Model tests for observing the deformation characteristics of micropile boreholes during drilling in a soil-limestone mixture

2021 ◽  
Author(s):  
Chunye Ying ◽  
Xinli Hu ◽  
Sumi Siddiqua ◽  
Gehad Mohamed Hossam Makeen ◽  
Peng Xia ◽  
...  
Keyword(s):  
Model Tests ◽  
Deformation Characteristics

scholarly journals Laboratory Model Study on the Pile-Forming Mechanisms and Bearing Deformation Characteristics of CFA Piles

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Deliang Zhu ◽  
Yue Li ◽  
Lingwei Zheng ◽  
Pengfei Fang ◽  
Xinyu Xie
Keyword(s):  
Model Test ◽  
Load Transfer ◽  
Soil Improvement ◽  
Model Tests ◽  
Laboratory Model ◽  
Drilling Process ◽  
Deformation Characteristics ◽  
Friction Resistance ◽  
Total Settlement ◽  
Lateral Friction

To study the pile-forming mechanism and bearing deformation characteristics of continuous flight auger (CFA) piles, a series of procedures, including helical drilling, pulling up/grouting, and inserting cage/pile forming, were simulated in clay-sand double-layer foundations by a homemade model drilling machine system in laboratory model tests. The effects of two different pile-forming methods on the load transfer and bearing characteristics of the piles were investigated by performing a model test comparison of CFA piles and bored piles. The experimental results show that there exist a soil improvement effect around the pile and a diameter expansion effect during the drilling process and grouting process for the CFA pile, which can effectively improve the lateral friction resistance of the pile. Compared with the bored pile, the pile diameter in the middle of the CFA pile increased by 19%, and the total lateral friction resistance of the CFA pile increased by 9.1% at a high load (1500 N). The comparative results of the model tests show that the bearing capacity of a single CFA pile increased by 50.0% and that the total settlement decreased by 40.5%. The results of the in situ test piles show that the load-settlement curves of the two pile types are similar under low-medium loads and that the lateral friction resistance of the CFA pile under high loads is better developed, which is relatively consistent with the model test results.

Transmission Electron Microscopic Observations of Al3Li and Al3Ti Precipitation in A Rapidly Solidified Al-3Li-0.2Ti ALLOY

1980 ◽  
Vol 38 ◽  
pp. 336-337
Author(s):  
J. E. O’Neal ◽  
K. K. Sankaran ◽  
S. M. L. Sastry
Keyword(s):  
Rapid Solidification ◽  
Metallic Substrate ◽  
Deformation Characteristics ◽  
Phase Decomposition ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Supersaturated Solid Solutions ◽  
Transmission Electron Microscopic ◽  
Rapidly Solidified ◽  
Microstructural Homogeneity

Rapid solidification of a molten, multicomponent alloy against a metallic substrate promotes greater microstructural homogeneity and greater solid solubility of alloying elements than can be achieved by slower-cooling casting methods. The supersaturated solid solutions produced by rapid solidification can be subsequently annealed to precipitate, by controlled phase decomposition, uniform 10-100 nm precipitates or dispersoids. TEM studies were made of the precipitation of metastable Al3Li(δ’) and equilibrium AL3H phases and the deformation characteristics of a rapidly solidified Al-3Li-0.2Ti alloy.

Effect Of Elevated Temperatures On Complete Concrete Deformation Diagrams

2019 ◽  
pp. 9-14
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Elevated Temperatures ◽  
Peak Load ◽  
Relative Deformation ◽  
Deformation Characteristics ◽  
Compression Tests ◽  
Strain Behavior ◽  
Different Temperatures ◽  
Deformation Diagrams

The analysis of the previous results of the study on concrete stress-strain behavior at elevated temperatures has been carried out. Based on the analysis, the main reasons for strength retrogression and elastic modulus reduction of concrete have been identified. Despite a significant amount of research in this area, there is a large spread in experimental data received, both as a result of compression and tension. In addition, the deformation characteristics of concrete are insufficiently studied: the coefficient of transverse deformation, the limiting relative compression deformation corresponding to the peak load and the almost complete absence of studies of complete deformation diagrams at elevated temperatures. The two testing chambers provided creating the necessary temperature conditions for conducting studies under bending compression and tension have been developed. On the basis of the obtained experimental data of physical and mechanical characteristics of concrete at different temperatures under conditions of axial compression and tensile bending, conclusions about the nature of changes in strength and deformation characteristics have been drawn. Compression tests conducted following the method of concrete deformation complete curves provided obtaining diagrams not only at normal temperature, but also at elevated temperature. Based on the experimental results, dependences of changes in prism strength and elastic modulus as well as an equation for determining the relative deformation and stresses at elevated temperatures at all stages of concrete deterioration have been suggested.

Influence of Air Entrappment on Flood Embankment Failure Mechanism - Model Tests

2008 ◽  
Vol 11 (-1) ◽  
pp. 188-201 ◽  
Author(s):  
Piotr Bogacz ◽  
Jarosława Kaczmarek ◽  
Danuta Leśniewska
Keyword(s):  
Failure Mechanism ◽  
Model Tests ◽  
Mechanism Model
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