scholarly journals Three-dimensional numerical simulation of mechanical properties of soil-tire mixture by discrete element method

2019 ◽  
Vol 92 ◽  
pp. 14011
Author(s):  
Mohsen Asadi ◽  
Ahmad Mahboubi
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Damping Ratio ◽  
Strain Curve ◽  
Young Modulus ◽  
Engineering Properties ◽  
Triaxial Tests ◽  
Sand Particle ◽  
Arithmetic Average ◽  
Harmonic Average

Soil engineering properties can be improved employing different methods. Among them is mixing soil with tire derived additives (TDA). TDAs generally increase some parameters of mixture such as damping ratio, permeability, ductility and also in some cases shear strength. Various properties of TDAs from mechanical properties to their geometry can affect the mixture behavior. In this paper using the YADE platform, simulations of triaxial tests on sand tire mixtures are presented. To take compressibility into consideration, each rubber crumb particle is made of several spheres connected elastically to each other. For sand particle generation the clump technique was employed. Shapes of both sand and rubber particles are inspired from real grains. As properties of sand and rubber are different, especially Young modulus, rubber sand interaction is considered as soft rigid contact. Therefor harmonic average and arithmetic average was used to compute contact Young modulus (and then stiffness). The model was validated by comparison of results of triaxial tests simulation on pure rubber sample with literature ones which both exhibited linear stress-strain curve. Then triaxial tests with different sand to rubber ratio were simulated to see whether harmonic average or arithmetic average gives the best match to literature. The results show shear strength reduces by decreasing of sand to rubber ratio. This is the same as what is reported in literature.

Structure characteristics and mechanical properties of kaolinite soils. II. Effects of structure on mechanical properties

2006 ◽  
Vol 43 (6) ◽  
pp. 601-617 ◽  
Author(s):  
Y -H Wang ◽  
W -K Siu
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Shear Modulus ◽  
Critical State ◽  
Soil Structure ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Undrained Shear Strength ◽  
Interparticle Forces ◽  
Undrained Shear

This paper reports the effects of structure on the mechanical responses of kaolinite with known and controlled fabric associations. The dynamic properties and strength were assessed by resonant column tests and undrained triaxial compression tests, respectively. The experimental results demonstrate that interparticle forces and associated fabric arrangements influence the volumetric change under isotropic compression. Soils with different structures have individual consolidation lines, and the merging trend is not readily seen under an isotropic confinement up to 250 kPa. The dynamic properties of kaolinite were found to be intimately related to the soil structure. Stronger interparticle forces or higher degrees of flocculated structure lead to a greater small-strain shear modulus, Gmax, and a lower associated damping ratio, Dmin. The soil structure has no apparent influence on the critical-state friction angle (ϕ′c = 27.5°), which suggests that the critical stress ratio does not depend on interparticle forces. The undrained shear strength of kaolinite is controlled by its initial packing density rather than by any interparticle attractive forces, and yet the influence of the structure on the effective stress path is obvious.Key words: interparticle forces, shear modulus, damping ratio, stress–strain behavior, undrained shear strength, critical state.

scholarly journals Initial investigation of the intrinsic geomechanical properties of soils in area of landslide Černá Pole

2019 ◽  
Author(s):  
Karolína Faktorová ◽  
Juraj Chalmovský ◽  
Pavel Koudela ◽  
Lumír Míča
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Laboratory Tests ◽  
Triaxial Tests ◽  
Geomechanical Properties ◽  
Important Type ◽  
Initial Investigation ◽  
Loading And Unloading ◽  
Oedometer Tests

One of the most important type of Brno’s subsoil is Miocene’s clay. Mechanical properties of these clays were already studied by various methods, authors, in several locations. These parameters, however, varies across the locations and therefore new data are needed to further refineme them. The objective of the laboratory tests presented in this paper was to determine shear strength and compressibility parameters on reconstituted samples, locality Černá Pole. Stiffness parameters for primary loading and unloading – reloading were obtained from series of oedometer tests. Consolidated undrained triaxial tests were performed for evaluation of soil critical shear strength. Obtained results were compared with another available data.

