The Effect of Confining Pressure and Water Content on Compressive Strength and Deformation of Ice-Rich Silty Sand

2016 ◽  
Vol 28 (1) ◽  
pp. 298-305 ◽  
Author(s):  
Shujuan Zhang ◽  
Haimin Du ◽  
Jon Harbor
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Confining Pressure ◽  
Silty Sand ◽  
Strength And Deformation

scholarly journals Experimental Study on Anisotropic Strength and Deformation Behavior of a Coal Measure Shale under Room Dried and Water Saturated Conditions

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Jingyi Cheng ◽  
Zhijun Wan ◽  
Yidong Zhang ◽  
Wenfeng Li ◽  
Syd S. Peng ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Young’S Modulus ◽  
Deformation Behavior ◽  
Young's Modulus ◽  
Triaxial Compression ◽  
Coal Measure ◽  
Anisotropic Strength ◽  
Strength And Deformation ◽  
Water Saturated

This paper presents an experimental investigation of anisotropic strength and deformation behavior of coal measure shale. The effect of two factors (i.e., anisotropy and water content) on shale strength and deformation behavior was studied. A series of uniaxial and triaxial compression tests were conducted on both room dried and water saturated samples for different lamination angles. The test results indicate that (1) the compressive strength, cohesion, internal friction angle, tangent Young’s modulus, and axial strain corresponding to the peak and residual strengths of room dried specimens exhibit anisotropic behavior that strongly depends on the orientation angle(β); (2) in comparison to the room dried samples, the compressive strength and Young’s modulus as well as the anisotropy are all reduced for water saturated specimens; and (3) the failure mechanism of the samples can be summarized into two categories: sliding along lamination and shearing of rock material, with the type occurring in a particular situation depending strongly on the lamination orientation angles with respect to the major principal stress. According to the findings, it is strongly recommended that the effect of anisotropy and water content on the strength and deformation behavior of the rock must be considered in ground control designs.

scholarly journals Experimental and Theoretical Investigations of the Constitutive Relations of Artificial Frozen Silty Clay

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3159
Author(s):  
Zhiming Li ◽  
Jian Chen ◽  
Chaojun Mao
Keyword(s):  
Water Content ◽  
Strain Softening ◽  
Constitutive Relations ◽  
Random Variable ◽  
Confining Pressure ◽  
Silty Clay ◽  
Softening Behavior ◽  
Theoretical Investigations ◽  
Confining Pressures ◽  
Strength And Deformation

The strength and deformation characteristics of artificial frozen soils are quite sensitive to temperature, confining pressure, and water content. To investigate these effects, a series of triaxial compressive tests on frozen Harbin silty clay were conducted at temperatures of −5 °C, −10 °C, and −15 °C under different confining pressures and water contents. From the stress–strain curves under lower water content and confining pressure, strain–softening behavior was observed. The modified Duncan–Chang (MDC) model was employed to describe the constitutive relations of artificial frozen silty clay while considering the strain–softening effects. After introducing statistical damage (SD) theory, an SD constitutive model with the failure strain as a random variable was proposed, which is able to overcome the drawbacks of the MDC model. The predicted SD model results are found to be consistent with the experimental results.

Test Study on the Compressive Strength Properties of Compacted Clayey Soil

2016 ◽  
Vol 703 ◽  
pp. 380-385
Author(s):  
Han Bing Liu ◽  
Hu Zhu Zhang ◽  
Jing Wang
Keyword(s):  
Compressive Strength ◽  
Stress State ◽  
Bearing Capacity ◽  
Water Content ◽  
Clayey Soil ◽  
Triaxial Compression ◽  
Quadratic Function ◽  
Confining Pressure ◽  
Strength Properties ◽  
And Function

In order to study the effect of water content, degree of compaction and stress state on bearing capacity of subgrade, the engineering compacted clayey soil was taken as the subject investigated, regulation of compressive strength changing with water content, degree of compaction and confining pressure were analyzed through triaxial compression test, and function relationships between compressive strength and water content, degree of compaction and stress state were fitted based on the test data. Results show that effects of water content, degree of compaction and confining pressure on compressive strength properties of subgrade compacted clayey soil are all remarkably. The compressive strength decreases according to a quadratic function with the increase of water content, as well as increases in accordance with a quadratic function with the increase of the degree of compaction, and increases linearly with the increase of confining pressure. Improving the construction compaction standard properly, adopting the essential lateral confinement measure and keeping a lower water content of the subgrade in service can improve the bearing capacity and stability of the highway subgrade.

