Exploitation Of Underground Space Research Articles

Geo-environmental Suitability Assessment for Shallow Foundition Pit in Urban Zhengzhou City Based on GIS and AHP Methods

With the objective of the security and sustainability of underground space, the geo-environment suitability assessment for shallow foundation pit was conducted by GIS and AHP methods combining with the characteristics of the study area on the basis of the investigation of the current exploitation of underground space and the geological environment conditions in Zhengzhou City and the advanced experiences at home and abroad. Computer technology provides powerful tools and methods to the geo-environmental suitability assessment of underground space, and supports decision-making and planning. In the research, the suitability of geo-environment was assessed using the multi-objective linear weighted function model. The results indicate that the elements influencing the geo-environment suitability of shallow foundation pit in the study area mainly include stability of foundation pit, active earth pressure of slope, and shallow groundwater depth and water enrichment of aquifer according to the impact of evaluation factors on the foundation pit engineering. The results showed that the suitable area with an area of about 96.2 km2 is located to the west of Beijing–Guangzhou Railway, the medium-suitable area with an area of about 174.4 km2 is located to the east of Beijing–Guangzhou Railway and to the west of the Beijing-Guangzhou high-speed railway, the poor-suitable area with an area of about 111.3 km2 is located to the east of Dongfeng canal-Jingguang high-speed Railway and we should particularly focus on the impact of surface water, groundwater, soft soil and land subsidence during construction. The application of GIS and AHP method provided key technical support for the assessment. The geo-environment suitability evaluation of the foundation pit engineering by GIS and AHP methods has a strong pertinence and can offer technical assistance for the exploitation of underground space in Zhengzhou City.

Peculiarities of urban planning organization of underground research complexes

The relevance of the construction and operation of underground research facilities specializing in the fields of astrophysics, particle physics, geophysics and biology has developed significantly over the past 30 years. Underground research facilities are able to provide the necessary conditions for conducting experimental studies of physical phenomena that go beyond the Standard Model of Physics. Among the publications devoted to the theoretical foundations of the development of underground urbanism, it is worth noting the works of E. Reynolds, R. Sterling, W. Breuer, and G. Haiko. The main aspects of the architectural and planning and volumetric-spatial structure of underground buildings and structures are outlined in the works of H. Admiral, A. Cornaro, J. Besner. The exploitation of underground space in the conditions of sustainable development of modern cities is studied in the works of L. von der Tann and S. Ritter, Fang-Le Peng, Yong-Kang Xiao. Ukrainian scientists have made a significant contribution to the theoretical issues of underground urbanism: S.V. Ryndyuk, M.A. Maksymenko. Prospects for the integrated development of underground space in Ukraine are highlighted in the works of T.O. Nishchyk. Scientific works of G.I. Gayko are devoted to the priority tasks of development of underground urbanism in Ukraine, assessment of risks of underground construction, historical development of underground space in Ukraine. The historical development of underground buildings and structures is also studied in the works of V. Biletskyi, L. Korkushko, A. Pleshkanovska. The overview of the planning structure of modern underground research complexes is presented in the articles by A. Ianni, A. Bettini, E. Coccia. The article presents a number of prerequisites that influence the choice of a site for the design of underground research complexes in Ukraine. Their brief description is presented. Based on a preliminary analysis of the world experience in designing this type of facilities, important criteria that should be used when choosing a design site are identified. A complete set of functional zones of the master plan of the above-ground territory of the underground research complex is defined. A number of basic recommendations have been formulated that should guide the designer in the development of the master plan.

Effect of underground structures on groundwater residence time distributions in confined aquifers

Anthropic pressure and property economics lead to the vertical development of urban space, but groundwater residence time can be influenced by the urban underground structures constructed in it. Meanwhile, groundwater residence time is critical to the renewability of aquifers and the vulnerability to contamination. The effects of underground structures on local and regional residence times for confined aquifers remain unclear. This paper presents novel analytical solutions for groundwater residence time distributions (RTDs) affected by impervious underground structures in confined aquifers under three boundary conditions (BCs), namely the fixed-flux BC, the fixed-head BC, and the diffuse-leakage BC, respectively. The analytical solutions show a good agreement with numerical results for barriers fully obstructing the aquifer. For barriers partially obstructing the aquifer, discrepancies can be found between the analytical and the numerical RTDs due to the hydrodynamic dispersion of flow pathlines. Nevertheless, the calculated mean residence time (MRT) presents a good correspondence with numerical results for all parameter realizations, indicating that analytical solutions can be used to estimate regional MRT even for three-dimensional flow fields. Global sensitivity analysis (GSA) using Sobol’ method identifies influential parameters for residence times and underlines the importance of boundary conditions in determining the MRT. Finally, two successful applications of the analytical solutions in Barcelona aquifers indicate that the modification in residence times does not correspond to the modification in hydraulic heads. Overall, the proposed analytical solutions successfully quantify the barrier effect on residence times and prove to be useful in supporting underground space exploitation, and aiding the environmental risk assessment.

