A Research on Technology Development in response to Slope Reinforcing Facility (Anchor) Aging

2020 ◽  
Author(s):  
Byungsuk Park ◽  
Oil Kwon ◽  
Seunghyn Kim ◽  
Jonghyun Lee ◽  
Yonghoon Woo
Keyword(s):  
Technology Development ◽  
Slip Surface ◽  
Tension Force ◽  
Bending Stress ◽  
Fractured Bedrock ◽  
Anchor Length ◽  
Reinforced Slopes ◽  
Excessive Load ◽  
Lift Off ◽  
Design Construction

<p>Recently, various drawbacks have been pointed out on the aspects of design, construction, and maintenance of anchor-reinforced slopes, and in some research the causes of increases and decreases of the tension force of the anchor are analyzed. However, research on the development of technology to cope with increases and decreases of the tension force in terms of maintenance is rare. In case that slipping occurs on an anchor-reinforced slope, shear and bending stress will occur in the shear section along the slip surface, and the anchor force may increase when slipping persists due to the deformation of the anchor body. Additionally, if shear deformation occurs in the anchor, cracks will occur in the grout at a relatively low deformation rate, and when deformation continues, the tension force may be further reduced due to the destruction of the grout. We tried to define investigation methodologies and safety plans through the analysis of case studies on functional loss sections, such as fractures of strands due to the excessive load placed on the anchors. From the results of the anchor lift-off test of 466 holes, the number of anchors that could not be retensioned was 177 holes, and the number of anchors with an increased tension force was 49 holes. From the results of ground exploration, it was found that soiled weathering zones or weathering zones with fractured bedrock were distributed at depths of 30m or more. It is analyzed that most anchor settlement with insufficient anchor forces were located in the slip surface and lacked anchor length. It is found that the safety of the slope can be secured if additional reinforcing anchors are installed around anchors with poor strand strength or anchors that cannot be retensioned.(Project Number: 20SCIP-C151408-02).</p>

Application de la méthode de Bishop simplifiée aux remblais renforcés par les géosynthétiques

1993 ◽  
Vol 30 (5) ◽  
pp. 812-820 ◽  
Author(s):  
Abdelkader Houam ◽  
Jean Nuyens
Keyword(s):  
Tensile Strength ◽  
Stability Analysis ◽  
Key Words ◽  
Safety Factor ◽  
Slip Surface ◽  
New Approach ◽  
Analysis And Design ◽  
Reinforced Slopes ◽  
Bishop’S Method ◽  
Slope Safety

A new approach to stability analysis and design of geosynthetic reinforced slopes based on Bishop's method is presented. The effect of sheet inclination across the slip surface on the safety factor or on tensile strength of the sheet is materialized by the introduction, in the computation, of a factor varying from 0 to 1. The reason for this move is to take the flexibility of the sheet into account. Two tables of procedure were made up in case of analysis and design. Some examples are presented by way of illustrations. Key words : slope, safety, slip surface, slice, geosynthetics.

Photographic Study on Bubble Motion in Subcooled Pool Boiling

2009 ◽  
Author(s):  
Tomio Okawa ◽  
Takahiro Harada ◽  
Yuta Koutsusa
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Pool Boiling ◽  
Surface Tension Force ◽  
Nucleate Boiling ◽  
Tension Force ◽  
Test Fluid ◽  
Static Contact ◽  
Short Period ◽  
Lift Off

Using a static contact angle as a main experimental parameter, photographic study was carried out to investigate the dynamics of vapor bubbles during subcooled pool boiling on a vertical heated surface. Test fluid was distilled water and the experiments were performed under the atmospheric pressure; liquid subcooling was set to around 5 K. To enable clear observation of bubble behavior with a high speed camera, the experiments were conducted in an isolated bubble regime near the onset of nucleate boiling. Distinctly different bubble behaviors were observed on hydrophobic and hydrophilic surfaces: the bubbles were adhered to the surface for a long period of time when the contact angle was large while lifted off the surface within a short period of time after the nucleation when the contact angle was small. Since buoyancy does not remove the bubble from a vertical surface, mechanisms of lift-off were investigated. It was shown that the change in bubble shape induced by the surface tension force, unsteady growth force and local liquid flow induced by heterogeneous condensation around the bubble are considered to promote the bubble lift-off and the surface tension force acting on the three-phase common line prevents the lift-off. Dependences of bubble size and time at lift-off and the condensation rate on the surface wettability were also investigated.

