scholarly journals Strength Characteristics of Clay–Rubber Waste Mixtures in Low-Frequency Cyclic Triaxial Tests

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 315
Author(s):  
Małgorzata Jastrzębska ◽  
Krzysztof Tokarz
Keyword(s):  
Shear Strength ◽  
Cyclic Loading ◽  
Cyclic Load ◽  
Low Frequency ◽  
Strength Characteristics ◽  
Excess Pore Pressure ◽  
Triaxial Tests ◽  
Stress Deviator ◽  
Red Clay ◽  
Rubber Waste

This paper presents the results of consolidated and undrained (CU) triaxial cyclic tests related to the influence of tire waste addition on the strength characteristics of two different soils from Southern Poland: unswelling kaolin and swelling red clay. The test procedure included the normally consolidated remolded specimens prepared from pure red clay (RC) and kaolin (K) and their mixtures with two different fractions of shredded rubber powder (P) and granulate (G) in 5%, 10%, and 25% mass proportions. All samples were subjected to low-frequency cyclic loading carried out with a constant stress amplitude. Analysis of the results includes consideration of the effect of rubber additive and number of load cycles on the development of excess pore pressure and axial strain during the cyclic load operation and on the maximum stress deviator value. A general decrease in the shear strength due to the cyclic load operation was observed, and various effects of shear strength depended on the mixture content and size of the rubber waste particles. In general, the use of soil–rubber mixtures, especially for expansive soils and powder, should be treated with caution for cyclic loading.

scholarly journals Strength Characteristics of Clay-Rubber Waste Mixtures in UU Triaxial Tests

Geosciences ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 352 ◽  
Author(s):  
Jastrzębska
Keyword(s):  
Inverse Relationship ◽  
Failure Strain ◽  
Strength Characteristics ◽  
Triaxial Tests ◽  
Shear Stresses ◽  
Confining Stress ◽  
Red Clay ◽  
Angle Of Internal Friction ◽  
Angle Of Friction ◽  
Rubber Waste

This paper presents results of undrained and unconsolidated (UU) triaxial tests related to the influence of tire waste addition on strength characteristics of red clay from Patoka in Southern Poland. Angle of internal friction and cohesion values were estimated for 30 specimens prepared from pure red clay (RC), its mixtures with two different fractions of shredded rubber in 5%, 10%, and 25% mass proportions as well as for pure powder (P) and granulate (G). It has been observed that the addition of granulate contributes more to the increase in the angle of friction than the addition of powder (uu = +1% (G-5) / +16% (G-10) / +31% (G-25), uu = +1% (P-5) / +10% (P-10) / +19% (P-25)). On the other hand, rubber additions reduce cohesion in mixtures, and the effect is enhanced with increases in their grain size and percentage composition (cuu = −31% (G-5) / −63% (G-10) / −87% (G-25), cuu = −67% (P-5) / −58% (P-10) / −58% (P-25)). It has been noticed that a change of parameters uu and cuu causes a decline of shear stresses at increasing granulate content. There is an inverse relationship for powder. At the same time, it has been shown that the failure strain, hence a change in red clay-rubber (RCR) mixtures plasticity, is related to the level of confining stress 3 and the type of rubber waste. Results of tests and their comparison with results of other researchers show that each time it is necessary to experimentally verify a given soil with specific rubber waste.

scholarly journals Microscopic Mechanism Affecting Shear Strength in Lignin-Treated Loess Samples

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Wei Liu ◽  
Juan Wang ◽  
Gaochao Lin ◽  
Li Wen ◽  
Qian Wang
Keyword(s):  
Shear Strength ◽  
Lignin Content ◽  
Axial Stress ◽  
Water Pressure ◽  
Excess Pore Pressure ◽  
Triaxial Tests ◽  
Microscopic Mechanism ◽  
Valley Fill ◽  
Fill Material ◽  
Excess Pore

