Behavior of a Sandy Silt Reinforced with Discontinuous Recycled Fiber Inclusions

2000 ◽  
Vol 1714 (1) ◽  
pp. 9-17 ◽  
Author(s):  
J. J. Murray ◽  
J. D. Frost ◽  
Y. Wang
Keyword(s):  
Shear Strength ◽  
Axial Strain ◽  
Triaxial Compression ◽  
Value Added ◽  
Strength Loss ◽  
Dry Density ◽  
Compression Tests ◽  
Maximum Dry Density ◽  
Deformation Response ◽  
Sandy Silt

Laboratory compaction and triaxial compression tests were performed to assess the compaction characteristics and load deformation response of a sandy silt reinforced with randomly oriented recycled carpet fibers. Discrete, randomly distributed fiber inclusions significantly increase the peak shear strength, reduce the postpeak strength loss, increase the axial strain to failure, and, in some cases, change the stress-strain behavior from strain softening to strain hardening for a sandy silt. Fiber inclusions also impede the compaction process, causing a reduction in the maximum dry density of reinforced specimens with increasing fiber content. The strength losses associated with in-service saturation are significantly reduced with fiber reinforcement. It is suggested that large volumes of recycled waste fibers can be used as a value-added product to enhance the shear strength and load deformation response of soils.

scholarly journals Effect of Sand Percentage on the Compaction Properties and Undrained Shear Strength of Low Plasticity Clay

2021 ◽  
Vol 9 (1) ◽  
pp. 16-20
Author(s):  
Iyad Alkroosh ◽  
Ali Al-Robay ◽  
Prabir Sarker ◽  
Saif Alzabeebee
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Undrained Shear Strength ◽  
Optimum Moisture Content ◽  
Dry Density ◽  
Sand Content ◽  
Compression Tests ◽  
Maximum Dry Density ◽  
Sand Mixture ◽  
Undrained Shear

This paper investigates the influence of sand content on the mechanical behavior of a low plasticity clay that collected from south of Iraq (Sumer town). Samples have been prepared with sand contents of 0%, 10%, 20%, 30%, and 40% of the clay weight. Standard Proctor and unconfined compression tests have been carried out and the optimum moisture content, maximum dry density, and undrained shear strength have been determined. The results show a gradual increasing trend of the maximum dry density with the increase of the sand content up to 30%. The highest dry density reaches 1.90 g/cm3 corresponding to an optimum moisture content of 12%. In addition, this paper shows that the undrained shear strength is inversely proportional to the increase of the percentage of sand. The results of this work provide a useful addition to the literature regarding the behaviour or low plasticity clay-sand mixture.

Effect of sand percentage on the compaction properties and undrained shear strength of low plasticity soft clay

2021 ◽  
Author(s):  
Iyad Alkroosh ◽  
◽  
Ali Al-Robay ◽  
Prabir Sarker ◽  
Saif Alzabeebee ◽  
...  
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Soft Clay ◽  
Undrained Shear Strength ◽  
Optimum Moisture Content ◽  
Dry Density ◽  
Sand Content ◽  
Compression Tests ◽  
Maximum Dry Density ◽  
Undrained Shear

This study investigated the influence of sand content on the mechanical behaviour of a low plasticity clay found in Iraq. Samples were prepared with sand contents of 0%, 10%, 20%, 30%, and 40% of the weight of the clay. Standard Proctor and unconfined compression tests were carried out and the optimum moisture content, maximum dry density, and undrained shear strength were determined. The results showed a gradual increasing trend of the maximum dry density with the increase of the sand content up to 30%. The highest dry density reached was 1.90 gm/cm3 corresponding to an optimum moisture content of 12%. In addition, it was also found that the undrained shear strength was inversely proportional to the increase of the percentage of sand. Thus, the dry density of the clay could be increased well above 1.70 g/cm3, which is the minimum dry density accepted as a compacted subgrade according to the Iraqi General Specifications for Roads and Bridges (2003); hence, the rejected low plasticity clay could be utilised by mixing with sand. The reasons for the increase of the dry density and the decrease of the undrained shear strength has been extensively discussed in the paper.

