Test method of damage mechanism of the half-section concrete expanded-plates pile with undisturbed soil model

The concrete expanded pile is a new type of pile in the field of foundation engineering, which exhibits improved performance compared to the ordinary straight-hole pile. The expanded technique increases the bearing capacity of the pile, changes the overall load-bearing function of the pile body, and offers great development prospects. While the performance of the expanded pile has been studied for vertical loading, the performance of expanded pile when subjected to horizontal loading is not adequately understood. In order to investigate the performance of concrete expanded pile in resisting horizontal loads, particularly the anti-overturning capacity of rigid and flexible piles, this paper conducts an experimental model test and performs a numerical simulation. In the experiment, an innovative model test method is used for testing small-scale half-face pile with undisturbed soil. A custom-made soil extractor and a loading device are used to observe various stages of pile-soil interaction in real-time during the whole process of loading. Meanwhile, finite element simulation analysis is conducted on a pile model and the corresponding data on displacement, load, stress, and strain are collected to verify the experimental results. Based on the horizontal bearing capacity of rigid and flexible piles and the failure states of soil mass around the piles, two calculation models are proposed for the horizontal bearing capacity of rigid and flexible concrete expanded piles. The models will provide reliable theoretical guidance for the application of concrete expanded pile in engineering applications and for the research and development of pile foundation.

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Experimental Study on Effect of Disc Form on Soil Failure State of Expanded Piles under Horizontal Force

Materials Science Forum ◽

10.4028/www.scientific.net/msf.980.291 ◽

2020 ◽

Vol 980 ◽

pp. 291-300

Author(s):

Yong Mei Qian ◽

Yu Chen Song ◽

Yu Jie Jin ◽

Thato Molomo Pius Moshoeshoe

Keyword(s):

Test Method ◽

Scale Model ◽

Small Scale ◽

Horizontal Force ◽

Paper Test ◽

Loading Test ◽

Undisturbed Soil ◽

Soil Failure ◽

Failure State ◽

Small Scale Model

In this paper, test method of half-section small-scale model with indoor undisturbed soil is used to study the effect of difference disc forms on bearing mechanism of concrete disc piles and soil failure state around piles under horizontal force. The model piles with different disc cross-section forms were designed under the condition of undisturbed soil, and loading test was carried out to analyze soil failure state around the pile. The results show that: under the action of horizontal force, soil around the pile is cracked along the midline; asymmetric bearing disc is more reasonable than symmetrical bearing disc. The minimum load difference between the disc end fillet and the disc tip fillet is less than 5%. The curved end of bearing disc has little effect on the horizontal bearing capacity of concrete expanded disc pile.

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Wear Resistance of Elastomeric Based Composites by Continuous Multi-Cycle Indentation Used in Manufacturing Engineering

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.939.106 ◽

2014 ◽

Vol 939 ◽

pp. 106-113 ◽

Cited By ~ 5

Author(s):

Diana Zaimova ◽

Emin Bayraktar ◽

Ibrahim Miskioglu ◽

Nikolay Dishovsky

Keyword(s):

Wear Resistance ◽

Wear Behavior ◽

Damage Mechanism ◽

Test Method ◽

Indentation Hardness ◽

Rubber Compound ◽

Additional Information ◽

Alternative Approaches ◽

Cut Resistance ◽

Made In

Wear resistance is an important rubber compound property related to useful product life. The rubber compound properties that affect wear behavior are very complicated. Wear is related to a rubber compound’s cut resistance, tear resistance, fatigue resistance hardness, etc. The most commonly used test method to determine the wear resistance of rubber materials is abrasion test. Tested compounds are usually compared on a “volume loss” basis which is calculated from the weight loss and density of the compound. This method is known to be variable and doesn’t give additional information for the wear behavior. For this reason we propose alternative approaches for examination of the wear behavior of rubber composites, giving information not only for the wear resistance but also for elastic the modulus, stiffness of the material, damage mechanism, etc. Continuous multi-cycle indentation is used to determine the indentation hardness, elastic modulus and the stiffness with two indenter types –Vickers and sphero-conical. Comparison of both results is made in order to investigate the effect of the indenter type.

