Ground deformation around a tunnel excavation in bunter sandstone

Research at home and abroad shows that subway excavation often causes soil stress loss, resulting in settlement deformation and horizontal displacement of stratum. Therefore, combined with the special engineering geological conditions in Kunming area, the foundation deformation caused by subway excavation is studied, so as to provide an important foundation for proposing the protection measures of surrounding buildings and buried pipelines and promoting the construction of subway.

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Study on the Method of Construction of Large Section Tunnel Crossing the Ancient Great Wall

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.226-228.1504 ◽

2012 ◽

Vol 226-228 ◽

pp. 1504-1508

Author(s):

Ai Bing Jin ◽

Long Fu Li ◽

Fu Gen Deng ◽

Min Zhe Zhang

Keyword(s):

High Efficiency ◽

Surface Deformation ◽

Ground Deformation ◽

Three Dimensional ◽

Horizontal Displacement ◽

Tunnel Excavation ◽

Construction Scheme ◽

Construction Experience ◽

Strata Deformation ◽

Great Wall

While the tunnel crossing the ancient Great Wall, we must take effective measures to control ground deformation, prevent ground deformation is too large, destroying the heritage. In order to study the effects of tunnel excavation types on strata deformation, a three-dimensional computational model is built to simulate surface settlement and horizontal displacement by three different excavation types which are both-side heading method, CRD method, and hole pile method. Following comparative analysis, in line with the realistic program is recommended. The results show that both-side heading method can better control the surface deformation, and has a high efficiency of construction, which was selected as the construction scheme of tunnel crossing the ancient great wall. The results of this study are expected to provide construction experience to the works of a similar background.

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Study on Influencing Factor of Ground Deformation Induced by Shield Tunneling

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.734-737.690 ◽

2013 ◽

Vol 734-737 ◽

pp. 690-693

Author(s):

Meng Lin Xu ◽

De Shen Zhao

Keyword(s):

Ground Deformation ◽

Influencing Factor ◽

Ground Movement ◽

Shield Tunnel ◽

Shield Tunneling ◽

Tunnel Excavation ◽

Security Issues ◽

Surrounding Environment ◽

Strata Deformation ◽

Complex Construction

The complex construction behavior inevitably disturb surrounding environment, even when the tunneling goes through building, which may be wrecked. The security issues of the subway project stems from ground movement and structure dynamic interaction. So it is academic and application good value for study on construction influences of shield tunnel excavation to the neighboring buildings. This paper focuses on the shield tunnel construction strata deformation factors. The results provided the theory basis for safety construction.

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Research on Pre-Reinforcing Composite Foundation with a Shield Tunnel Under-Passing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.243-249.3556 ◽

2011 ◽

Vol 243-249 ◽

pp. 3556-3559

Author(s):

Zhi Yong Peng ◽

Wei Ning Liu ◽

Qiao Ling Zeng

Keyword(s):

Ground Deformation ◽

Composite Foundation ◽

Shield Tunnel ◽

Replacement Rate ◽

Tunnel Excavation ◽

Optimum Reinforcement ◽

Reinforcing Effects ◽

Soil Foundation ◽

Pile Length ◽

Separation Model

This paper analyzes the per-reinforcing effects of composite foundation with a shield tunnel under-passing, and tries to find the regularity in soil foundation improvement under such conditions. The paper establishes piles-soil separation model using software FLAC3D in a finite difference method and research the influence of effective pile length and effective replacement rate on ground deformation under the condition of shield-driver tunnel excavation. there does exist the optimum reinforcement range about pile length and replacement rate between the surface and the top of tunnel. Moreover this can offer reference for similar projects to a certain extent.

