Resist Liquefaction of Subsoil of Metro and Improvement of Segments of Shield Tunneling

2012 ◽  
Vol 588-589 ◽  
pp. 1979-1982
Author(s):  
Wen Hua Chen ◽  
Qi Song ◽  
Meng Li
Keyword(s):  
High Pressure ◽  
Machine Construction ◽  
Shield Tunneling ◽  
Soil Layers ◽  
Seismic Liquefaction ◽  
Foundation Treatment ◽  
Jet Grouting ◽  
Tunneling Method ◽  
Liquefaction Index ◽  
Shield Machine

Nanjing’s metro is studied as a example to introduce resist liquefaction method in this paper. Dynamic diffuse theory of structure is supposed to evaluate the width and depth of foundation treatment to resist the seismic liquefaction to think of metro structure, liquefied soil layers and different liquefaction-index. High pressure jet grouting method is researched as shield machine construction through foundations of buildings or ancient wall. An improved segments of shield tunneling method is suggest to ensure the resist liquefaction method to success.

Impact of Double-O-Tube Shield Tunnel Construction on Grillage Beams Foundation Frame Building

2011 ◽  
Vol 71-78 ◽  
pp. 32-36 ◽  
Author(s):  
Xin Jiang Wei ◽  
Jie Hong ◽  
Gang Wei
Keyword(s):  
Principal Stress ◽  
Differential Settlement ◽  
Shield Tunnel ◽  
Tunnel Construction ◽  
Foundation Settlement ◽  
Ground Settlement ◽  
Shield Tunneling ◽  
Frame Building ◽  
Shield Machine ◽  
The Impact

Considering the interaction of building-soil-tunnel, the grillage beams foundation frame building vertical crossed by Double-O-Tube (DOT) shield tunnel was simulated by 3D MIDAS/ GTS software, and the impact of construction on the building was analyzed. The results show that: the ground settlement trough caused by DOT shield tunnel can be fitted by peck formula; during the passage of the shield tunneling through the building, the settlement of the building increased and settlement trough was wilder; the settlement was stable and had a little rebound when shield machine already passed the building; with the increase of driving distance, the first principal stress P1 increased and then was stable; with the increase of L, the shape of foundation settlement curve changed, and the maximum differential settlement between columns increased but was small.

Preliminary Ideas of the Metro Station Constructed by Shield Tunneling Method Combined with Prefabricated Method

2014 ◽  
Vol 580-583 ◽  
pp. 1013-1018 ◽  
Author(s):  
Hui Feng Su ◽  
Wei Ning Liu ◽  
Fu Chun Liu
Keyword(s):  
The Other ◽  
Shield Tunnel ◽  
Spring Stiffness ◽  
Underground Engineering ◽  
Shield Tunneling ◽  
Metro Station ◽  
Key Technology ◽  
Tunneling Method ◽  
Assembly Technology ◽  
Northeast Of China

Confronting with the difficulties of the construction metro station in the Northeast of China, a new idea of shield method combined prefabricated method is put forward. In the paper the research status of the underground engineering precast assembly technology was analyzed and classified firstly. The method of single round interval shield combined with open-cut (or covered excavation) prefabricated sections and on the basis of shield tunnel to build single arch station is especially worth studying and promotion. Then the key prefabricate theory needing to deal with such as how to calculating the spring stiffness and so forth of the calculating model. The key technology such as joint formation, waterproof and the other of shield method combined with prefabricated method was discussed.

Compact shield tunneling method

2005 ◽  
Author(s):  
Setsuo Takaku ◽  
Masayuki Matsuura ◽  
Yasushi Nagashima ◽  
Yoichi Moriya
Keyword(s):  
Shield Tunneling ◽  
Tunneling Method

scholarly journals Effect of Graphene and Carbon Nanotubes on the Thermal Conductivity of WC-Co Cemented Carbide

2019 ◽  
Author(s):  
Kui Chen ◽  
Wenkai Xiao ◽  
Zhengwu Li ◽  
Jiasheng Wu ◽  
Kairong Hong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Service Life ◽  
Bending Strength ◽  
Cemented Carbide ◽  
Engineering Practice ◽  
Shield Tunneling ◽  
Hardness Tester ◽  
Engineering Costs ◽  
Shield Machine

In recent years, it has been found in engineering practice that the service life of cemented carbide shield machine tools used in uneven soft and hard strata is substantially reduced. The study found that thermal stress is the main reason for the failure of cemented carbide shield tunneling tools when shield tunneling is carried out in uneven soft and hard soil. To maintain the hardness of cemented carbide, improving the thermal conductivity of the shield machine tool is of great importance for prolonging its service life and reducing engineering costs. In this paper, graphene and carbon nanotubes were mixed with WC-Co powder and sintered by SPS (Spark Plasma Sintering). The morphology was observed by using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). A Rockwell hardness tester and bending strength tester were used to test hardness, bending strength and thermal conductivity. The results show that adding trace graphene or carbon nanotubes can increase the bending strength of the cemented carbide by approximately 50% while keeping the hardness of the cemented carbide unchanged. The thermal conductivity of the cemented carbide can be increased by 10% with the addition of 0.12% graphene alone.

scholarly journals Features of Earthquake-Induced Seabed Liquefaction and Mitigation Strategies of Novel Marine Structures

