scholarly journals Attempt to reproduce the mechanical behavior of cement-treated soil using elasto-plastic model considering soil skeleton structure

Author(s):  
Takayuki Sakai ◽  
Masaki Nakano
2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Yue Qiang ◽  
Yulong Chen

In order to study the mechanical behavior of lime-treated soil under different loading rates, a series of monotonous three-axial compression tests are carried out under different lime contents, different loading rates, and different curing periods. The test results indicate that the lime content can significantly improve the mechanical behaviors of soil, such as shear strength and elastic modulus. On the other hand, three-axial compression test of soil is carried out under the loading rate ranging from 0.1%/min to 8%/min. Experimental results indicate that the mechanical behavior of lime-treated soil is sensitive to loading rate. Besides, the corresponding relationship between internal friction angle, cohesion, lime content, and loading rate is discussed. The results indicate that the loading rate almost has no influence on internal friction angle but significant influence on lime content. Cohesion is affected by lime content and loading rate. Shear strength, elastic modulus, and cohesion all increase with the increase of loading rate. Longer curing period is associated with greater parameter value. Shear strength, elastic modulus, and internal friction angle all firstly increase and then decrease when lime content increases, which all reach the maximum at 6%.


2010 ◽  
Vol 113-116 ◽  
pp. 1429-1432
Author(s):  
Xi Zhong Yuan ◽  
Cheng Cheng Liu ◽  
Wei Cui ◽  
Fei Liu

The workability of excessively wet subgrade can be effectively improved by using a “green materials” based entirely on industry byproduct of combination of fly ash (FA) with carbide lime (CL) and flue gas desulfurization gypsum (FGDG). This paper presents the results of a further systematic investigation on the mechanical behavior and durability of FA/CL/FGDG treated silt from Dezhou in Shandong province. FA, CL and FGDG were added at 3 levels in percentages of 8%-24%, 2%-6% and 1%-3% by dry weight of the soils, respectively. The unconfined compressive strength as well as splitting tensile strength (STS), volumetric expansion (VE), California bearing ratio (CBR), dry-wet cycles test and freeze-thaw cycles test were performed. The best strength of 0.802MPa was achieved for 24%FA/6%CL/1%FGDG treated soil, while the 16%FA/6%CL/1%FGDG treated soil also produce good strengths of 0.742MPa, after 7 days curing. STS keeps increasing with curing period in the first 8 weeks throughout the investigation. According to the VE test, a mellowing period may help prevent swelling from ettringite precipitation by letting these minerals form and hydrate before compaction. The FA/CL/FGDG treated soil has a better durability with strength loss ratio less than 15% after 10 wet-dry cycles, and the maximum weight loss around 25% after 10 freeze–thaw cycles. CBR decreases with decrease of compaction degree, but the values are still around 70 even in a poor compaction degree of 93%, meeting the general requirements of subgrade. So, if the silt subgrade is in excessively wet state and could not be compacted to the required density, the modified subgrade would still serve as a strong platform and could provide necessary support for pavement.


SPE Journal ◽  
2013 ◽  
Vol 18 (02) ◽  
pp. 196-206 ◽  
Author(s):  
Assaf Klar ◽  
Shun Uchida ◽  
Kenichi Soga ◽  
Koji Yamamoto

Summary This paper presents an explicit time-marching formulation for the solution of the coupled thermal flow mechanical behavior of gas-hydrate sediment. The formulation considers the soil skeleton as a deformable elastoplastic continuum, with an emphasis on the effect of hydrate (and its dissociation) on the stress-strain behavior of the soil. In the formulation, the hydrate is assumed to deform with the soil and may dissociate into gas and water. The formulation is explicitly coupled, such that the changes in temperature because of energy flow and hydrate dissociation affect the skeleton stresses and fluid (water and gas) pressures. This, in return, affects the mechanical behavior. A simulation of a vertical well within a layered soil is presented. It is shown that the heterogeneity of hydrate saturation causes different rates of dissociation in the layers. The difference alters the overall gas production and also the mechanical-deformation pattern, which leads to loading/unloading shearing along the interfaces between the layers.


2012 ◽  
Vol 504-506 ◽  
pp. 673-678 ◽  
Author(s):  
Laurent Tabourot ◽  
Pascale Balland ◽  
Jonathan Raujol-Veillé ◽  
Mathieu Vautrot ◽  
Christophe Déprés ◽  
...  

As close as you watch them, the materials (especially metals) present discontinuities that can easily be qualified as strong. Dislocations, structures formed by these dislocations, phases and grains are all discontinuities, also sources of heterogeneity, with effects on material behavior that are not really well reproduced by a model based on a continuity assessment. Consequently, the materials should be considered as a set of compartments with different behaviors. This promotes an alternative way to define models. A coherent modeling process is probably the integration of the different behaviors of the material compartments within the global model. The objective is here to build an efficient elasto(visco)plastic model of the mechanical behavior of titanium combining compartmentalized behaviors. After setting the frame of the study, which is of primary importance, the proposed modeling process is running as follows (i) choose a local behavior, (ii) identify the parameters of crystalline texture that must be integrated into the simulation and (iii) finally formulate a way of combining local compartments behaviors. The intrinsic properties of Finite Element codes are used to achieve the integration of the whole system.


Author(s):  
B. J. Hockey

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.


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