Underground Construction Projects Research Articles

Study on Shield Machine Technology

The shield machine is a specialized construction equipment used for excavating tunnels, particularly in underground construction projects. The shield machine plays a pivotal role in modern engineering and construction, minimizing surface disruption and environmental impact. Shield machines can adapt to different geological conditions and project requirements, and efficiently excavate tunnels in various ground conditions, reducing construction time and costs. Shield machines improve worker safety by reducing risks associated with manual tunneling, and digging tunnels with high precision, crucial for projects like subways. In essence, shield machines are essential tools in modern tunnel construction, offering efficiency, safety, and precision in building underground infrastructure for various purposes, including transportation, utilities, and more. This paper summarizes the development history of the shield machine and its basic structure, discusses its limitations and challenges, and makes a certain analysis of the application of the shield machine while discussing the innovations and methods of the hydraulic propulsion mechanism of the shield machine. This paper may offer a reference for the development of shield machine.

An integrated risk and productivity assessment model for public–private partnership projects using fuzzy inference system

Infrastructural projects based on public–private partnership (PPP) schemes usually struggle with large amounts of resources. Given such projects’ relatively long lifetime, it is expected to encounter a wide range of risks when executing them. This implies that increasing productivity based on cost, time, and quality goals requires accurately identifying and assessing risks in these projects. This study aims at risk assessment and analysing productivity in PPP projects based on an integrated analysis method. To this end, first, library studies are utilized to identify the most significant risks by surveying the PPP-based urban underground construction projects. Expert opinions and the fuzzy Delphi (FD) technique are then employed in three stages to identify 48 secondary risk factors. By identifying the sources of these secondary risk factors, we identify five primary risk dimensions: government, financing, operation, constructability, and organization-related risks. A questionnaire is distributed to acquire experts’ opinions and screen the most critical risks by integrating FD with fuzzy failure mode and effects analysis (FFMEA). Results showed that, in total, 23 secondary risk factors in the five primary risk dimensions exhibited risk priority number (RPNNormalized) values above 0.5, indicating their relatively more critical impacts. In the next phase, a multi-stage fuzzy inference system is designed to evaluate the impacts of critical risks on the productivity of PPP projects. Output results of the inference system indicated very high, high, and medium impacts of the risks on the overall productivity of the PPP projects in terms of time, cost, and quality, respectively.

Localization of underground pipe jacking machinery: A reliable, real-time and robust INS/OD solution

Accurate positioning is important for guidance control in pipeline construction, but traditional approaches fail in GPS-denied environments. This paper addresses the underground localization problem for the pipe jacking machine by presenting an Inertial Navigation System (INS)/ODometry (OD) scheme. It is a loosely coupled navigation system that combines an INS and an OD to provide reliable, real-time, and robust location estimation in an enclosed and restricted space. The combination is achieved by a multi-sensor fusion algorithm to avoid the divergence of standalone INS. Compared with the traditional localization technologies, the advantage of the INS/OD scheme is that there is no performance degradation or service failure despite severe blockage of the thick soil layer due to the selection of dead reckoning-based sensors. Moreover, an Unbiased Finite Impulse Response (UFIR) filter serves as the fusion mechanism to improve the robustness against a prior knowledge of noise, considering unknown and time-varying noise statistics in practice. The INS/OD scheme is verified through a numerical simulation and employed on-site in a real underground sewage pipeline construction project. Despite the construction site being more than 10 meters deep underground, the INS/OD scheme continues to perform reliably and robustly in real-time, significantly benefiting the engineering guidance enterprise.

