scholarly journals Study of Material Composition Effects on the Mechanical Properties of Soil-Rock Mixtures

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yanxi Zhao ◽  
Zhongxian Liu
Keyword(s):  
Mechanical Properties ◽  
Control System ◽  
Internal Friction ◽  
Strain Curve ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Material Composition ◽  
Medium Scale ◽  
Random Location ◽  
Rock Size

Soil-rock mixtures are often seen in geological deposits. Mechanical properties of these mixtures are controlled by microstructural characteristics such as rock size distribution, rock shape, locations, and content. The effects of material composition on soil-rock mechanical properties were studied in the laboratory. The soil-rock material was screened into different size categories. Medium-scale shearing and triaxial experiments were used to study the relationships among macrodeformation, strength, content, size, and random location of rocks. The medium-scale triaxial shearing instrument included the computer control system, EDC control system, and sensor response. The stress-strain curve of soil-rock mixtures was found as a hardening curve which is approximately hyperbolic, and there was no obvious peak intensity value. When the Mohr–Coulomb criterion was used to depict the curve under a shear strain of 0.15, cohesion first increased and then decreased, a finding opposite to the internal friction angle with a decrease in particle size. Elastic modulus increased with an increase in rock size, but Poisson’s ratio remained constant. In similar conditions, the random location of rocks can lead to a variation range of 4 degree of the internal friction angle, and cohesion values can change in a large range than the mean value.

Dry and Wet Cycle Tri-Axial Test Research of Silt

2011 ◽  
Vol 90-93 ◽  
pp. 41-43
Author(s):  
Hong Liang ◽  
Yan Wang ◽  
Tian Ping Zhou ◽  
Zhen Tao Zhang ◽  
Zhi Gang Li ◽  
...  
Keyword(s):  
Internal Friction ◽  
Mechanical Performance ◽  
Strain Curve ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Intensity Change ◽  
Cycle Index ◽  
Stress Strain ◽  
Systematic Analysis ◽  
Engineering Characteristic

Abstract. Silt in some areas of our country is very extensive, its distribution is different from the cohesive soil, or sand soil, has unique engineering characteristic. Silt regional characteristics make it has many unique physic-mechanical performance. This article take the G209 (Inner Mongolia Helin to Qingshuihe section) the roadbed silty soil as the study object, study its basic physics, the mechanical properties as well as the distortion and the intensity change rule under the dry-wet circulation, do a comprehensive and systematic analysis about varieties of basic engineering characteristic of the silt in the region Through the condition of dry-wet circulation of unconsolidated tri-axial tests, this article study the silt sample failure pattern under different degree of compaction, stress-strain relations and the change rule of strength. The test results show that: as cycle index less and confining pressure down, test sample is basically brittle failure, on the contrary case, it is behaved for plastic failure and stress-strain curve is close to sclerosis type; When cycle index increase gradually, the cohesion of silt reduced significantly ,with the increase of dry-wet circulation times internal friction angle is on the trend of the attenuation oscillation ; On this basis, we build the relationship expression of shear strength parameters cohesion internal friction angle and dry-wet circulation times.

scholarly journals Effect of Freeze-Thaw Cycles on the Mechanical Properties of Polyacrylamide- and Lignocellulose-Stabilized Clay in Tibet

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Haiping Shi ◽  
Zhongyao Li ◽  
Wenwei Li ◽  
Shaopeng Wang ◽  
Baotian Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Internal Friction ◽  
Unconfined Compressive Strength ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Test Results ◽  
Freeze Thaw ◽  
Original Strength ◽  
Compressive Tests

