scholarly journals Experimental Study on the Mechanical Property of Loess Mixed with Bentonite-HDTMA

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zhang Ming ◽  
Chen Guozhou ◽  
Liu Yang ◽  
Huang Shouhai
Keyword(s):  
Mechanical Property ◽  
Shear Strength ◽  
Yellow River ◽  
Negative Impact ◽  
Friction Angle ◽  
Cohesive Force ◽  
Dry Density ◽  
Lining Material ◽  
Significant Negative Impact ◽  
Compressibility Coefficient

Malan loess in the middle and lower reaches of the Yellow River after mixed with different bentonite and HDTMA ratios was selected to carry out shear and consolidation tests for discussing the influence of bentonite-HDTMA on the mechanical property of loess lining material in landfills. Studies have shown that, after mixing 6% to 14% bentonite, the cohesive force of modified loess is significantly increased, the friction angle is reduced and remains stable, and the shear strength is improved. The compressibility of materials slightly decreases with the increase of bentonite ratio. The addition of 2%–4% HDTMA weakens the increment for the cohesive force caused by bentonite, but the friction angle is effectively recovered. The compressibility of materials increases with the increase of HDTMA ratio. As the dry density increases, the shear strength of the modified loess increases, and the compressibility coefficient decreases. The mechanical property of loess lining material can be optimized by adding 6%–14% bentonite. The incorporation of 2%–4% HDTMA does not have a significant negative impact on the optimization effect of bentonite. From the perspective of the mechanical property, it is recommended that the dry density of modified loess is 1.70 g/cm3, the bentonite ratio is 10%–14%, and the HDTMA ratio is 2%–4%.

Study on the Clay Mechanical Characteristics of “Ripping Up the Bottom” in the Yellow River

2012 ◽  
Vol 212-213 ◽  
pp. 108-112 ◽  
Author(s):  
Wen Sheng Dong ◽  
Xiu Fang Jiang ◽  
Xian Feng He ◽  
Ying Ying Zai
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Mechanical Strength ◽  
Water Content ◽  
Critical Condition ◽  
Mechanical Characteristics ◽  
Yellow River ◽  
The Yellow River ◽  
Dry Density ◽  
The Relationship

Aim to the high sandy river “ripping up the riverbed” phenomenon, by experiment, analyzing the relationship between clay dry density, water content, plasticity index and its shear strength, and its mechanical properties. Create the conditions for studying clay mechanical strength and the critical condition of “bottom tearing scour”.

scholarly journals Influence of water content on the shear strength parameters of clayey soil in relation to stability analysis of a hillside in Brno region

2013 ◽  
Vol 61 (6) ◽  
pp. 1583-1588 ◽  
Author(s):  
Kristýna Bláhová ◽  
Lenka Ševelová ◽  
Pavla Pilařová
Keyword(s):  
Shear Strength ◽  
Stability Analysis ◽  
Water Content ◽  
Clayey Soil ◽  
Friction Angle ◽  
Dry Density ◽  
Stability Analyses ◽  
Influence Of Water ◽  
Moisture Conditions ◽  
Processing Stability

Shear strength of soils is highly affected by moisture conditions (i.e. water content), especially if the soil contains clay materials. Usually the laboratory specimen, which are used to determine shear strength of soil are prepared at water content and dry density same as in the field conditions, without respect to the fact, that the conditions in the future might not remain the same. For the purpose of this study soil specimen were compacted and the optimum moisture content was identified. After compaction soil was tested at the dry side of optimum water content at w = 9 %, 10 % and 11 %. Parameters of shear strength were obtained and used for stability analysis with software GEOSLOPE/W 2012. According to referenced literature, it was expected for the shear strength of the soil to decrease with increasing water content. This hypothesis was not proven for clayey soil from Brno region. Development of values of friction angle and cohesion exhibited anomalous behaviour and such development was found also for values of Factor of safety (FOS) obtained from stability analyses. Results proved the necessity of taking moisture conditions into account, when processing stability analyses, in order to achieve reliable and safe constructions.

scholarly journals Experimental Investigation on Shear Strength Parameters of Lime Stabilized Loess

