scholarly journals Study on ground settlement and structural deformation for large span subway station using a new pre-supporting system

2019 ◽  
Vol 6 (2) ◽  
pp. 181035 ◽  
Author(s):  
Pengjiao Jia ◽  
Wen Zhao ◽  
Xi Du ◽  
Yang Chen ◽  
Chaozhe Zhang ◽  
...  
Keyword(s):  
Steel Tube ◽  
Structural Deformation ◽  
Subway Station ◽  
Ground Settlement ◽  
Soft Soils ◽  
Supporting System ◽  
Steel Pipes ◽  
Large Span ◽  
First Time ◽  
Surrounding Soil

This study presents a novel construction pre-supporting system for large underground space excavation with shallow depth, Steel Tube Slab system (STS), in which adjacent steel pipes are connected by a couple of flanges, bolts and concrete for flexural capacity and lateral stiffness of the whole structure. The STS method is employed for the first time for the construction of the ultra-shallow buried and large span subway station in China, during which ground settlement and structural deformation are monitored. A numerical model for the subway station is established with reliability verified by monitored data comparison from numerical results and investigation on the effect of large span underground excavation on surrounding soil surrounding soil and existing buildings in soft soils. Unlike traditional methods, the STS method can effectively control and reduce the ground settlement during construction, thereby rendering it ideally suited for application in soft soils.

Geosynthetic Encased Column: comparison between numerical and experimental results

2021 ◽  
Vol 44 (4) ◽  
pp. 1-12
Author(s):  
Nima Alkhorshid ◽  
Gregório Araújo ◽  
Ennio Palmeira
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Soft Soil ◽  
Experimental Tests ◽  
High Permeability ◽  
Soft Soils ◽  
Column Comparison ◽  
Surrounding Soil ◽  
Granular Column

The use of granular column is one of the ground improvement methods used for soft soils. This method improves the foundation soils mechanical properties by displacing the soft soil with the compacted granular columns. The columns have high permeability that can accelerate the excess pore water pressure produced in soft soils and increase the undrained shear strength. When it comes to very soft soils, the use of granular columns is not of interest since these soils present no significant confinement to the columns. Here comes the encased columns that receive the confinement from the encasement materials. In this study, the influence of the column installation method on the surrounding soil and the encasement effect on the granular column performance were investigated using numerical analyses and experimental tests. The results show that numerical simulations can reasonably predict the behavior of both the encased column and the surrounding soil.

The Monitoring Data Analysis of Cover System in Subway Station

2011 ◽  
Vol 94-96 ◽  
pp. 1814-1817
Author(s):  
Ming Li Huang ◽  
Shu Feng Pei ◽  
Wen Zheng Wang ◽  
Hua Kuan Liu
Keyword(s):  
Wear Resistance ◽  
Data Analysis ◽  
System Design ◽  
Monitoring Data ◽  
Subway Station ◽  
Cover System ◽  
First Time

Fengtail North Road Station uses a open and cover combination of laying fabricated strap method for the first time, so we monitor the Cover system very closely. We draw schedule curves and analysis the monitoring data for the main component’s monitoring projects of the Cover system. Results show that the deformation values of the components of the Cover system are small, but the values of piles top displacement and settlement are large, at the same time, the lattices of Cover boards have good wear-resistance ability. The conclusion has very great help for optimizing the system design and the promotion of laying fabricated strap method.

Self-Compacting and Tiny Expanding Steel Tube Concrete Using in Large Span Bridges

2014 ◽  
Vol 1004-1005 ◽  
pp. 1460-1463
Author(s):  
Xiu Li ◽  
Ming Hui Su
Keyword(s):  
Experimental Studies ◽  
High Strength ◽  
Steel Tube ◽  
The State ◽  
The Self ◽  
Bridge Structure ◽  
Large Span ◽  
Small Loss ◽  
Early Strength ◽  
Low Ability

The experimental studies on self-compacting and tiny expanding concrete filled in steel tube are introduced, which including the measurement of low ability of mixtures, the proportioning of the concrete filled in steel tube. The self-compacting and tiny expanding steel tube concrete has been applied in a large span bridge structure. The state of construction shows that the concrete have a good pump ability, a small loss of slump, a high strength early strength and a better self-compacting property.

Analysis of the ground settlement control of a large span metro station in Dalian city using the Centre Drift Method

2014 ◽  
Vol 18 (9) ◽  
pp. 1042-1069
Author(s):  
Xin-Bo Ji ◽  
Wen Zhao ◽  
Shen-Gang Li ◽  
Yong-Wei Zhou ◽  
Yong-Ping Guan
Keyword(s):  
Ground Settlement ◽  
Metro Station ◽  
Large Span ◽  
Dalian City

scholarly journals AirCore-HR: a high-resolution column sampling to enhance the vertical description of CH<sub>4</sub> and CO<sub>2</sub>

