Influence of Ground Improvement on Deflections of Diaphragm Walls in Deep Excavations

10.3850/gi019 ◽  
2009 ◽  
Author(s):  
Bin-Chen Benson Hsiung ◽  
Richard Nan Huei Hwang
Keyword(s):  
Ground Improvement ◽  
Deep Excavations ◽  
Diaphragm Walls

Ground Improvement. Recycle of Construction Sludge in Soil-Cement Diaphragm Walls.

2000 ◽  
Vol 49 (1) ◽  
pp. 46-49
Author(s):  
Takeo SUZUKI ◽  
Toshimitsu KUNITO ◽  
Motohiro NISHI
Keyword(s):  
Ground Improvement ◽  
Soil Cement ◽  
Diaphragm Walls

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.

Analysis and design of partial ground improvement in deep excavations

2008 ◽  
Vol 35 (4) ◽  
pp. 576-584 ◽  
Author(s):  
Chang-Yu Ou ◽  
Fu-Chen Teng ◽  
I-Wen Wang
Keyword(s):  
Ground Improvement ◽  
Deep Excavations ◽  
Analysis And Design

scholarly journals Design and construction of a deep excavation in soft soils adjacent to the Shanghai Metro tunnels

2003 ◽  
Vol 40 (5) ◽  
pp. 933-948 ◽  
Author(s):  
Z F Hu ◽  
Z Q Yue ◽  
J Zhou ◽  
L G Tham
Keyword(s):  
Ground Improvement ◽  
Soft Soil ◽  
Soft Clay ◽  
Theoretical Method ◽  
Horizontal Displacement ◽  
Deep Excavation ◽  
Construction Methods ◽  
Diaphragm Walls ◽  
Shanghai Metro ◽  
Design And Construction

This paper presents the design and construction of a deep excavation for building foundations in saturated soil. This deep excavation was of particular interest because it was located above and beside the Shanghai Metro tunnels. The twin Shanghai Metro tunnels had to be in full operation during the deep excavation. Potential large deformation of the twin tunnels was one of the main concerns during the design and construction for the deep excavation. The paper discusses in detail the criteria and measures for controlling the soil and tunnel deformation. The measures included cast-in-place concrete diaphragm walls with bracing structural members, pumping consolidation, cement–soil mix pile systems, and rational excavation procedures. A simplified theoretical method was proposed to estimate the increment in undrained shear strength in a soft clay layer due to pumping consolidation. Furthermore, conventional finite element methods were used to predict the soil vertical and horizontal displacements induced by the excavation. Using the design and construction methods discussed in the paper, the settlement and horizontal displacement of the tunnels were successfully controlled within 5.0 mm and 9.0 mm, respectively. The curvature of longitudinal deformation curve of the tunnels was less than 1/15 000. The horizontal displacement of the braced diaphragm walls was less than 0.12% of the total excavation depth. Key words: Metro tunnels, saturated soft soil, deep excavation, design, construction, ground improvement, case studies.

scholarly journals Novel Excavation and Construction Method for a Deep Shaft Excavation in Ultrathick Aquifers

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Chengyong Cao ◽  
Chenghua Shi ◽  
Linghui Liu ◽  
Jianwen Liu ◽  
Mingfeng Lei ◽  
...  
Keyword(s):  
Ground Surface ◽  
Lateral Wall ◽  
The Novel ◽  
Deep Excavations ◽  
Deep Aquifers ◽  
Pumping Wells ◽  
Ground Surface Settlement ◽  
Innovative Solution ◽  
Diaphragm Walls ◽  
Drainage Technique

Dewatering using the dewatering systems composed of diaphragm walls and pumping wells is commonly adopted for deep excavations that are undertaken in deep aquifers. However, dewatering can sometimes induce environmental problems, especially when diaphragm walls cannot effectively cut off the aquifers. This paper mainly presents an innovative excavation technique combining dewatering excavation and underwater excavation without drainage, which is employed for a deep shaft excavation in ultrathick aquifers (up to 60–70 m thick aquifer) in Fuzhou, China. The shaft excavation with the depth of 41.6 m below the ground surface (BGS) is divided into two major phases, that is, (1) the first part of the excavation (the depth of 23.6 m BGS) is conducted by the way of conventional dewatering and braced excavation (Phase I) and (2) the second excavation with the depth of 23.6 m to 41.6 m BGS is carried out by the novel underwater excavation without drainage technique (Phase II). Field monitoring results show that the ratios of maximum ground surface settlement δvm to the excavation depth He in this case ranged from 0.03% to 0.1%. Most of the ratios of maximum lateral wall deflection δhm to excavation depth He are less than 0.1%. All these results are lesser than that predicted by empirical methods, which also confirmed the applicability of this innovative excavation. Thus, this innovative solution can be applicable to other deep excavations that are undertaken in ultrathick aquifers, especially for the excavation of coarse sediments with high permeability.

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