A sectorisation-based method for geostatistical modeling of pressuremeter test data: Application to the Grand Paris Express project (France)

In the context of underground construction projects such as large-scale linear projects, knowledge of subsoil geotechnical properties is of major importance. An effective way to analyze and represent the variability of these properties is to use geostatistical methods. Despite the good performance of such methods, their use is not yet widespread in the field of underground projects. This paper aims to show the usefulness of geostatistics in the field of tunneling by proposing an original 3D sectoral modeling approach that allows dividing the geological formations in homogeneous geotechnical areas to better take into account the vertical and lateral variations of geotechnical properties. The approach is tested by developing a 3D geostatistical model of the pressuremeter tests on a section of a massive tunneling project in Paris (France): the Grand Paris Express. A strong focus is also made on the model input data: a methodology is proposed to overcome the limitations of the pressuremeter test in order to better study the spatial variability of the net limit pressure. A twofold analysis is conducted by comparing the modeling results obtained with and without pressuremeter data processing and those obtained with and without sectoral modeling. The results of the comparison show that: a) data processing is useful to better discern areas of extremes values of net limit pressure; b) dividing the geological units into homogeneous geotechnical sectors provides an advantage for geological units with geotechnical heterogeneities, as it leads to improved reliability of results.

Triaxial direct shear properties, cohesive damage behavior and shear constitutive model of sandstone under high confining pressure

The shear mechanical properties of rock under high confining stresses are required in deep underground construction projects for stability evaluation. This paper tested the sandstone shear properties under high confining pressures by a novel triaxial direct shear device with a self-balancing structure for both low and high confining pressure. The triaxial direct shear experiments on Zigong sandstone from a deep tunnel were carried out to evaluate its strength and deformability. Our experimental results suggested that the shear stress-displacement curves exhibited two distinct characteristics under different confining pressures. The damaging stage occurs initially and turns wider in the shear stress-displacement curve as the confining pressure exceeds the threshold stress. The confining pressure threshold of Zigong sandstone is observed to be 10–20 MPa. Meanwhile, a statistical damage model based on Beta distribution was proposed to describe the shear stress (cohesion contribution) during the whole shearing process, which demonstrates better prediction performance than previously existing models, especially under high confining pressures. This study provides important insights into the high-pressure induced rock shear properties and sheds light on the engineering stability assessment under high stress of tunnels.

Damage evolution process and damage precursor law under cyclic splitting action of different types of rocks

During the construction of underground projects, different types of rock are often in a cyclic state of loading and unloading. Therefore, cyclic fracturing experiments have been carried out on metamorphic sandstone, slate and granite from one mine site. Based on the basic parameters of acoustic emission (AE), the damage processes and damage precursor patterns of different types of rock samples are analysed. The results of the study show that there is basically no AE signal generated during the unloading phase of the first two cycles of loading, and less acoustic emission signal is generated in the loading stage. In the experimental process on different types of rock samples, when the value of CV( r ) (standard deviation of the ratio between rise time, amplitude and mean frequency of acoustic emission parameters) is larger, it can be considered as large-scale crack dominance, and as small-scale crack dominance when the value of CV( r ) is small; also, CV( r ) values are more accurate than AE b -values in determining the pattern of cracking within a rock sample. With different internal crack development during cyclic splitting, we can focus on the changes in the AE loading energy ratio and CV( r ) values before damage destabilization occurs. The Felicity ratio, CV( r ) value and loading energy ratio can be used in combination in practical engineering to improve the accuracy of determining rock stability.

Review on Potential Risks in Construction Process

Abstract: Risk assessment is an important part of project management in the construction industry. It includes identifying, identifying and mitigating risks that may affect project objectives. This article provides an overview of the various risk assessment methods used in the construction industry, from quantitative to fuzzy methods. This study introduces validation methods such as Monte Carlo simulation, sensitivity analysis, critical path analysis, fault tree analysis, tree analysis and failure models, effects and critical analysis. These versatile methods provide an overview of the likelihood of their occurrence and its impact on the objectives of the project, making them effective tools in the field. In addition, the article explores the idea of turbidity as a way to quantify the quality of certain risks in underground construction projects. Legislative frameworks and tools for assessing land development related issues that offer new solutions for risk management in complex situations are also discussed. Analysis pointed out that there is no single method of risk assessment that concerns all organizations and activities. In summary, risk assessment plays an important role in construction decision making, resource allocation and the development of risk mitigation strategies. Continuous research and development in this area will further refine and improve the risk assessment method, resulting in the overall success and sustainability of construction.

