scholarly journals Study Effect of Water Content and Dry Density on the Shear Strength Parameters for Expansive Soil

2020 ◽  
Vol 25 (2) ◽  
pp. 22-29
Author(s):  
Ali Mohammed ◽  
Amina Khalil
Keyword(s):  
Shear Strength ◽  
Water Content ◽  
Expansive Soil ◽  
Dry Density ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Effect Of Water

scholarly journals Physical and Mechanical Characteristics of Shallow Expansive Soil due to Freeze-Thaw Effect with Water Supplement

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yanlong Li ◽  
Zili Wang ◽  
Yang Luo
Keyword(s):  
Shear Strength ◽  
Water Content ◽  
Expansive Soil ◽  
Freezing Temperature ◽  
Strength Reduction ◽  
Dry Density ◽  
Direct Shear ◽  
Soil Columns ◽  
Freeze Thaw ◽  
Shear Strength Reduction

Shear strength of shallow expansive soil varies along with the depth under the freeze-thaw effect. This work investigates shear strength characteristics of shallow expansive soil by simulating the actual freeze boundary conditions of seasonal frozen areas with water supplement. An integrated approach incorporating the freeze-thaw test and direct shear test was adopted. Firstly, unidirectional freezing tests for expansive soil columns under three different freezing temperature gradients were carried out. Secondly, direct shear tests under low vertical stress were performed on the standard samples, which were prepared by using cutting rings cut the thawed expansive soil columns into nine segments along with the depth. Temperature, water content, and dry density at different depths were also investigated after the freeze-thaw process. The test results showed that, after the freeze-thaw process, the shear strength of expansive soil columns showed significant differences along with the depth and highly correlated with water content, specifically the higher water content and the lower shear strength. The minimum shear strength in the expansive soil columns occurred at the soil layer below the frozen and unfrozen zones interface. The expansive soil column’s shear strength changed most under the moderate freezing temperature gradient corresponding to the most considerable shear strength reduction. Moreover, the significant decrease in cohesion was the main reason for the shear strength reduction of expansive soil after the freeze-thaw process. These results indicate significant depth variability in shear strength of expansive soil under the freeze-thaw effect.

scholarly journals Strength Characteristics and Slope Stability of Expansive Soil from Pingdingshan, China

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Ju-yun Zhai ◽  
Xiang-yong Cai
Keyword(s):  
Shear Strength ◽  
Slope Stability ◽  
Expansive Soil ◽  
Friction Angle ◽  
Natural Soil ◽  
Soil Slope ◽  
The Finite Element Method ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
The Stability

By analyzing the characteristics of expansive soil from Pingdingshan, China, the shear strength parameters at different water contents, dry densities, and dry-wet cycles of expansive soil are obtained. It is found that, at higher soil-water content, the internal friction angle is 0° and the shallow layer of expansive soil slope will collapse and destroy; this has nothing to do with the height of the slope and the size of the slope. The parameters of soil influenced by atmosphere are the ones which have gone through dry-wet cycles, and the parameters of soil without atmospheric influence are the same as those of natural soil. In the analysis of slope stability, the shear strength parameters of soil can be determined by using the finite element method, and the stability coefficient of the expansive soil slope can be calculated.

scholarly journals Influence of Zeolite on the Compaction Characteristics and Shear Strength Parameters of Cemented Sand

2021 ◽  
Vol 50 (11) ◽  
pp. 3181-3191
Author(s):  
Ghasem Norouznejad ◽  
Issa Shooshpasha ◽  
Seyed Mohammad Mirhosseini ◽  
Mobin Afzalirad
Keyword(s):  
Shear Strength ◽  
Soil Stabilization ◽  
Dry Weight ◽  
Dry Density ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Maximum Dry Density ◽  
Cemented Sand ◽  
Direct Shear Tests ◽  
Calcium Silicate Hydrates

