scholarly journals Improvement of Clayey Soils by Combined Bamboo Strip and Flax Fiber Reinforcement

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Fang Tong ◽  
Qiang Ma ◽  
Wenwen Xing
Keyword(s):  
Internal Friction ◽  
Tensile Force ◽  
Fiber Reinforcement ◽  
Friction Angle ◽  
Tensile Tests ◽  
Flax Fiber ◽  
Internal Friction Angle ◽  
Fiber Reinforced ◽  
Confining Pressures ◽  
Reinforced Clay

A combined bamboo strips and flax fiber reinforcement method to reinforce clay is proposed in this paper, and in order to study the mechanical properties of bamboo strips and flax fiber-reinforced clay (BFRC), a series of tensile tests were carried out to obtain the relationship between the average tensile force and deformation of flax fiber and bamboo strip; after that, triaxial shear tests were carried out under the conditions of different confining pressures. In addition, the reinforcement mechanism of the bamboo strips and flax fiber-reinforced clay (BFRC) is analyzed. The test results show that the cohesion and internal friction angle of the bamboo strips and flax fiber-reinforced clay (BFRC) are improved compared with the pure clay. In the case of flax fiber-reinforced clay, the cohesion of reinforced clay is increased by 18.34% and the friction angle is only increased by 0.39%. In the case of bamboo strips and flax fiber-reinforced clay, the cohesion of reinforced clay is increased by 26.36% and the friction angle is only increased by 10.24%. The addition of bamboo strips improves the shear strength of the reinforced clay and effectively improves the deformation resistance of the flax fiber-reinforced clay (FRC). And it increases the internal friction angle and cohesion of the clay, although the increase in the strength is mainly reflected in the influence on the cohesion.

Experimental Study of Rockfill Particle Breakage

2014 ◽  
Vol 900 ◽  
pp. 445-448
Author(s):  
Zhi Hua Xu ◽  
Da Wei Sun
Keyword(s):  
Internal Friction ◽  
Large Scale ◽  
Reference Value ◽  
Friction Angle ◽  
Confining Pressure ◽  
Particle Breakage ◽  
Internal Friction Angle ◽  
Dam Construction ◽  
Confining Pressures ◽  
The Relationship

As the high concrete faced rockfill dams construction, grain breakage gradually become the factors that influence the high dam construction which can not be ignored. This text based on the master of rockfill of shuibuya dam as the experimental material, getting and analyzing the particle breakage data under different confining pressure through the large-scale triaxial test, and the results show that the particle breakage index increases with the increase of confining pressures. The relationship between particle breakage index and confining pressure can be expressed by formula;Particle breakage increase leading to reduced internal friction angle and the shear strength of rockfill, and the author newly introduced two broken variable to describe the relationship which can be expressed by the formula between the particle breakage and internal friction angle, it has certain reference value for establishing constitutive model considering particle breakage.

Gravel Content Effect on the Shear Strength of Clay-Gravel Mixtures

2011 ◽  
Vol 71-78 ◽  
pp. 4685-4688 ◽  
Author(s):  
Chen Wang ◽  
Chuan Ni Zhan
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Triaxial Compression ◽  
Constant Strain Rate ◽  
Friction Angle ◽  
Confining Pressure ◽  
Internal Friction Angle ◽  
Compression Tests ◽  
Gravel Content ◽  
Confining Pressures

Gravel content is an important factor affecting the mechanical properties of clay-gravel mixtures. To study the effects of gravel content on the shear strength of clay-gravel mixtures, constant-strain-rate drained triaxial compression tests were conducted for various mixtures. The gravel contents were 30%, 40%, 50% and 70%. The confining pressures were varied from 50kPa to 300kPa. Test results indicate that the deviator stress at failure under the same confining pressure increases with the increase in gravel content. As the gravel content in the mixtures is between 30% and 50%, the shear strength is jointly attributed by clay and gravel. An increase in gravel content results in slight increases in both the cohesion intercept and internal friction angle. At gravel content of up to 70%, the shear strength of the mixture is controlled by that of the gravel, and the cohesion intercept and the internal friction angle increase sharply.

scholarly journals Effect of Dry-Wet Cycles and Freeze-Thaw Cycles on the Antierosion Ability of Fiber-Reinforced Loess

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Changgen Yan ◽  
Ning An ◽  
Yachong Wang ◽  
Weifeng Sun
Keyword(s):  
Internal Friction ◽  
Permeability Coefficient ◽  
Friction Angle ◽  
Reinforced Soil ◽  
Internal Friction Angle ◽  
Hyperbolic Function ◽  
Fiber Reinforced ◽  
Disintegration Rate ◽  
Freeze Thaw ◽  
Number Of Cycles

