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

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.

2021 ◽  
Vol 9 (1) ◽  
pp. 16-20
Author(s):  
Iyad Alkroosh ◽  
Ali Al-Robay ◽  
Prabir Sarker ◽  
Saif Alzabeebee

This paper investigates the influence of sand content on the mechanical behavior of a low plasticity clay that collected from south of Iraq (Sumer town). Samples have been prepared with sand contents of 0%, 10%, 20%, 30%, and 40% of the clay weight. Standard Proctor and unconfined compression tests have been carried out and the optimum moisture content, maximum dry density, and undrained shear strength have been determined. The results show a gradual increasing trend of the maximum dry density with the increase of the sand content up to 30%. The highest dry density reaches 1.90 g/cm3 corresponding to an optimum moisture content of 12%. In addition, this paper shows that the undrained shear strength is inversely proportional to the increase of the percentage of sand. The results of this work provide a useful addition to the literature regarding the behaviour or low plasticity clay-sand mixture.


2013 ◽  
Vol 710 ◽  
pp. 348-351
Author(s):  
Zheng Rong Zhao ◽  
Lei Wang ◽  
Hong Xia Yang

Through compaction test discussed about the compaction characteristics of expansive soil by lime modified in middle of Shandong province. The results show that the optimum moisture content is lower when the expansive soil is cured by dry compaction method, and the maximum dry density is higher. Compaction curve appeared the phenomenon of two peaks when expansive soil is cured by wet compaction method.Lime content of lime improved expansive soil, particle size composition, age and compaction function have influence on compaction curve.With the increase of the quantity of lime, the optimum moisture content increases, the maximum dry density decreases. With the age growth, the optimum moisture content increase slightly,the maximum dry density decreases slightly. The bigger the compaction work, the smaller moisture content is, the larger the maximum dry density is.


Each soil type has different behavior with regard to determination of maximum dry density and optimum moisture content and therefore any soil type has its own compaction requirements for experimental purposes and for control the compaction in the field. The general purpose of this study is to a better understanding of the compaction characteristics of high expansive soils, with emphasis on the relationships of moisture content and dry density of high expansive soils at a range of compaction energy levels. To achieve this purpose, high expansive soils samples were subjected to Atterberg limit and a set of laboratory compaction tests to find compaction characteristics namely; maximum dry unit weight and optimum water content of high expansive soils at different compaction energy (compaction effort) for different number of hammer blows per each layer range from 10 to 50, which varied the energy per unit volume from 356 KN/m3 to 1188 KN/m3.Rather than single peak compaction curves, the most achieved compaction curves are an irregular one and half peak compaction curves. According to the comparison results of different compaction energy, it was concluded that the maximum dry unit weight of high expansive soil was not highly affected by gradually increase of applied energy. The results showed that, the maximum dry density of tested expansive soils sample increased from 1.48g/cm3 to 1.6g/cm3 with increase of compaction energy from 356 KN/m3 to 1188 KN/m3.


2021 ◽  
Author(s):  
Iyad Alkroosh ◽  
◽  
Ali Al-Robay ◽  
Prabir Sarker ◽  
Saif Alzabeebee ◽  
...  

This study investigated the influence of sand content on the mechanical behaviour of a low plasticity clay found in Iraq. Samples were prepared with sand contents of 0%, 10%, 20%, 30%, and 40% of the weight of the clay. Standard Proctor and unconfined compression tests were carried out and the optimum moisture content, maximum dry density, and undrained shear strength were determined. The results showed a gradual increasing trend of the maximum dry density with the increase of the sand content up to 30%. The highest dry density reached was 1.90 gm/cm3 corresponding to an optimum moisture content of 12%. In addition, it was also found that the undrained shear strength was inversely proportional to the increase of the percentage of sand. Thus, the dry density of the clay could be increased well above 1.70 g/cm3, which is the minimum dry density accepted as a compacted subgrade according to the Iraqi General Specifications for Roads and Bridges (2003); hence, the rejected low plasticity clay could be utilised by mixing with sand. The reasons for the increase of the dry density and the decrease of the undrained shear strength has been extensively discussed in the paper.


2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Jianhua Guo ◽  
Zhangjun Dai ◽  
Shichang Li ◽  
Nadeem Muhammad ◽  
Hui Gao

In the Nanyang section of the midroute of the South-to-North Water Transfer Project, the expansive soil is often used as a filler for high-fill channels. After the channel is stabilized, the expansive soil undergoes creep deformation over time. Studying the creep characteristics of expansive soils in different environments is particularly important for evaluating the safe operation of high-fill channels. In the current study, the creep test of expansive soil under different moisture content and dry density was carried out. It is proposed that the slope of the fitted straight line in the compression curve of the expansive soil can be used to represent the secondary consolidation coefficient of unsaturated expansive soil, and the variation law of the secondary consolidation coefficient under different environmental factors is obtained. The modified Bjerrum calculation method considering the influence of additional load and lateral deformation yields the postexpansion soil settlement curve model to determine the control index range of the project site. Moreover, it is also observed that the secondary consolidation coefficient of unsaturated expansive soil increases with the increase of moisture content and decreases with the increase of dry density. The coefficient of secondary compression of unsaturated expansive soil is linearly related to dry density and moisture content. After the preconsolidation treatment of the expansive soil, when the load level is less than the preload, the secondary consolidation coefficient is smaller, otherwise the secondary consolidation coefficient is larger.