scholarly journals Evaluation of the stability of anchor-reinforced slopes

2005 ◽  
Vol 42 (5) ◽  
pp. 1342-1349 ◽  
Author(s):  
D Y Zhu ◽  
C F Lee ◽  
D H Chan ◽  
H D Jiang
Keyword(s):  
Stress Distribution ◽  
Normal Stress ◽  
Factor Of Safety ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Load Factor ◽  
Normal Stress Distribution ◽  
Abrupt Changes ◽  
Reinforced Slopes ◽  
The Stability

The conventional methods of slices are commonly used for the analysis of slope stability. When anchor loads are involved, they are often treated as point loads, which may lead to abrupt changes in the normal stress distribution on the potential slip surface. As such abrupt changes are not reasonable and do not reflect reality in the field, an alternative approach based on the limit equilibrium principle is proposed for the evaluation of the stability of anchor-reinforced slopes. With this approach, the normal stress distribution over the slip surface before the application of the anchor (i.e., σ0) is computed by the conventional, rigorous methods of slices, and the normal stress on the slip surface purely induced by the anchor load (i.e., λpσp, where λp is the load factor) is taken as the analytical elastic stress distribution in an infinite wedge approximating the slope geometry, with the anchor load acting on the apex. Then the normal stress on the slip surface for the anchor-reinforced slope is assumed to be the linear combination of these two normal stresses involving two auxiliary unknowns, η1 and η2; that is, σ = η1σ0 + η2λpσp. Simultaneously solving the horizontal force, the vertical force, and the moment equilibrium equations for the sliding body leads to the explicit expression for the factor of safety (Fs)—or the load factor (λp), if the required factor of safety is prescribed. The reasonableness and advantages of the present method in comparison with the conventional procedures are demonstrated with two illustrative examples. The proposed procedure can be readily applied to designs of excavated slopes or remediation of landslides with steel anchors or prestressed cables, as well as with soil nails or geotextile reinforcements.Key words: slopes, factor of safety, anchors, limit equilibrium method.

The Problems in Solar Building Integrated Development

2011 ◽  
Vol 374-377 ◽  
pp. 296-299
Author(s):  
Ping Cao ◽  
Nan Wu
Keyword(s):  
Solar Energy ◽  
Construction Projects ◽  
Technology Development ◽  
Integrated Development ◽  
Simple Addition ◽  
Energy Product ◽  
Heat Technology ◽  
The World ◽  
Three Stages ◽  
Design Construction

Energy conservation for building on the use of solar energy has been the attention all over the world. However, the process of building integrated solar energy, went through three stages: passive accept era, simple addition era and building integrated era. There are flaws on the solar energy light heat technology development and application, it reflects on the design, construction and solar energy product itself. These flaws can be compensated if the solar energy and the building integration energy-saving construction projects can be treated as the key link during the life cycle ,cooperating with the project participants , can reach the goal of the solar energy and the building integration.

Photographic Study on Bubble Motion in Subcooled Pool Boiling

2010 ◽  
Vol 132 (10) ◽  
Author(s):  
Tomio Okawa ◽  
Takahiro Harada ◽  
Yuta Kotsusa
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Pool Boiling ◽  
Surface Tension Force ◽  
Nucleate Boiling ◽  
Tension Force ◽  
Heated Wall ◽  
Test Fluid ◽  
Static Contact ◽  
Lift Off

Using a static contact angle of a vertical heated wall as a main experimental parameter, a photographic study was carried out to elucidate the mechanisms to determine the vapor bubble dynamics during subcooled pool boiling. The test fluid was distilled water and the experiments were performed under the atmospheric pressure; liquid subcooling was set to around 5 K. To enable clear observation of bubble behavior with a high speed camera, the experiments were conducted in an isolated bubble regime near the onset of nucleate boiling. Distinctly different bubble behaviors were observed on hydrophobic and hydrophilic surfaces: the bubbles were adhered to the surface for a long period of time when the contact angle was large while lifted-off the surface within a short period of time after the nucleation when the contact angle was small. Since buoyancy does not remove the bubble from the vertical surface, the mechanisms of bubble lift-off were investigated. It was indicated that the change in bubble shape induced by the surface tension force, unsteady growth force, and local liquid flow induced by heterogeneous condensation around the bubble are considered to promote the bubble lift-off while the surface tension force acting on the three-phase common line prevented the lift-off. Effects of the surface wettability on the lift-off bubble diameter, the elapsed time from the nucleation at the lift-off, and the condensation rate after the lift-off were also investigated.