Compared with plain soil, polypropylene (PP) fiber-reinforced soil has markedly improved mechanical properties and can be used in slope protection projects. To investigate the reduction law of the antierosion ability parameters of PP fiber-reinforced loess under dry-wet (D-W) cycles and freeze-thaw (F-T) cycles, we took loess from Yan’an, China, mixed them with PP fiber, and did shear strength tests, disintegration tests, and permeability tests under D-W cycles and F-T cycles. The experimental results show that D-W cycles or F-T  cycles had a less deteriorating effect on the cohesion, disintegration rate, and permeability coefficient of the fiber-reinforced samples than on plain loess; however, the reduction in their internal friction angle was more obvious. Under D-W cycles or F-T cycles, the cohesion and internal friction angle of the reinforced soil decreased as the number of cycles increased, while the disintegration rate and permeability coefficient increased as the number of cycles increased. The relation between the reduction in the antierosion ability parameters of reinforced soil and the number of D-W cycles or F-T cycles accorded with the hyperbolic function fitting results. The most obvious reduction effect the D-W cycles had on the reinforced soil was on the disintegration rate, followed by cohesion, internal friction angle, and permeability coefficient. The most obvious effect of F-T cycles was also on the disintegration rate, followed by cohesion, permeability coefficient, and internal friction angle. Compared with D-W cycles, F-T cycles had a stronger effect on the reduction in the cohesion, disintegration rate, and permeability coefficient of reinforced soil, but the reduction in the friction angle was greater in D-W cycles.

Testing Study on the Change Law about Internal Friction Angle of Geogrid Reinforced Clay under many Times Freezing-Thawing Cycles

2012 ◽  
Vol 594-597 ◽  
pp. 186-193
Author(s):  
Rong Fei Zhao ◽  
Yong Ning Mi ◽  
Wei Gao
Keyword(s):  
Internal Friction ◽  
Initial Moisture Content ◽  
Influence Factors ◽  
Friction Angle ◽  
Regression Equation ◽  
Internal Friction Angle ◽  
Engineering Practice ◽  
Angle Change ◽  
Testing Data ◽  
Reinforced Clay

This paper uses quadric orthogonal rotating combination design test, obtains the internal friction angle change values under given many times freezing-thawing cycles for the geogrid reinforced clay with different degree of compactions, moisture contents and reinforcement spacings. Through analysis of the test data and mathematical calculation to get the regression equation about the internal friction angle change value related with fillers compaction degree, initial moisture content and reinforcement spacing, and test the conspicuousness about the equation and the influence factors. Applies the equation to calculate the internal friction angle change values in the else test conditions, the results show that the calculated values and the testing data fit well, the equation can be used for initial calculation of the under many times freezing-thawing cycles. The regression equation provides a theoretical reference for the engineering practice of geogrid reinforced clay.

Characterization of Shear Strength and Interface Friction of Organic Soil

2020 ◽  
Vol 857 ◽  
pp. 203-211
Author(s):  
Majid Hamed ◽  
Waleed S. Sidik ◽  
Hanifi Canakci ◽  
Fatih Celik ◽  
Romel N. Georgees
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Internal Friction ◽  
Moisture Content ◽  
Water Content ◽  
Friction Angle ◽  
Structural Materials ◽  
Organic Soil ◽  
Internal Friction Angle ◽  
Interface Friction

This study was undertaken to investigate some specific problems that limit a safe design and construction of structures on problematic soils. An experimental study was carried out to examine the influence of loading rate and moisture content on shear strength of organic soil. Influece of moisture content on interface friction between organic soil and structural materials was also attempted. A commonly used soil in Iraq was prepared at varying moisture contents of 39%, 57% and 75%. The experimental results showed that the increase in water content will decrease the shear stress and the internal friction angle. An increase of the shearing rate was found to decrease the shear stress and internal friction angle for all percetanges of water contents. Further, direct shear tests were carried out to detect the interface shear stress behavior between organic soil and structural materials. The results revealed that the increase in water content was shown to have significant negetavie effects on the interface internal friction and angle shear strength.

scholarly journals Influence of Structural Plane Microscopic Parameters on Direct Shear Strength

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yanhui Cheng ◽  
Weijun Yang ◽  
Dongliang He
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Internal Friction ◽  
Direct Shear Test ◽  
Shear Test ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Direct Shear ◽  
Stiffness Ratio ◽  
Structural Plane

Structural plane is a key factor in controlling the stability of rock mass engineering. To study the influence of structural plane microscopic parameters on direct shear strength, this paper established the direct shear mechanical model of the structural plane by using the discrete element code PFC2D. From the mesoscopic perspective, the research on the direct shear test for structural plane has been conducted. The bonding strength and friction coefficient of the structural plane are investigated, and the effect of mesoscopic parameters on the shear mechanical behavior of the structural plane has been analyzed. The results show that the internal friction angle φ of the structural plane decreases with the increase of particle contact stiffness ratio. However, the change range of cohesion is small. The internal friction angle decreases first and then increases with the increase of parallel bond stiffness ratio. The influence of particle contact modulus EC on cohesion c is relatively small. The internal friction angle obtained by the direct shear test is larger than that obtained by the triaxial compression test. Parallel bond elastic modulus has a stronger impact on friction angle φ than that on cohesion c. Under the same normal stress conditions, the shear strength of the specimens increases with particle size. The shear strength of the specimen gradually decreases with the increase of the particle size ratio.

