scholarly journals Study on Deformation Law of Subway Construction under Passing Existing Line in Short Distance

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Cong-Shuang Luo ◽  
Yi-Hong Cheng ◽  
Zhe Bai ◽  
Tong Shen ◽  
Xu-Yang Wu ◽  
...  
Keyword(s):  
Large Scale ◽  
Subway Tunnel ◽  
Deformation Law ◽  
Space Projects ◽  
Development And Utilization ◽  
Grouting Reinforcement ◽  
Track Surface ◽  
Shield Machine ◽  
Safety And Stability ◽  
Tunnel Shield

With the large-scale development and utilization of underground space projects, the subway-led Rail Transit Project is developing vigorously, and the safety and stability of subway under passing existing projects have become a key issue for the future. In this paper, the deformation law of subway tunnel under the existing track is studied by using the method of ROCSCIENCE software and field measurement, which is based on the construction of a new double-tunnel shield-driven subway tunnel under the existing city of pile rapid track project. In the crossing area, the distance between the top of the tunnel and the pile foundation is 6.2 m and the distance between the tunnel and the existing track surface is 19.6 m. It is required that the settlement of track caused by the new tunnel construction should not exceed 2 mm. The results show that the settlement of the existing track is greatly influenced by the new tunnel without reinforcement and grouting, and the maximum settlement is more than 9.92 mm. The settlement of the existing track can be controlled to 1.93 mm by adjusting the construction parameters of the shield machine and grouting reinforcement at different stages during construction.

The Monitoring and Analysis of Surface Subsidence of Soft Soil Rock Large Section of Subway Tunnel Shield Construction

2013 ◽  
Vol 848 ◽  
pp. 78-82
Author(s):  
Jin Kui Li ◽  
Bing Wei Yan ◽  
Yong Jian Shi
Keyword(s):  
Surface Deformation ◽  
Soft Soil ◽  
Reference Value ◽  
Lateral Position ◽  
Surface Subsidence ◽  
Subway Tunnel ◽  
Tunnel Excavation ◽  
Working Face ◽  
Shield Machine ◽  
Tunnel Shield

In this paper use the shield construction of Dalian subway 202 bid section as an example, carried out the monitoring measurement of surface subsidence and crown surface subsidence during the shield construction, detailed analysis the monitoring data, explored the characteristics and distribution of surrounding rock and surface deformation of large cross section shield construction. Construction transverse deformation has a relationship with lateral position and the tunnel excavation length. The closer from shield machine working face, the closer to the center line of the tunnel, the greater impact is. The research results have reference value for the future similar engineering design and construction.

Overview on the Liquid Metal Battery for Grid-Level Large-Scale Energy Storage

2016 ◽  
Vol 723 ◽  
pp. 572-578
Author(s):  
Li Fu ◽  
Qi Chi Le ◽  
Xi Bo Wang ◽  
Xuan Liu ◽  
Wei Tao Jia
Keyword(s):  
Energy Storage ◽  
Liquid Metal ◽  
Large Scale ◽  
Low Cost ◽  
Advantages And Disadvantages ◽  
Comprehensive Comparison ◽  
Development And Utilization ◽  
Working Principle ◽  
Liquid Metal Battery ◽  
Grid Level

In recent years, the development and utilization of renewable generation have attracted more and more attention, and the grid puts forward higher requirements to the energy storage technology, especially for security, stability and reliability. The liquid metal battery (LMB) consists of two liquid metal electrodes and a molten salt electrolyte, which will be segregated into three liquid layers naturally. Being low-cost and long-life, it is regarded as the best choice for grid-level large-scale energy storage. This paper describes the main structure and working principle of the LMB, analyzes the advantages and disadvantages of the LMB when compared with the traditional batteries, and explores the feasibility and economy when it is used as a kind of large-scale energy storage applied in the power grid. The paper also makes a comprehensive comparison on the performance of several LMBs, and points out the LMB’s research and development in the future.

scholarly journals Integration and Verification Approach of ISTSat-1 CubeSat

Aerospace ◽  
2019 ◽  
Vol 6 (12) ◽  
pp. 131 ◽  
Author(s):  
João P. Monteiro ◽  
Rui M. Rocha ◽  
Alexandre Silva ◽  
Rúben Afonso ◽  
Nuno Ramos
Keyword(s):  
Ionizing Radiation ◽  
Large Scale ◽  
Scale Space ◽  
Development Stage ◽  
System Level ◽  
Thermal Vacuum ◽  
Battery Model ◽  
Engineering Costs ◽  
Space Projects ◽  
Radiation Testing