scholarly journals A Research Roadmap for Off-Site Construction: Automation and Robotics

2019 ◽  
pp. 173-180
Author(s):  
Jeremy Bowmaster ◽  
Jeff Rankin
Keyword(s):  
Technology Development ◽  
Construction Materials ◽  
Basic Research ◽  
Building Science ◽  
Construction Automation ◽  
Research Areas ◽  
Production Technologies ◽  
Government Initiative ◽  
And Robotics ◽  
Design Construction

The development of a research roadmap was undertaken to further the activities of a joint industry-university-government initiative in off-site construction research in Canada. The roadmap identifies the general research areas of structural design, construction materials, building science, advanced manufacturing, logistics and transportation, automation and robotics, and digitized construction. The development of the roadmap included a broad literature review of peer reviewed academic journals, select conference proceedings, and industry publications. The review of recent research in these areas was analyzed from the perspectives of application area, technology area and innovation phase. The purpose of the analysis was to identify the current activities and opportunities for further research. For example, in the area of automation and robotics, the results showed the majority of construction automation research relates to the actual production phase, as opposed to planning or operations. In terms of innovation maturity, little research is being undertaken with respect to the implementation and adoption of automation technologies, and very little research in technology development or prototyping. In addition, applied research is being conducted at approximately half the rate of basic research. A more recent trend has been greater research interest in industrial production technologies, particularly in additive manufacturing. Very little research is being conducted with respect to non-robotic cyber-physical systems including, IoT connectivity, drone technologies, or construction focused actuator and manipulator technologies. This paper will discuss the broader results of the research roadmap with a focus on automation and robotics.

Gas Bearing Technology for Oil-Free Microturbomachinery: Research Experience for Undergraduate (REU) Program at Texas A&M University

2009 ◽  
Author(s):  
Luis San Andre´s ◽  
Tae Ho Kim ◽  
Keun Ryu ◽  
Thomas A. Chirathadam ◽  
Kathleen Hagen ◽  
...  
Keyword(s):  
Engineering Students ◽  
Technology Development ◽  
Research Experience ◽  
Metal Mesh ◽  
Advanced Degrees ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Technological Advances ◽  
Lift Off ◽  
Gas Bearing

The education of undergraduate mechanical engineering students (UGME) in state of the art technology development for microturbomachinery (MTM) is of importance to ensure the availability of qualified labor satisfying MTM manufacturer and end used needs, as well as to encourage the students towards pursing advanced degrees in science and engineering. National Science Foundation (NSF) funds a three-year summer Research Experience for Undergraduates (REU) Program (#0552885) to conduct hands-on training and research in mechanical, manufacturing, industrial, or materials engineering topics related to technological advances in microturbomachinery. The paper details the progress in research achieved by four UG students during 10 weeks in the summer of 2008. The students, assisted by seasoned graduate students and expert faculty, conducted work in aspects of gas bearing technology from manufacturing bearing components, to conducting rotordynamic performance tests, and to predicting rotordynamics performance. During the program, the students attended to a number of technical seminars including vocational and counseling presentations and preparation for admission to graduate school. The paper showcases the students’ technical posters produced upon completion of their 10 week research program: (1) Precision Tooling for Manufacturing an Underspring of a Generation II Foil Bearing, (2) Measurements of Imbalance Response of a Rotor Supported on Gas Foil Bearings, (3) Predictions of Nonlinear Rotordynamics of Rotor-Foil Bearing Systems, and (4) Measurements of Rotor Lift-Off and Break Up Torque in a Metal Mesh Foil Bearing. NASA GRC and Honeywell Turbocharging Technologies also provided support that enabled the success of the NSF REU program. URL http://reumicro.tamu.edu provides full descriptions on the program, topics of study, faculty involved and participating students.

Some applications of electron beam microanalysis techniques in VLSI process evaluation

1983 ◽  
Vol 41 ◽  
pp. 160-161
Author(s):  
Simon Thomas
Keyword(s):  
Integrated Circuits ◽  
Process Evaluation ◽  
Large Scale ◽  
Technology Development ◽  
Analytical Techniques ◽  
Successful Implementation ◽  
Analysis Of Failures ◽  
Characterization Of Materials ◽  
Circuits Vlsi

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.

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