Determination of minimum overburden depth for underwater shield tunnel in sands: Comparison between circular and rectangular tunnels

With the development of global urbanization, the utilization of underground space is more critical and attractive for civil purposes. Various shapes of shield tunnels have been gradually proposed to cope with different geological conditions and service purposes of underground structures. Generally, reducing the burial depth of shield tunnel is conducive to construction and cost saving. However, extremely small overburden depth cannot provide sufficient uplift resistance to maintain the stability and serviceability of the tunnel. To this end, this paper firstly reviewed the status of deriving the minimum sand overburden depth of circular shield tunnel using mechanical equilibrium (ME) method. It revealed that the estimated depth is rather conservative. Then, the uplift resistance mechanism of both circular and rectangular tunnels was deduced theoretically and verified with the model tests. The theoretical uplift resistance is consistent with the experimental values, indicating the feasibility of the proposed equations. Furthermore, the determination of the minimum soil overburden depth of rectangular shield tunnel under various working conditions was presented through integrated ME method, which can provide more reasonable estimations of suggested tunnel burial depth for practical construction. Additionally, optimizations were made for calculating the uplift resistance, and the soil thickness providing uplift resistance is suggested to be adjusted according to the testing results. The results can provide reference for the design and construction of various shapes of shield tunnels in urban underground space exploitation.

Hydraulic Characteristics Analysis of Double-Bend Roadway of Abandoned Mine Pumped Storage

The roadway of an abandoned mine is an ideal site for the construction of underground pumped storage hydropower, but the operation of the power station is deeply restricted by the structural characteristics of the roadway. With the common double-bend roadway of an abandoned mine as the research object, this study conducted numerical simulations based on the theory of mass conservation and momentum conservation and explored the law of the flow field characteristics and energy loss of a double-bend roadway with the roadway structure and angle. The results showed that a velocity gradient and a pressure gradient form from the outer wall to the inner wall when the fluid flows through the two bends of the roadway. The low-speed zone and maximum positive pressure appeared at the outside of the bend, while the high-speed zone and maximum negative pressure appeared at the inside of the bend. As the angle rose, the peak value of positive pressure increased correspondingly when the fluid flowed through Model A, whereas the negative pressure displayed a fluctuating trend of increasing first and then decreasing and reached its peak when β = 45°. By contrast, when the fluid flowed through Model B, the velocity gradient was symmetrically distributed at the two bends. The peak value of the positive pressure of the first bend increased, and the other positive and negative pressures displayed a trend of “first increasing and then decreasing” when the angle increased, and they reached their peak when β = 45°. When β ≥ 60°, the fluid formed a backflow zone when it flowed through each bend. With an increase in the angle, the area of the backflow zone increased correspondingly. The head loss of the two models increased with the angle. At the same angle, the head loss of Model B was greater than that of Model A. According to the requirement of abandoned mine pumped storage, the roadways with a bend angle of 15° or 30° in Model A and 15° in Model B can be used. The research results can provide some reference for the underground space exploitation and utilization of abandoned mine pumped storage.

Mechanism of Detecting the Construction Quality of a Diaphragm Wall by an Infrared Thermal Field and Engineering Application.

During underground space exploitation in the urbanization process, numerous foundation pits were constructed where a diaphragm wall was often used as a retaining structure and waterproof curtain. Due to complicated engineering geological conditions or improper construction, diaphragm walls and wall joints often exhibit quality defects. Groundwater leaked from these quality defects to foundation pits during excavation, endangering the safety of the pit and surrounding facilities. The current leakage identification of the underground retaining structure was performed by artificial visual detection, which cannot satisfy the engineering requirement. The temperature field in the leakage area of the diaphragm wall was different from other areas. The leakage wall imaging system using a thermal imager was efficient in visualizing leaking, which was not visible to the naked eye. In this study, infrared thermal imaging technology was introduced in potential leakage detection for the diaphragm wall of a foundation pit. The infrared radiation characteristics of the diaphragm wall leakage and the potential leakage parts were studied through laboratory simulation tests and on-site detection methods. The maximum temperature appeared at the water outlet and the surface of the defect with hidden defect, and the temperature field was symmetrically distributed along the cross-section direction. In the potential leakage area, the temperature difference at the penetration point was 23.4 °C when the initial water pressure was 10 kPa. The temperature difference at the penetration point was 21.8 °C when the initial water pressure was 30 kPa. In the field test, the maximum temperature difference between the leakage area and the surrounding wall was 4.5 °C. The study can provide a reference for similar engineering.