2019 ◽  
Vol 11 (19) ◽  
pp. 5397 ◽  
Author(s):  
Liang Jia ◽  
Jian Guo ◽  
Yanbin Jiang ◽  
Yong Fu ◽  
Zhidong Zhou ◽  
...  
Keyword(s):  
Shear Strength ◽  
Yellow River ◽  
Friction Angle ◽  
Experimental Results ◽  
Triaxial Tests ◽  
Curing Time ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Lime Content ◽  
Coulomb Failure

Loess is a typical collapsible soil, which is widely distributed in the upper and middle areas around the Yellow River of China. The stabilization of loess with lime provides a significant improvement in the physical and the mechanical characteristics of the loess and is therefore widely used in the pavement base and subgrade. Therefore, a systematic investigation of Mohr-Coulomb failure envelope of lime stabilized loess needs to be conducted. In this pursuit, the present research envisages the investigation of the effects of the lime content, porosity and curing time on the strength parameters (friction angle (φ) and cohesion (c)), using a series of triaxial tests performed on lime stabilized loess specimens. The experimental results revealed that the friction angle (φ) was independent of the lime content, the porosity and the curing time of the specimen for a given lime stabilized loess, while the factors mentioned above had a significant effect on the cohesion (c) of the lime stabilized loess. For a relatively short curing time (7 days), the change in the lime content did not present an obvious effect on the cohesion (c) of the stabilized loess. However, when the curing time (28, 90 and 180 days) was longer, the increase of the lime content significantly enhanced the cohesion of the stabilized loess. When the lime content was constant, the cohesion (c) of the stabilized loess increased linearly with the decrease in the void ratio. A power function equation was proposed to assess the comprehensive influences of the factors like the lime content, porosity and curing time on cohesion (c). Finally, the Mohr-Coulomb failure envelopes were drawn based on the triaxial test for 47 specimens with various curing time and confining pressure, and the shear strength parameters obtained by the proposed equation were also compared with the experimental results.

scholarly journals Study on Mechanical Properties of the Expansive Soil Treated with Iron Tailings Sand

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Chengfu Chu ◽  
Fei Zhang ◽  
Daoxiang Wu ◽  
Meihuang Zhan ◽  
Yun Liu
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Friction Angle ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Occlusal Force ◽  
Optimal Moisture Content ◽  
Tailings Sand

Aiming at researching shear strength parameters of expansive soil modified by industrial waste iron tailings sand, the enhancement of expansive soil is explored from macroscopic and microscopic aspects. After characterization and testing by various means, the results show that expansive soil modified by iron tailings sand will increase the maximum dry density of the improved soil and reduce its optimal moisture content, which is beneficial in tuning the moisture content at the construction site. In addition, iron tailings sand can improve the shear strength of expansive soils. The influence of iron tailings sand on cohesion increases first, then decreases, and reaches the peak value at 30%, while the effect on internal friction angle exhibits a continuously increasing trend. Furthermore, according to mercury intrusion tests and microangle analysis, the addition of iron tailings sand can reduce the tiny pores and enhance the occlusal force of the soil. Simultaneously, it increases the number of large pores, maximizing the macroscopic strengthening of iron tailings sand towards the expansive soil.

scholarly journals Experimental Study on Main Physical Parameters Controlling Shear Strength of Unsaturated Loess

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Wen-tong Tian ◽  
Jian-hua Dong ◽  
Jun-jie Sun ◽  
Bo Yang
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Water Content ◽  
Quartz Sand ◽  
Clay Content ◽  
Friction Angle ◽  
Dry Density ◽  
Physical Parameters ◽  
Sandy Silt ◽  
Unsaturated Loess

