Development Of Underground Space Research Articles

Elements of the core area transport system oriented to station–city integration

Currently, China's urban rail transit construction projects are faced with several challenges including inconsistent planning and execution, lack of alignment with urban development, overly protracted timelines for some projects, sub-optimal land utilization rates, and significant wastage of precious urban resources. To mitigate these issues, it is essential to enhance land utilization around stations, implement scientific planning, and adopt intelligent management for underground space development. Moreover, all parties involved in construction must adhere strictly to planning guidelines during project execution. This study investigates the integrated development strategy of urban rail transit stations and their correlating cities, with the primary objective of enhancing the land utilization of stations and their surrounding areas. This involves fortifying the functionality of transportation, commerce, offices, residences, entertainment, and leisure in these areas, thereby catering to the varying needs of residents for travel, work, or entertainment activities. This type of an approach is anticipated to ease the pressure on urban road traffic, stimulate the economic growth of the stations and the areas along the routes, decrease environmental pollution, conserve urban space resources, and address issues associated with urban rail transit development. The insights gained from this research offer a valuable reference for future rail transit construction endeavors, carrying substantial practical significance.

Urban geophysical exploration: case study in Chengdu International Bio-City

Abstract Understanding the shallow geological structure of urban areas is crucial for effective planning and development of underground spaces. Geophysical methods that are well-suited for site-specific investigation and have robustly anti-interference capabilities can provide important geological information for urban areas. In support of investigating the 3D geological structure of the shallow subsurface in Chengdu International Bio-City, a geophysical exploration study was conducted using three methods: the electrical resistivity tomography (ERT), micro-seismic exploration and opposing-coil transient electromagnetic method (OCTEM). Results from the study showed that the ERT method was greatly affected by local high-resistance bodies, construction sites and industrial currents, therefore leading to poor detection results that did not match well with the area’s layered structure characteristics. The micro-seismic exploration method showed good layering effects and correlation with the drilling data in the elevation range of ∼350 to 436 m, but poor layering effects and low correlation with drilling data in the elevation range of ∼235 to 350 m, with relatively slow construction efficiency. The OCTEM showed good correlation with the drilling data for shallow depths up to 200 m and good identification capabilities for gypsum and mudstone in the area. Additionally, the instrument’s anti-interference ability was suitable for complex urban conditions. Thus, OCTEM was selected for the area-based exploration with a 100 × 10 m grid, rapidly obtaining 3D resistivity information for depths up to 200 m in the study area. By integrating the 3D resistivity information with known engineering geological information, a comprehensive 3D geological model of the study area was created.

Обоснование выбора материала для изготовления ножа исполнительного органа геохода

Introduction. The use of geohods for the development of underground space is an innovative approach, the essence of which is the use of geo-media in the rock mass to create traction forces. The constructive and functional requirements for the working bodies are being developed, which take into account the nature of the movement and functionally constructive differences, the formation of a specific form of slaughter obtained during the operation of the working body, in which the working body is made in the form of helicoids shape. To implement technological solutions, it is necessary to select and justify the materials of the working body of the geohod. Materials and methods. The paper considers the basic requirements for the materials of the working body of the geohod, based on the structural, functional and technological features of the design of the geohod. The paper notes that the cutting edge of the working works in particularly harsh conditions, therefore, materials such as alloy steels with high wear resistance are recommended for this type of construction. Foundry alloy steels and high-strength alloy alloys are considered as rational options. Research results and their discussions. Taking into account the features of the equipment, the physical and mechanical properties of the rock being destroyed, the strength characteristics of the recommended materials and their technological properties, when choosing materials, emphasis is placed on the mechanical properties of materials and wear-resistant properties, which are important parameters, since abrasive wear of the working surfaces occurs when the working body of the geohod. Conclusion. The recommended alloyed alloys with high strength meet all the requirements that are imposed on the design of the knife of the executive body, but do not meet the technological requirements, namely, they are quite difficult to deform, difficult to process by cutting and welded. Considering all the technological properties that are significant in the implementation of the manufacturing technology of the working body of the geohod, it is recommended to choose more durable materials that withstand large continuous loads. Resume. The article presents the results of research to determine the choice of material for the manufacture of the working body of the geohod. It is established that for the manufacture of the working body, when using the casting technology of production, steel 30ХГСА can be used, when processing pressures – steel 18Х2Н4МА. Suggestions for practical application and direction of future research may be useful for the development of manufacturing technology of the main elements of the working body of the geohod.