2017 ◽  
Vol 10 (6) ◽  
pp. 2163-2181 ◽  
Author(s):  
Olivier Membrive ◽  
Cyril Crevoisier ◽  
Colm Sweeney ◽  
François Danis ◽  
Albert Hertzog ◽  
...  
Keyword(s):  
High Resolution ◽  
Steel Tube ◽  
Stainless Steel Tube ◽  
Vertical Profiles ◽  
Vertical Resolution ◽  
Low Resolution ◽  
Sampling System ◽  
Air Sample ◽  
Variable Bias ◽  
First Time

Abstract. An original and innovative sampling system called AirCore was presented by NOAA in 2010 Karion et al.(2010). It consists of a long ( >  100 m) and narrow ( <  1 cm) stainless steel tube that can retain a profile of atmospheric air. The captured air sample has then to be analyzed with a gas analyzer for trace mole fraction. In this study, we introduce a new AirCore aiming to improve resolution along the vertical with the objectives to (i) better capture the vertical distribution of CO2 and CH4, (ii) provide a tool to compare AirCores and validate the estimated vertical resolution achieved by AirCores. This (high-resolution) AirCore-HR consists of a 300 m tube, combining 200 m of 0.125 in. (3.175 mm) tube and a 100 m of 0.25 in. (6.35 mm) tube. This new configuration allows us to achieve a vertical resolution of 300 m up to 15 km and better than 500 m up to 22 km (if analysis of the retained sample is performed within 3 h). The AirCore-HR was flown for the first time during the annual StratoScience campaign from CNES in August 2014 from Timmins (Ontario, Canada). High-resolution vertical profiles of CO2 and CH4 up to 25 km were successfully retrieved. These profiles revealed well-defined transport structures in the troposphere (also seen in CAMS-ECMWF high-resolution forecasts of CO2 and CH4 profiles) and captured the decrease of CO2 and CH4 in the stratosphere. The multi-instrument gondola also carried two other low-resolution AirCore-GUF that allowed us to perform direct comparisons and study the underlying processing method used to convert the sample of air to greenhouse gases vertical profiles. In particular, degrading the AirCore-HR derived profiles to the low resolution of AirCore-GUF yields an excellent match between both sets of CH4 profiles and shows a good consistency in terms of vertical structures. This fully validates the theoretical vertical resolution achievable by AirCores. Concerning CO2 although a good agreement is found in terms of vertical structure, the comparison between the various AirCores yields a large and variable bias (up to almost 3 ppm in some parts of the profiles). The reasons of this bias, possibly related to the drying agent used to dry the air, are still being investigated. Finally, the uncertainties associated with the measurements are assessed, yielding an average uncertainty below 3 ppb for CH4 and 0.25 ppm for CO2 with the major source of uncertainty coming from the potential loss of air sample on the ground and the choice of the starting and ending point of the collected air sample inside the tube. In an ideal case where the sample would be fully retained, it would be possible to know precisely the pressure at which air was sampled last and thus to improve the overall uncertainty to about 0.1 ppm for CO2 and 2 ppb for CH4.

The Quality Control on Shengmi Bridge Arch Rib Construction

2014 ◽  
Vol 1004-1005 ◽  
pp. 1464-1467
Author(s):  
Xiu Li
Keyword(s):  
Quality Control ◽  
Steel Tube ◽  
Bridge Construction ◽  
Construction Quality ◽  
Arch Bridge ◽  
Large Span ◽  
Type Steel ◽  
Protection Coating

Introduced the essential construction craft of Nanchang Shengmi bridge (75+2×228+75m center bearing type steel tube concrete tie bar arched bridge). According to the construction craft and the quality specification request, discussed the steel arched bridge manufacture and the anticorrosion, the steel arched bridge rib erects, the steel arched bridge rib welding, the steel arched bridge in concrete configuration and the scene constructs, the steel tube protection coating construction, then proposed the construction quality control of large span steel tube concrete arch bridge. The conclusion of the article may be used at the similar steel tube concrete arched bridge construction.

Supporting Design and Stability Analysis of a Subway Station's Main Body Tunneling

2013 ◽  
Vol 470 ◽  
pp. 970-975
Author(s):  
Zhao Guang Li ◽  
Zhi Li Sui ◽  
Quan Zhen Zhang ◽  
Tie Jun Xu
Keyword(s):  
Surrounding Rock ◽  
Design Parameters ◽  
Subway Station ◽  
Soil Stability ◽  
Main Body ◽  
Main Structure ◽  
Analogy Method ◽  
Segment Model ◽  
Rock Stability ◽  
Surrounding Soil

In this paper, taking a subway station as the design background, combining with the design conditions and the surrounding rock stability, hydrogeology conditions, and using numerical simulation and engineering analogy method, the main structure of the station excavation section is excavated and the tunneling segment supports is designed. Using FLAC3D software to build a subway station tunneling segment model, with reference to the analog out of the design parameters and excavation program, strictly in accordance with the small block and step into the ring principle, the excavation and support are simulated, and the numerical calculation is performed, then from the stress, displacement, plastic zone and other aspects, the station shallow section stability of the support is analyzed, the effect of excavation station bringing to the surrounding soil stability is calculated.

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