Large-scale space projects rely on a thorough Assembly, Integration, and Verification (AIV) process to provide the upmost reliability to spacecraft. While this has not traditionally been the case with CubeSats, their increasing role in space science and technology has led to new verification approaches, including in educational CubeSats. This work describes the integration and verification approach for ISTSat-1, which is an educational CubeSat from the Instituto Superior Técnico in Portugal that partially discards the typical stage-gate approach to spacecraft development in favor of a more iterative approach, allowing for the system-level verification of unfinished prototypes. Early verification included software functional testing on a flatsat model, thermal vacuum and vibration testing on a battery model, ionizing radiation testing on the on-board computer, and non-ionizing radiation (EMC) testing on all subsystems. The testing of functional prototypes at an early development stage led to uncovering system-level errors that would typically require hardware redesign at a later project stage. The team considers the approach to be useful for educational projects that employ a small, co-located team with low non-recurring engineering costs.

scholarly journals Comparative Study of Soil Grouting with Cement Slurry and Cement-Sodium Silicate Slurry

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Mingting Zhu ◽  
Qingsong Zhang ◽  
Xiao Zhang ◽  
Bing Hui
Keyword(s):  
Sodium Silicate ◽  
Large Scale ◽  
Setting Time ◽  
Initial Pressure ◽  
Cement Slurry ◽  
Viscosity Change ◽  
Grouting Pressure ◽  
Curtain Grouting ◽  
Grouting Reinforcement

Cement slurry and cement-sodium silicate slurry are most widely applied for soil grouting reinforcement project. The viscosity change of cement slurry is negligible during grouting period and presumed to be time independent, while the viscosity of cement-sodium silicate slurry increases with time quickly and is presumed to be time dependent. Due to the significant rheological differences between them, the grouting quality and the increasing characteristics of grouting parameters may be different. Those are main factors for grouting design. In this paper, a large-scale 3D grouting simulation device was developed to simulate the surrounding curtain grouting for a tunnel. Two series of surrounding curtain grouting experiments under different initial pressures of 100 kPa, 150 kPa, and 200 kPa were performed. The overload test on the tunnel was performed to evaluate the grouting quality of all surrounding curtain grouting experiments. The results show that the increasing trend of grouting pressure for cement-sodium silicate is similar to its viscosity; the setting time of cement-sodium silicate slurry obtained from the laboratory test is less than that in the practical grouting environment where grout slurry solidifies in soil; the grouting quality of cement-sodium silicate slurry is better than cement slurry, and the grouting quality decreases with initial pressure.

scholarly journals Lateral meltwater transfer across an Antarctic ice shelf

2020 ◽  
Author(s):  
Rebecca Dell ◽  
Neil Arnold ◽  
Ian Willis ◽  
Alison Banwell ◽  
Andrew Williamson ◽  
...  
Keyword(s):  
Surface Water ◽  
Large Scale ◽  
Water Bodies ◽  
Seasonal Development ◽  
Water Volume ◽  
Landsat 8 ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Melt Ponds ◽  
Track Surface

Abstract. Surface meltwater on ice shelves can be stored as slush, in melt ponds, in surface streams and rivers, and may also fill crevasses. The collapse of the Larsen B Ice Shelf in 2002 has been attributed to the sudden drainage of ~ 3000 surface lakes, and has highlighted the potential for surface water to cause ice shelf instability. Surface meltwater systems have been identified across numerous Antarctic ice shelves, however, the extent to which these systems impact ice shelf instability is poorly constrained. To better understand the role of surface meltwater systems on ice shelves, it is important to track their seasonal development, monitoring the fluctuations in surface water volume and the transfer of water across the ice shelf. Here, we use Landsat 8 and Sentinel-2 imagery to track surface meltwater across the Nivlisen Ice Shelf in the 2016–2017 melt season. Using the Fully Automated Supraglacial-Water Tracking algorithm for Ice Shelves (FASTISh), we identify and track the development of 1598 water bodies. The total volume of surface meltwater peaks on 26th January 2017 at 5.5 × 107 m3. 63 % of this total volume is held within two large linear surface meltwater systems, which are orientated along the ice shelves north-south axis and appear to migrate away from the grounding line during the melt season, facilitating large scale lateral water transfer towards the ice shelf front. This transfer is facilitated by two large surface streams, which encompass smaller water bodies and follow the surface slope of the ice shelf.

scholarly journals Lateral meltwater transfer across an Antarctic ice shelf

2020 ◽  
Vol 14 (7) ◽  
pp. 2313-2330 ◽  
Author(s):  
Rebecca Dell ◽  
Neil Arnold ◽  
Ian Willis ◽  
Alison Banwell ◽  
Andrew Williamson ◽  
...  
Keyword(s):  
Surface Water ◽  
Large Scale ◽  
Water Bodies ◽  
Seasonal Development ◽  
Water Volume ◽  
Landsat 8 ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Track Surface ◽  
South Axis