It is particularly important to study the strength of unsaturated loess, and its accurate determination is crucial to the stability analysis of soil slope and foundation and calculation of earth pressure. In order to reveal the control mechanism of physical parameters on the shear strength of unsaturated loess, the intact and remolded loess were used as the research object; sandy silt, quartz flour, and quartz sand were used as contrast; the systematic direct shear tests of unsaturated loess, sandy silt, and quartz sand under different conditions of water content, dry density, and clay content were carried out. The results show that the cohesion, internal friction angle, and shear strength of unsaturated loess piecewise functionally decrease with the increase of water content, its shear strength increases linearly with the increase of dry density, and its internal friction angle shows an upward quadratic function relation with the increase of clay content. The law results of comparing sandy silt, quartz flour, and quartz sand with loess considering water content and dry density are the same; therefore, the equation of shear strength of unsaturated loess is proposed for practical engineering reference, and by the first derivative analysis of the equation, it is feasible to determine the control proportion of the three parameters on the shear strength of unsaturated loess. A stage-like difference between the three control proportions is observed, depending on the combination variations of water content and clay content.

Dynamic Triaxial Experimental Study on Wave-Induced Strength Weakening of Subaqueous Yellow River Delta Silty Soil Under Wave Action

2009 ◽  
Author(s):  
Guohui Xu ◽  
Huixin Liu ◽  
Xin Wang ◽  
Congcong Wei ◽  
Minsheng Zhang
Keyword(s):  
Shear Strength ◽  
Failure Modes ◽  
Yellow River ◽  
Yellow River Delta ◽  
Friction Angle ◽  
Wave Action ◽  
River Delta ◽  
Dynamic Shear ◽  
Silty Soil ◽  
Dynamic Shear Strength

Silty soil in the Chengbei region of the Yellow River Delta is prone to geological hazards including landslides, collapses, silt flow, etc. The failure of silty soil is closely correlated with its strength change induced by wave action. In this study, dynamic triaxial experiments were employed to explore the relationship between oscillation times and dynamic shear strength of silty soil in the Subaqueous Yellow River Delta by modeling wave-seabed interactions. This paper studies the change law of dynamic shear strength, cohesion and internal friction angle with the oscillation time. The results indicate that the strength weakening of silty soil follows the rule of power function attenuation. In addition, failure modes, variations in pore pressure together with the microstructures are also discussed in this paper through careful observation of the samples.

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.

Improvement of the Shear Strength Parameters of a Granular Volcanic Soil Using Type I Portland Cement

2021 ◽  
Vol 896 ◽  
pp. 165-172
Author(s):  
Jordy Frank Viso Chachayma ◽  
Jhian Franco Torres Alvarez ◽  
Gary Durán Ramírez ◽  
Carlos Mario Fernández Díaz
Keyword(s):  
Shear Strength ◽  
Direct Shear Test ◽  
Shear Test ◽  
Friction Angle ◽  
Natural Soil ◽  
Dry Density ◽  
Type I ◽  
Direct Shear ◽  
Volcanic Soil ◽  
Maximum Dry Density

The purpose of this research is to improve the parameters of shear strength in granular volcanic soil, by adding a percentage of Portland type I cement. The first step for this research was to classify the soil through a Granulometry test, according to the Unified Soil Classification System (USCS), the result was considered as a poorly graded sand with gravel also considered by The American Association of State Highway and Transportation Officials (AASHTO) as “A-1-b”. In addition, the compaction curve of the volcanic soil has a Maximum Dry Density (MDD) of 1.21 kg/cm2 and an optimum moisture content of 17.8%. Also, the friction angle of 33.5° and a cohesion of 0 kg/cm2, and the results of the Direct Shear Test indicate the Residual Stresses of 0.63, 1.34 and 2.65 kg/cm2 according to the Normal Stresses 1, 2 and 4 kg/cm2, respectively. The second step was to apply a Modified Proctor Test as following: one sample for natural soil and four samples adding 3%, 5%, 7% and 9% of cement. Finally, applied the Direct Shear Test: one sample for natural soil and three samples adding 3%, 5%, and 7% of cement after 7 days of curing, then three more samples are taken adding 3, 5% and 7% of cement at 14 days of curing. The results of the Modified Proctor Test of the volcanic soil with the addition of 5% cement has a maximum peak of a Maximum Dry Density of 1.33 kg/cm2 and with an Optimal Moisture Content of 22.7%, improved the MDD by 10% in regard to the natural soil. And the results of the Direct Shear Test shown in each sample an increase from 14.6% to 79.1% in the friction angle in comparison with the natural soil from 25.8% to 161.5% in shear strength. Likewise, the behavior of the volumetric deformation is shown, presenting a greater contraction when a normal stress of 1 kg/cm2 is applied and a greater expansion when a normal stress of 4 kg/cm2 is applied. Also, the volcanic soil at 7 days of curing with 7% cement addition increases its resistance by 67.34% and the volumetric variation decreases by 50% and the volcanic soil at 14 days of curing with 5% addition of cement increases its resistance by 103.40% and the volumetric variation decreases by 25%.