Stability Analysis of Dam Slope by Double Safety Factors of Dynamic Local Strength Reduction Method

2015 ◽  
Vol 744-746 ◽  
pp. 593-596
Author(s):  
Yuan Meng
Keyword(s):  
Internal Friction ◽  
Reduction Method ◽  
Failure Process ◽  
Friction Angle ◽  
Strength Reduction ◽  
Internal Friction Angle ◽  
Material Strength ◽  
Strength Reduction Method ◽  
Strength Parameters ◽  
Local Strength

When calculating the dam slope failure process, traditional strength reduction method doesn't consider the difference of decay rate between cohesion and internal friction angle and discount the strength parameters for all elements. This paper uses two different reduction factors for material strength parameters, slope cohesion and internal friction angle. Based on the yield approach index criterion, we change the reduction region in time and put forward a double safety factor of dynamic local strength reduction method for engineering analysis of dam slope stability.

scholarly journals Stabilization of Algerian Clayey Soils with Natural Pozzolana and Lime

2017 ◽  
Author(s):  
Khelifa Harichane ◽  
Mohamed Ghrici ◽  
Said Kenai
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Plasticity Index ◽  
Engineering Properties ◽  
High Plasticity ◽  
Expansive Clay ◽  
Clayey Soils ◽  
Natural Pozzolana

Cohesive soils with a high plasticity index present difficulties in construction operations because they usually contain expansive clay minerals. However, the engineering properties of soils can be improved by different techniques. The aim of this paper is to study the effect of using lime, natural pozzolana or a combination of both lime and natural pozzolana on plasticity, compaction and shear strength of two clayey soils classified as CH and CL according to the unified soil classification system (USCS). The obtained results indicated that for CH class clay soil, the plasticity index decreased significantly for samples stabilized with lime. On the other hand, for the soil classified as CL class clay, a high decrease in the plasticity index value was observed for samples stabilized with natural pozzolana compared to those stabilized with lime. Also, both the cohesion and internal friction angle in lime added samples were demonstrated to increase with time. The combination of lime and natural pozzolana exhibits a significant effect on the enhancement of both the cohesion and  internal friction angle at later stages. The lime-natural pozzolana combination appears to produce higher shear strength parameters than lime or natural pozzolana used alone.

scholarly journals Effect of Glutinous Rice Slurry on the Reinforcement of Silt in the Yellow River Basin by Microbially Induced Carbonate Precipitation (MICP): Mechanical Property and Microcosmic Structure

2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Jianwei Yue ◽  
Limin Zhao ◽  
Baoxi Zhang ◽  
Qingmei Kong ◽  
Siyuan Wang ◽  
...  
Keyword(s):  
Internal Friction ◽  
Yellow River ◽  
Friction Angle ◽  
Yellow River Basin ◽  
Reinforced Soil ◽  
Internal Friction Angle ◽  
The Yellow River ◽  
Mass Ratio ◽  
Glutinous Rice ◽  
The Yellow River Basin

The silty clay in the lower reaches of the Yellow River is characterized by loose structure, low strength, and strong capillary effect. Based on the technology of ancient glutinous rice mortar and microbial-induced calcium carbonate precipitation (MICP), experiments on optimal mass ratio of cementitious liquid to bacterial liquid and optimal concentration of cementitious liquid for MICP and improved MICP technology were carried out by measuring the production of CaCO3, and direct shear test and unconfined compressive strength test of plain silt, glutinous mixing silt, and improved silt with MICP and modified MICP were conducted. The microstructure of the reaction products of MICP and improved MICP technology were also evaluated based on scanning electron microscopy (SEM). Research results showed that the mechanical properties of silt with glutinous rice slurry were effectively improved. With the increase in the concentration of glutinous rice slurry, the strength and internal friction angle of soil samples first increased and then decreased, and the cohesion presented a linear increasing trend. When the concentration of cementitious liquid was 0.5 M and the mass ratio of cementitious liquid to bacterial liquid was 2 : 1, the amount of CaCO3 formed was the most, and the conversion rate of Ca2+ was more than 80%. The improved MICP could increase the conversion rate of Ca2+ (93.44%). An improved MICP showed that glutinous rice slurry could improve bacterial activity, increase the urease content in the bacterial solution, and promote the production of CaCO3. Silt cohesion and internal friction angle of the silt were improved by the improved MICP technology, and the strengthening effect of mechanical properties of modified MICP-reinforced soil is better than that of the MICP-reinforced soil; conventional MICP technology could also improve the soil cohesion, but the improvement in the internal friction angle was not obvious. The SEM results indicated that compared with the reaction product of MICP technology, the structure of the product of improved MICP technology is more compact, resulting in a marked reinforcement of MICP performance with glutinous rice slurry. This study provides new insights into enhancing the mechanical behaviour of MICP-treated silt in the Yellow River Basin with glutinous rice slurry.

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