scholarly journals The Influence of Kaolinite - Illite toward mechanical properties of Claystone

2019 ◽  
Vol 11 (1) ◽  
pp. 440-446
Author(s):  
Supandi Supandi ◽  
Zufialdi Zakaria ◽  
Emi Sukiyah ◽  
Adjat Sudradjat
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Void Ratio ◽  
Correlation Coefficients ◽  
Physical And Mechanical Properties ◽  
Friction Angle ◽  
Engineering Properties ◽  
Rock Properties ◽  
Triaxial Tests ◽  
Mineralogical Characteristics

Abstract This study investigates the relationship between clay minerals (kaolinite and illite) and rock properties of the claystone, including both mechanical (cohesion, friction angle, stress, and strain) and physical properties (natural water content, void ratio, and wet density), belonging to Warukin Formation of Kalimantan, Indonesia. Mineralogical characteristics of these rocks were studied using petrological and X-ray diffraction techniques, whereas the mechanical and physical properties were tested by conducting uniaxial and triaxial tests. Relationship among the variables was determined using correlation coefficients. It was observed that the mineralogy of the rocks pose strong constraints on their engineering properties. The results showed that an increase in illite content decreases cohesion, friction angle, strength, and safety factor; and increases natural moisture content, void ratio, and wet density. Although illite content of these rocks was just about 10.8% of the total minerals, it has significantly contributed to the modification of physical and mechanical properties. In contrast, kaolinite did not have a significant impact; since the correlation between various parameters was significantly low (correlation coefficient was much less, <0.3). Therefore while selecting the materials for geotechnical engineering applications, illite emerges as a safer alternative to kaolinite, especially when its concentration is less than 10.8% of the total rock mass.

scholarly journals Shear Strength Characteristics of Recycled Concrete Aggregate and Recycled Tire Waste Mixtures from Monotonic Triaxial Tests

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7400
Author(s):  
Katarzyna Gabryś ◽  
Algirdas Radzevičius ◽  
Alojzy Szymański ◽  
Raimondas Šadzevičius
Keyword(s):  
Shear Strength ◽  
Construction Projects ◽  
Fine Fraction ◽  
Recycled Concrete ◽  
Engineering Properties ◽  
Triaxial Tests ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Angle Of Internal Friction ◽  
Anthropogenic Soil

Recycled concrete aggregate (RCA) is a promising substitute for natural aggregates and the reuse of this material can benefit construction projects both economically and environmentally. RCA has received great attention in recent years in the form of aggregate as well as a geotechnical material of sand size. Next to RCA, another recycled material, which reduces the waste volume and is a part of the present challenges in civil engineering, is tire waste. Despite the good engineering properties of recycled tire waste (RTW), its use is still limited, even after almost 30 years since they were first introduced. To broaden the applicability of reused concrete and rubber, a further understanding of their properties and engineering behavior is required. For this reason, the main subject of this paper is composite materials that consist of anthropogenic soil recycled concrete aggregate (RCA) and crushed pieces of recycled tire waste (RTW). In this study, a series of isotropic consolidated drained triaxial tests were undertaken to characterize the shear strength of eight mixtures of variable grain-size distribution, rubber inclusion (RC), and fine fraction (FF) content. The results show that the introduction of rubber waste leads to changes in the strength parameters of the tested mixtures. Improvements in RCA shear strength were observed, the largest for the mixture M7 with 10% of recycled tire waste. Similarly, the effect of fine fraction content on the angle of internal friction and cohesion was found. Dilation characteristics were observed in all analyzed composites. Based on the results of all tests performed, including physical, geometric, chemical, and mechanical properties of the created composites, it can be stated that the samples would meet local road authority requirements for sub-base applications.