Geotechnical challenges and innovations in urban underground construction – The Klang Valley Mass Rapid Transit project

AbstractThe Klang Valley Mass Rapid Transit (KVMRT) project involves the construction of an urban passenger transport system, i.e., Mass Rapid Transit (MRT) system, together with the existing urban rail network, will form the backbone of the public transport system in the Greater Kuala Lumpur/Klang Valley region in Malaysia. The first MRT line implemented is the 47 km Kajang Line, of which 9.5 km is underground tunnels with seven underground stations. Construction of the line began on 8 July 2011 and achieved the full line opening on 17 July 2017. The second MRT line―Putrajaya Line―began fully operations on 16 March 2023, stretches from Sungai Buloh to Serdang and ends at Putrajaya for a length of 57.7 km, of which 13.5 km is underground tunnels with 10 new underground stations. Like all other metro underground stations/tunnels designed as part of the urban city, the KVMRT underground construction faces challenges from a technical (engineering design and construction) as well as social (environmental and land related) point of view. Needless to say, underground construction in Klang Valley is intensified with the inherent geotechnical challenges presented by complex ground conditions ranging from hard granite, heterogeneous Kenny Hill formation and extreme karstic limestone with fully developed weathered profiles to soft recent deposits including alluvium and mine tailing that is under‐consolidated in places due to past mining activities. The development of this large‐scale infrastructure project has not only opened up tremendous works and new frontier for tunnelling and geotechnical engineering in Malaysia, but it also provided a wealth of information of unique geotechnical challenges/accomplishments as well as technology breakthrough and design innovation in underground engineering. This article discusses some aspects of geotechnical challenges and interesting lessons learnt as well as numerous innovations embedded into this highly complex urban underground construction project.

Numerical Simulation and Analysis of the Influencing Factors of Foundation Pit Dewatering under a Coupled Radial Well and Curtain

It is crucial to use a suitable dewatering technique to prevent land subsidence and substantial decreases in groundwater levels caused by the dewatering of groundwater during the construction of underground projects. Therefore, in this study, a generalized three-dimensional numerical model of groundwater flow was implemented for an underground station pit project. The dewatering efficiency of the coupled radial well-curtain method was investigated and compared with that of a traditional method. In addition, the influence of different structures and parameters (radial pipe diameter, conductance, number of radial pipes, and shaft drawdown) on the dewatering efficiency was assessed. The results showed the following: (1) radial wells caused less disturbance to the groundwater seepage field and extracted less groundwater during the dewatering process compared with pumping wells; (2) the structure and parameters of the radial wells positively correlated with the dewatering efficiency; (3) the curtain improved the dewatering efficiency, resulting in lower amounts of groundwater discharged and less disturbance to the groundwater flow field; and (4) the coupled radial well-curtain method is an efficient dewatering method that could effectively prevent the lowering of groundwater level outside the foundation pit, thus reducing the risk of land subsidence in the surrounding area.

Progressive Evolution Model of Fault Water Inrush Caused by Underground Excavation Based on Multiphysical Fields

Underground fault water inrushes are frequent hydrogeological disasters associated with underground mining and tunnel construction projects. In this study, we analyze the water inrush mechanism of underground engineering by building a numerical simulation model to evaluate the process of water inrush, analyze water inrush changes under various working conditions, and consider the fluid-solid coupling effect of rock mass and water. These analyses provide effective suggestions for preventing water inrush from faults. The study establishes a two-dimensional numerical model based on Darcy’s law and plane strain field to analyze water inrush from faults in underground engineering. The analysis shows that factors such as aquifer pressure, permeability between the aquifer and fault zone, and permeability sensitivity coefficient are important considerations that affect the occurrence of water-inrush disasters. The study also identifies the sudden change in water inrush speed at the fault zone and the roadway when the working condition is changed as an indication of the nature of water inrush at the fault. Additionally, the study presents preventive measures such as drainage grouting to ensure the safety of underground engineering constructions. Overall, this research provides important insights into the causes and effects of water inrush from faults and can inform practical measures to mitigate the risks associated with underground engineering.

