Strength Design of Reinforced Soil in the Front of Shield Departure Shaft

2011 ◽  
Vol 261-263 ◽  
pp. 1584-1588
Author(s):  
Xian Yang ◽  
Ke Neng Zhang
Keyword(s):  
Shear Strength ◽  
Thin Plate ◽  
Maximum Stress ◽  
Reinforced Soil ◽  
Shield Tunnel ◽  
Plate Model ◽  
Elastic Structures ◽  
Strength Design

In the construction of shield tunnel, the strength of reinforced soil in the front of departure shaft concerns directly the security of construction. Based on Mechanics of Elastic Structures theory, a thin plate model about reinforced soil is introduced, the maximum stress on reinforced soil is calculated. The security of strength in reinforced area is discussed. With the derived formulas, the needed bending and shear strength of reinforced soil in the project of Beijing Metro Line No. 4 is calculated beforehand, and appropriate material and construction parameters are selected in reinforcement according to the calculate result.

scholarly journals A Modified Elastic Plate Model for the Thickness of Reinforced Soil of Shield Tunnel End

2020 ◽  
Vol 570 ◽  
pp. 022010
Author(s):  
Sun Tingshuai ◽  
Song Kezhi ◽  
Huang Teng ◽  
Luo Junhao ◽  
Zhuang Sukun
Keyword(s):  
Elastic Plate ◽  
Reinforced Soil ◽  
Shield Tunnel ◽  
Plate Model

scholarly journals Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 750
Author(s):  
Jun-Hao Lee ◽  
Pin-Kuan Li ◽  
Hai-Wen Hung ◽  
Wallace Chuang ◽  
Eckart Schellkes ◽  
...  
Keyword(s):  
Shear Strength ◽  
Joint Strength ◽  
Maximum Stress ◽  
Geometrical Parameters ◽  
Experimental Demonstration ◽  
Joint Shear Strength ◽  
Element Analysis ◽  
Ultrasonic Bonding ◽  
Simulation Results ◽  
Geometrical Effects

This study employed finite element analysis to simulate ultrasonic metal bump direct bonding. The stress distribution on bonding interfaces in metal bump arrays made of Al, Cu, and Ni/Pd/Au was simulated by adjusting geometrical parameters of the bumps, including the shape, size, and height; the bonding was performed with ultrasonic vibration with a frequency of 35 kHz under a force of 200 N, temperature of 200 °C, and duration of 5 s. The simulation results revealed that the maximum stress of square bumps was greater than that of round bumps. The maximum stress of little square bumps was at least 15% greater than those of little round bumps and big round bumps. An experimental demonstration was performed in which bumps were created on Si chips through Al sputtering and lithography processes. Subtractive lithography etching was the only effective process for the bonding of bumps, and Ar plasma treatment magnified the joint strength. The actual joint shear strength was positively proportional to the simulated maximum stress. Specifically, the shear strength reached 44.6 MPa in the case of ultrasonic bonding for the little Al square bumps.

scholarly journals On well-posedness of time-harmonic problems in an unbounded strip for a thin plate model

2019 ◽  
Vol 17 (6) ◽  
pp. 1487-1529 ◽  
Author(s):  
Laurent Bourgeois ◽  
Lucas Chesnel ◽  
Sonia Fliss
Keyword(s):  
Thin Plate ◽  
Well Posedness ◽  
Plate Model ◽  
Time Harmonic

scholarly journals Strength and Deformation of Sand-Tire Rubber Mixtures (STRM): An Experimental Study

2019 ◽  
Vol 41 (2) ◽  
pp. 74-80
Author(s):  
Alaa H. J. Al-Rkaby
Keyword(s):  
Shear Strength ◽  
Stress Ratio ◽  
Maximum Stress ◽  
Retaining Walls ◽  
Engineering Properties ◽  
Rubber Content ◽  
Tire Rubber ◽  
Strength And Deformation ◽  
Principal Strains ◽  
Properties Of Soil

Abstract Waste material such as used tires is increasing every year, which poses environmental problems. However, such material has been used in several geotechnical applications as alternative lightweight backfill in highway embankments and/or behind retaining walls, providing environmental, economic and technical benefits. These applications require knowledge of engineering properties of soil-tire rubber mixtures. The present study aims to show the possibility of tire rubber usage in sand by evaluating the shear strength and deformability of sand mixed with granulated rubber, in weight percentages between 0 and 50%. The tire rubber content was found to influence the stress-strain and deformation behavior of the mixtures. The shear strength of sand mixed with 10% or 20% tire rubber was higher than that measured for sand only. However, the trend for TRC = 30–50% was different. Samples with a rubber content of 30-50% exhibited a rapid decrease in the stress ratio compared with that of sand. The major principal strain at maximum stress ratio was found to increase with increasing tire rubber content. However, it was observed that the lateral strains (minor and intermediate principal strains) of samples reduced significantly with the addition of tire rubber to the sand.

scholarly journals Measuring the Strength of Root-Reinforced Soil on Steep Natural Slopes Using the Corkscrew Extraction Method

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1135 ◽  
Author(s):  
Gerrit Meijer ◽  
Glyn Bengough ◽  
Jonathan Knappett ◽  
Kenneth Loades ◽  
Bruce Nicoll
Keyword(s):  
Shear Strength ◽  
Soil Analysis ◽  
Soil Strength ◽  
Effective Field ◽  
Reinforced Soil ◽  
Wind Loading ◽  
Rapid Estimation ◽  
Soil Shear Strength ◽  
Soil Component ◽  
Natural Slopes