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Analysis of Affecting Factors of Ground Deformation Based on Shield Tunnel Excavation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.441.615 ◽

2013 ◽

Vol 441 ◽

pp. 615-618

Author(s):

Li Xin Li ◽

Qi Yun Zou ◽

Jun Jia Wang

Keyword(s):

Ground Deformation ◽

Ground Surface ◽

Surface Displacement ◽

Element Model ◽

Shield Tunnel ◽

Affecting Factors ◽

Tunnel Excavation ◽

Tunnel Diameter ◽

The Relationship ◽

The Finite Element Model

The shield tunnel method is a way that widely used in tunnel build. However, the ground surface displacement and deformation because of tunnel excavation will bring a series of affections in our engineering. By using the finite element model of different tunnel excavation depth, different elastic modulus and different tunnel diameter of the tunnel, we predicted it correctly. Finally, we get the relationship between the surface displacement and the depth of tunnel excavation, diameter, strength of soil.

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Pre- and Postcollapse Ground Deformation Revealed by SAR Interferometry: A Case Study of Foshan (China) Ground Collapse

Journal of Sensors ◽

10.1155/2020/8899054 ◽

2020 ◽

Vol 2020 ◽

pp. 1-17

Author(s):

Wu Zhu ◽

Yan Zhang ◽

Zhanke Liu ◽

Qian Zhu

Keyword(s):

Ground Deformation ◽

Southern China ◽

Soft Soil ◽

Soil Layer ◽

Sar Interferometry ◽

Ground Subsidence ◽

Soil Consolidation ◽

Tunnel Excavation ◽

Ground Collapse ◽

Before And After

On the evening of 7 February 2018, a deadly collapse of a metro tunnel under construction in the Southern China city of Foshan caused 11 deaths, 8 injuries, and 1 missing person. For disaster prevention and mitigation, the spatiotemporal ground deformations before and after the collapse event were derived from 55 Sentinel-1A synthetic aperture radar (SAR) images spanning from March 2017 to January 2019. The results showed that prominent ground subsidence in the shape of a funnel with a maximum rate of 42 mm/year was observed in the vicinity of the collapse area before the accident. After the accident, the area and magnitude of subsidence decreased compared with precollapse subsidence. This decrease is related to the progress of tunnel excavation and groundwater changes. In the temporal domain, continuous subsidence was observed over a year before and after the accident, and accelerated subsidence appeared one month before the collapse accident. Soft soil consolidation and tunnel-induced soil losses were the main reasons for the subsidence over the study area. The leakage of groundwater accounted for the collapse event. The leaked groundwater eroded the soil, resulting in the formation of an arched hole. The connection between the arched hole and the tunnel reduced the bearing capacity of the soil layer above the arched hole, triggering the collapse event. The findings provide scientific evidence for future collapse monitoring and early warning due to tunnel excavation.

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Failure Analysis Of Buried Gas Pipelines Crossing Seismic Faults

Academic Perspective Procedia ◽

10.33793/acperpro.03.02.2 ◽

2020 ◽

Vol 3 (2) ◽

pp. 781-790

Author(s):

M. Rizwan Akram ◽

Ali Yesilyurt ◽

A.Can. Zulfikar ◽

F. Göktepe

Keyword(s):

Ground Deformation ◽

Warning System ◽

Strike Slip ◽

Gas Pipelines ◽

Steel Pipes ◽

Seismic Fault ◽

Fault Parameters ◽

Dip Angle ◽

Permanent Ground Deformation ◽

Recent Earthquakes

Research on buried gas pipelines (BGPs) has taken an important consideration due to their failures in recent earthquakes. In permanent ground deformation (PGD) hazards, seismic faults are considered as one of the major causes of BGPs failure due to accumulation of impermissible tensile strains. In current research, four steel pipes such as X-42, X-52, X-60, and X-70 grades crossing through strike-slip, normal and reverse seismic faults have been investigated. Firstly, failure of BGPs due to change in soil-pipe parameters have been analyzed. Later, effects of seismic fault parameters such as change in dip angle and angle between pipe and fault plane are evaluated. Additionally, effects due to changing pipe class levels are also examined. The results of current study reveal that BGPs can resist until earthquake moment magnitude of 7.0 but fails above this limit under the assumed geotechnical properties of current study. In addition, strike-slip fault can trigger early damage in BGPs than normal and reverse faults. In the last stage, an early warning system is proposed based on the current procedure.&nbsp;

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