Ground fissures in Xi’an and measures to prevent damage to the Metro tunnel system due to geohazards

At present, systems of infrastructure are built and developed very strongly in Hanoi. The metro tunnel system is also being designed and built in Hanoi to meet the requirements of economic and social development. The paper uses analytical methods (the Wang's method, Penzien’s method), hyperstatic reaction method and a numerical analysis method by Abaqus software to evaluate the effect of the strongest earthquake that could occur in to the lining tunnel in Hanoi metro system. Based on results obtained from assessing the effect of earthquakes to the lining tunnel in Hanoi metro system, this paper has compared and commented to these results for the purpose of finding the most accurate results about the impact of earthquakes on the lining tunnel in Hanoi metro system. These results and comments will be used in the design and construction tunnel in the Hanoi metro system under the impact of the earthquakes that could occur in Hanoi.

Download Full-text

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.

Download Full-text

Mechanical Analysis of Tunnel Crossing Ground Fissure

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.243-249.3376 ◽

2011 ◽

Vol 243-249 ◽

pp. 3376-3380

Author(s):

Kai Ling Li ◽

Hong Jia Liu ◽

Yang Liu

Keyword(s):

Numerical Simulation ◽

Frictional Force ◽

Mechanical Characteristics ◽

Mechanical Analysis ◽

Evolution Process ◽

Distribution Law ◽

Ground Fissure ◽

Ground Fissures ◽

Interface Mechanics ◽

Metro Tunnel

Ground fissures is one of typical geo-hazards in Xi’an area, which may cause damage of various types of buildings, city lifeline projects and resources, especially endangering the construction and running of Xi’an Subway. Ground fissures in Xi’an were introduced firstly, and models of land deformations and section destroy were found around Xi’an subway. Secondly, based on the interface mechanics, mechanical characteristics of interface between stratum on fissure and metro tunnel are studied, and void underneath metro tunnel are analyzed emphatically. At last, the result of numerical simulation shows that distribution law and amount of frictional force, scale and location of void under the tunnel, influence deformation and stress of tunnel; and then it also provides a theory basis for effective forecast evolution process of void underneath.

Download Full-text

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.

Download Full-text

Pollution based real time control strategies for combined sewer systems

Water Science & Technology ◽

10.2166/wst.1997.0688 ◽

1997 ◽

Vol 36 (8-9) ◽

pp. 331-336 ◽

Cited By ~ 8

Author(s):

Gabriela Weinreich ◽

Wolfgang Schilling ◽

Ane Birkely ◽

Tallak Moland

Keyword(s):

Real Time ◽

Control Strategies ◽

Ammonia Nitrogen ◽

Simple Extension ◽

Real Time Control ◽

Time Control ◽

Sewer Systems ◽

Receiving Waters ◽

Tunnel System

This paper presents results from an application of a newly developed simulation tool for pollution based real time control (PBRTC) of urban drainage systems. The Oslo interceptor tunnel is used as a case study. The paper focuses on the reduction of total phosphorus Ptot and ammonia-nitrogen NH4-N overflow loads into the receiving waters by means of optimized operation of the tunnel system. With PBRTC the total reduction of the Ptot load is 48% and of the NH4-N load 51%. Compared to the volume based RTC scenario the reductions are 11% and 15%, respectively. These further reductions could be achieved with a relatively simple extension of the operation strategy.

Download Full-text