Use of Grouting to Reduce Deformations of an Existing Tunnel Underpassed by Another Tunnel

Mazek, Sherif A.; Law, KT; Lau, David T.

doi:10.1061/40663(2003)93

Cited by 6 publications

(8 citation statements)

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“…이에 따라 기존의 지하시 설물을 관통하여 교통시설물의 건설이 필연적으로 발생하 게 되며 선형계획을 깊은 심도로 하여 기존 지하시설물과의 근접시공을 배제할 수 있으나 교통의 기능과 이용객의 편 의성으로 인해 근접시공이 불가피한 경우가 빈번하다. 이러 한 경우 기술적 안전성이 검증되지 않은 경우 붕괴사고가 발 생 할 수 있으며, 이에 대하여 연구 및 분석이 진행되었다 [1][2][3][4][5][6] . 이때 기존구조물의 안전성을 확보하기 위해 주변지반에 대한 보강을 실시하며, 지반 그라우팅이 가장 널리 사용 하는 방법 중의 하나이다.…”

Section: 서 론unclassified

Stability Analysis of Upper Structures by Soil Grouting

Hwang

2013

Journal of the Korean Society of Safety

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Transportation and further expansion of social infrastructure was needed along the development of urbanization and population concentration. To use the underground space due to the lack of availability of land, it is inevitable to intersect between present structure and tunnel during construction. Soil grouting is one of the ground improvement methods to reinforce weak soil around the underground structures by injection of grouting liquid. Some of central columns of an upper structure are damaged during injection of grouting liquid by injection pressure. To investigate and improve the stability of the tunnel, three dimensional analysis are performed with full construction stages which includes the construction of present underpass, damaging columns of the underpass, reinforcing the columns by H-pile and shear walls, and excavation and construct tunnel. The arrangement of grouting holes such as curtain and horizontal type affects largely to the stability of upper structure and horizontal arrangement diminish the shear forces which is the cause of damage of central columns. The liquid injection type of reinforcement for tunnel is not recommended while the presence of upper structure with columns. Wall type reinforcing is utilize for permant support of upper structures which is affected by grouting injection pressure. H-pile is utilize for temporary support, but not for permanent since the sharing of shear forces is not much to shear wall during tunnel construction.

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Section: 서 론unclassified

Stability Analysis of Upper Structures by Soil Grouting

Hwang

2013

Journal of the Korean Society of Safety

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“…Parametric studies are conduct at different tunnel depths from the ground surface. The soil depth underneath tunnel invert is set to be three times the tunnel diameter (Mazek, 2005).…”

Section: Ground Response Under Loose Sand Impactmentioning

confidence: 99%

“…The numerical techniques are widely used to predict the ground movements. During the last three decades, numerical analysis has been grown rapidly (Abu Krisha, 2001;El-Nahhass, 1986;1999;Mazek, 2005). Finite element method is considered the most appropriate analytical technique to solve geotechnical problems (Abu-Farsakh and Tumay, 1999; El-Nahhas, 1999; Mazek et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…Finite element method is considered the most appropriate analytical technique to solve geotechnical problems (Abu-Farsakh and Tumay, 1999; El-Nahhas, 1999; Mazek et al, 2004). Modeling of geotechnical properties and details of tunneling procedure are the sophisticated geotechnical problem (El-Nahhass, 1986;Mazek, 2005;Mazek et al, 2004). The surface displacement is calculated by both the FEA and the SDE developed by Peck (1969) and Schmidt (1969) based on different sand soil densities.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Surface Displacement Equation due to Tunneling in Cohesionless Soil

