics of traffic flow dominated by heavy-goods vehicles

The real-time acquisition of surrounding rock information is important for the efficient tunneling and hazard prevention in tunnel boring machines (TBMs). This study presents an ensemble learning model based on classification and regression tree (CART) and AdaBoost algorithm to predict the classification of surrounding rock mass. Statistical indicators (i.e., mean value and standard deviation) of TBM

Detecting sudden changes in geological conditions (e.g., karst cavern and fault zone) during tunnelling is a complex task. These changes can cause shield machines to jam or even induce geo-hazards such as water ingress and surface subsidence. Tunnelling parameters that relate closely to the surrounding geology have proliferated in recent years and present a substantial opportunity for the application

This paper investigated the plug-holing phenomenon in the tunnel fire with two-point extraction ventilation based on a reduced-scale tunnel model. The effect of the heat release rate (HRR) and extraction vent settings, i.e. the area and aspect ratio (a ratio of the width to the length), on the occurrence of plug-holing was addressed experimentally and theoretically. Experimental results show that the

Installing a rescue station in an extra-long railway tunnel is an important measure to reduce the loss from tunnel fires. After a fire breaks out in the tunnel, the temperature distribution and smoke control in the rescue station are two important factors for disaster prevention and rescue. In this paper, a series of 1:10 small-scale model experiments were carried out to study the effects of transverse

In theory, if the plug-holing phenomenon can be effectively eliminated, the application of natural ventilation with vertical shaft will no longer be limited to shallow buried tunnels, or even extended to deep buried tunnels. Researches have validated that the board-coupled shaft (BCS) can efficiently eliminate the plug-holing phenomenon and promote the smoke extraction performance in a shallow buried

Smoke control is a key issue in tunnel fire accidents. While jet fans have been widely used in road tunnels, mobile fans provide a good complement, due to its flexibility to operate, especially if there are no fixed jet fans present. To confirm the feasibility of a mobile fan system, full scale fire tests were conducted in Kalldal tunnel in Sweden, with fire size in the range of 1–2.6 MW and a mobile

Structural supports used for tunnels and other underground civil structures in soft rock are often prone to severe damage due to large deformation. To overcome this issue, a new steel circular closed support with I-section of sinusoidal corrugated webs is proposed to mitigate such damage caused by deformation. Large scale experiments of the proposed support with corrugated webs were carried out to

To provide an effective support device for dealing with the instability problems in geotechnical engineering, this paper proposes a new energy-absorbing rock bolt based on the existing energy-absorbing devices, called compression-expansion-friction bolt (abbreviated as the CEF bolt). The CEF bolt mainly consists of two parts, a variable-diameter tube and a hollow cone attached at the distal end of

Controlling rock damage induced by lateral blasting excavation is a source of concern. In underground mines, large-diameter-hole lateral blasting excavation often causes engineering disasters such as large blocks falling and overall collapse of the remaining rock mass. Because of their high cost and cumbersome operation, conventional contour blasting techniques, such as smooth and presplit blasting

Five years of semi-continuous displacement records from extensometers installed though a concrete mine shaft lining are analysed and interpreted. The data includes multiple episodes of contraction which have amplitudes up to 15 mm in individual extensometers. Detailed analysis of extensometer data suggests transient high stresses occur in the shaft lining. The amplitude, wavelength and frequency of

Effect of blockage on critical ventilation velocity in longitudinally ventilated tunnel fires was investigated based on small-scale experiments and numerical simulations. Blockages were located right upstream of the fire or 3.5 m upstream of the fire. At each location, blockages have five blockage ratios and two orientations. Experimental data shows that the factors as blockage ratio, blockage-fire

Adjacent building damages induced by excavations is crucial for excavations in urban areas. Excavation induced damage involved complex soil-structure interactions and complicated ground movements which should be evaluated at the depth of foundation of adjacent buildings. Empirical or semi-empirical methods for evaluation of ground movements induced by excavations have not been well-established because

Proper soil conditioning is critical for effective earth pressure balanced tunnel boring machine (EPBM) operation. Foam as a soil conditioner has been extensively used in EPBM tunneling to modify the excavated soil properties. A critical characteristic of foam-conditioned soil is stability, i.e., the ability to maintain the engineering properties throughout the residency time (30–90 min) in the mixing

Scale criterion has been proposed for tunnel fires, however, some parameters are usually not feasible to be implemented. In this study, numerical and experimental simulations have been performed to validate the scale criterion. First, the wall thickness parameter was studied since it plays an important role in the heat conduction. The results of the simulations were compared with Hu’s full-scale experimental