It is well known that in geotechnical engineering, soil stabilization using cement is one of the appropriate approaches for enhancing soil characteristics. With respect to zeolite, its impact on the characteristics of cemented soil has not been fully evaluated. Thus, in the current research, a set of laboratory tests including standard Proctor compaction and direct shear tests (DSTs) considering four cement contents (2, 4, 6, and 8% of sand dry weight) and four zeolite contents (0%, 30%, 60%, and 90% of cement percentage as a replacement material) was carried out. The results indicated that the zeolite reduced Maximum Dry Density (MDD) while it increased value of Optimum Moisture Content (OMC) of cemented sand. Through the DSTs, it has been found that the replacement of cement by zeolite up to 30%, leads to the highest values of shear strength parameters due to the occurrence of pozzolanic and chemical reactions, particularly the production of higher amounts of calcium aluminate and calcium silicate hydrates in comparison with zeolite-free samples.

scholarly journals Influence of vetiver root on strength of expansive soil-experimental study

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244818
Author(s):  
Gui-yao Wang ◽  
Yong-gang Huang ◽  
Run-fa Li ◽  
Jing-mei Chang ◽  
Jin-liang Fu
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Root System ◽  
Shear Test ◽  
Expansive Soil ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Strength Parameter ◽  
Shear Strength Parameters ◽  
Strength Parameters

Grassroots have received more attention than the traditional method as soil reinforcement materials, especially the use of vetiver and other vegetation protection methods to treat expansive soil slope, have been tried and applied. To study the influence of grassroots on the strength properties of expansive soil, the laws of vetiver root growth over time and its vertical distribution of root content(δ) were firstly investigated by the experiment of planting vetiver. Then different δ and depth of planted soil were obtained. Simultaneously different δ and water content(ω) of grafted soil were made. With the direct shear test, the shear strength parameters of root-soil with different δ were analyzed. The shear test on root-soil composites with different δ was carried out to compare the strength characteristics of planted and grafted soil. The results showed that the δ of vetiver decreased with the increase of depth, and the δ of each layer increased with the growth period. The δ of 180d was 70.5% higher than that of 90d. The cohesion(c) of root-soil can be increased by more than 97%, and internal friction angle(φ) can be increased by more than 15.4% after 180 days. The c of 90 d vetiver root system can be increased by more than 18%, and the φ can be increased by more than 1.5%. At each depth, the c and φ of composite soil increases with the increase of δ, and the increment of cohesion (Δc) and the increment of internal friction angle (Δφ) increase with the increment of δ. But the increase in the ω will weaken the shear strength parameters of root-soil. Under the condition of the planted root system and grafted root system, the influence degree of δ on strength parameter of root-soil is different, and the law of strength parameters versus δ of grafted soil of 365d is similar to that of planted soil of 90d. And the root reinforcement of grafted soil is weaker than planted soil. Hence the grafted soil can´t accurately reflect the root-soil interaction of the existing root system.

scholarly journals Studi Pendahuluan Sifat Teknis Tanah Lempung Pada Daerah Rawan Gerakan Tanah Di Dusun Beji Desa Cirahab Kecamatan Lumbir Kabupaten Banyumas

2021 ◽  
Vol 22 (1) ◽  
pp. 35
Author(s):  
Ary Sismiani ◽  
Iwan Rustendi
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Moisture Content ◽  
Water Content ◽  
Strength Parameter ◽  
Soil Slope ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Soil Movement ◽  
Soil Shear Strength

In several places in the Banyumas Regency area, land movement problems have often occurred. Several locations have been declared as red zones, one of which is Beji, Cirahab Village, Lumbir District. With such regional conditions, it is necessary to conduct a study of the technical and mechanical properties of the soil in that location including moisture content, density and shear strength parameters related to the possibility of soil movement that will occur. From the results of the test and analysis using 3 specimens, the following data were obtained: water content of 20.22%, 30.36%, 40.31% with a cohesion value of 0.14 kg / cm2, 0.56 kg / cm2, 0.33 kg / cm2, and the internal friction angles of the soil are 30.22 °, 24.47 °, and 18.93 °. While the value of shear stress and displacement at maximum normal stress and moisture content of 20.22%, 30.36%, 40.31% are t(w1) = 0.68 kg / cm2,  t(w2) = 1.01 kg / cm2 ,t (w3) = 0.68 kg / cm2 and dn1 = 15.02%, dn2 = 10.02, dn3 = 13.35%. It can be concluded that the water content always has a very big influence on the value of the soil shear strength parameter. Therefore, the condition of the water content on the soil slope needs to be considered, and it is necessary to carry out further tests and more serious handling at that location.

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