scholarly journals Experimental Study on the Effect of Freezing and Thawing on the Shear Strength of the Frozen Soil in Qinghai-Tibet Railway Embankment

2022 ◽  
Vol 2022 ◽  
pp. 1-12
Author(s):  
B. Wang ◽  
J. H. Gao ◽  
Y. Q. Wang ◽  
X. J. Quan ◽  
Y. W. Gong ◽  
...  
Keyword(s):  
Growth Rate ◽  
Internal Friction ◽  
Moisture Content ◽  
Initial Moisture Content ◽  
Friction Angle ◽  
Frozen Soil ◽  
Internal Friction Angle ◽  
Freezing Process ◽  
Dry Density ◽  
Freezing And Thawing

The direct shear tests of different dry density and moisture content samples at different temperatures of the frozen soil in the Qinghai-Tibet Railway embankment between Tanggula South and Anduo section were carried out to analyze the influence rules of each experimental factor on the mechanical properties of frozen soil during the freeze-thaw process. The results show the following. (1) When the frozen soil temperature is below 0°C and continues to drop during the freezing and thawing process, each sample shows the law of a significant increase in cohesion and a slight decrease in the internal friction angle. In the meantime, the cohesion obtained during the thawing process of the sample at the same temperature point is higher than that obtained during the freezing process. In contrast, the internal friction angles exhibit an opposite law, where the internal friction angle during the melting process is lower than the internal friction angle during the freezing process. After freezing-thawing action, it deserves to be mentioned that the cohesion increases slightly while the internal friction angles present a slight decrease trend compared to the initial state. (2) With the decrease in temperature and the gradual increase in cohesion, the temperature curve can be divided into a fast-growing section from 0 to −2°C, a slow-growing section from −2 to −8°C, and a second fast-growing section from −8 to −10°C owing to the combined effect of the pressure-thawing action and ice-water phase change. In addition, the rate of decrease in the internal friction angle also shows a similar pattern. (3) The cohesion and the internal friction angle of samples both tend to increase first and then decrease with the rise of the initial moisture content, and the critical initial moisture content is near the optimal moisture content of 15%. (4) Both the cohesion and the internal friction angle of the samples increase with dry density growth. The growth rate of cohesion will gradually increase as the temperature decreases. Moreover, the growth rate of cohesion of low dry density samples is more susceptible to temperature, while the internal friction angle growth rate is not affected by temperature.

Experimental Study on Shear Strength of West Sichuan Unsaturated Mixed-Soil

2013 ◽  
Vol 353-356 ◽  
pp. 772-778 ◽  
Author(s):  
Kai Cui ◽  
Bang Wen Huang
Keyword(s):  
Internal Friction ◽  
Moisture Content ◽  
Water Content ◽  
Mineral Water ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Cohesive Force ◽  
Dry Density ◽  
Control Matrix ◽  
Matrix Suction

By controlling moisture content to control matrix suction indirectly, three typical unsaturated remolded mixed-soil from west Sichuan are studied by the consolidated untrained triaxial shear test .The test data show that for different kinds of soil samples, the sample with less amount of clay and high content of quartz has bigger internal friction angle relatively, and the sample with hydrophilic mineral and high content of clay has bigger cohesive force. Meanwhile, for the sample without or less hydrophilic mineral, cohesive force is affected mainly by water content, and for the sample with large content of hydrophilic mineral, water content and dry density affect cohesive force together. For a certain sample, the variation of moisture content and dry density affects internal friction angle less, while affects cohesive force more. In addition, the change of internal friction angle resulting from the variation of matrix suction is less, and cohesive force increases as matrix suction increases.

Determine the Shear Strength of Aeolian Sand and Bearing Capacity

2014 ◽  
Vol 580-583 ◽  
pp. 165-168
Author(s):  
Ying Zi Yin ◽  
Ya Lei Wang
Keyword(s):  
Internal Friction ◽  
Moisture Content ◽  
Bearing Capacity ◽  
Retaining Wall ◽  
Friction Angle ◽  
Optimum Moisture Content ◽  
Internal Friction Angle ◽  
Dry Density ◽  
Filling Material ◽  
Aeolian Sand

In this article, through aeolian sand sample study in Inner Mongolia Baotou area, to determine the aeolian sand maximum dry density and optimum moisture content. On this basis, the aeolian sand cohesion and internal friction angle were measured by the quick direct shear test when aeolian sand was at the optimum moisture content and near the most largest compactness. And the bearing capacity of retaining wall model which regarded aeolian sand as fillers was determined. Then bearing capacity change of aeolian sand wrapped before and after was compared. Experimental results showed that: when the aeolian sand was in the wet and compacted state, its cohesion was 3.31 kPa and internal friction angle was 36.8°. The aeolian sand bearing capacity was 153.8kPa by the plate loading test. The aeolian sand wrapped with a geotextile bearing capacity was 194.1kPa. Through the aeolian sand research of Baotou area, it provides a useful reference for the construction of highway and railway and application of wrap-reinforced retaining wall which is a new retaining structure in the region, and the aeolian sand is treated as a special filling material in these structures.  