During the construction of the interconnection tunnel from Tianqiao Station to Yongdingmen Station of Metro Line 8 in Beijing, the Earth Pressure Balance (EPB) shield machine had to excavate in sandy cobble soil. Because the sandy cobble soil has varying moisture content along the tunnel route and shows the characteristics of loose particle structure, large pores and no cohesion between the cobble

This paper deals with the analysis of overbreak in tunnels excavated with the drill-and-blast method. The overbreak phenomenon has many negative impacts on tunnelling organisation and economy and its precise assessment plays a fundamental role in the process of construction optimisation. The study proposes an operative methodology to estimate overbreak volumes and to distinguish so-called technical

A series of shaking table model tests were performed to investigate dynamic responses and damage mechanisms of prefabricated corrugated steel utility tunnels holding various brackets and pipelines. Details of the shaking table experimental setup for this kind of new utility tunnel are presented in this paper for the first time. Multiple seismic responses are measured, including the displacement of

The distance between the fault and the underground cavern affects the surrounding rock mass stability, which is of great importance to the design and construction of the large-scale underground cavern especially the underground powerhouse. This study focuses on the distance effects of the fault on the rock mass stability of the main powerhouse at the Huanggou pumped-storage power station. Firstly,

The shape of rock particle can profoundly affect its mechanical behaviors due to the interlocking force associated with morphological features. In this study, a hybrid extension method encompassing both convexity control and overlap detection was developed to generate three-dimensional (3D) polyhedrons for simulating irregularly shaped rock particles by discrete-element-method (DEM). Based on a random

In this study, the natural ventilation of a horizontal entrance of a typical subway station is investigated based on numerical simulations and experiments. In addition, a renormalization group k-ɛ model (RNG k-ɛ model) is applied to compute both the internal and external airflow patterns. Computational fluid dynamics (CFD) simulations are validated based on the experimental results. Furthermore, a

The acoustic quality of long spaces is often a problem confronting the designer. Ensuring adequate speech reception in relation to sound alarm systems in such spaces is one of the key factors determining the acoustic quality of a space. The aim of this paper is to present an initial, index-based method for the assessment of the acoustic quality of long spaces during the design process, taking into

A series of scale model tests were conducted to investigate the influence of canyon cross wind on burning and flame characteristics of ethanol pool fires inside a tunnel, considering pool size and fire location. At the same time, the characteristics of the flow field inside the tunnel were investigated by Fire Dynamics Simulator (FDS). Results show that an uneven three-dimensional flow field structure

Tunnel boring machines (TBMs) are considered to be the most efficient tunneling method for long tunnels because of their higher productivity, adaptability to a variety of subsurface conditions, and providing a safer work environment. The number of TBMs utilized over the past decade has escalated, testimony to their continuing success and flexibility for application on projects of different diameter

A pressure adaptable concrete lining (PACL) for hydraulic tunnels with high water pressure and high groundwater pressure was developed based on the thick-walled cylinder theory. One of the functions of the designed lining structure is that it can transfer the tunnel water pressure to the lining outer wall such that the lining bears compressive stress only. Moreover, the groundwater around the lining

With the design and development of the first fully prefabricated subway station structure (assembled structure) in Changchun, China as the engineering background, large-scale shaking table tests were carried out on the new single-arch and long-span assembled structure and the traditional cast-in-place subway station structure (cast-in-place structure). Based on the seismic response of the cast-in-place

Modern technologies have enabled the development of high quality work environments in underground spaces (UGS).Yet, the fundamental issue of whether UGS are suitable for people intensive functions, such as office or manual work, is largely not well understood. Here, we examine whether full-time white collar (office [WCW]) and blue collar (mostly manual [BCW]) workers of UGS have different responses

In order to solve the problem of steady-state temperature field with complex boundary conditions and provide a more complete theoretical guidance for Freeze-Sealing Pipe Roof (FSPR) method, which is a new pre-supporting system for tunnel construction. This paper proposed a FSPR freezing model based on the simplification of Gongbei tunnel considering the operation of limiting tubes, and the analytical

Despite the widespread use of soil excavating tools, including soft ground shield TBMs, there is not any universally accepted method for soil abrasivity assessments. However, different experimental models have recently developed to study the abrasivity of soil materials. LCPC test, developed in Laboratoire Central des Ponts et Chaussées, is one of the most common, simplest, and most available approaches