DETERMINATION OF BOUNDARIES PARAMETERS OF THE COMPUTATIONAL MODEL FOR ASSESSING THE IMPACT ON THE SURROUNDING FACILITIES FROM TUNNELING

As a result of active development of Moscow underground space, as well as due to the increased density of urban development, it is necessary to forecast additional displacements of surrounding buildings from new construction in order to prevent emergency situations. For this reason, one of the important directions is mathematical modeling of the additional displacements of the surrounding building after erection. Establishing the parameters of design boundaries of a geotechnical model is one of the factors that greatly influence the results of the simulation. This study deals with the assignment of the lower boundary of the scheme when estimating the impact from tunneling works in a two-dimensional formulation. A review of international experience in simulating the design scheme depth for various geotechnical problems and its comparison with Russian experience in modeling schemes has been made. The deformation marks located on the ground surface in the zone of influence of the Rublevo-Arkhangelskaya and Troitskaya (Kommunarskaya) lines of the Moscow Metro under construction were selected for the analysis. The authors carried out the selection of the lower boundary of the scheme by changing it in proportion to the outer diameter of the tunnels in dispersed and rocky soils. The obtained data were compared with geodetic monitoring one. Calculations were made for three different soil models such as Mohr-Coulomb, Mohr-Coulomb with increasing deformation modulus of the prism under the excavation and Hardening soil. In addition, calculations were made for two cases of assignment of the overburden coefficient - according to normative documentation and available research on the subject. As a result of this work, more than 600 calculated cases were obtained. Based on these cases, recommendations were developed for adjusting the scheme depth for the considered soil models.

Monitoring and Prediction of Horizontal Displacement of Underground Enclosure Piles in Subway Foundation Pits.

Urban rail transportation and underground space development and utilization are initiatives to solve urban traffic congestion. The monitoring and prediction of the stability of underground enclosure piles in foundation pits is a key index for the dynamic evaluation of the stability of underground space engineering. In this paper, we focused on the problem that the dynamic prediction accuracy and stability of foundation pit retaining piles in the Qingdao area are not high. Based on the analysis of various time function curves and the physical meaning of the parameters, we proposed the Adjusted-Logistic time function model, which introduces three physical parameters to adjust the deformation velocity and deformation acceleration in different stages for better accuracy. It could predict the deformation process of underground enclosure piles under different geological engineering conditions. It was verified in the field that the root-mean-square error (RMSE) of the Adjusted-Logistic function was 0.5316, MAE was 0.3752, and R2 was 0.9937, which were better than those of Gompertz, Weibull, and Knothe time function models. Meanwhile, it showed that with the increase of excavation depth, the maximum horizontal displacement of the underground enclosure piles gradually decreased and finally stabilized at 0.62-0.71 H. We established a catastrophe model of the horizontal displacement cusp at the observation point of the underground enclosure piles by using the time series of the measured data. It could determine the weak location of the underground enclosure pile stability and realize the multipoint warning of the foundation pit stability, which would ensure safe construction.

A novel voxel-particle energy approach to predict 3D microscopic fracture surface of porous geomaterials and fracture permeability modeling

Characterizing and predicting 3D microscopic fractures are rarely reported due to the challengeable difficulty to determine its spatial trajectories. In this study, a double threshold segmentation algorithm is proposed to obtain 3D microstructure models of porous geomaterials by X-ray computing tomography (CT) images. A novel voxel-particle energy (VPE) approach is proposed to predict 3D fracture characteristics, and fracture permeability modeling is conducted. Results show that excellent agreements are found between the experimental and numerical results, showing the accuracy of proposed VPE method. As dynamic viscosity increases, microscopic fracture permeability increases. Microscopic fracture permeability decreases with increasing input pressure, and it increases with increasing voxel scale. The proposed VPE method provides an effective tool to predict 3D cracks and its spatial trajectories, which is helpful for the deep resource and underground space development.