Using digital technologies to plan and manage the pipelines network in city

AbstractPromoting the intelligent level of urban pipelines network planning and management is an important way to improve the rational development and utilisation of urban underground space and ensure the safe operation of urban infrastructure systems. The research on using the rapid and visual expression technology of 3D pipelines network model data, which has the functions of techno‐economic indexes calculation and automatic comparison of underground pipeline construction projects, effectively avoids possible errors in manual calculation and comparison and improves the efficiency and accuracy of the digital declaration process for project planning. In the 3D Geographic Information Systems (GIS) platform environment, this research help to develop many analysis and approval functions based on the data of the underground pipelines network model and the integrated pipes gallery Building Information Modelling, such as evaluating the compliance, feasibility and scientific of the planning scheme of the underground pipeline construction project, comparing the completion data with the data approved by the administrative departments of the project, evaluating the consistency of them and judging the compliance of the project completion data. The application results of some actual projects cases show that this research can improve the efficiency of planning declaration and approval analysis.

Analysis of Excavation Parameters on Face Stability in Small Curvature Shield Tunnels

This study investigates the face stability of small curvature shield tunnels during excavation and its relationship with various excavation parameters. The stability of the excavation face is critical to the safety and efficiency of underground construction projects. Despite the increase in the use of small curvature shield tunnels in urban areas, research works on this type of tunnel are limited and the existing literature focuses only on straight shield tunnels. This study addresses this research gap through numerical simulations, analyzing the effects of different excavation parameters such as jacking force, cutting speed, and soil conditioning on face stability. The results of the study show that the excavation parameters significantly affect face stability. The findings can be used to optimize the performance of small curvature shield tunnels and support their continued development in urban areas.

Innovative contract and compensation model in mechanised tunnelling – Calculation of the deviating construction time based on digital excavation and process data

AbstractThe handling of a tunnel construction project poses great challenges for all those involved. Variables that cannot be clearly quantified can arise during the entire process of the project. The subsoil in tunnelling is one of these parameters which is difficult to forecast. The geological and hydrogeological conditions must be assessed during the planning phase with the help of exploratory measures and from the experience from projects that have already been built.During the execution work, deviations from the documents on which the target determination is based occur in almost all underground construction projects. These changes can either cause a change in the construction process and/or lead to a different construction time in relation to the calculated duration.Based on this initial situation, the development of an innovative contract and remuneration model for machine tunnelling appears to be important. The main focus of the model is to generate a transparent and comprehensible method of how the remuneration‐worthy portion can be calculated in the case of a different construction time in mechanised tunnelling. In order to ensure this transparency and traceability of the system to be developed, the data records that can be digitally recorded during the tunnelling work are used as a fundamental basis for the created model.

Experimental research on the influence of stratum permeability on the time-varying properties of active grout

In the construction of underground projects, the water-binder ratio is generally considered as one of the main factors affecting the cement-based backfill grouting performance. In addition, when the backfill grouting is consolidated in the formation. The difference in the permeability of the formation will affect the consolidation rate and consolidation drainage of the backfill grouting, resulting in changes in the water-binder ratio of the grout, which in turn affects the development of its performance after consolidation. However, it is difficult to simulate the consolidation and hardening process of backfill grouting in the formation with the current indoor test equipment. Therefore, the influence of the permeability difference of the stratum on the time-varying law of backfill grouting and consolidation is less studied. In this paper, the self-made consolidation test device is used to study the time-varying law of grout consolidation in different permeable formations, and the time-varying law of grout performance is studied by using the samples after consolidation. The results show that with the increase of formation permeability coefficient, the dissipation time of excess pore water pressure of grout decreases, and the volumetric strain increases. The grout consolidation rate is determined by the relative permeability coefficient between the grout and the formation, and the difference in consolidation causes changes in the moisture content of the grout after consolidation. The change of the ratio of bound water to free water affects the time-varying law of strength after consolidation.

