scholarly journals A Novel Excavation and Construction Method for an Extra-Long Underwater Tunnel in Soft Soils

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Jian Wu ◽  
Zhifang Zhou ◽  
Wenjun Xia ◽  
Haixiao Wang ◽  
Zhongqiang Fang
Keyword(s):  
Environmental Impact ◽  
Low Cost ◽  
Construction Method ◽  
Construction Technology ◽  
Tunnel Engineering ◽  
Foundation Pit ◽  
Double Row ◽  
Element Analysis ◽  
Underwater Tunnel ◽  
Pass Through

The cut-and-cover technique is widely used in the field of tunnel engineering owing to its simple construction technology, high working efficiency, and low cost. However, the safety of the foundation pit and the environmental impact during excavation are of great concern, especially for tunnels that pass through lakes and/or rivers. In this paper, a novel excavation and construction method is presented for the Taihu tunnel, which is the longest lake-crossing tunnel in China. In this method, a cofferdam of double-row steel sheet piles (DSSPs) was designed in order to divide the overlying excavation into several closed zones. During the construction, four zones were regarded as a unit, and different construction steps were carried out simultaneously in each zone. Therefore, an assembly line for the tunnel excavation was established to accelerate the construction speed. The most distinctive advantage of this method is that the excavation did not cut off the normal flow of the lake water and the shipping routes, with low environmental impact. To investigate the tunnel deformation during excavation, a finite element analysis combined with field monitoring data was adopted, indicating that the magnitude of the tunnel deformation was notably less than those reported from other excavation projects. Moreover, the effect of groundwater on the piles and the safety of the foundation pit was revealed using numerical modelling. This study provides a new idea for the design and construction of tunnel engineering, especially for extra-long underwater tunnels in soft deposits.

Finite Element Analysis and Investigation of Double-Row Piles Supporting Structure

2013 ◽  
Vol 838-841 ◽  
pp. 779-785
Author(s):  
Liang Gu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Maximum Shear Stress ◽  
Horizontal Displacement ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Double Row ◽  
Element Analysis ◽  
Supporting Structure

The double-row piles supporting structure is a new type of supporting and protecting for deep foundation excavation. It is widely used to in design of deep foundation pit. Now how to simply and effectively design the structure of double-row piles is in a research and discuss stage. Using the Midas GTS finite element method, the displacement and stress distribution of double-row piles in the different stages of excavation are obtained, and the horizontal displacement and stress distribution of double-row piles in the different stages of excavation are calculated. The results of Midas GTS finite element analysis as follows: (1) after the excavation of foundation pit, the horizontal displacement of pile-top is maximum. The horizontal displacement decreases gradually with depth increases. And the displacement of front row piles is larger than that of back row piles; (2) the maximum shear stress is at the distance 5m to the foundation basement. The higher bending moment at the pile-top and the distance 10m to the foundation basement are consistent with the actual monitoring date. (3) the results of finite element analysis is close to the Richard software and actual monitoring data. It is show that using the finite element analysis to analyze the double-row piles supporting structure with is veritable and credible.

Manufacturing and Hoisting Technology for Reinforcement Cage of Deep Foundation Excavation Bored Piles

2014 ◽  
Vol 1044-1045 ◽  
pp. 633-637 ◽  
Author(s):  
Xin Zhou ◽  
Guang Xiu Fang ◽  
Ping Zhang ◽  
Yuan Qing Leng
Keyword(s):  
Steel Reinforcement ◽  
Detailed Calculation ◽  
Construction Technology ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Element Analysis ◽  
Bored Pile ◽  
Steel Processing ◽  
Deep Foundation Excavation ◽  
Set Up

Combined with the Beijing Business Center (CBD) core district Z14 plots commercial finance project (hereinafter referred to as the "CBD project") foundation pit construction, introduces the deep foundation pit of bored pile reinforcement cage fabrication and erection construction technology. In the construction process, through the site set up a special steel processing and production platform, the localization of the flange and other measures to solve the steel reinforcement cage positioning and connection construction difficulties. Combining the engineering fact, detailed calculation process of lifting steel cage hanging position, lifting machinery and hoisting rigging selection, and through the ANSYS software of finite element analysis and put forward specific measures to ensure the quality of steel reinforcement cage.

Model of Deep Foundation Pit Supporting Technology - Hanging Pit

2013 ◽  
Vol 353-356 ◽  
pp. 2827-2830
Author(s):  
Qing Min Gao ◽  
Kai Chao Jin
Keyword(s):  
Low Cost ◽  
Retaining Wall ◽  
Engineering Application ◽  
Point Of View ◽  
Construction Technology ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Concrete Pile ◽  
New Construction

From the point of view of engineering application, this paper systematically discusses the characteristics of soil retaining, watertight aspects of retaining wall which combined mixing piles of waterproof curtain and bored concrete pile . Aiming at the shortcomings of construction process of the open caisson , this paper puts forward a new type of supporting technology of deep foundation pit - hanging construction technology for foundation pit supporting.It is security construction ,no effect on environment, low cost, and so on. The thesis introduces the technology principal, construction procedures and related points of the new construction technology.