General Architecture of Sustainable Urban Spatial Development Model Based on Smart Cities

Abstract With the rapid growth of China’s national economy and urbanization, the use of urban space in China has developed greatly. At the same time, there are also many problems, the relationship between urban space planning and ground planning is not coordinated enough, and there are certain contradictions in the development of different levels of space, which will inevitably affect the sustainable development of urban space in China in the long run. The fuzzy comprehensive evaluation method is adopted as the evaluation method for the sustainability of urban space development. Firstly, the AHP method is applied to determine the weights of each specific indicator in the index layer. The sustainability of the current status of underground space development reflected by each indicator is determined by the expert scoring method. Finally, the evaluation results of “sustainable urban spatial development” were obtained using the spatial sustainability model for the example of the cities. In summary, the sustainable urban spatial development model based on smart cities can reflect the development status, development trend, and coordination with the comprehensive external environment of urban space in a comprehensive manner, and can measure and evaluate the degree of sustainable development, thus helping to identify problems that limit sustainable development.

Grouting reinforcement strategy for tunnel sand layer based on BP neural network

Abstract Tunnel sand layer grouting reinforcement is a major difficulty in the current development of underground space. Finding a suitable method strategy for grouting reinforcement of the road sand layer to ensure the smooth implementation of the construction is imminent. In this paper, by building a BP neural network model, using signal forward propagation algorithm and error back propagation algorithm, back propagation of the error signal through the implied layer to the input layer, increased accuracy of calculations. To prove that BP neural network based on can effectively enhance the effect of tunnel grouting reinforcement, propose strategies for tunnel sand layer grouting reinforcement. Proven by simulation experiments: the effect of grouting reinforcement is influenced by the grouting material, grouting pressure, and the condition of the injected medium. The grouting parameters, grouting compressive strength and grouting age are the three major factors affecting the grouting reinforcement effect as deduced from the BP neural network input layer and implicit layer, a BP neural network model can be built to derive the parameters of these three major influencing factors. The calculation shows that, BP neural networks can provide specific data that can be relied upon for grout reinforcement, its effect prediction accuracy can reach 98%. It can be seen that BP neural network has practical application in tunnel sand layer grouting reinforcement strategy.

Modern Trends of Organization of the Underground Urban Space

Abstract The article is devoted to important issues of perspective modern organizational tendencies of underground urban space. Innovative world experience of organization of underground space and its use by creating underground buildings and structures for optimal working, living, recreation and movement of the urban population, increasing the area of open green spaces on the surface, creating a comfortable and aesthetically attractive urban environment are reviewed. The ecological, economic, political and cultural features that influence the formation and development of underground space in terms of sustainable development are analyzed. The architectural and spatial structure and functional features of underground permanent cities are considered. The basic modern tendencies of the organization of underground urban space are defined in the town-planning architectural-spatial, functional aspects and aspects of sustainable development.

Numerical simulation of freezing temperature field and frost heave deformation for deep foundation pit by AGF

With the continuous development of the urban underground space, the depth of the underground structures is also increasing. As a typical soft soil area, the geological environment in Shanghai is very complex and rich in groundwater. Unlike traditional support measures, the artificial ground freezing method can be applied to various complex geological conditions with its unique advantages. In this paper, the distribution of the freezing temperature field and the frost heave deformation for a deep foundation pit constructed by the pile freezing method were studied by the numerical simulation. The distribution of the freezing temperature field in the single freezing hole, the double freezing holes and the single row holes were analyzed, respectively. After the excavation of the deep foundation pit, the temperature fields of straight and corner sections were also studied. The effect of the piles on the distribution of the freezing temperature field and the frost heave deformation of the ground was compared. The research results of this paper can provide a design basis and a reference for the construction of deep foundation pits by the artificial ground freezing.