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.

Seafloor Polymetallic Sulfides Mechanical Property Test

2014 ◽  
Vol 1015 ◽  
pp. 316-319
Author(s):  
Zhong Hua Huang ◽  
Shao Jun Liu ◽  
Ying Guang Xu ◽  
Wang Hu
Keyword(s):  
Compressive Strength ◽  
Internal Friction ◽  
Uniaxial Compressive Strength ◽  
Compression Strength ◽  
Triaxial Compression ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Test Method ◽  
Dry Density ◽  
Average Value

Seafloor polymetallic sulfide specimens were developed according to engineering rock test method standard (GB/T 50266-2013). Seafloor polymetallic sulfide wet density and dry density were tested. Uniaxial compressive strength and triaxial compression strength of seafloor polymetallic sulfide were tested using rock mechanics test system MTS 815. Elasticity modulus and Poisson's ratio of seafloor polymetallic sulfide were calculated based on specimens stress-strain curves. Cohesion and internal friction angle were calculated based on specimens triaxial test Mohr stress circle. Test results show that seafloor polymetallic sulfide dry density average value is 2.6 g/cm3, wet density average value is 2.94 g/cm3. Uniaxial compressive strength and triaxial compression strength of seafloor polymetallic sulfide are unstable. Average value of the uniaxial compressive strength is 10.243MPa. Average value of triaxial compression strength test peak load is 47.166KN. Cohesion is 2.447MPa and internal friction angle is 38.04o.

scholarly journals The influence of organic polymer on properties of mineral concentrates

2013 ◽  
Vol 20 (2) ◽  
pp. 90-93
Author(s):  
Marzenna Popek
Keyword(s):  
High Risk ◽  
Internal Friction ◽  
Moisture Content ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Organic Polymer ◽  
Biodegradable Materials

AbstractTransport of mineral concentrates is associated with high risk of liquefaction of the cargoes. This type of goods containing water may liquefy and shift dangerously across the cargo compartments. Therefore, it is rational to limit the moisture content of the cargoes which may liquefy. To prevent sliding and shifting of ore concentrates in storage biodegradable materials composed of starch are added to the mineral concentrates. The influence of adding starch materials to the mineral concentrates on its parameters determining ability for safe shipment was assessed on the basis of determination of the following parameters: permeability, cohesion and internal friction angle of concentrates.

scholarly journals Study and Application of Similar Material Ratio in Collapsible Loess

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Bingchao Zhao ◽  
Yunxiang Ma ◽  
Yaxin Guo ◽  
Hao Sun ◽  
Jingbin Wang ◽  
...  
Keyword(s):  
Internal Friction ◽  
Moisture Content ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Similar Material ◽  
Range Analysis ◽  
River Sand ◽  
Collapsible Loess ◽  
Seam Mining ◽  
Similar Simulation

The similar material of collapsible loess is the basis and premise of the experimental study on the surface movement and deformation law of coal seam mining in collapsible loess-covered areas. The orthogonal experiment is used to make up similar material with different proportions using river sand and barite powder as aggregate, clay and gypsum as cementing material, and diatomite as adjusting material. The reasonable proportion of similar material in collapsible loess is studied by using range analysis, similar simulation, and field measurement. The results show that the content of diatomite plays a leading role in the collapsibility coefficient of similar material, and the collapsibility coefficient is positively correlated with the content of diatomite; moisture content is the main control of the cohesion of the material, and cohesion is negatively correlated with the moisture content; the ratio of bone-to-glue has the most significant effect on the internal friction angle, and the internal friction angle is positively correlated with the ratio of bone-to-glue. The reasonable ratio of the similar material in collapsible loess is 8 : 2 of the ratio of bone-to-glue, the ratio of clay-to-gypsum is 9 : 1, the barite powder content is 6%, the diatomite content is 23%, and the moisture content is 13%, and the mechanical parameters of the collapsible loess are 5.3%–6.3% different from the target value of similar material through laboratory tests, which can meet the experimental requirements. It is verified by a similar simulation experiment that the maximum surface subsidence value and the surface fracture width in the simulation results are 6.9% and 7.8% different from the field measured results, indicating a high degree of agreement. The results of the study have important references and guiding significance for the preparation of similar material with similar models.