Performance of Low-Cost 3D Printer in Medical Application

2021 ◽  
Author(s):  
Nor Aiman Sukindar ◽  
Azib Azhari Awang Dahan ◽  
Sharifah Imihezri Syed Shaharuddin ◽  
Nor Farah Huda Abd Halim
Keyword(s):  
Low Cost ◽  
Medical Application ◽  
Fused Deposition Modelling ◽  
3D Printer ◽  
Layer By Layer ◽  
Total Deformation ◽  
Element Analysis ◽  
Porosity Level ◽  
Fused Deposition ◽  
Printing Parameters

Abstract Fused Deposition Modelling (FDM) is an additive manufacturing (AM) process that produces a physical object directly from a CAD design using layer-by-layer deposition of the filament material that is extruded via a nozzle. In industry, FDM has become one of the most used AM processes for the production of low batch quantity and functional prototypes, due to its safety, efficiency, reliability, low cost, and ability to process manufacturing-grade engineering thermoplastic. Recently, the market is flooded with the availability of low-cost printers produced by numerous companies. This research aims to investigate the effect of different porosity levels on a scaffold structure produced using a low-cost 3D printer. Comparisons of these porous structures were made in terms of Von-Mises strain, total deformation, as well as compressive stress. Various porosity levels were created by varying printing parameters, including layer height, infill density, and shell thickness by slicing the initial solid CAD file using Repetier Host 3D printing software. Finite Element Analysis (FEA) simulation was then performed on the created scaffold structures by using Ansys Workbench 19.2. The simulation result indicates that the greater porosity level will result in higher total deformation of the structure. Meanwhile, the compression test shows that the minimum strength value obtained was favourable at 22 MPa and had exceeded that of the trabecular femur (15 MPa). However, its porosity level (maximum at 52%) was still below that of the minimum threshold of porosity level of 70 percent. However, the printing parameters currently used can be adjusted in the future. Therefore, it was deduced that the low-cost 3D printer offers promising potential to fabricate different porosity structures with multiple outcomes.

Buckling analysis of natural fiber reinforced composites

2021 ◽  
Vol 7 (2) ◽  
pp. 58
Author(s):  
Celal Çakıroğlu ◽  
Gebrail Bekdaş
Keyword(s):  
Composite Plate ◽  
Natural Fiber ◽  
Low Cost ◽  
Natural Fibers ◽  
Experimental Studies ◽  
Fiber Reinforced Composites ◽  
Fiber Types ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Element Analysis

In the recent years natural fiber reinforced composites are increasingly receiving attention from the researchers and engineers due to their mechanical properties comparable to the conventional synthetic fibers and due to their ease of preparation, low cost and density, eco-friendliness and bio-degradability. Natural fibers such as kenaf or flux are being considered as a viable replacement for glass, aramid or carbon. Extensive experimental studies have been carried out to determine the mechanical behavior of different natural fiber types such as the elastic modulus, tensile strength, flexural strength and the Poisson’s ratio. This paper presents a review of the various experimental studies in the field of fiber reinforced composites while summarizing the research outcome about the elastic properties of the major types of natural fiber reinforced composites. Furthermore, the performance of a kenaf reinforced composite plate is demonstrated using finite element analysis and results are compared to a glass fiber reinforced laminated composite plate.

scholarly journals MANUFACTURE OF A DIE PROTOTYPE FOR DIDACTIC PURPOSES IN MECHATRONIC ENGINEERING

2020 ◽  
pp. 1-40
Author(s):  
ELIEL EDUARDO MONTIJO-VALENZUELA ◽  
SAUL DANIEL DURAN-JIMENEZ ◽  
LUIS ALBERTO ALTAMIRANO-RÍOS ◽  
JOSÉ ISAEL PÉREZ-GÓMEZ ◽  
OSCAR SALMÓN-AROCHI
Keyword(s):  
Mechanical Design ◽  
Theoretical Calculations ◽  
Low Cost ◽  
Die Design ◽  
Element Analysis ◽  
Technological Institute ◽  
Computer Aided ◽  
Cad Models ◽  
Functional Prototype ◽  
Definition Of

The objective of this research is to manufacture a prototype of a teaching die for the specialty of precision mechanical design in mechatronic engineering, in order to achieve the skills required in unit two, regarding dies. The methodology used consists of five stages: 1. Definition of the preliminary conditions. 2. Theoretical calculations for die design. 3. Design, modeling and assembly using computer-aided software (CAD) of the parts that make up the die. 4. Validation with simulation of finite element analysis (AEF). 5. Manufacture of parts and physical assembly of the die. A functional prototype was obtained with which the teacher and student can perform calculations, designs and CAD models, AEF analysis of the static and fatigue type, manufacture of rapid prototypes using 3D printing, the identification of the parts that make up a die and their functioning. The advantage of this prototype, compared to metal die-cutting machines, is its low cost of production and manufacturing, it does not require expensive and specialized machinery for manufacturing, specific designs can be made by the students and its subsequent manufacture within the laboratories of the Technological Institute of Hermosillo.

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