Laboratory freezing experiments were conducted to evaluate the effect of polyacrylamide (PAM) and lignocellulose on the mechanical properties and microstructural characteristics of Tibetan clay. Direct shear and unconfined compressive tests and field emission scanning electron microscopy analyses were performed on clay samples with different contents of stabilizers. The test results show that the addition of PAM can improve the unconfined compressive strength and cohesion of Tibetan clay, but an excessive amount of PAM reduces the internal friction angle. After several freeze-thaw cycles, the unconfined compressive strength and cohesion of samples stabilized by PAM decrease significantly, while the internal friction angle increases. Samples stabilized by PAM and lignocellulose have higher internal friction angles, cohesion, and unconfined compressive strength and can retain about 80% of the original strength after 10 freeze-thaw cycles. PAM fills the pores between soil particles and provides adhesion. The addition of lignocellulose can form a network, restrict the expansion of pores caused by freeze-thaw cycles, and improve the integrity of PAM colloids. It is postulated that the addition of a composite stabilizer with a PAM content of 0.4% and a lignocellulose content of 2% may be a technically feasible method to increase the strength of Tibetan clay.

scholarly journals Improving the Mechanical Properties of Red Clay Using Xanthan Gum Biopolymer

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Lina Wang ◽  
Zhiyu Weng ◽  
Qiang Liu ◽  
Tianliang Wang ◽  
Xuemin Pan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Internal Friction ◽  
Xanthan Gum ◽  
Friction Angle ◽  
Inorganic Materials ◽  
Internal Friction Angle ◽  
Red Clay ◽  
Clay Particles ◽  
Gum Content ◽  
Curing Age

The traditional treatment of red clay using inorganic materials leads to many serious environmental problems. The study investigates the mechanical properties of red clay using an environmental-friendly material—xanthan gum—through confined compression, direct shear, and scanning electron microscope tests. At the macroscale, xanthan gum content and curing age had obvious effects on the compressibility, presenting the treated red clay was in the category of low compressibility which gradually increased when xanthan gum content exceeded 1.5%. The xanthan gum content and curing age also had significant influences on the cohesion but not on the internal friction angle. The shear strength of red clay can be improved by increasing the cohesion without obviously changing the friction characteristics. After curing for 28 days, the cohesion and internal friction angle of 2.0% xanthan gum-treated soil were effectively improved to 170.44 kPa and 20.56°, which were increased by 69.79% and 9.36°, respectively, compared with untreated red clay. Microscopic analysis indicated that the strengthening mechanism by xanthan gum was derived from changing the arrangement characteristics of soil particles and forming hard biopolymer-red clay matrices. The proper xanthan gum can effectively wrap clay particles and fill pore spaces. However, the extensive stacking of gels would also reduce the effective connection of clay particles and produce local weak points in the soil, resulting in attenuation of mechanical properties. This study enriches the treatment measure of red clay and provides beneficial experiences for biopolymer application on special clay.

scholarly journals Macro-Micromechanical Properties of Sandy Pebble Soil of Different Coarse-Grained Content

2018 ◽  
Vol 22 (1) ◽  
pp. 65-71
Author(s):  
Junfu Lu ◽  
Di Li ◽  
Xiaoqiang Xue ◽  
Shenlin Ling
Keyword(s):  
Internal Friction ◽  
Triaxial Test ◽  
Large Scale ◽  
Strain Curve ◽  
Friction Angle ◽  
Confining Pressure ◽  
Discrete Element ◽  
Internal Friction Angle ◽  
Coarse Grained ◽  
Research Results

Sandy pebble stratum is a typical discrete particle unstable stratum, mainly consisting of sand and pebble. However, the effect of coarse-grained content on the stability of stratum is not clear. This paper defined the sandy pebble soil of different coarse-grained content in Chengdu City, Sichuan Province, China as the research object. Research on macro-mesomechanical properties of sandy pebble soil of different coarse-grained content was carried out using the method combining the indoor large-scale triaxial test of coarse-grained soil with the discrete element numerical triaxial test. The research results showed that the stress-strain curve of sandy pebble soil exhibited strain softening with the increase of coarse-grained content; when the confining pressure was the same, the stress peak increased and the strain when the peak was reached decreased gradually with the increase of coarse-grained content. It revealed the functional relationship between coarse-grained content and mechanical indexes of sandy pebble soil such as internal friction angle and cohesion. The internal friction angle and cohesion of sandy pebble soil linearly increased with the rise of coarse-grained material; it proposed the particle discrete element micro parameters of sandy pebble soil of different coarse-grained content, including contact modulus, friction coefficient, particle stiffness ratio, contact bond strength. The research results provided the theoretical support for the new design and construction of sandy pebble stratum project. 