Evolution of construction risk management research: historiography and keyword co-occurrence analysis

PurposeThis study collected the bibliographic data of 2034 journal articles published in 2000–2021 from Web of Science (WoS) core collection database and adopted two bibliometric analysis methods, namely historiography and keyword co-occurrence, to identify the evolution trend of construction risk management (CRM) research topics.Design/methodology/approachCRM has been a key issue in construction management research, producing a big number of publications. This study aims to undertake a review of the global CRM research published from 2000 to 2021 and identify the evolution of the research topics relating to CRM.FindingsThis study found that risk analysis methods have shifted from simply ranking risks in terms of their relative importance or significance toward examining the interrelationships among risks, and that the objects of CRM research have shifted from generic construction projects toward specified types of construction projects (e.g. small projects, underground construction projects, green buildings and prefabricated projects). In addition, researchers tend to pay more attention to an individual risk category (e.g. political risk, safety risk and social risk) and integrate CRM into cost, time, quality, safety and environment management functions with the increasing adoption of various information and communication technologies.Research limitations/implicationsThis study focused on the journal articles in English in WoS core collection database only, thus excluding the publications in other languages, not indexed by WoS and conference proceedings. In addition, the historiography focused on the top documents in terms of document strength and thus ignored the role of the documents whose strengths were a little lower than the threshold.Originality/valueThis review study is more inclusive than any prior reviews on CRM and overcomes the drawbacks of mere reliance on either bibliometric analysis results or subjective opinions. Revealing the evolution process of the CRM knowledge domain, this study provides an in-depth understanding of the CRM research and benefits industry practitioners and researchers.

CERN Future Circular Collider – the Mining the Future competition

AbstractCERN (Conseil Européen pour la Recherche Nucléaire) is the world's largest research centre for high‐energy and particle physics. The research infrastructure contributed to the greatest successes in the field of experimental physics. A new, approximatively 91 km long subsurface infrastructure connected to the existing particle accelerator complex is being conceived in the frame of the Future Circular Collider. It would serve a global community of researchers with two subsequently operated particle colliders until the end of the 21st century. Even at an early stage of such a project, comprehensive investigations have to be carried out into the nature of the subsoil in order to find an optimal utilisation strategy for the excavated material in accordance with the national and international regulations in order to promote the recycling of excavated tunnel material in terms of resource conservation and the improvement of the sustainability of underground construction projects.

Leakage Analysis and Hazardous Boundary Determination of Buried Gas Pipeline Considering Underground Adjacent Confined Space

Urban underground construction projects are intertwined vertically and horizontally, and adjacent confined spaces such as water supply and drainage pipelines, side ditches and underground canals may exist near buried gas pipelines. Once the buried gas pipeline leaks, the gas will diffuse into the confined space through the soil and even enter the residential room by the confined space, which brings serious potential safety hazards. In this paper, the underground adjacent confined space hazardous boundary (HB) of underground gas pipeline leakage was defined, the distribution properties of gas leakage diffusion flow field were analyzed by numerical simulation and the distribution law of gas entering the confined space was studied. Using the least-squares method and multiple regression theory, the gas concentration prediction model in the adjacent confined space of buried gas pipeline leakage was established, the HB calculation model was further deduced, and the HB drawing board was drawn. The results showed that in the initial stages, the internal and external pressure and velocity distribution of the pipeline near the leakage hole were unstable, reaching a stable state after 60 s, and then the reverse flow occurred in the pipeline downstream of the leak hole. Reducing the minimum construction distance between the buried gas pipeline and the confined space improved the gas distribution concentration in the confined space. When the minimum construction distance increased from 3 m to 9 m, the gas concentration distribution decreased from 90.21% to 0.88%. Meanwhile, increasing the pipeline pressure and leakage diameter enhanced the gas concentration distribution in the confined space. The HB calculation model and HB drawing board realize the rapid determination of the HB between buried gas pipeline and confined space and offer a more reasonable basis for the design of gas pipeline safe distance in urban underground engineering construction.

