Soil Pressure Analysis of Subway Tunnel Across Ground Fissures

Ground fissure is a kind of serious geological disaster. There will be more unprecedented challenges during the construction of the urban subway in ground fissures-developed zone. How to ensure the long-term operation safety of the subway crossing ground fissure belts are the first problems for the subway under construction in the cities with ground fissure developed. One of the important problems is that dynamic interaction and disaster effect control among ground fissure-stratum-subway tunnel under subway dynamic loading, which is also the important problem to be solved in the engineering. This problem involves the following three aspects: (a) the determination of subway dynamic loading; (b) the structure dynamic response of subway tunnel; (c) the interaction among stratum-ground fissure-subway tunnel. According to make a comment on these researches, some issues which are necessary to carry out in this field are suggested.

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Physical Modeling and Numerical Simulation of the Seismic Responses of Metro Tunnel near Active Ground Fissures

Complexity ◽

10.1155/2019/9014641 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11

Author(s):

Nina Liu ◽

Quanzhong Lu ◽

Jun Li ◽

Jianbing Peng ◽

Wen Fan ◽

...

Keyword(s):

Numerical Simulation ◽

Hanging Wall ◽

Shaking Table ◽

Burial Depth ◽

Soil Pressure ◽

Ground Acceleration ◽

Ground Fissures ◽

Railway Systems ◽

Face Threats ◽

Metro Tunnel

Ground fissures pose serious hazards to underground, as well as aboveground, structures. In underground railways, which are near ground fissures, the potential for disasters is even higher since tunnels face threats from fissure activities. To determine the interaction between a tunnel and ground fissure in the event of an earthquake, field surveys and data analysis were applied to study the activity and damage caused by the fissure. Shaking table tests and a numerical simulation model were used to understand the dynamic response of the fissure site and tunnel. The fissure site had a clear hanging wall effect, where the acceleration amplification was larger in the hanging wall than that in the footwall both on the surface and at the middle of the fissure site. The zone of influence was also wider in the hanging wall. The acceleration magnification factor increased with the burial depth and peak acceleration of the input earthquake. The peak ground acceleration (PGA) decreased with the burial depth on both sides of the fissure. The greatest PGA coefficient was obtained at the surface of the site. The vertical soil pressure was influenced by the metro tunnel and fissure. The vertical soil pressure was larger in the hanging wall, especially in the zone near the fissure, but was less near the tunnel. The horizontal soil pressure above the tunnel was less than that near the fissure. The results of this study are essential for the safe design of underground railway systems.

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Experimental Study of the Behavior of Rectangular Excavations Supported by a Pipe Roof

Applied Sciences ◽

10.3390/app9102082 ◽

2019 ◽

Vol 9 (10) ◽

pp. 2082 ◽

Cited By ~ 3

Author(s):

Xiongyao Xie ◽

Mingrui Zhao ◽

Isam Shahrour

Keyword(s):

Experimental Study ◽

Experimental Investigation ◽

Experimental Tests ◽

Soil Pressure ◽

Sand Soil ◽

Soil Settlement ◽

Effective Role ◽

The Stability ◽

Pressure Analysis

This paper presents an experimental investigation of the role of pipe-roofs in the improvement of the stability of rectangular excavations constructed using pipe-roof technology. This technology is suitable for the construction of underground passages in crowded areas subjected to high requirements concerning soil settlement and stability during excavation construction. The design of a rectangular pipe-roof excavation required an understanding of the interaction between the soil, the pipe-roof and the excavation. This interaction is complex and plays an important role in the features of the pipe roof excavation. This paper presents a series of 1g physical experimental tests conducted in dry sand soil with an advanced monitoring system, which allows tracking of the soil settlement, the pipe deformation and the soil pressure. Analysis of these tests shows the effective role of the pipe-roof in reducing both the soil settlement and the soil pressure on the excavation. It also shows the influence of pipes on the deformation mechanism of the soil and its evolution from low deformation to the instability phase.

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Differential Settlement due to Ground Fissures in Xi’an

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1065-1069.410 ◽

2014 ◽

Vol 1065-1069 ◽

pp. 410-413 ◽

Cited By ~ 1

Author(s):

Xin Yuan Wang ◽

Song He Mao ◽

Yao Jun Zhang

Keyword(s):

Ground Water ◽

Differential Settlement ◽

Water Model ◽

Subway Tunnel ◽

Ground Fissures ◽

Downtown Area ◽

Factors Influencing ◽

Governing Factor ◽

Xi’An City ◽

Good Agreement

From 1950s 13 NEE ground fissures have been found in the suburb and downtown area of Xi’an city. Ground fissures bring harm to the Xi'an municipal construction, especially to the subway construction. By dynamic characteristics of Xi’an ground fissures, factors influencing differential settlement are analyzed and a conclusion is drawn that exploitation of ground water and the differential clay thickness on both sides of ground fissures is the governing factor. The amount of differential settlement in the following 50 years is predicted by ground-water Model and Verhulst Model. Good agreement is shown between these results. It leads us to suggest that the differential settlement will cut off the subway tunnel in the future and actions must be taken in the design phase of subway tunnel.