DETERMINATION OF EXPANSIVE SOIL STRENGTH USING A FRACTAL MODEL

Fractals ◽  
2001 ◽  
Vol 09 (01) ◽  
pp. 51-60 ◽  
Author(s):  
YONGFU XU ◽  
DE'AN SUN
Keyword(s):  
Shear Strength ◽  
Soil Sample ◽  
Expansive Soils ◽  
Triaxial Compression ◽  
Expansive Soil ◽  
Fractal Model ◽  
Dry Density ◽  
Compression Tests ◽  
Surface Fractal ◽  
Strength Formula

The micropore surface fractal model for expansive soils is proposed in this paper. Based on the results of the mercury intrusion tests, it is found that the micropore surface fractal dimension is 2.40 for the soil sample with the dry density of 1.50 g/cm 3, and is 2.47 for the soil sample with the dry density of 1.60 g/cm 3. By using the micropore surface fractal model, the shear strength formula for expansive soils is obtained. All the parameters in the proposed shear strength formula are constant, and are independent of matric suction. The validation of the proposed shear strength formula is proven by the results of the triaxial compression tests on an expansive soil taken from Ningxia, China.

scholarly journals Semi-empirical elastic–thermoviscoplastic model for clay

2016 ◽  
Vol 53 (10) ◽  
pp. 1583-1599 ◽  
Author(s):  
David Kurz ◽  
Jitendra Sharma ◽  
Marolo Alfaro ◽  
Jim Graham
Keyword(s):  
Stress Level ◽  
Axial Strain ◽  
Triaxial Compression ◽  
Compression Tests ◽  
One Dimensional ◽  
Load Duration ◽  
Compression Creep ◽  
Overconsolidated Clays ◽  
Semi Empirical ◽  
Triaxial Compression Tests

Clays exhibit creep in compression and shear. In one-dimensional compression, creep is commonly known as “secondary compression” even though it is also a significant component of deformations resulting from shear straining. It reflects viscous behaviour in clays and therefore depends on load duration, stress level, the ratio of shear stress to compression stress, strain rate, and temperature. Research described in the paper partitions strains into elastic (recoverable) and plastic (nonrecoverable) components. The plastic component includes viscous strains defined by a creep rate coefficient ψ that varies with plasticity index and temperature (T), but not with stress level or overconsolidation ratio (OCR). Earlier elastic–viscoplastic (EVP) models have been modified so that ψ = ψ(T) in a new elastic–thermoviscoplastic (ETVP) model. The paper provides a sensitivity analysis of simulated results from undrained (CIŪ) triaxial compression tests for normally consolidated and lightly overconsolidated clays. Axial strain rates range from 0.15%/day to 15%/day, and temperatures from 28 to 100 °C.

Shear Strength of a Cemented Paste Backfill Submitted to High Confining Pressure

2016 ◽  
Vol 858 ◽  
pp. 219-224 ◽  
Author(s):  
Eduardo Eiler Batista de Araújo ◽  
Dragana Simon ◽  
Fagner Alexandre Nunes de França ◽  
Osvaldo de Freitas Neto ◽  
Olavo Francisco dos Santos Jr.
Keyword(s):  
Shear Strength ◽  
Triaxial Compression ◽  
Binder Content ◽  
Cemented Paste Backfill ◽  
Compression Tests ◽  
Mining Operations ◽  
Geomechanical Properties ◽  
Confining Pressures ◽  
Paste Backfill ◽  
Curing Method

Deep mining operations require special measures in order to keep safe and economic aspects. After mine ore is extracted, voids are created and need to be filled with high-strength, low-cost materials. Cemented Paste Backfill (CPB) has recently become one of the main alternatives in filling stopes. Although numerous papers have mentioned the magnitudes of the strength of this material, its behavior under high confining pressures is still not well understood. Therefore, the purpose of this study is to increase the knowledge regarding the CPB behavior. Triaxial compression tests were performed using a Hoek Cell and Load Frame System under high confining pressures. Samples with two different binder contents were used in order to obtain the CPB strength improvement. Besides the self-weight consolidation curing method, samples were subjected to a different curing method that simulated a zero gravity condition (rotating wheel) in the first curing day to compare their mixture properties. The results suggested that both curing method and binder content have influenced the geomechanical properties of Cemented Paste Backfill. By increasing the curing time, the CPB shear strength has increased slightly, whereas specimens with higher binder content presented a significant increase in shear strength values.