Variation of Mechanical Properties of Soft Marine Clay With Methane Gas Content

2013 ◽  
Author(s):  
Raúl Nava Castro ◽  
Jean M. E. Audibert ◽  
Willard DeGroff ◽  
Kuat C. Gan ◽  
Paul Ruckman
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Soil Structure ◽  
Load Transfer ◽  
Gas Bubbles ◽  
Gas Content ◽  
Triaxial Tests ◽  
Marine Clay ◽  
Methane Gas ◽  
Partial Load

To quantify the effects of methane gas on mechanical properties of soft marine clay, an exhaustive laboratory testing program was developed using zeolite to uniformly disseminate gas bubbles inside the clay matrix. Results from controlled rate-of-strain (CRS) tests indicated that as the gas content increases, there is a reduction in the interpreted preconsolidation pressure, although the rigidity of the clay with more gas increased throughout the test. Minivane test results indicated that the undisturbed shear strength decreases as the amount of methane gas increases, while the residual and remolded strengths remain practically unchanged, i.e., are independent of the gas content. Similarly results from triaxial tests indicated that the undisturbed shear strength is reduced as the gas content increases, but there was no change in the failure mode. Interestingly, the normalized shear strength increased for the clay with gas, when the samples were tested at 100 percent of deformation per hour. It is theorized that the methane gas bubbles interact with both the clay platelets and the pore water, and, to certain point, bear part of the load, thus modifying the distribution of the load in the soil structure; that is to say, there is a partial load transfer from the gas bubbles to the soil structure, as the clay particles confine the methane gas.

scholarly journals Study on Shear Strength of Xanthan Gum-Amended Soil

2019 ◽  
Vol 11 (21) ◽  
pp. 6142 ◽  
Author(s):  
Antonio Soldo ◽  
Marta Miletić
Keyword(s):  
Shear Strength ◽  
Xanthan Gum ◽  
Soil Improvement ◽  
Silty Sand ◽  
Engineering Properties ◽  
Triaxial Tests ◽  
Negative Effects ◽  
Environment Friendly ◽  
Sustainable Engineering ◽  
Different Types

When construction work is planned on soil with inadequate shear strength, its engineering properties need to be improved. Chemical stabilization is one of the solutions for soil strength improvement. Currently, the most common additive that is used for chemical soil improvement is cement. Cement is an effective solution, but it has several negative effects on the environment. Therefore, the urges for environment-friendly solutions that can replace cement and show good potential for sustainable engineering are rising. One of the promising environment-friendly solutions is the use of biopolymers. Therefore, the main aim of the present study was to investigate the effect of the biopolymer xanthan gum on the strength of different types of soil. Xanthan gum was mixed with three different types of soil: sand, clay, and silty sand. The strength of treated and non-treated soil was experimentally investigated by performing unconfined compression, direct shear, and triaxial tests. From the results, it was observed that xanthan gum significantly increased the strength of each soil, which shows its major potential for the future of sustainable engineering.

scholarly journals Undrained shear strength of Lisbon Miocene clay: a reappraisal based on triaxial and pressuremeter test results

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mafalda Lopes Laranjo ◽  
Manuel Matos Fernandes
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Physical And Mechanical Properties ◽  
Undrained Shear Strength ◽  
Triaxial Tests ◽  
Relevant Parameter ◽  
List Type ◽  
Test Results ◽  
Overconsolidated Clays ◽  
Undrained Shear

Abstract Undrained shear strength plays a fundamental role on the behaviour of clays. In overconsolidated clays, this parameter is largely influenced by test conditions, namely consolidation stress. “Prazeres Clay” is a Miocene overconsolidated formation, that can be found in a significant part of Lisbon area. Over the last decades a number of very relevant constructions have generated a large database for physical and mechanical properties of Miocene clays. Included in a broader study at the Faculty of Engineering of Porto University about Miocene clay’s physical and mechanical properties, existing data was gathered, treated and critically analysed, in order to establish a useful framework for geotechnical designers. This paper presents the results obtained for undrained shear strength, obtained from triaxial tests and Ménard Pressuremeter tests. It addresses the main difficulties associated with test’s interpretation and presents a discussion on how theoretical values relate to experimental ones. The paper proposes a range of variation for Prazeres Clay’ undrained shear strength based on a significant amount of test results, that is considered to be useful for geotechnical design. Article Highlights Undrained Shear strength is a relevant parameter for clays, and is usually derived from triaxial tests For overconsolidated clays, this parameter is highly dependent on preconsolidation stress, and on its relation to in situ stress. Based on a significant set of data, the paper presents a simple methodology for estimating this parameter