Experimental Research on the Characteristics of Soil Strength Freeze-Thaw Weakening in Songhua River Songpu Bank

2014 ◽  
Vol 501-504 ◽  
pp. 403-409
Author(s):  
Xue Han ◽  
Zi Long Zhao ◽  
Zi Rui Gao
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Friction Angle ◽  
Soil Strength ◽  
Internal Friction Angle ◽  
Physical Parameters ◽  
Freezing And Thawing ◽  
Songhua River ◽  
Freeze Thaw ◽  
Soil Shear Strength

In order to study characteristics of soil strength freeze-thaw weakening in the Songhua River Songpu bank，basic physical parameters tests and triaxial compression tests were performed on that paragraph bank .The results showed that: after thawing the sample cohesion will drop substantially, the internal friction angle will increase greatly and soil shear strength will increase significantly; the cohesion of sample after repeated freezing and thawing will significantly decline，internal friction angle of soil will greatly increase，the soil shear strength will increase after the first freezing and thawing，with the increase in the number of freeze-thaw cycles, the soil shear strength will significantly decline. The results can provide Songhua slope stability analysis with a scientific basis.

scholarly journals Plastic Design Theory of Frozen Wall Thickness in an Ultradeep Soil Layer Considering Large Deformation Characteristics

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Bo Zhang ◽  
Weihao Yang ◽  
Baosheng Wang
Keyword(s):  
Internal Friction ◽  
Large Deformation ◽  
Wall Thickness ◽  
Design Theory ◽  
Soil Layer ◽  
Friction Angle ◽  
Frozen Soil ◽  
Internal Friction Angle ◽  
Frozen Wall ◽  
New Formula

Frozen wall design theory is a key technique of the freezing method. However, previous design theories for a deep artificial frozen wall have neglected the influence of shaft flank displacement, that is, the displacement of the inner boundary of a frozen wall. Thus, the associated designs tend to be unsafe and earthwork excavations tend to be underestimated. This study builds a new design theory for frozen wall thickness which considers the influence of a large strain and obtains new solution formulas for the thickness and excavation radius before deformation occurs. The analytical results are compared with numerical calculation results by analyzing the influences of various parameters, such as crustal stress, cohesion and internal friction angle of frozen soil, and cohesion and internal friction angle of unfrozen soil as well as the elastic modulus of the ground, on the frozen wall thickness and the shaft flank displacement. The results indicate that the new formula is applicable for large deformation calculation with a strain of up to 0.2. The new formula can accurately calculate the amount of excavation earthwork and serves as a safer and more reasonable theoretical support for the design of frozen walls in ultradeep soil layers.

scholarly journals Experimental Study on Moisture Migration of Unsaturated Loess during the Freezing Process

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Hui Zhang ◽  
Tiehang Wang ◽  
Enlong Liu ◽  
Mengling Hu
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Freezing Process ◽  
Dry Density ◽  
Freezing Front ◽  
Slow Cooling ◽  
Moisture Migration ◽  
Cooling Stage ◽  
Large Size ◽  
Unsaturated Loess

To reveal the water-heat transfer mechanism of unsaturated loess, the effects of soil dry density (1.30 g/cm3, 1.50 g/cm3, and 1.65 g/cm3), moisture content (13.3%, 16.2%, and 19.4%), cold end temperature (−7°C, −10°C, and −13°C), and freezing mode on moisture migration in unsaturated loess in this paper are studied through indoor tests of moisture migration under the freezing action of large-size unsaturated loess. The results show that the temperature change in soil samples in the freezing process can be divided into three stages: rapid cooling stage, slow cooling stage, and stable stage. The higher the dry density, the closer the freezing front is to the cold end, with the initial moisture content having little effect on the freezing front, while the temperature at the cold end has a significant effect on the location of the freezing front. The total amount of moisture migration decreases with the increase of dry density, increases with the increase of moisture content, and increases with the decrease of cold end temperature. The freezing mode directly affects the distribution of moisture content and total amount of moisture migration in the frozen area.

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