The Physical and Mechanic Properties of the Loess Landslide

2012 ◽  
Vol 446-449 ◽  
pp. 3003-3006
Author(s):  
Li Hua Li ◽  
Meng Dang ◽  
Heng Lin Xiao ◽  
Hui Ming Tang
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Internal Friction ◽  
Water Content ◽  
Maximum Shear Stress ◽  
Friction Angle ◽  
Dry Density ◽  
Disaster Prevention ◽  
Loess Landslide ◽  
Landslide Disaster

The loess landslide in BaDong city, HuBei province China suffers great losses, which is an extremely typical landslide disaster. Variation in water level in the Yangtse River and rainfall has enormous influence on the loess landslide disaster. Some tests on loess have been done, which mainly include water content influence on shear strength of the loess, the relation between water content and dry density etc. The results have shown that When the water content average increasing with 3%, the cohesive strength reduces with 57%，49%，54% respectively and the internal friction angle average reduces 43%. The bigger the water content, the bigger the shear displacement at the same imposed load. When water content average increases with 3%, the corresponding maximum shear stress reduces with 50%, which may be in favor of loess landslide disaster prevention.

scholarly journals Experimental Study on Shear Strength of Saturated Remolded Loess

2021 ◽  
Author(s):  
Jie Lai ◽  
Yun Liu ◽  
Yuzhou Xiang ◽  
Wei Wang ◽  
Jiangbo Xu ◽  
...  
Keyword(s):  
Shear Strength ◽  
Shear Rate ◽  
Strain Curve ◽  
Confining Pressure ◽  
Cohesive Force ◽  
Dry Density ◽  
Stress Strain ◽  
Loess Area ◽  
Confining Pressures ◽  
Homogeneous Composition

Abstract Loess has the characteristic of macropore, loose structure, homogeneous composition and collapsibility. It is easy to saturate when it encounters heavy rainfall and irrigation, resulting in landslides, roadbed subsidence and dam instability in the loess area. To study the influence of dry density and shear rate on shear strength of saturated remolded loess, an SLB-6A stress-strain controlled triaxial shear penetration tester was used to conduct Consolidated Undrained(CU) test in the Yan'an area. During the test, three variables of shear rate, confining pressure and dry density were controlled. The dry densities of the samples were 1.5g/cm3, 1.6g/cm3 and 1.7g/cm3 respectively. The CU test of the saturated remolded loess at a confining pressure of 100kPa, 150kPa, and 200kPa was performed at a shear rate of 0.04mm/min, 0.08mm/min, 0.16 mm/min, and 0.4mm/min respectively. It is found that the stress-strain curve of saturated remolded loess gradually moves up with the increase of dry density. When the dry density is equal to ρd=1.5g/cm3, the deviatoric stress under different confining pressures there is a tendency to increase first and then decrease with increases of shear rate. When the dry density is equal to ρd=1.6g/cm3 and ρd=1.7g/cm3, the deviational stress under different confining pressures shows the trend of increasing first, decreasing and then increasing with the increase of shear rate, which is different from that at the dry density ρd =1.5g/cm3 at a shear rate v=0.4mm/min. When the dry density ρd=1.5g/cm3, the cohesive force decreases first and then increases with the increase of shear rate. When the dry density ρd=1.6g/cm3 and ρd=1.7g/cm3, the cohesive force first increases at 0.08 mm/min, and then decreases with the increase of shear rate. The cohesion and internal friction angles tend to increase as the dry density increases.

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