Utility tunnel detection by 2D elastic PSV/Rayleigh-wave multi-parameter full waveform inversion

Accurate characterization of the low-velocity anomalies such as utility tunnels in the near-surface by effective geophysical imaging methods has been a valuable but challenging task for urban hazard assessment, underground space development and infrastructure construction. As a current research hotspot, the full waveform inversion (FWI) has been proven to be a promising technique for high-precision imaging of substructures, and has been applied in related practical engineering fields. However, most previous studies have focused on single-parameter (S-wave velocity) or double-parameter (S-wave and P-wave velocities) inversion. So, a complete PSV/Rayleigh-wave multi-parameter (S-wave and P-wave velocities and density) FWI method is developed in this paper to achieve accurate detection of underground utility tunnels. In this approach, the multi-parameter of the model are updated simultaneously during the inversion process to alleviate the negative influence on the S-wave velocity inversion accuracy due to the far deviation of the other two parameters from their true values. We tested the performance of the approach with a synthetic test and a real experiment. In the synthetic test, this method well characterized the position, shape and size of the embedded tunnel in the model, proving its effectiveness. Subsequently, the approach was applied to a field case investigated in Changsha city, China, and the inversion images revealed a tunnel with a burial depth of 4.5 m, height and width of 2 m and 4 m, respectively, which was identified as the detection target. The available borehole data verified the conclusion. The above results demonstrate the validity and time-effectiveness of the approach. It is expected to provide a reference for practical engineering applications at the same scale.

Spatiotemporal characteristics of Chinese metro-led underground space development: A multiscale analysis driven by big data

Nowadays, the use of metro-led underground spaces (MUS) has become imperative in high-density urban environments. However, a comprehensive and systematic understanding of MUS development patterns in densely-populated countries like China is still lacking. Therefore, this study employed a data-driven spatiotemporal analytical framework based on multisource big data to investigate the development mechanism of Chinese MUSs using a full sample. The multiscale analysis, covering MUS, urban, and regional scales, was conducted to identify the driving forces of MUS development over five temporal stages. The results revealed that the development characteristics of Chinese MUSs varied across different spatiotemporal contexts. At the micro level, the primary driving factors, including density, diversity, distance to transit, and destination accessibility, had a strong explanatory power, which is consistent with the mainstream transit-oriented development (TOD) theory. At the macro level, the main drivers included economic factors, environmental factors, and development scale factors. This study provides new insights for MUS development in high-density regions worldwide, and the obtained regularities could be effectively adopted in the planning and design for MUS.

Response Monitoring and Analysis in Deep Foundation Pit Excavation: A Case Study in Soft Soil at Subway Tunnel Intersections

With the rapid development of urban rail transit and underground space development, the occurrence of excavation near existing tunnels is becoming more common. This excavation and unloading will inevitably cause soil deformation outside the pit and the tunnel buried therein. This paper presents an investigation into the entire excavation process and the deformation effects on the adjacent subway structure under complex construction environments, including soft soil foundations and adjacent subway intersections, based on measured data of pit construction. The horizontal and vertical displacements of deep soils in two pits were analyzed along with safety management measures to determine the horizontal displacement curve pattern and the lateral displacement development distribution law of deep soils. The analysis of subway deformation data shows that after excavation, the subway tunnel undergoes “lateral expansion” and “vertical compression” type deformation, accompanied by “in-pit” horizontal displacement and “settlement” vertical displacement. Furthermore, a correlation analysis reveals a clear linear relationship between pit deformation and subway structure deformation, which can be used as a prediction method for adjacent structure deformation. Finally, a comparative analysis of existing relevant influence zone models and tunnel deformation prediction formulas is carried out based on the monitoring. The results of this study have significant guiding implications for the excavation construction of soft soil foundations in the vicinity of subway crossings.