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An Overview of Moisture Damage in Asphalt Mixtures

Jurnal Teknologi ◽

10.11113/jt.v73.4305 ◽

2015 ◽

Vol 73 (4) ◽

Cited By ~ 4

Author(s):

Meor Othman Hamzah ◽

Muhammad Rafiq Kakar ◽

Mohd Rosli Hainin

Keyword(s):

Permanent Deformation ◽

Asphalt Mixture ◽

Material Design ◽

Damage Mechanism ◽

Moisture Damage ◽

Short Review ◽

Testing Procedure ◽

Asphalt Mixtures ◽

Test Method ◽

Wide Range

This paper presents a short review on moisture induced damage in asphalt mixtures. Moisture induced damage is one of the most common causes of pavement distress that results in loss of strength, stripping, raveling, fatigue damage and permanent deformation. Different mechanisms have been used to explain the process of moisture damage in asphalt pavements. However, the moisture damage mechanism takes place due to the interaction of several different processes. The applicability of a single test method to evaluate moisture damage is impractical to a wide range of materials and conditions. Therefore, a new laboratory based testing procedure and analysis protocol is required, with the aim to simultaneously consider the effects of both traffic impact and moisture damage. The proper material design, efficient construction methods, reliable laboratory techniques and well planned highway surface and subsurface drainage systems may lead towards a sustainable asphalt pavement that is sufficiently durable to resist moisture damage. Although considerable advances concerning the subject have been reported, yet there is still a need to address certain issues that are actually involved in the process of asphalt mixture moisture susceptibility.

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Test study on thickness of soil layer at top of plate affecting uplift failure of the NT-CEPP

CONVERTER ◽

10.17762/converter.126 ◽

2021 ◽

pp. 258-268

Author(s):

Yongmei Qian, Jiyuan Zhang, Ruozhu Wang, Yujie Jin

Keyword(s):

Carrying Capacity ◽

Soil Layer ◽

Test Method ◽

Small Scale ◽

Undisturbed Soil ◽

Soil Thickness ◽

Test Study ◽

Disturbed Soil ◽

Adjacent Soil ◽

Under Construction

This paper studies the influence of the thickness of the soil layer on the head of the plate on the carrying capacity of the new type concrete plates-expanded pile (NT-CEPP) under vertical tension, and innovatively uses the half-section pile test method to measure undisturbed soil and ANSYS is used for comparative analysis. Due to the small-scale test based on the half-section pile and disturbed soil, not only can the overall invalidation mechanism of the soil around the pile be seen more clearly, but the undisturbed soil can also be used to better ensure the stability of the soil. At the same time, in the test, depending on the real station under construction, the authenticity and economy of the test should be ensured. The results of test reveal that the invalidation behaviour of the on the top of plate of the NT-CEPP has little effect on the adjacent soil layer when the soil thickness of embedded slab is more than 3 times the length of the cantilever of the slab, and the characteristics of adjacent soil-layer had no influence on the carrying capacity of the plate.

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Elemental mass loss in silicate minerals during x-ray analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177155 ◽

1990 ◽

Vol 48 (4) ◽

pp. 804-805

Author(s):

P.E. Champness ◽

R.W. Devenish

Keyword(s):

Mass Loss ◽

Current Density ◽

Damage Mechanism ◽

Beam Current ◽

Single Chain ◽

Plagioclase Feldspar ◽

X Ray ◽

Alkali Ions ◽

Structural Order ◽

Sheet Silicate

It has long been recognised that silicates can suffer extensive beam damage in electron-beam instruments. The predominant damage mechanism is radiolysis. For instance, damage in quartz, SiO2, results in loss of structural order without mass loss whereas feldspars (framework silicates containing Ca, Na, K) suffer loss of structural order with accompanying mass loss. In the latter case, the alkali ions, particularly Na, are found to migrate away from the area of the beam. The aim of the present study was to investigate the loss of various elements from the common silicate structures during electron irradiation at 100 kV over a range of current densities of 104 - 109 A m−2. (The current density is defined in terms of 50% of total current in the FWHM probe). The silicates so far ivestigated are:- olivine [(Mg, Fe)SiO4], a structure that has isolated Si-O tetrahedra, garnet [(Mg, Ca, Fe)3Al2Si3AO12 another silicate with isolated tetrahedra, pyroxene [-Ca(Mg, Fe)Si2O6 a single-chain silicate; mica [margarite, -Ca2Al4Si4Al4O2O(OH)4], a sheet silicate, and plagioclase feldspar [-NaCaAl3Si5O16]. Ion- thinned samples of each mineral were examined in a VG Microscopes UHV HB501 field- emission STEM. The beam current used was typically - 0.5 nA and the current density was varied by defocussing the electron probe. Energy-dispersive X-ray spectra were collected every 10 seconds for a total of 200 seconds using a Link Systems windowless detector. The thickness of the samples in the area of analysis was normally 50-150 nm.

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