Mazek¹

2013

International Conference on Aerospace Sciences and Aviation Tec

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Construction of tunnels in soft ground induces soil movement, which could seriously affect the stability of existing structures. Evaluation of the effect of tunnel construction on the soil movement requires the solution of a complex soil-structure interaction problem. Finite element method (FEM) is considered as a good numerical tool to model tunnel system performance. The soil stresses and the soil displacements around a tunnel system are affected by the tunnel construction. The influence zone depends on subsoil properties, tunnel depth, tunnel size, and tunnel support system. In the present study, finite elements analysis (FEA) is used to model soil-tunnel system performance based on a case study to investigate surface displacement due to tunneling. The Greater Cairo metro tunnel (Line 3) is considered in the present study as case study. The surface displacements obtained by surface displacement equation (SDE) proposed by Peck (1969) and Schmidt (1969) are presented and discussed. The main objective of this study is to examine surface displacements obtained by the FEA with those obtained by the SDE based on different sand soil types. However, the SDE does not consider the impact of different sand soil types on the surface settlement due to tunneling. The study focuses on the parameters used in the SDE based on different sand soil densities. The limitation of the parameters used in the SDE is discussed and established to predict the surface displacement due to tunneling at different sand soil densities.

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“…Cooper and Chapman ( 2002 ) and Cooper et al ( 2002 ) dealt with the monitoring within the Piccadilly Line tunnels during construction of the Heathrow Express tunnels constructed in close proximity to the Central Terminal Area Station, Angel Station as well as Old Street Reconstruction, and a description was given of the instruments used, which included electrolevels, precise levels and tape extensometers, and the relative merits of manual methods and remote reading methods were discussed. Mazek et al ( 2003 ) introduced the construction of the Greater Metro Line 2 and El-Azhar road tunnels under an existing sewage tunnel, and a 3-D model of the multi-crossing tunnel incorporating the effect of grouting was provided to evaluate the usefulness of permeation grouting in reducing deformation around the sewage tunnel when the metro and the road tunnels passed underneath it at different crossing zones. Wang ( 2003 ) introduced more than twenty applications of electrolevel beam sensors in the existing tunnels on Lines 1–3 of Shanghai subway to ensure safety of the subway traffic.…”

Section: Introductionmentioning

confidence: 99%

Development of the safety control framework for shield tunneling in close proximity to the operational subway tunnels: case studies in mainland China

Yuan

2016

SpringerPlus

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IntroductionChina’s largest cities like Beijing and Shanghai have seen a sharp increase in subway network development as a result of the rapid urbanization in the last decade. The cities are still expanding their subway networks now, and many shield tunnels are being or will be constructed in close proximity to the existing operational subway tunnels. The execution plans for the new nearby shield tunnel construction calls for the development of a safety control framework—a set of control standards and best practices to help organizations manage the risks involved.Case description Typical case studies and relevant key technical parameters are presented with a view to presenting the resulting safety control framework. The framework, created through collaboration among the relevant parties, addresses and manages the risks in a systematic way based on actual conditions of each tunnel crossing construction. The framework consists of six parts: (1) inspecting the operational subway tunnels; (2) deciding allowed movements of the existing tunnels and tracks; (3) simulating effects of the shield tunneling on the existing tunnels; (4) doing preparation work; (5) monitoring design and information management; and (6) measures and activation mechanism of the countermeasures. The six components are explained and demonstrated in detail.Discussion and EvaluationIn the end, discussions made involve construction and post-construction settlement of the operational tunnel, application of the remedial grouting to rectify excessive settlements of the operational tunnel, and use of the innovative tool of the optical fiber measurement for tunnel movement monitoring.ConclusionsIt is concluded that the construction movement of the tunnel can be controlled within 15 mm when the shield machine is <7 m in excavation diameter. The post-construction settlement of the tunnel buried in the very soft ground is much greater than its construction settlement, and last several years until reaching a final stable state. Two cases are outlined to demonstrate the feasibility of using the remedial grouting to reduce the long-term settlement of the operational tunnels. The more and more segmental tunnels being constructed, there is an increasing need of the optical fiber measurement for tunnel movement monitoring in the near future.

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Use of Grouting to Reduce Deformations of an Existing Tunnel Underpassed by Another Tunnel

Cited by 6 publications

References 0 publications

Stability Analysis of Upper Structures by Soil Grouting

Stability Analysis of Upper Structures by Soil Grouting

Evaluation of Surface Displacement Equation due to Tunneling in Cohesionless Soil

Development of the safety control framework for shield tunneling in close proximity to the operational subway tunnels: case studies in mainland China

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