Fractals ◽  
2001 ◽  
Vol 09 (01) ◽  
pp. 51-60 ◽  
Author(s):  
YONGFU XU ◽  
DE'AN SUN

The micropore surface fractal model for expansive soils is proposed in this paper. Based on the results of the mercury intrusion tests, it is found that the micropore surface fractal dimension is 2.40 for the soil sample with the dry density of 1.50 g/cm 3, and is 2.47 for the soil sample with the dry density of 1.60 g/cm 3. By using the micropore surface fractal model, the shear strength formula for expansive soils is obtained. All the parameters in the proposed shear strength formula are constant, and are independent of matric suction. The validation of the proposed shear strength formula is proven by the results of the triaxial compression tests on an expansive soil taken from Ningxia, China.


AGROFOR ◽  
2018 ◽  
Vol 2 (3) ◽  
Author(s):  
Eugeniusz ZAWISZA ◽  
Andrzej GRUCHOT

The subject-matter of the work is a mixture of rock and soil from the LafargeDubie mine in Rudawa, southern Poland. The conducted tests aimed at thedetermination of the geotechnical characteristics of this mixture and the evaluationof its suitability for the construction of earth embankments, in particular road ones.The range of the tests comprised determination of parameters characterisingphysical properties, such as granulometric composition, natural moisture content,density of solid particles, optimum moisture content and maximum dry density ofsolid particles, as well as mechanical ones, like shear strength. The obtained resultsshow that the tested mixture is suitable for the construction of road embankments,since as coarse-grained soil, it has a high value of the uniformity coefficient (Cu =1913). Therefore, this is very well graded soil, which provides a good compactionwhen it is built into the embankment. The natural moisture content (on average wn= 9.5%) is close to the optimum one (wopt = 8.5%). The maximum dry density ofsolid particles (ds = 2.16 gcm-3) is much higher than the minimum required (d ≥1.6 gcm-3). The values of the angle of internal friction (on average  = 36) andcohesion (c = 42 kPa) indicate great shear strength, therefore this soil can besubjected to considerable mechanical stresses.


2013 ◽  
Vol 405-408 ◽  
pp. 548-553
Author(s):  
Xin Zhong Wang ◽  
Rui Liu ◽  
Shu Jun Peng

The compaction characteristics of the lime-treated expansive soils from the planning airport in China's Ankang were studied through the heavy compaction tests. The results show that all these elements such as lime content, water content, soil height, wetting time have a certain effect on dry density. As the lime quality ratio increases, the optimum water content under heavy compacting standard of improved soils increases but the maximum dry density decreases. With the increase of lime content, the effect of water content on dry density decreases while the water content near to its optimum value. Soils with the lower height have higher dry density when compaction energy, lime content and water content unchanged. As the wetting time increases, the maximum dry density shows a decreasing tendency until after 48 h it remained stable. It indicates that with the same lime content the order of primary factors influence on dry density are water content, wetting time, soil height. Finally, the lime stabilizing principle to expansive soil is explained through by applying scanning electron microscope technique.


2018 ◽  
Vol 206 ◽  
pp. 01002
Author(s):  
Zheng Su ◽  
Daokun Qi ◽  
Xinju Guo ◽  
Xiaojuan Xi ◽  
Liang Zhang

In recent years, engineering constructions increase rapidly in western and central areas of China, where expansive soil widely distributes. Since expansive soil is sensitive to water content, the characterization of its shear strength should be carefully conducted. For simplicity and ease of use, the Mohr-Coulomb criterion is often adopted to describe the shear strength of expansive soil. In this paper, the physical meaning of the cohesion and frictional strength of expansive soil are explained, and the variations of the strength parameters with water content are investigated. By fitting to the experimental results from direct shear test and triaxial tests, the changing characteristics of cohesion and friction angle with water content are obtained.


Author(s):  
Muhannd Waleed Majeed ◽  
Lubna Mohammed Abd ◽  
Mohammed Nsaif Abbas

Soil moisture content is one of the most important ecological factors affecting natural ecosystems. This study deals with the soil moisture distribution and its effect on the different types of soil used such as sandy soil, clayey soil, expansive soil and gypsum soil. Each type is brought to the laboratory to determine the physical properties then prepared for compaction test to determine the maximum dry density and optimum water content and discussed the result by comparing the values with them. The largest value of maximum dry density was for clayey soil while the smallest value was for gypsum soil. The largest optimum moisture content was for expansive soil while the smallest value was for gypsum soil too.


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