Abstract. Surface meltwater on ice shelves can exist as slush, it can pond in lakes or crevasses, or it can flow in surface streams and rivers. The collapse of the Larsen B Ice Shelf in 2002 has been attributed to the sudden drainage of ∼3000 surface lakes and has highlighted the potential for surface water to cause ice-shelf instability. Surface meltwater systems have been identified across numerous Antarctic ice shelves, although the extent to which these systems impact ice-shelf instability is poorly constrained. To better understand the role of surface meltwater systems on ice shelves, it is important to track their seasonal development, monitoring the fluctuations in surface water volume and the transfer of water across ice-shelf surfaces. Here, we use Landsat 8 and Sentinel-2 imagery to track surface meltwater across the Nivlisen Ice Shelf in the 2016–2017 melt season. We develop the Fully Automated Supraglacial-Water Tracking algorithm for Ice Shelves (FASTISh) and use it to identify and track the development of 1598 water bodies, which we classify as either circular or linear. The total volume of surface meltwater peaks on 26 January 2017 at 5.5×107 m3. At this time, 63 % of the total volume is held within two linear surface meltwater systems, which are up to 27 km long, are orientated along the ice shelf's north–south axis, and follow the surface slope. Over the course of the melt season, they appear to migrate away from the grounding line, while growing in size and enveloping smaller water bodies. This suggests there is large-scale lateral water transfer through the surface meltwater system and the firn pack towards the ice-shelf front during the summer.

scholarly journals Study on the Instability Mechanism and Grouting Reinforcement Repair of Large-Scale Underground Stopes

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Chengyu Xie ◽  
Nan Jia ◽  
Liwen He
Keyword(s):  
Large Scale ◽  
Slip Surface ◽  
Underground Mining ◽  
Diffusion Mechanism ◽  
Combination Method ◽  
Chain Process ◽  
Maximum Shear Strain ◽  
Analysis Theory ◽  
Multiphysics Coupling ◽  
Grouting Reinforcement

The environmental conditions due to unreasonable mining in underground stopes, the slurry diffusion mechanism in the grouting reinforcement of a stope within its influence, the causes of large-scale instability collapse, and the catastrophic stope process are analyzed, and limit upper line analysis theory and numerical analysis methods are comprehensively adopted, revealing the continuous catastrophic collapse mode of large-scale underground stopes. The method of determining the stope instability collapse boundary and the slip surface within the range based on the theory of the maximum shear strain increment is proposed, and the diffusion radius and range of the grouting slurry during the reinforcement process, which considers the multifield coupling factors, are obtained. The results show that the U-shaped hidden danger area formed after the collapse of the large-scale underground stope. The influence range reaches six adjacent stopes, which are symmetrically distributed around the collapse; the mining instability is manifested as a catastrophic chain process of stress change, energy accumulation, state change, and instability collapse. The damage mode of instability collapse is a combination method of wedge collapse, circular arc rotation, triangular translation, and strip slip. According to the multiphysics coupling numerical calculation, the diffusion radius of the grouting slurry is 12 m, exhibiting an elliptical distribution. The research results can be used to comprehensively control the underground mining environment, thus effectively solving the safety problems faced by tunnel or roadway excavations above the goaf.

scholarly journals Research on Security Protection Architecture of Energy Internet Information Communication

2018 ◽  
Vol 228 ◽  
pp. 02010
Author(s):  
Xinde Song
Keyword(s):  
Information Security ◽  
Large Scale ◽  
New Technology ◽  
Power Grids ◽  
Information Communication ◽  
Energy Internet ◽  
Internet Information ◽  
The Face ◽  
Development And Utilization ◽  
Major Trend

The large-scale development and utilization of renewable energy has become a major trend in the development of the global energy sector. Compared with traditional power grids, energy Internet information security has many features and complex technologies, and the hidden dangers of information security risks are more prominent. In the face of various cyber threats, effective measures must be taken to ensure the safe operation of the power information network. This paper introduces the relationship between energy Internet and smart grid, sorts out the current new technology of energy Internet application, analyzes the risks it faces, and designs the security architecture of energy Internet information communication system.

Unconventional Gas Development and Prospect in China

2014 ◽  
Vol 675-677 ◽  
pp. 1546-1550
Author(s):  
De Xun Liu ◽  
Hong Yan Wang ◽  
Qun Zhao ◽  
Ying Liu ◽  
Lei Dong
Keyword(s):  
Shale Gas ◽  
Large Scale ◽  
Early Stage ◽  
Low Cost ◽  
Tight Gas ◽  
Unconventional Gas ◽  
Initial Stage ◽  
Development And Utilization ◽  
Environmental Technologies ◽  
Unconventional Gas Development

Many countries in the world begin to attach great importance to the utilization of the unconventional gas. The resources of unconventional gas in China are abundant. The development of unconventional gas is still in the early stage. Tight gas enters large scale and commercializing stage. Shale gas is in the initial stage of commercialization. There are mainly three challenges need to confront, uncertainties of unconventional gas resources, key technology with low cost and environmental pollution. So in the future, resource evaluation, engineering technologies and environmental technologies need to be strengthened in China. Tight gas is the most realistic resources to develop in China and the development and utilization of shale gas is the most anticipated. In the next ten or twenty years, the production of unconventional gas in China will increase considerably and play a major role in national hydrocarbon resources.

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