Reduction of Carbon Emission Is Optimized During the Life Cycle of Commonly Used Force Main Pipe Materials

With increasing attention to global warming and greenhouse gas (GHG) emissions and providing a better environment for coming generations, there is a critical need to quantify and decrease the environmental impact. Underground construction projects are one of the biggest constructions in North America; consequently, it is one of the GHG emissions' primary sources. This research focused on optimizing the carbon dioxide (CO2) emissions for a 91 cm (36 in) diameter sewer pressure pipe with 3 m (10 ft) depth and 30 m (100 ft) length, operating at 690 kPa (100 psi) during the commonly used pipeline materials' life cycle: Cured-in-Place Pipe (CIPP), Pre-stressed Concrete Cylinder Pipe (PCCP), High-density polyethylene (HDPE) pipe, and Polyvinyl Chloride (PVC) pipe. The life operations for this study were considered 100-years. The four phases of a pipeline life cycle included in this study are fabrication, installation, operation, and disposal phases. Life cycle assessment (LCA) is a methodology to evaluate the environmental impacts of products or service systems throughout the complete life cycle from the cradle to the grave. The study results show that the CO2 emissions have been reduced by 16% on the PCCP pipe, 4% on PVC pipe, 1% on HDEP pipe, and by 3.2% and 2.0% on CIPP lining (50 years and 100 years life expectancy, respectively). It is recommended that field studies be conducted in future research to obtain the necessary data to overcome the dependence on assumptions made in this study. Also, I recommended including the direct and social costs, which will make the decision easier for engineers and decision-makers to choose the right choice.

Evaluating the Application of Rock Breakage without Explosives in Underground Construction—A Critical Review of Chemical Demolition Agents

The method of drilling and blasting with explosives is widely used in rock fragmentation applications in underground construction projects, such as tunnels and caverns. However, the use of explosives is associated with rigorous safety and environmental constraints, since blasting creates toxic fumes, ground vibrations, and dust. Because of these constraints, there has been a growing interest in transitioning away from explosives-based rock fragmentation. The use of explosives-free methods could lead to continuous operation by eliminating the need for idle time with additional ventilation required to exhaust the blast fumes. This paper first presents a critical review of various methods that have been developed so far for rock fragmentation without explosives. Such methods include thermal fragmentation, plasma blasting, controlled foam injection, radial-axial splitter, and supercritical carbon dioxide. Thermal fragmentation, as the name implies, uses high heat to spall high-grade ore. However, it requires high heat energy, which requires additional ventilation as compared to normal conditions to cool the work area. Plasma blasting uses a high temperature and pressure plasma to fracture rock in a safe manner. While this method may be environmentally friendly, its usage may significantly slow tunnel development due to the need to haul one or more large energy capacitor banks into and out of the work area repeatedly. Controlled foam injection is another chemical method, whereby foam is the medium for fracturing. Although claimed to be environmentally friendly, it may still pose safety risks such as air blast or flyrock due to its dynamic nature. A radial-axial splitter (RASP) is an instrument specially designed to fracture a borehole in the rock face but only at the pace of one hole at a time. Supercritical carbon dioxide is used with the equipment designed to provide a high-pressure jet stream to fracture rock, and replaces water in these instruments. The method of soundless chemical demolition agents (SCDA) is evaluated in more detail and its merits over others are highlighted, making it a potentially viable alternative to blasting with explosives in underground excavation applications. Future work involves the optimization of SCDA for implementation in underground mines. The discussion compares the key features and limitations, and future work needs are underlined.

Successfully managing Covid-19 on tunnelling operations for the Thames Tideway Tunnel, UK

The Covid-19 pandemic had a huge impact on the way the UK population lived and worked during 2020. This paper explores the challenges faced while boring the west section of the Thames Tideway Tunnel in London, UK, with particular focus on the first national lockdown that began in March 2020. It discusses how the reduction in personnel triggered closure of the site, the technical challenge of safely stopping a tunnel boring machine for extended periods of time and the practical difficulties of creating a Covid-safe environment in a challenging space. This case study can be used to inform other underground construction projects coping with coronavirus.