Roots can help to stabilise slopes against landslides and anchor trees against wind loading, but their mechanical contribution to the strength of soil is difficult to rapidly quantify under field conditions. A new field measurement method, quantifying the shear strength of rooted soil by measuring the resistance against extraction of soil cores using a large corkscrew device, was tested across three heterogeneous slopes (unforested, forested and clearfelled) in Scotland. The presence of roots significantly increased the measured shear strength in the surface layer of the Sitka spruce forested slope. Differences in strength between the three areas were however not significant. This could be attributed to the large variation in the soil component of the combined root–soil shear strength, which was strongly affected by variations in both soil density and gravel content. Measured strength on these natural slopes were much more variable compared to previously investigated sites. These results highlight the importance of investigating the variation in soil strength during root-reinforcement measurements, and furthermore demonstrate the need for a sufficiently large number of tests to address this variation. The corkscrew provides rapid estimation of root-reinforced soil shear strength on sites with difficult accessibility. Compared to the more conventional shear vane method, which yielded comparable soil strength results, the corkscrew proved more suitable in stony soil layers and has the additional benefit of simultaneously extracting small (rooted) soil samples that could be used for further root and soil analysis. It therefore proved a useful and effective field tool for use when a rapid estimation of root-reinforced soil shear strength is required.

A Simplified Large Thin Plate Model for Modeling Fracture Behavior of a Hydrided Irradiated Zr-2.5Nb Pressure Tube Specimen With an Axial Crack

2019 ◽  
Author(s):  
Shin-Jang Sung ◽  
Jwo Pan ◽  
Cheng Liu ◽  
Douglas A. Scarth
Keyword(s):  
Thin Plate ◽  
Crack Front ◽  
Pressure Tube ◽  
Upper And Lower Bounds ◽  
Plastic Strains ◽  
Plate Model ◽  
Constraint Condition ◽  
Symmetry Constraint ◽  
Modeling Fracture ◽  
Axial Crack

Abstract The crack tip opening displacements (CTODs) and the effective plastic strains ahead of the crack front in a hydrided irradiated Zr-2.5Nb pressure tube specimen with an axial crack are investigated using two 3-D finite element models in this paper. The first model is a pressure tube with 80 split circumferential hydrides distributed through the thickness ahead of the crack front. The second model is a large thin plate with a central crack with four split circumferential hydrides under symmetry/symmetry, free/symmetry and free/free constraint conditions. The results for CTOD indicate that the CTOD of the pressure tube specimen with 80 hydrides is slightly smaller than that for the large thin plate with the free/symmetry constraint condition and larger than that for the large thin plate with the symmetry/symmetry constraint condition. The effective plastic strain of the pressure tube specimen with 80 hydrides is smaller than that for the large thin plate with the free/symmetry constraint condition and larger than that for the large thin plate with the symmetry/symmetry constraint condition at large normalized loads. The computational results show that instead of modeling a full 3-D pressure tube with a larger number of hydrides, a large thin plate model with a limited number of hydrides can be used to efficiently determine the upper and lower bounds of the CTODs and the effective plastic strains ahead of the crack front in a pressure tube specimen.

Interfacial stresses of shield tunnel strengthened by a thin plate at inner surface

2019 ◽  
Vol 91 ◽  
pp. 103021
Author(s):  
Dejun Liu ◽  
Fei Wang ◽  
Dongming Zhang ◽  
Kang Duan
Keyword(s):  
Thin Plate ◽  
Shield Tunnel ◽  
Interfacial Stresses ◽  
Inner Surface

scholarly journals Application of FRP Bolts in Monitoring the Internal Force of the Rocks Surrounding a Mine-Shield Tunnel

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2763 ◽  
Author(s):  
Zhen Liu ◽  
Cuiying Zhou ◽  
Yiqi Lu ◽  
Xu Yang ◽  
Yanhao Liang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Internal Force ◽  
Shield Tunnel ◽  
Corrosive Environment ◽  
High Tensile Strength ◽  
Technological Support ◽  
Remote Monitoring System ◽  
Initial Support ◽  
Low Shear

Monitoring the internal force of the rocks surrounding a mine-shield tunnel for the initial support of a mine-shield tunnel, in complex geological and hydrological environments, requires bolts with specific features such as high tensile strength, low shear strength, good insulation and resistance to corrosion. As such, internal force monitoring has become an important issue in safety monitoring for such tunneling projects. In this paper, the adaptability of a mine-shield tunnel project in a corrosive environment is investigated. A fiberglass reinforced plastic (FRP) bolt with high tensile strength, low shear strength, resistance to fatigue, non-conductivity and resistance to corrosion is used as a probe in tandem with an anchor-head dynamometer to monitor the internal force of the rocks surrounding a mine-shield tunnel for initial support. Additionally, solar energy collection technology is introduced to create a remote monitoring system. Using a 2.5 km long railway tunnel located in the northeast of the Pearl River Delta of China as a case study, the present study shows that, compared with a conventional steel bolt, the FRP bolt has advantages, such as avoidance of the risks associated with the shield machine, insulation and resistance to corrosion. As a probe, the response of the FRP bolt to events such as a blasting vibration and a construction disturbance that results in internal changes in the surrounding rock demonstrates a clear pattern that is appropriate for monitoring the internal force of the rocks surrounding a mine-shield tunnel in a corrosive environment. FRP bolt-based monitoring not only provides new technological support for controlling the risk involved in the initial support of a mine-shield tunnel but can also be widely deployed in projects with special requirements for disassembly, conductivity and corrosion.

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