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Model Tests of Regolith Packaging Mechanism

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2012.p1023 ◽

2012 ◽

Vol 24 (6) ◽

pp. 1023-1030 ◽

Cited By ~ 1

Author(s):

Daisuke Inoue ◽

◽

Yoshitaka Yanagihara ◽

Hiroshi Ueno ◽

Shin’ichiro Nishida ◽

...

Keyword(s):

Lunar Surface ◽

Construction Method ◽

Model Tests ◽

Critical Element ◽

Basic Design ◽

Soil Pressure ◽

Space Operations ◽

Manned Space ◽

Pressure Analysis

A robot construction method is developed for burying a lunar outpost. With this method, sandbags are made and piled up on the lunar surface to build a sandbag stack around an outpost and bury it. This method makes it possible to build a lunar base efficiently while minimizing risky manned space operations. In this study, we focused on the “sandbag,” which is the most critical element in a burying mission using a sandbag stacking robot, made a basic design based on soil pressure analysis, and evaluated the validity of design by conducting model tests. We confirmed the validity of the basic design of the sandbag stacking robot from these studies.

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Study on Interaction between Soil and U-Shaped Subway Tunnel in the Environment of Ground Fissures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.2342 ◽

2011 ◽

Vol 250-253 ◽

pp. 2342-2345 ◽

Cited By ~ 1

Author(s):

Yang Liu ◽

Kai Ling Li ◽

Yu Ming Men ◽

Guang Yuan Weng ◽

Hong Jia Liu

Keyword(s):

Hanging Wall ◽

Interaction Mechanism ◽

Vertical Displacement ◽

Soil Mass ◽

Relative Displacement ◽

Tunnel Structure ◽

Subway Tunnel ◽

Ground Fissure ◽

Ground Fissures ◽

Deformation Area

The interaction mechanism, between soil and U-shaped Subway tunnel, is studied by numerical simulation in the environment of ground fissures. The Subway Line 2 through the ground fissures in Xi’an. The analysis results show that the soil mass influenced by the relative displacement and the vertical displacement gradually increases with the relative displacement increasing of ground fissures movement. The deformation area of tunnel lies in the two sides of presupposed ground fissure, and the area enlarge with vertical relative displacement increasing. The tunnel structure damages at the ground fissures when the relative displacement reaches to 100mm. The footwall part is in tension and the hanging wall part is under pressure on the top of tunnel structure at the ground fissure. The footwall part is under pressure and the hanging wall part is in tension on the bottom of tunnel structure at the ground fissure. In the practical projects, the sectional type tunnel should be employed when the Subway tunnel through the ground fissures.

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Analysis on Surface Settlement Caused by Soil Pressure in the Chamber of Shield-Tunneling

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.322 ◽

2012 ◽

Vol 446-449 ◽

pp. 322-325

Author(s):

Hai Xia Sun ◽

Wen Zhao ◽

Qi Zhou ◽

Zhao Zhang

Keyword(s):

Earth Pressure ◽

Good Control ◽

Progressive Increase ◽

Ground Settlement ◽

Subway Tunnel ◽

Soil Pressure ◽

Shield Tunneling ◽

Element Simulation ◽

Set Up ◽

The Cost

Soil Pressure in the chamber is one of the important construction parameters. It is very important to set up reasonable soil Pressure in the chamber for controlling the ground settlement, promoting the peed of drift and lowering the cost of drifting. Take some subway tunnel for example, and carry out the 3D finite element simulation. In order to investigate the influence on ground settlement from soil pressure in the chamber, take 15% of the progressive increase in earth pressure to simulate over-balance conditions and also take 15% of the progressive decrease in earth pressure to simulate under-balance conditions. The results indicated that while the soil pressure achieves equilibrium, the swell and the settlement are all small. While over-equilibrium, the swell increases, on the contrary, the settlement increases while under-equilibrium. So, a good control over the soil pressure is one of the most effective therapies for decreasing the ground settlement.

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Model Test of the Impact of Active Ground Fissures on Metro Tunnel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.405-408.1334 ◽

2013 ◽

Vol 405-408 ◽

pp. 1334-1339

Author(s):

Yi Yuan ◽

Qiang Bing Huang ◽

Jie Han ◽

Ming Li Li

Keyword(s):

Model Test ◽

Hanging Wall ◽

Foot Wall ◽

Test Results ◽

Soil Pressure ◽

Ground Fissure ◽

Ground Fissures ◽

Tunnel Diameter ◽

Metro Tunnel ◽

The Impact

A model test was performed to investigate the impact of active ground fissure on metro tunnel. The test results show that under the action of active ground fissure, the metro tunnel behaviors as a cantilever elastic foundation beam, and the top is in tension and its bottom is in compression. The tensile parts are located in the foot-wall with the range 0.75～2.33D（D is tunnel diameter） distance from active ground fissure and the compressive parts are mainly located in the foot-wall with the range 3D distance from the fissure. When the settlement of hanging wall of ground fissure reaches 1cm（25cm in prototype）, the tunnel bottom appear cavity in the hanging wall and cracks in the foot-wall. With the settlement development of the hanging wall of active ground fissure the vertical soil pressure on the top of tunnel greatly increases and reduces at the bottom of tunnel in the hanging wall.

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