Theoretical and experimental bases for the equivalent circuit model for interpretation of silty soil at different temperatures

The exploitation of underground space is accompanied by complex geotechnical problems. The development of electromagnetic exploration technology provides a new perspective for preventing and avoiding these problems. In this work, electrochemical impedance spectroscopy (EIS) was used to test the single-phase and mixed-phase medium. Based on the unsaturated soil theory and the dual-water conductivity theory, an equivalent circuit model to describe the electrochemical characteristics and microstructure of silty soil with temperature changes through comparative research. The results indicate that the resistance of near-water layer is not affected by temperature, the resistance of silty soil increases mainly results from the influence of the far-water layer until which increases significantly after freezing. The capacitance change of silty soil is mainly affected by the slowing down of the orientation movement of polar molecules in the far-water layer. Based on the fitting data, a mathematical model for calculating the unfrozen water content of frozen soil was proposed, which reasonably verified the relationship between the unfrozen water content and electrical resistance. By improving the testing conditions of electrochemical impedance spectroscopy, this method may provide new insights for future research of soil electromagnetic testing technology.

Deep Rock Mass Engineering: Excavation, Monitoring, and Control

With the continuing development of the global economy and society, the exploitation of underground space is undergoing an unprecedented prosperity period [...]

Effect of soil Young’s modulus on Sub-rectangular tunnels behavior under quasi-static loadings

Tunnels are an important component of the transportation and utility system of cities. They are being constructed at an increasing rate to facilitate the need for space expansion in densely populated urban areas and mega-cities. The circular and rectangular tunnels cannot completely meet the requirements of underground space exploitation regarding the cross-section. Sub-rectangular tunnels are recently used to overcome some drawbacks of circular and rectangular tunnels in terms of low utilization space ratio and stress concentration, respectively. However, the behavior of the sub-rectangular tunnels under seismic loading is still limited. This need to be regarded and improved. This paper focuses on conducting a numerical analysis to study the behavior of the sub-rectangular tunnels under seismic loadings. Here seismic loadings in this study are represented by quasi-static loadings. Based on the numerical model of the circular tunnel that was validated by comparison with analytical solutions, the numerical model of the sub-rectangular tunnel is created. This paper is devoted to highlight the differences between the behavior of the sub-rectangular tunnels compared with the circular ones subjected to quasi-static loadings. The soil-lining interaction, i.e., full slip and no-slip conditions are particularly considered. The influence of soil’s Young’s modulus on the sub-rectangular tunnel behavior under quasi-static loading is also investigated. The results indicated that soil’s Young’s modulus significantly affects static, incremental, and total internal forces in the tunnel lining under quasi-static loadings. Special attention is a significant difference in total internal forces in the sub-rectangular tunnel lining in comparison with the circular tunnel ones and the stability of the lining tunnel for both the full slip and no-slip conditions when subjected to quasi-static loadings.

Analytical study on limit support pressure of working face in underground space exploitation based on improved 3D wedge-prism model

Analytical study on limit support pressure of working face in underground space exploitation based on improved 3D wedge-prism model

Large-scale field test on abandoned deep anhydrite mine-out for reuse as crude oil storage – A case study

The reuse of abandoned anhydrite mine-outs has significant potential to reduce the cost and period of construction of crude oil storage facilities and provides a new option for exploiting underground space. Based on a case study of the Anhui Hengtai anhydrite mine located in East China, this study formulated a comprehensive field test program to investigate its tightness and stability and evaluate its feasibility for reuse as crude oil storage. Combining the field tests with laboratory tests, the underlying mechanism of interaction among anhydrite, water, and crude oil was revealed, and the stability and tightness of anhydrite mine-out during the storage of crude oil was evaluated. The results indicate that the anhydrite mine-out has good stability and tightness, which is not affected by the presence of crude oil. Additionally, the anhydrite has negligible effects on the crude oil quality; however, the presence of water reduces the strength of anhydrite rock, which has the potential to affect the stability and tightness of the mine-out. It is concluded that the anhydrite mine-out has the potential to be used as underground crude oil storage space, but the long-term contact between anhydrite rock and water should be avoided. This work is expected to benefit future underground space exploitation through reuse of mine-out.