In China, engineers have worked to create additional usable land for building construction by flattening the ridges of hills and filling in the adjacent valleys. China’s Loess Plateau comprises a type of soil (loess) with a large pore structure that can collapse and become unstable when exposed to groundwater. Conventional valley fill materials include remolded loess or remolded loess treated with cement, lime, gypsum, or other stabilizing additives. These stabilizers are often detrimental to the surrounding environment. Moreover, loess treated with conventional stabilizers exhibits excessive brittleness, which is not suitable for building foundations. Adequate stability of the building foundations in the filled valleys is required to ensure public safety. In this study, we tested 50 remolded loess samples treated with a lignin polymer compound to determine its potential as a valley fill material. Triaxial tests, scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to study the mechanical characteristics of each sample, determine the effects of the lignin treatment on the loess, and identify the microscopic mechanism affecting shear stress in the lignin-treated loess. The corresponding development of excess pore pressure and volumetric responses under monotonic triaxial testing were also considered. Based on this study’s results, the optimum lignin content in the treated loess samples was 4%; lignin contents exceeding 4% decreased axial stress and increased dilation after saturation. The shear strength and strain-hardening phenomenon of the lignin-treated loess samples increased as the lignin content increased, while the excess pore water pressure decreased. Microscopically, the addition of lignin increased cohesion in the loess samples, while slightly contributing to the internal friction angle. The use of lignin as a stabilizing additive for valley fill material shows potential for controlling building foundation deformation by increasing soil strength and minimizing environmental impacts by maintaining the soil pH and limiting pollutant production.

scholarly journals Deformation Characteristics of Soft Marine Soil Tested under Cyclic Loading with Low Frequency

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yu Lu ◽  
Wenbin Fu ◽  
Danxuan Xue
Keyword(s):  
Cyclic Loading ◽  
Pore Pressure ◽  
High Stress ◽  
Low Frequency ◽  
Load Level ◽  
Triaxial Tests ◽  
Deformation Characteristics ◽  
Confining Stress ◽  
The Difference ◽  
Marine Soil

Soft marine soil which could be found widely at the coastal and offshore areas is usually associated with high settlement and instability, especially under cyclic loading. Many research studies have been conducted on its deformation characteristics under the cyclic loading with high frequency, whereas few works have been reported on that under the low-frequency cyclic loading which largely existed in engineering. In this work, a comprehensive series of undrained triaxial tests under cyclic loading with low frequency was conducted to investigate the deformation characteristics of soft marine soil. The results demonstrate that soil specimens accumulate plastic deformation and pore pressure under cyclic loading. Specimens tested under conditions such as high confining stress, high-stress ratio, and long cyclic period generally reveal higher deformation and pore pressure. Meanwhile, the rectangular wave presents the largest contribution to plastic strain and pore pressure, followed by the trapezoidal and triangular waves, respectively, whereas the difference between the various waves decreased gradually with the increasing load level and cyclic period. The undisturbed specimens displayed lower deformations and pore pressures than the reconstructed specimens, whereas the differences are not significant when the confining stress is much higher than the structural yield stress. Furthermore, an empirical model for predicting the evolution of pore pressure is proposed and then validated against the experimental data in both this work and the literature.

scholarly journals Cyclic load Analysis of beam column joint using ANSYS

2021 ◽  
Vol 1197 (1) ◽  
pp. 012056
Author(s):  
Pranali Wasnik ◽  
Prof. Sanket Sanghai ◽  
P.Y. Pawade
Keyword(s):  
Shear Strength ◽  
Cyclic Loading ◽  
Cyclic Load ◽  
Fe Analysis ◽  
Seismic Zone ◽  
Column Joint ◽  
Load Analysis ◽  
Lateral Reinforcement

Abstract Work on FE analysis with the addition stirrup bar at different spacing in beam under the cyclic loading for strengthen the joint. The most important part of developing the beam column joint when cyclic loading take place in seismic zone. Six samples with different characteristic are chosen, design as per ductile detailing IS 13920-2016 and non-ductile detailing as per IS 456-2000 and design on ANSYS. The result shows that addition of lateral reinforcement have more shear strength. From the all sample the shear strength is high in addition of stirrups at L/3 scaled and L/4 scaled.