Shear Strength of BC-Soil Admixed with Lime and Bio-Enzyme

2019 ◽  
Vol 969 ◽  
pp. 327-334
Author(s):  
C. Jairaj ◽  
M.T. Prathap Kumar ◽  
H. Muralidhara
Keyword(s):  
Shear Strength ◽  
Soil Stabilization ◽  
Morphological Changes ◽  
Ground Improvement ◽  
High Strength ◽  
Sem Analysis ◽  
Dry Density ◽  
Test Results ◽  
Maximum Dry Density ◽  
Lime Content

This BC Soil are expansive in nature and are problematic because of low shear strength and high compressibility. Review of literatures have proven that addition of lime imparts high strength with a corresponding reduction in swell of BC soils. In addition, Bio-enzymes have also been found to play a key role as activators in improving the characteristics of clayey soils such as BC soil. Development and use of non-traditional ground improvement techniques such as bio-enzymes in combination with lime for soil stabilization helps to reduce the cost and the detrimental effects on the soil environment. In the present study lime and bio-enzymes were used as soil stabilizing agents. Compaction test results on BC soil admixed with different percent of lime indicated that 3% addition lime gives higher maximum dry density of 17kN/m3 with OMC of 21% compare to other addition of lime percentages. Keeping 3% of lime as optimum lime content(OLC), BC Soil was admixed with different dosages of Bio-enzymes 25ml/m3, 50ml/m3, 100 ml/m3,150ml/m3, and 200ml/m3 along with OLC was tested for compaction and unconfined compressive strength(UCC). Further UCC test was carried out for different curing period of 0, 7, 15, 30, and 60 Days to analyse the long term effect of BC soil admixed with bio-enzymes with and without lime content. Morphological and chemical analysis was done by using XRD and SEM analysis, from all the test results it was found that 3%OLC + 75ml/m3 of bio-enzymes for 7 day of curing gives higher UCC of 450 kPa. From the SEM it was found that better bond between particles found to develop in bio-enzyme+ lime admixed BC soil in comparison with lime alone admixed BC soil. XRD studies indicated morphological changes in crystallinity and structure of stabilized BC soil in comparison to BC soil alone.

Anisotropic shear strength of a residual soil of sandstone

2008 ◽  
Vol 45 (3) ◽  
pp. 367-376 ◽  
Author(s):  
Adriano Virgilio Damiani Bica ◽  
Luiz Antônio Bressani ◽  
Diego Vendramin ◽  
Flávia Burmeister Martins ◽  
Pedro Miguel Vaz Ferreira ◽  
...  
Keyword(s):  
Shear Strength ◽  
Effective Stress ◽  
Yield Surface ◽  
Triaxial Compression ◽  
Strength Properties ◽  
Triaxial Tests ◽  
Residual Soil ◽  
Compression Tests ◽  
Soil Stiffness ◽  
Particle Bonding

This paper discusses results of laboratory tests carried out with a residual soil originated from the weathering of eolian sandstone from southern Brazil. Parent rock features, like microfabric and particle bonding, are remarkably well preserved within this residual soil. Stiffness and shear strength properties were evaluated with consolidated drained (CID) and consolidated undrained (CIU) triaxial compression tests. Undisturbed specimens were tested with two different orientations between the specimen axis and bedding surfaces (i.e., parallel (δ = 0°) or perpendicular (δ = 90°)) to investigate the effect of anisotropy. When CID triaxial tests were performed with δ = 0°, the yield surface associated with the structure was much larger than when tests were performed with δ = 90°. Coincidently, CIU tests with δ = 0° showed peak shear strengths much greater than for δ = 90° at comparable test conditions. Once the peak shear strength was surpassed, CIU tests followed collapse-type effective stress paths not shown by corresponding tests with remolded specimens. A near coincidence was observed between the yield surface determined with CID tests and the envelope of collapse-type effective stress paths for δ = 0° and δ = 90°.