Research on Geological Safety Evaluation Index Systems and Methods for Assessing Underground Space in Coastal Bedrock Cities Based on a Back-Propagation Neural Network Comprehensive Evaluation–Analytic Hierarchy Process (BPCE-AHP)

With the rapid development of the economy in China, the scale and quantity of urban underground space development continue to grow rapidly; as such, geological safety problems in urban underground space development and utilization are a research hotspot at present. Therefore, it is important to establish a high-quality evaluation index system and method for assessing the geological safety of urban underground spaces in coastal bedrock. Taking the typical area of Qingdao as an example, this study establishes an effective system for evaluating the geological safety of urban underground space according to the geological background, hydrogeology, engineering geology, and unfavorable geological phenomena in the Hongdao Economic Zone of Qingdao. Then, the method of evaluating the geological safety of urban underground space was studied. Through a comprehensive analysis and comparison of the fuzzy comprehensive evaluation–analytic hierarchy process (FCE-AHP), the grey relation comprehensive evaluation–analytic hierarchy process (GRCE-AHP), the matter-element comprehensive evaluation–analytic hierarchy process (MECE-AHP), and the back-propagation neural network comprehensive evaluation–analytic hierarchy process (BPCE-AHP), it was determined that the back-propagation neural network comprehensive evaluation–analytic hierarchy process (BPCE-AHP) was an ideal method for evaluating the geological safety of underground space in Qingdao’s coastal bedrock area. This method was used to evaluate the geological safety of the study area, and the evaluation results were verified; this further proved the practicability and rationality of the back-propagation neural network comprehensive evaluation–analytic hierarchy process (BPCE-AHP).

An Investment Decision Model for Underground Urban Utility Tunnel Based on MIVES and Real Option Theory from a Sustainable Perspective

Although the importance of urbanization, urban renewal and sustainable development have been increasingly recognized, with the accelerating process of urbanization, the urban above-ground space is no longer sufficient for the process of urbanization, and downward development of the city has become inevitable. Underground Urban Utility Tunnel (UUUT) is an effective measure to promote the sustainable development of urban underground space (UUS). However, decision makers still cannot fully consider the economic, social, environmental and technological factors, as well as the future risks of the project and the value of flexibility in management. In this paper, an investment decision model for UUUT is proposed that combines the Integrated Value Model for Sustainable Assessment (MIVES) and the real option theory, which comprehensively considers the social, economic, environmental and technological impacts, and assists the government in carrying out the investment decision analysis of UUUT from a sustainability perspective by applying the real option theory to the economic evaluation process. The primary process of this study can be divided into four steps. (1) establishment of the investment decision index system for UUUT; (2) determination of the quantitative criteria for each indicator; (3) calculation of the feasibility of UUUT; and (4) a case study to demonstrate the feasibility of the proposed model, as well as the achieved results. The proposed investment decision model can be used as an auxiliary tool in the early planning stage of UUUT, and also for the comparison and selection of different options for UUUT.

The numerical simulation of rapid excavation technologies under the combined form of hydraulic fracturing and drill-and-blast method

With the aim of the drilling and blasting in underground space, there are problems of poor tunnel formation, large crushing and loosening area, difficult support, low driving efficiency, and special geological conditions that are not suitable for drilling and blasting. According to the fracturing and blasting theory and auxiliary hole effect, a combined hydraulic fracturing and drilling blasting tunneling technology was proposed in this research. Establish a rock breaking model, and according to the mechanism of swelling and breaking, the rock breaking efficiency and effect of swelling and breaking, the number of drill holes and the arrangement of drill holes affect the rock breaking performance; the traditional drilling and blasting method used the change of dynamic pressure and vibration velocity to judge the propagation and attenuation process of blasting vibration, as well as the range of damage area. The ANSYS LS-DYNA, a numerical simulation software, was used to determine the position and size of the top facing holes, the optimal spacing of fracturing holes, blasting holes and auxiliary holes. The static load applied to the arc part can effectively reduce the crushing area, the crack area and the elastic area. The lower rectangular part is arranged with the auxiliary holes reasonably to inhibit the propagation of the blasting shock wave, slow down the development of the fracture, guide the extension direction of the crack, and reduce the damage range of the three areas, avoid low efficiency of deep hole blasting, and judge the practicability and operability of this method based on the timeliness of each stage of excavation. The combined pressing and blasting method with the high-efficiency and short-distance, multi-frequency and high-efficiency excavation effectively controlled the shape of the upper area of the roadway, which contributes to reducing the damage area of the surrounding rock, developing a safe working environment, decreasing the maintenance cost of the roadway in the later stage, and providing a innovative way for the development of underground space in the future.