Combined Application of Multiple Support Forms in Design of Large Deep Foundation Pits

With the constant exploitation of underground space, the single support pattern is not able to meet the needs of the foundation ditch design. This paper is based on a design case of the large-deep foundation ditch in Hangzhou and took the different geological environment requirements into consideration. In this paper our research team put forward the composite design of support pattern which adopts steel support, bored grouting pipe, soil nailed wall etc. We hope this paper can provide suggestions and references for other analogous projects.

A review of CPT based axial pile design in the Netherlands

Because of the deltaic nature of the Netherlands, deep soft soil deposits are widespread. Due to the population density exploitation of underground space is vital for commercial developments and transport networks. Piles are used as primary support elements in deep excavations, cut and cover tunnels, quay walls, flood defences and to provide uplift resistance to the base of tunnels and basements. This paper examines empirical correlations linking the Cone Penetration Test (CPT) end resistance qc and the resistance of deep foundations in sand. It is found that correlations between qc and pile end resistance are independent of pile diameter. However, the impact of installation method, residual load, plugging and sand creep should be considered. In the case of shaft resistance, constant correlation factors between qc and average shaft resistance are possible for non-displacement piles. For the case of displacement piles, correlations that include the effects of friction fatigue and pile plugging during installation are recommended.

Responses of deep soil layers to combined recharge in a leaky aquifer

Groundwater withdrawal during exploitation of underground space greatly affects the hydrogeological environment, causing severe land subsidence. Artificial recharge is considered to be an effective way to minimize dewatering-induced land subsidence. However, well clogging often affects the recharge efficiency. To avoid well clogging, it is necessary to periodically redevelop recharge wells. Field measurements show that well redevelopment can cause visible environmental settlements. To solve this problem, some researchers have proposed a method called combined recharge, which can successfully restrict redevelopment-induced settlement at the ground surface. However, if the protected area is located in deep soils, whether this method can still be applicable is unclear since the deformation response of the deep soil layers to combined recharge is unknown due to the current lack of investigations. In this study, a combined recharge test is simulated by a numerical model. The model is verified by field measurements and is used to study the response of deep soils during combined recharge. The results show that much greater amounts of soil heave can appear in deep soils (compared to those at surface) during combined recharge. The reason is that the soils between the ground surface and the recharged aquifer will show a strong restraining effect on the transfer of deformation from the recharged aquifer to the ground surface. If we use combined recharge to protect deeply buried targets, some measures should be taken to reduce the deep soil heave to within an acceptable range.

Fiscal obligations of the subsoil users

The article of research is operating financial relations of subsoil users before the state for mining, exploitation of underground space and system of forming of monetary resources for a budget after the Internal revenue code of Ukraine. The aim of writing of the article is development after resource approach of concept vehicle and mechanism of input of payments on the fiscal obligations of subsoil users. Methodology of realization of work is application of abstractly-logical, system-structural and comparative analysis (for forming of the system and mech- anism of forming of fiscal obligation of subsoil users); to the analysis (research of right base of production of paying is for using the bowels of the earth); mono- graphic analysis (at application of resource approach); generalization (forming of the system of bills of debt is before the state); interpretation (application of tran- sition from fiscal payments to the budgetary resources from position of more generalized concept; fiscal resources ). Job performances – reasonably: resource approach is to forming of profits of the state budget; system of bills of debt of subsoil users before the state; name of operating pay in different forms for using the bowels of the earth for mining after her essence by a subsoil fiscal profit as to payment of subsoil users, that is brought in by them in the state budget; actu- ality of replacement far of past origin of concept of taxes is on fiscal obligations for using the bowels of the earth; concept of money, fiscal, budgetary resources. Conclusions – instead of the operating system of taxes it is necessary to enter payments on the fiscal obligations of subsoil users for using the bowels of the earth for mining and using underground space, with bringing of these inputs in the Internal revenue code of Ukraine.

Progress on the exploitation of urban underground space (UUS) in China

With the rapid urbanization in China, the disasters and the problems related with the urban underground space (UUS) exploitation increase. As an inevitable choice for sustainable urban development, how to increase the efficiency of the underground space use and augment the resilience of the UUS are the main challenges today in China. In this study, the strategic demands of the sustainable urban development on the underground space exploitation in Chinese cities have been analyzed and discussed. The associated problems and difficulties on the underground space exploitation were discussed. Moreover, the possible solutions were also proposed.