Mechanical Properties of Bentonite-Sand Mixtures Under Triaxial Stress Condition

1994 ◽  
Vol 353 ◽  
Author(s):  
M. Umedera ◽  
A. Fujiwara ◽  
N. Yasufuku ◽  
M. Hyodo ◽  
H. Murata
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Water Content ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Strength Properties ◽  
Compression Tests ◽  
Optimum Water Content ◽  
Triaxial Compression Tests ◽  
Optimum Water

AbstractA series of triaxial compression tests is being conducted under the drained condition on bentonite and sand mixtures, known as buffer, in saturated and optimum water content states to clarify the mechanical properties of the buffer.It was found that the mechanical properties of bentonite and sand mixtures are strongly influenced by water and bentonite contents: shear strength in a saturated state is less than that in an optimum water content state; shear strength decreases rapidly with increasing bentonite content. Strength properties are much dependent on confining pressure.

Influence of Water Contents on Shear Strength of Rammed Earth Wall of Earth-Building

2011 ◽  
Vol 382 ◽  
pp. 172-175
Author(s):  
Ren Wei Wu ◽  
Xing Qian Peng ◽  
Li Zhang
Keyword(s):  
Shear Strength ◽  
Water Content ◽  
Triaxial Compression ◽  
Friction Angle ◽  
World Heritage Site ◽  
Rammed Earth ◽  
Compression Tests ◽  
Rammed Earth Wall ◽  
Influence Of Water ◽  
Water Contents

As the "Fujian earth-building" have been inscribed by UNESCO in 2008 as World Heritage Site, attentions of protection about the "Fujian earth-building" has getting more and more. This article takes samples of a rammed-earth wall from Yongding earth-buildings and determines the shear strength of the samples with different water content through triaxial compression tests. The influence on shear strength of water content of rammed-earth samples is analyzed. Test results show that the shear strength of rammed-earth has much to do with the water content of the soil, the greater the water content is，the smaller the shear strength is. With water content increasing, cohesion and internal friction angle of rammed-earth were decreases, and its changing trend is of marked characteristic of stage. When water contents of rammed-earth is under some value, its cohesion changes in small ranges; when water contents of rammed-earth is over the value, its cohesion decreases with water content increasing.

Experimental Study on Shear Strength Considering Initial Void Ratio and Plasticity Index

2013 ◽  
Vol 405-408 ◽  
pp. 63-67
Author(s):  
Xing Chen Wang ◽  
Ri Qing Xu ◽  
Jian Feng Zhu
Keyword(s):  
Shear Strength ◽  
Void Ratio ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Deviatoric Stress ◽  
Plasticity Index ◽  
Test Results ◽  
Compression Tests ◽  
Functional Relationships ◽  
Initial Void Ratio

A series of drained triaxial compression tests under different conditions were performed to quantitatively study the influence of the initial void ratio and plasticity index on the shear strength of remolded saturated clays. The test results show that both the peak stress friction angle and peak deviatoric stress decrease with increasing initial void ratio and plasticity index of the soil under the same confining pressure; whereas, they increase with increasing confining pressure of the soil under the same initial void ratio and plasticity index. A new synthesized physical parameter λ, which simultaneously represent both the type and the condition of remolded saturated clays, is defined based on the test results in this work. The functional relationships among the parameters φd and peak deviatoric stress in Mohr-Coulomb equation and the parameter λ are established to develop a modified Mohr-Coulomb equation by considering physical properties of soil. In this equation, only two input parameters, i.e., λ and the confine pressure, are needed to predict the shear strength of the soil. In order to check the accuracy of the proposed equation, laboratory tests were conducted to evaluate against the predicted results. The results show that the peak shear strength of remolded saturated clays can be well described by the proposed equation. Key words: shear strength; Mohr-Coulomb equation; remolded saturated clays; initial void ratio; plasticity index.

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