Study on mechanical properties and damage evolution of carbonaceous shale under triaxial compression with acoustic emission

2021 ◽  
pp. 105678952199119
Author(s):  
Kai Yang ◽  
Qixiang Yan ◽  
Chuan Zhang ◽  
Wang Wu ◽  
Fei Wan
Keyword(s):  
Mechanical Properties ◽  
Acoustic Emission ◽  
Water Content ◽  
Damage Evolution ◽  
Damage Assessment ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Damage Variable ◽  
Natural State ◽  
Carbonaceous Shale

To explore the mechanical properties and damage evolution characteristics of carbonaceous shale with different confining pressures and water-bearing conditions, triaxial compression tests accompanied by simultaneous acoustic emission (AE) monitoring were conducted on carbonaceous shale rock specimens. The AE characteristics of carbonaceous shale were investigated, a damage assessment method based on Shannon entropy of AE was further proposed. The results suggest that the mechanical properties of carbonaceous shale intensify with increasing confining pressure and degrade with increasing water content. Moisture in rocks does not only weaken the cohesion but also reduce the internal friction angle of carbonaceous shale. It is observed that AE activities mainly occur in the post-peak stage and the strong AE activities of saturated carbonaceous shale specimens appear at a lower normalized stress level than that of natural-state specimens. The maximum AE counts and AE energy increase with water content while decrease with confining pressure. Both confining pressure and water content induce changes in the proportions of AE dominant frequency bands, but the changes caused by confining pressure are more significant than those caused by water content. The results also indicate that AE entropy can serve as an applicable index for rock damage assessment. The damage evolution process of carbonaceous shale can be divided into two main stages, including the stable damage development stage and the damage acceleration stage. The damage variable increases slowly accompanied by a few AE activities at the first stage, which is followed by a rapid growth along with intense acoustic emission activities at the damage acceleration stage. Moreover, there is a sharp rise in the damage evolution curve for the natural-state specimen at the damage acceleration stage, while the damage variable develops slowly for the saturated-state specimen.

Effect of internal water content on carbonation progress in cement-treated sand and effect of carbonation on compressive strength

2018 ◽  
Vol 85 ◽  
pp. 9-21 ◽  
Author(s):  
Lanh Si Ho ◽  
Kenichiro Nakarai ◽  
Yuko Ogawa ◽  
Takashi Sasaki ◽  
Minoru Morioka
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Internal Water

scholarly journals Utilization of Electroplating Sludge as Subgrade Backfill Materials: Mechanical and Environmental Risk Evaluation

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Yu Zhang ◽  
Peixin Shi ◽  
Lijuan Chen ◽  
Qiang Tang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Content ◽  
Environmental Risk ◽  
Coal Fly Ash ◽  
Surrounding Environment ◽  
Electroplating Sludge ◽  
Backfill Materials ◽  
Standard Limit ◽  
The Impact

The electroplating sludge may pose serious threat to human health and surrounding environment without safe treatment. This paper investigated the feasibility of using electroplating sludge as subgrade backfill materials, by evaluating the mechanical properties and environmental risk of the cement-coal fly ash solidified sludge. In this study, Portland cement and coal fly ash are used to solidify/stabilize the sludge. After curing for 7, 14, and 28 days, the stabilization/solidification sludge specimens were subject to a series of mechanical, leaching, and microcosmic tests. It was found that the compressive strength increased with the increase of cement content, curing time, and the cement replacement by coal fly ash besides water content. Among these factors, the impact of water content on the compressive strength is most noticeable. It was observed that the compressive strength declined by 87.1% when the water content increased from 0% to 10%. Besides, leaching tests showed that the amount of leaching heavy metals were under the standard limit. These results demonstrated utilization of electroplating sludge in subgrade backfill material may provide an alternative for the treatment of electroplating sludge.

Testing Study on the Effects of Water Content on Permeability for Coal

2014 ◽  
Vol 580-583 ◽  
pp. 201-204
Author(s):  
Chun Hui Zhang ◽  
Xiao Pan Xu
Keyword(s):  
Water Content ◽  
Pore Pressure ◽  
Coal Sample ◽  
Channel Wall ◽  
Confining Pressure ◽  
Liaoning Province ◽  
Air Drying ◽  
Slippage Effect

To obtain the effects of water content on the permeability of coal, briquette specimen were obtained from Wulong Mine, Liaoning Province. The permeability of the air drying, bounding water and saturating specimens were tested with self-made equipment respectively, and the effects of water content on permeability for coal were studied. The results showed that: (1)The permeability of specimens decreases with confining pressure increasing, and the air drying and bounding water specimens take on obvious slippage effect. However the saturated specimens never take on slippage effects. It is because the channels of saturated coal sample are occupied by water. When the gas goes through specimens, gas never is absorbed. Collision between gas and the channel wall decreases, and the slippage effect disappears. (2) With water content increasing, the permeability of specimens decreases. (3)The permeability of specimens increases when pore pressure increases.

scholarly journals Preparation and properties of magnesite aggregate radiation - proof concrete

2018 ◽  
Vol 175 ◽  
pp. 01003
Author(s):  
Bingquan Sun ◽  
Jiajia Sun
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Structure ◽  
Water Content ◽  
Radiation Protection ◽  
Point Of View ◽  
Crystal Water ◽  
Ordinary Concrete ◽  
Mixing Water

This paper, from the point of view of improving compactness of density and crystal water content of radiation-proof concrete, using magnesite with high crystal water content as aggregate and alkaline potential water as mixing water, prepared ordinary density radiation-proof concrete and studied its mechanical properties, resistivity and pore structure. The results show that, compared to base ordinary concrete, the prepared concrete has better 28d compressive strength and resistivity, overall porosity decreases by 17%, and pore gradation at all ages improves significantly. It is indicated that the prepared magnesite aggregate radiation concrete has good density and durability, improves concrete radiation protection performance.

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