Key Technologies and Applications of the Design and Manufacturing of Non-Circular TBMs

Abstract With the rapid development of the exploitation of underground space, more and more large- or super-large-diameter tunnel-boring machines (TBMs) are being employed to construct underground space projects. At present, because conventional circular TBMs cannot completely meet the requirements of underground space exploitation regarding the cross-section and space-utilization ratio, non-circular TBMs, which are the tunneling equipment for an ideal cross-section, have become the new market growth point. This paper first presents the technical features and development status of non-circular TBMs. Next, in reference to typical projects and technological innovation, this paper investigates key techniques including shield design optimization, multi-cutterhead excavation, special-shaped segment erection, and soil conditioning in loess strata for a rectangular pipe-jacking machine and a horseshoe-shaped TBM, in order to provide a set of feasible solutions for the design, manufacture, and construction of non-circular TBMs. Relevant engineering practice shows that non-circular TBMs with customized design and manufacture have great advantages in terms of construction schedule, settlement control, and space utilization.

Mechanism of core discing in the relaxation zone around an underground opening under high in situ stresses

Core discing is a brittle rock failure during borehole drilling in intact rock subjected to high in situ stresses. This failure mode has been recognized as an important index for assessing underground projects under high in situ stresses. With increasing depth of underground space exploitation, core discing occurs not only in highly-stressed intact rock, but also in the relaxation zone of the surrounding rock masses. In the latter case, the disc thickness is even smaller, and the mechanism is significantly different from that of core discing in highly-stressed intact rock. In this study, the correlation between the regional geological structures and the disc thickness in the relaxation zone is analyzed based on the deep auxiliary tunnel of the Jinping hydropower project. A “structural arch” model, applicable for analyzing the mechanical behaviors of fractures and rock blocks in the relaxation zone, is proposed. The model is then verified by laboratory similarity tests and numerical simulations. Finally, it is revealed that the “discontinuous” stress field in the relaxation zone is the main cause of core discing in the relaxation zone around underground openings subjected to high in situ stresses.

THE CHARACTERISTIC OF ENGINEERING GEOLOGY AND EVALUATION OF ENGINEERING GEOLOGICAL DIVISION OF YOCO PORT IN JIANGSU PROVINCE, CHINA

This paper examines the 147 engineering geological drilling holes through the construction and collection, the Yoco port in the area were divided into 6 engineering layers and 16 sub-layers according to their types of formation, chronology, lithology and mechanics. The authors also made a comprehensive study on the spatial distribution of soil, engineering geology and geotechnical changes of the foundation soil(less than 50 deep),as w ell as the paleo-geog raphy of different areas of engineering geology. The study area was divided into the marine plain of engineering geological zone, delta plain engineering geological zone and beach reclamation engineering geological zones by comprehensive considering geomorphologic unit, genetic types, structural characteristics of soil and the presence of mainly environmental engineering geological problems. On the basis of engineering geological division, the development and utilization of underground space exploitation and utilization of geological conditions are valuated with the main force bearing layer and poor soil mass, which provides basic geological basis for the planning, construction and management of the port area.

The Establishment and Application of Underground Space Safety Evaluation System in Shanghai

With nearly 10 years of large-scale construction of Shanghai subway network, the drive of expo 2010, and also the pressing needs of space extension for urban regeneration and modernization, the exploitation of underground space in Shanghai has been greatly advanced. By the end of 2015, the total volume of underground space in Shanghai had reached 65 million square meters, and the per capita possession of the area of underground space is nearly 3.0 square meters. In the meanwhile, the safety issues during the use of underground space facilities are also increasingly prominent, not only because of the internal closure features that easily cause and spread disasters, but also the safety management and disaster prevention hardware that hide great danger. These problems have already been the important restriction factor in the comprehensive utilization of underground space resource in Shanghai. The authors and their team began to undertake the government-sponsored research projects of underground space safety issues in 2008, and by combining the literature research and empirical research during the following several years, the team made site surveys of more than 100 underground architectures in use. On the basis of this, the team used experts experience analysis and bowknot analysis methods to identify the causes and risks of the disasters and accidents, therefore refined and summed up the underground space safety evaluation index system. In order to achieve the quantitative evaluation, the team also made the evaluation criteria system according to the current law and technical standards, and used the AHP methods to build the weight system, and finally established the whole underground space safety evaluation system. The system has already been used for trial evaluation practice of several underground projects in Shanghai and provided effective basis for the improvement of the disaster control facilities and safety management of these projects.