Stability threshold for cyclic loading of saturated clay

1989 ◽  
Vol 26 (1) ◽  
pp. 122-131 ◽  
Author(s):  
Guy Lefebvre ◽  
Denis LeBoeuf ◽  
Benoît Demers
Keyword(s):  
Shear Strength ◽  
Cyclic Loading ◽  
Strain Rate ◽  
Undrained Shear Strength ◽  
Triaxial Tests ◽  
Repeated Loading ◽  
Loading Test ◽  
Stability Threshold ◽  
The Stability ◽  
Undrained Shear

This paper presents the results of an experimental investigation performed to study the stability threshold under cyclic (repeated) loading, and the postcyclic static strength of a sensitive clay from the Hudson Bay region. The strain rate and structure effects were also studied by carrying out monotonic and cyclic triaxial tests at both slow and rapid strain rates or frequencies, and at confining pressures above and below the apparent preconsolidation pressure. The stability threshold for both structured and normally consolidated Grande Baleine clay is about 60–65% of the original undrained shear strength measured at the same strain rate as that used in the repeated loading test. The undrained shear strength and the failure envelope remain essentially unchanged if the repeated preloading is kept below the threshold. The clay structure remains unaltered by this preloading. Key words: clay, stability threshold, cyclic loading, earthquake, postcyclic strength.

scholarly journals Experimental Investigation on the Behavior of Gravelly Sand Reinforced with Geogrid under Cyclic Loading

2021 ◽  
Vol 11 (24) ◽  
pp. 12152
Author(s):  
Jia-Quan Wang ◽  
Zhen-Chao Chang ◽  
Jian-Feng Xue ◽  
Zhi-Nan Lin ◽  
Yi Tang
Keyword(s):  
Cyclic Loading ◽  
High Speed ◽  
Water Pressure ◽  
Excess Pore Pressure ◽  
Triaxial Tests ◽  
Sand Sample ◽  
Loading Frequency ◽  
Gravelly Soil ◽  
Embedding Effect ◽  
Excess Pore

In view of the dynamic response of geogrid-reinforced gravel under high-speed train load, this paper explores the dynamic characteristics of geogrid-reinforced gravel under semi-sine wave cyclic loading. A number of large scale cyclic triaxial tests were performed on saturated gravelly soil reinforced with geogrid to study the influence of the number of reinforcement layers and loading frequencies on the dynamic responses of reinforced gravelly sand subgrade for high speed rail track. The variation of cumulative axial and volumetric strains, excess pore pressure and resilient modulus with number of loading cycles, loading frequency, and reinforcement arrangement are analyzed. The test results reveal that the cumulative axial strain decreases as the number of reinforcement layers increases, but increases with loading frequency. The resilience modulus increases with the number of reinforcement layers, but decreases as the loading frequency increases. The addition of geogrid can reduce the excess pore water pressure of the sample, but it can slightly enhance the rubber mold embedding effect of the sand sample. As the loading frequency increases, the rubber mold embedding effect gradually weakens.

scholarly journals Behaviour of Cohesive Soil Subjected to Low-Frequency Cyclic Loading in Strain-Controlled Tests

2015 ◽  
Vol 36 (3) ◽  
pp. 21-35 ◽  
Author(s):  
Marta Kalinowska ◽  
Małgorzata Jastrzębska
Keyword(s):  
Cyclic Loading ◽  
Pore Water ◽  
Effective Stress ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Low Frequency ◽  
Cohesive Soil ◽  
Stress Deviator ◽  
Kaolinite Clay ◽  
Cyclic Shear

Abstract The subject of the paper comprises tests of cohesive soil subjected to low-frequency cyclic loading with constant strain amplitude. The main aim of the research is to define a failure criteria for cohesive soils subjected to this type of load. Tests of undrained cyclic shear were carried out in a triaxial apparatus on normally consolidated reworked soil samples made of kaolinite clay from Tułowice. Analysis of the results includes the influence of number of load cycles on the course of effective stress paths, development of excess pore water pressure and stress deviator value. Observed regularities may seem surprising. The effective stress path initially moves away from the boundary surface and only after a certain number of load-unload cycles change of its direction occurs and it starts to move consequently towards the surface. At the same time, it has been observed that pore water pressure value decreases at the beginning and after few hundred cycles increases again. It is a typical behaviour for overconsolidated soil, while test samples are normally consolidated. Additionally, a similar change in deviator stress value has been observed - at first it decreases and later, with subsequent cycles, re-increases.

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