scholarly journals Hazard Reduction in Deep Excavations Execution

2022 ◽  
Vol 14 (2) ◽  
pp. 868
Author(s):  
Mateusz Frydrych ◽  
Grzegorz Kacprzak ◽  
Paweł Nowak
Keyword(s):  
Cost Optimization ◽  
Bridge Engineering ◽  
Diaphragm Wall ◽  
Modern Approach ◽  
New Approach ◽  
Deep Excavations ◽  
Ground Anchors ◽  
Calculation Methodology ◽  
Diaphragm Walls ◽  
Bridge Technology

In this article, the authors consider a completely new approach in design, which is related to the use of previously un-adapted technologies known to bridge engineering in geotechnical issues for prestressing of diaphragm wall during deep excavations execution. The bridge technology described here is the prestressing of concrete structures. Hazards related to deep excavations and methods of digging them, such as the ceiling method and top&down method, are presented. Current problems in supporting deep excavation slopes are related to the use of extensive quantities of materials (such as steel struts, ground anchors, or concrete and reinforcement steel). The authors’ method helps to achieve a higher level of sustainability, which is important in a modern approach to geotechnical engineering. The non-linear arrangements of the cables according to the occurrence of the prestressing moments for a given phase are presented. Results related to numerical analysis—showing the correctness of the method and cost optimization results, showing possible savings are presented. The article is a part of the set. In the second (already published) article titled “Modern Methods of Diaphragm Walls Design”, the authors present the concept of the calculation methodology for diaphragm wall design.

scholarly journals BI-LAYER DIAPHRAGM WALLS: STRUCTURAL AND SECTIONAL ANALYSIS

2015 ◽  
Vol 22 (5) ◽  
pp. 645-654
Author(s):  
Luis SEGURA-CASTILLO ◽  
Antonio AGUADO ◽  
Albert DE LA FUENTE ANTEQUERA ◽  
Alejandro JOSA
Keyword(s):  
Reinforced Concrete ◽  
Steel Fibre ◽  
Cost Effective ◽  
Diaphragm Wall ◽  
Steel Fibre Reinforced Concrete ◽  
Slurry Wall ◽  
Promising Solution ◽  
Diaphragm Walls ◽  
Sectional Analysis ◽  
Section Analysis

The bi-layer diaphragm wall, a new slurry wall type designed to cope with the problem of watertightness is studied in this paper. These walls consist of two bonded concrete layers, the first, a conventional Reinforced Concrete (RC) diaphragm wall, and the second, a Sprayed Steel Fibre Reinforced Concrete (SFRC). The main objective of this paper is to analyze the structural and sectional behaviour of these walls. A study in the form of an uncoupled structural-section analysis based on various hypothetical cases of bi-layer diaphragm walls was performed to fulfil the objective. It is concluded that there exists a potential of reduction in the reinforcement of the RC layer through the structural use of the SFRC layer. However, when the reduction is quantified, even though a reduction of between 3.2% and 1.7% in the RC reinforcement is confirmed, it appears insufficient to offer a cost-effective solution. Nonetheless, the system becomes a promising solution when particular conditions are taken into account, such as basement space limitations.

scholarly journals Modern Methods of Diaphragm Walls Design

2021 ◽  
Vol 13 (24) ◽  
pp. 14004
Author(s):  
Mateusz Frydrych ◽  
Grzegorz Kacprzak ◽  
Paweł Nowak
Keyword(s):  
Geotechnical Engineering ◽  
Concrete Structures ◽  
Steel Reinforcement ◽  
Bridge Engineering ◽  
Sustainable Construction ◽  
Engineering Science ◽  
Hazard Reduction ◽  
Modern Methods ◽  
Diaphragm Walls ◽  
Innovative Concept

This article addresses hazard reduction in deep excavations. The authors present a possible combination of prestressing of concrete structures (from bridge engineering) and prestressed structures of diaphragm walls from geotechnical engineering science. This innovative concept has not yet been shown in scientific articles. The “Sofistik” software (with TENDON module–SYSP/AXES/TOPP/TGEO) and its use is shown, with graphical presentations of the suggested solution. The authors compare the provided solution through usage of Sofistik and Plaxis software. The results show possible strengthening of sustainable construction by limitation of hazards and decreasing costs (via limitation of use of expensive steel reinforcement).

scholarly journals Prediction of lateral deflection of diaphragm wall in deep excavations.

1994 ◽  
pp. 19-29 ◽  
Author(s):  
Toru Masuda ◽  
Herbert H. Einstein ◽  
Toshiyuki Mitachi
Keyword(s):  
Diaphragm Wall ◽  
Deep Excavations ◽  
Lateral Deflection

Analysis of Mechanical Behavior of Subway Tunnel Constructed by Cover and Cut Reverse Method

2012 ◽  
Vol 446-449 ◽  
pp. 3623-3627
Author(s):  
Tie Cheng Wang ◽  
Yang Gao ◽  
Hai Long Zhao
Keyword(s):  
Bending Moment ◽  
Horizontal Displacement ◽  
Internal Force ◽  
Surrounding Rock ◽  
Diaphragm Wall ◽  
Tunnel Construction ◽  
Construction Process ◽  
Subway Tunnel ◽  
Diaphragm Walls ◽  
Reverse Method

In the paper, not only the internal force and displacement of structure during subway tunnel construction with cover and cut reverse method, but also the displacement field and stress field of surrounding rock are analysed. From the numerical calculation it is shown that the bending moment of diaphragm wall is affected seriously by the distribution and value of the stiffness of horizontal support; the excavation phase of the soil of the second floor underground is the key phase of the construction process because the internal force of structure has large increase; the value of surface settlement, horizontal displacement of diaphragm wall, differential settlement between middle pillar and diaphragm walls all meet the requirements, so the construction is safe and the surrounding buildings are affected slightly.

scholarly journals Concrete properties in diaphragm walls embedded in non-cohesive soils

2018 ◽  
Vol 174 ◽  
pp. 01007 ◽  
Author(s):  
Magdalena Czopowska-Lewandowicz
Keyword(s):  
Diffraction Method ◽  
Physical And Mechanical Properties ◽  
Diaphragm Wall ◽  
Concrete Mixture ◽  
Cohesive Soils ◽  
Existing Building ◽  
Concrete Quality ◽  
Diaphragm Walls ◽  
Bentonite Suspension ◽  
The Impact

Although diaphragm walls are massive and responsible structures whose building history has many years' tradition, the discovery of a variety of material faults is still common throughout their exploitation. Some of the most common ones are associated with the occurrence of leaks along the wall surface. This paper reports on the results of a study conducted into concrete quality in an existing building structure. The issues identified in this case include the potential penetration of groundwater and particles suspended in non-cohesive soils into the bentonite suspension and into the concrete mixture. The scope of the analysis also involved the possible occurrence of a mixing zone of bentonite suspension with the concrete mixture. The solutions presented in this paper were practically tested using an existing structure and the results confirm that the adopted approach needs to be thoroughly researched. The laboratory specimens derived from an unreinforced diaphragm wall were subjected to the following tests: concrete bulk density in the air-dried state, water absorption by concrete, depth of water penetration under pressure, compressive strength and determination of the quantitative phase composition test using X-ray diffraction method. The results clearly demonstrate the decrease of the concrete quality applied in a monolithic diaphragm wall in comparison to the reference samples taken at the phase when it was built. Due to the fact that it was impossible to identify the impact of the particular variables on the investigated structure, this paper focuses on their descriptive assessment. This discussion is based on the analysis of the results defining the physical and mechanical properties of the examined concrete coupled with observations made by the author and insights derived from literature.

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