An Analysis on Engineering Properties of Peaty Soil in Kunming Civil Engineering

2012 ◽  
Vol 568 ◽  
pp. 21-26
Author(s):  
Zai Xi Yu ◽  
Jing Cao ◽  
Hui Min Zhao
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Stress Path ◽  
Engineering Properties ◽  
Burial Depth ◽  
Factors Affecting ◽  
Engineering Construction ◽  
The Poor ◽  
Peaty Soil ◽  
Biological Field

The poor engineering properties of peaty soil are unfavourable for engineering construction. Based on field test datum, the mechanical properties of peaty soil in different buried depth have been analyzed. The result shows that the shear strength of shallowly buried peaty soil reduce gradually with the increase of burial depth, however, which increase gradually along with the depth for deep buried peaty soil. The factors affecting the meso-structure of soil, for example, stress state, the stress history, the stress path, the variation of groundwater, chemical field, biological field and physical field is discussed.

Determination of Stress-Strain Curve through Berkovich Indentation Testing

2010 ◽  
Vol 636-637 ◽  
pp. 1186-1193 ◽  
Author(s):  
A.M.S. Dias ◽  
G.C.D. Godoy
Keyword(s):  
Mechanical Properties ◽  
Strain Curve ◽  
Young Modulus ◽  
Displacement Curve ◽  
Indentation Testing ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Research Areas ◽  
Versus Strain

Instrumented indentation testing is a technique widely used in different materials to evaluate the penetration depth in function of the indenter load. Considering Berkovich indenter, this methodology has been used to determine mechanical properties such as hardness, Young modulus and a stress versus strain curve of the elastic-plastic behaviour under compression of the tested materials. However, the implementation of this technique to evaluate mechanical properties and also its results have still brought doubts on research areas. Nowadays, the use of a numerical methodology able to evaluate the stress and strain fields during indentation cycle can lead to a more secure interpretation. The aim of this work was to simulate the Berkovich indentation testing and to propose a methodology to extract the stress-strain curve through experimental and numerical analyses. The obtained numerical results for the load-displacement curve were quite similar to the experimental curve presented in the literature.

scholarly journals Investigation of the Mechanical Behavior of Polypropylene Fiber-Reinforced Red Clay

2021 ◽  
Vol 11 (22) ◽  
pp. 10521
Author(s):  
Jia Liu ◽  
Xi’an Li ◽  
Gang Li ◽  
Jinli Zhang
Keyword(s):  
Shear Strength ◽  
Polypropylene Fiber ◽  
Strain Curve ◽  
Triaxial Tests ◽  
High Water Content ◽  
Hyperbolic Model ◽  
High Plasticity ◽  
Fiber Reinforced ◽  
Red Clay ◽  
Stress Strain

Red clay is not easy to use as a natural foundation because of its high water content, high plasticity index, large void ratio, and susceptibility to shrinkage and cracking. In this study, consolidated undrained triaxial tests were conducted to examine the mechanical properties of polypropylene fiber-reinforced red clay and to analyze the influence of the fiber content (FC), fiber length (FL), and cell pressure on its shear strength. By performing a regression analysis on the test data, a hyperbolic constitutive model that considers the influence of FC, FL, and cell pressure was established, and a method was developed to estimate the parameters of the model. The findings show that, in contrast with the nonreinforced red clay, the fiber-reinforced red clay had a stress-strain curve characterized by typical strain hardening, with the shear strength increasing with FC, FL and cell pressure. The calculated results of the model coincide with the test results well, confirming that the hyperbolic model could appropriately describe the stress-strain relationship of polypropylene fiber-reinforced red clay and have reference value for the design and construction of fiber-reinforced red clay foundations.

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