2020 ◽  
Vol 8 (5) ◽  
pp. 310 ◽  
Author(s):  
Yu Huang ◽  
Xu Han
Keyword(s):  
Mitigation Strategies ◽  
Marine Structures ◽  
Engineering Structures ◽  
Soil Layers ◽  
Seismic Liquefaction ◽  
Oil Platforms ◽  
Field Investigations ◽  
Marine Engineering ◽  
The Impact ◽  
Gas Component

With the accelerated development of marine engineering, a growing number of marine structures are being constructed (e.g., seabed pipelines, drilling platforms, oil platforms, wind turbines). However, seismic field investigations over recent decades have shown that many marine structures were damaged or destroyed due to liquefaction. Seismic liquefaction in marine engineering can have huge financial repercussions as well as a devastating effect on the marine environment, which merits our great attention. As the effects of seawater and the gas component in the seabed layers are not negligible, the seabed soil layers are more prone to liquefaction than onshore soil layers, and the liquefied area may be larger than when liquefaction occurs on land. To mitigate the impact of liquefaction events on marine engineering structures, some novel liquefaction-resistant marine structures have been proposed in recent years. This paper reviews the features of earthquake-induced liquefaction and the mitigation strategies for marine structures to meet the future requirements of marine engineering.

scholarly journals Study of the Construction Sequence of Overlapping Tunnels by the Shield Tunneling Method: A Case Study of the Longest Overlapping Tunnel in China

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Zhiyong Yang ◽  
Yaowen Ding ◽  
Yusheng Jiang ◽  
Kuanda Fang ◽  
Linwei Dong ◽  
...  
Keyword(s):  
Working Conditions ◽  
Radial Stress ◽  
Three Dimensional ◽  
Vertical Displacement ◽  
Tunnel Lining ◽  
Shield Tunneling ◽  
Construction Sequence ◽  
Tunneling Method ◽  
The Difference ◽  
Small Change

In this study, the reasonable construction sequence of an overlapping tunnel shield is investigated. Taking the overlapping tunnel of Tianjin Metro Line 5 as the background, a three-dimensional numerical model was established using Flac3D software to study the influence of the “first up and then down” and “first down and then up” construction sequences of the overlapping tunnel on the surface settlement, stratum displacement, lining radial stress, and displacement. The research results show that the shape and width of the final settlement tank on the ground under the two conditions are basically the same, and the difference between the maximum cumulative settlements is small. The accumulated ground settlement caused by the first up and then down construction sequence is 1.8 mm larger than that caused by the first down and then up sequence. The difference between the two working conditions on the vertical displacement of the stratum mainly occurs in the middle stratum of the upper and lower tunnels, and the proportion of the strata in the uplifted state and subsidence state is different. The construction sequence has little effect on the radial stress on the lining of the upper and lower tunnels. Under these two conditions, the excavation of the second tunnel causes a small change in the radial stress of the preceding tunnel lining, both within 4.2%. Under the working condition of first down and then up, the construction of the second tunnel causes the lining of the preceding tunnel to rise by 7.2∼9.2 mm. Under the condition of first up and then down, the construction of the second tunnel causes the lining of the preceding tunnel to sink again by 9.1∼10.4 mm. By comparing the effects of the two working conditions on the stratum and the tunnel lining, it is recommended that the construction be carried out in the order of first down and then up.

High Pressure Rotary Jet Grouting Pile with Undrained Caisson Combined Construction Technology on Nearby Yangtze River Levee Protection

2013 ◽  
Vol 718-720 ◽  
pp. 1938-1944
Author(s):  
You Sheng Zhao ◽  
Bin Zhou
Keyword(s):  
High Pressure ◽  
Yangtze River ◽  
Engineering Application ◽  
Reference Value ◽  
Construction Technology ◽  
The Yangtze River ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Jet Grouting

t is easy to cause the Yangtze River embankment soil of slip even collapse to have a deep foundation pit construction adjacent to the Yangtze River outsideembankment,there are a lot of risk. In this paper, a new combining technique of construction for large caisson is presented. Based on the construction environment, theconstructiontechnology,the smaller earthwork excavation of deep high pressure rotary jet grouting pile with undrained caisson combined construction technology combined with monitoring data for the open caisson excavation control is adopted. It has achieved relatively good results and summarized the advantages of deep high pressure rotary jet grouting pile with undrained caisson combined construction technology in engineering application owing the reference value for engineering applications.

Application of High Pressure Jet Grouting Technology in the Seepage Control of Earth Dam Reinforcement

2011 ◽  
Vol 291-294 ◽  
pp. 3259-3263
Author(s):  
Cong Jiao Zhang ◽  
Shi Bao Zhang ◽  
Feng Shan Fan
Keyword(s):  
High Pressure ◽  
Technological Process ◽  
Earth Dam ◽  
Construction Equipment ◽  
Dam Foundation ◽  
Jet Grouting ◽  
Design Requirements ◽  
Wall Construction ◽  
Construction Practice

Based on the construction practice of strengthening dam foundation and cross-strait dam end (0+149～0+330) high pressure jet grouting impervious wall of an earth dam, this paper expounds the construction equipment, technological process, construction parameters and construction method of high pressure jet grouting impervious wall construction. By analyzing the impervious wall’s depth, continuity, strength, permeable rate, the quality of the wall is eligible, and its indexes comfort the design requirements. The experiences are useful in similar earth dam reinforcement construction.

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