scholarly journals Microscopic Mechanism of the Macroscopic Mechanical Properties of Cement Modified Subgrade Silty Soil Subjected to Freeze-Thaw Cycles

2020 ◽  
Vol 10 (6) ◽  
pp. 2182
Author(s):  
Hanbing Liu ◽  
Shuang Sun ◽  
Lixia Wang ◽  
Yunlong Zhang ◽  
Jing Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Internal Friction ◽  
Particle Diameter ◽  
Morphological Characteristics ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Average Particle ◽  
Freeze Thaw ◽  
Silty Soil

In order to study the effects of the microstructure parameters of cement modified subgrade silty soil (CMSS) in a frozen area under freeze-thaw (F-T) cycles on the macroscopic mechanical properties, the static triaxial test, scanning electron microscopy (SEM), and grey relation analysis (GRA) were implemented on silty soil modified with 0% and 2% cement at optimum moisture content from the northwest in Jilin Province in China. The results showed that the shear strength, the cohesion of 0% and 2% CMSS, decreased with the increase of F-T cycles, while the internal friction angle was not obviously changed. The shear strength and its parameters of 2% CMSS doubled compared to that of 0% CMSS. The micro-parameters, representing the particle morphological characteristics, particle arrangement, and pore characteristics of CMSS, changed differently under F-T cycles. If the cement was not added, the cohesion and the internal friction angle were most sensitive to the average particle diameter (Dp) and the average particle abundance (C), respectively. When the cement content was 2%, the cohesion was chiefly affected by the particle size fractal dimension (Dps), while the internal friction angle was mainly related to the average pore diameter (Dh). The main principle of cement improvement was to decrease Dh of soil under F-T cycles.

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.

Strength and Deformation Characteristics of Stabilized Silty Soil

2012 ◽  
Vol 594-597 ◽  
pp. 512-515
Author(s):  
Zheng Rong Zhao ◽  
Hong Xia Yang
Keyword(s):  
Internal Friction ◽  
Brittle Failure ◽  
Yellow River ◽  
Strain Curve ◽  
Friction Angle ◽  
Confining Pressure ◽  
Alluvial Plain ◽  
The Yellow River ◽  
Stress Strain Curve ◽  
Silty Soil

Combined with the silty soil characteristics of the Yellow River alluvial plain and the subgrade filling of Ji-He expressway, the paper discusses silty soil, stabilized silty soil strength and stress-stain characteristics through the indoor triaxial shear test. The results show that the remodeling silty soil has obvious peak, brittle failure, low residual strength after being destroyed and the stress-strain curve shows a softening type in confining pressure 100kPa lower stress level. In the confining pressure 400kPa higher stress level, soil samples peak is not obvious,mainly plastic failure and the stress-strain curve is close to a hardening type. Compared to mixed with 8% lime, stabilized silty soil of mixed with 4% cement and 4% lime shows that the partial stress peak is more obvious when destroyed and the residual strength is drastically reduced and more incline to brittle failure. In different the age, compared to mixed with 8% lime, stabilized silty soil of mixed with 4% cement and 4% lime shows that internal friction angle becomes larger and cohesion improves gradually whose amplitude is much larger than internal friction angle. Therefore, a more effective way to stabilize the silty soil of the Yellow River alluvial plain is to select silty soil mixed with 4% cement and 4% lime.

Sign in / Sign up

Export Citation Format

Share Document