A Comprehensive Study of the Suitability of Urban Underground Spaces for Connection Development: A Case Study of the Erhai Lake Basin, China

Urban underground space (UUS) involves multiple stakeholders whose concerns span the entire life cycle of underground space. The government pays more attention to the social benefits of UUS to the region, developers pay more attention to the economic benefits brought by the development of UUS, and users pay more attention to the comfort level of UUS operation. This study used the analytic Hierarchy Process (AHP), government, developers, and users to construct a comprehensive evaluation index system of underground space development needs. Different from previous studies, considering the need for future connectivity development in the UUS circle, this paper proposes to comprehensively consider the impact of connectivity development on regional suitability through coupled AHP and cellular automata (CA). The results show that about 102.67 km2 (13.03%) underground area of Erhai Lake Basin is suitable for underground space development. Compared with the traditional evaluation method, the evaluation result of about 31.41 km2 (3.99%) area was improved, and the fragmentation problem between blocks was improved. This method is of great value to the comprehensive development of UUS in the Erhai Lake Basin and is helping to improve future underground space planning.

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.

Current tendencies of architectural and environmental organization of underground scientific and research complexes

The article provides an overview of the world experience in the design of underground laboratories. Underground research complexes must provide the necessary conditions for conducting experimental research in the scientific fields in which they specialize. An underground scientific research institution should also ensure a comfortable and safe stay of scientific and technical personnel on its territory and satisfy all their social, physiological, psychological and professional needs. Urban planning, volume-spatial and functional-planning organization are regulated by the technical requirements for conducting experiments and research in specific scientific fields: astrophysics, physics of elementary particles and others. The article examines the scientific works of world scientists and architects. The problem of the development of underground space and its urban planning organization was studied in their scientific works by G. I. Hayko, H. Admiral, A. Cornaro, A. Wright, R. Sterling. Strategies and tools for the organization of underground space, as well as the main planning systems of underground urban planning objects, are highlighted in the works of L. Von der Tann. The issue of optimization of the underground space is raised in the works of Paul H. Gilbert, P. Stones. Recommendations on the urban planning and architectural planning organization of underground spaces are found in Joanna Kozytska's doctoral dissertation. The global experience of designing underground spaces is highlighted in the works of T. Jung Heng, N. A. Bakhtadze, V. Biletskyi, N. D. Pankratova. The architectural and environmental organization of the space of underground research complexes is considered in the articles of A. Bettini, Aldo Ianni, E. Kochia. Modern trends in the development of underground buildings and structures are considered in the scientific works of G. I. Hayko and Pankratova N. D. The article presents common architectural features of the organization of complexes. The urban planning, volume-spatial, functional-planning organization of the underground environment of scientific and research complexes is analyzed. Modern trends in the design of underground scientific and research complexes are determined. Characteristic features of the urban planning, volumetric-spatial, functional-planning structure of underground scientific and research complexes are given.

Stability Analysis of the Foundation Pit and the Twin Shield Tunnels during Adjacent Construction

Due to the rapid development of urban rail transit and the development and use of underground space, foundation pit construction near existing subway tunnels is becoming increasingly common. When adjacent foundation pit projects are being constructed, it is difficult to avoid the influence on existing subway tunnels, which threatens the safe operation of subway tunnels. Thus, this study focused on the stability of the adjacent construction of foundation pits and twin shield tunnels. The finite element limit analysis (FELA) method was used to analyze the influences of construction scheme and relative position of the twin shield tunnels and adjacent foundation pit on the global stability of adjacent construction. Based on the research results, the guidance and design for the construction scheme and relative position are provided. The stability analysis on the foundation pit during the construction process is performed. The criteria of adjacent influential partition are proposed, and the influence of various input parameters (c/γD, φ, L/D and C/D) on the global stability of adjacent construction is discussed, respectively. A new design equation of safety factor of global stability of adjacent construction is obtained by curve fitting.