scholarly journals Study on Creep Characteristics of Expansive Soil in High-Fill Channel of South-to-North Water Transfer Project

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Jianhua Guo ◽  
Zhangjun Dai ◽  
Shichang Li ◽  
Nadeem Muhammad ◽  
Hui Gao
Keyword(s):  
Moisture Content ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Water Transfer ◽  
Load Level ◽  
Dry Density ◽  
Creep Characteristics ◽  
North Water ◽  
Consolidation Coefficient ◽  
Unsaturated Expansive Soil

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.

Test Research on Engineering Property of Expansive Rocks of Anyang Test Zone in Middle Route of South-North Water Transfer Project

2013 ◽  
Vol 321-324 ◽  
pp. 239-244
Author(s):  
Zhuang Cheng ◽  
Le Hua Wang ◽  
Yan Hua Dong ◽  
Xiao Ling Liu
Keyword(s):  
Moisture Content ◽  
Linear Correlation ◽  
Initial Moisture Content ◽  
Water Transfer ◽  
Dry Density ◽  
Rock Samples ◽  
Test Zone ◽  
Mineral Components ◽  
North Water ◽  
Different Depths

Test samples are selected in different depths of Pile No.1370 at Anyang test zone in Middle Route of South-North water transfer project. Through a series of experiment, the physical properties, mineral components and properties of mechanics, permeability and swelling-shrinking of expansive rock are well studied. The results show that hydrophilic mineral component of the expansive rock in different depths differ remarkably. To the same kind of expansive rock samples with the same dry density, cohesion and friction angles are negative linear correlation with moisture content respectively and cohesion is more sensitive to moisture content. With the same initial moisture content, the logarithm of saturated permeability coefficients of expansive rock samples are linear correlation with their dry densities. The initial moisture content has a much larger effect on maximum swelling ratio than shrinkage, thus the process of swelling-shrinking is not reversible. The results can supply scientific references for the South-North water transfer project.

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 Dynamic Resilient Modulus of Lime-Treated Expansive Soil

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Zheng Lu ◽  
Yang Zhao ◽  
Shaohua Xian ◽  
Hailin Yao
Keyword(s):  
Moisture Content ◽  
Environmental Changes ◽  
Resilient Modulus ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
The Stability ◽  
Compaction Degree

Dynamic resilient modulus is the design index of highway subgrade design code in China, which is significantly affected by the traffic loads and environmental changes. In this study, dynamic triaxial tests were conducted to investigate the influence of moisture content, compaction degree, cyclic deviator stress, and confining pressure on lime-treated expansive soil. The suitability of UT-Austin model to lime-treated expansive soils was verified. The results indicate that the dynamic resilient modulus of lime-treated expansive soils increases nonlinearly with the increase of compaction degree, while decreases nonlinearly with the increase of dynamic stress level. The dynamic resilient modulus decreases linearly with the increase of moisture content and increases linearly with the increase of confining pressure. Moreover, the moisture content has a more significant effect on the dynamic resilient modulus of lime-treated expansive soil. Therefore, it is necessary to ensure the stability of soil humidity state and its excellent mechanical properties under long-term cyclic loading for the course of subgrade filling and service. Finally, the calculated results of the UT-Austin model for dynamic resilient modulus show a good agreement with the test results.

Compaction Characteristic of Lime Modified Expansive Soil

2013 ◽  
Vol 710 ◽  
pp. 348-351
Author(s):  
Zheng Rong Zhao ◽  
Lei Wang ◽  
Hong Xia Yang
Keyword(s):  
Moisture Content ◽  
Expansive Soil ◽  
Size Composition ◽  
Optimum Moisture Content ◽  
Dry Density ◽  
Content Increase ◽  
Maximum Dry Density ◽  
Compaction Curve ◽  
Compaction Characteristic ◽  
Two Peaks

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.

Analyses of Anti-Seepage Measure for Expansive Soil Subgrade in Hefei

2014 ◽  
Vol 580-583 ◽  
pp. 552-555
Author(s):  
Yuan Wei ◽  
Wei Zhong Xing ◽  
Yan Shao
Keyword(s):  
Numerical Calculation ◽  
Moisture Content ◽  
Water Content ◽  
Engineering Design ◽  
Control Measure ◽  
Expansive Soil ◽  
Large Change ◽  
Time Range ◽  
Seepage Control ◽  
Unsaturated Expansive Soil

Deformation of expansive soil subgrade depends on moisture content. Anti-seepage measure of unsaturated expansive soil was carried out using ABAQUS as for the influence of atmosphere. The results show that there is large change in water content using anti-seepage measure measure. After using anti-seepage measure, range of water content decreases. At the same time, range of water content value obviously decreases with the increase of the depth of seepage control. Therefore, damage of pavement caused the deformation can decrease by seepage control measure. The results could be used for engineering design and numerical calculation.

scholarly journals Influence of Energy on Compaction Characteristics of High Expansive Soils

2020 ◽  
Vol 9 (5) ◽  
pp. 1344-1348
Keyword(s):  
Moisture Content ◽  
Soil Type ◽  
Expansive Soils ◽  
Unit Weight ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Compaction Characteristics ◽  
Dry Unit Weight ◽  
Comparison Results ◽  
Compaction Energy

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.

scholarly journals Effect of Lime and Fly ash on Load Bearing Capacity of Expansive Clay soil

2019 ◽  
Vol 8 (11) ◽  
pp. 554-563
Keyword(s):  
Fly Ash ◽  
Moisture Content ◽  
Bearing Capacity ◽  
Clay Soil ◽  
Expansive Soil ◽  
Atterberg Limits ◽  
Dry Density ◽  
Index Test ◽  
Expansive Clay ◽  
Compaction Test

Expansive soil is a problematic soil which found in wide part of the world that has a high degree of sensitivity, nature of expansion and shrink behavior during water adding and removing this caused insufficient bearing capacity, excessive differential settlement and instability on excavation and embankment forming those conditions accelerate damage of building structure, road highway and dam. Attempt to undertake construction in such type of soil result will be bearing capacity failure, settlement problem. One of the well-known application of Lime and fly ash were improve Atterberg limits, compaction characteristics, bearing capacity and prevention of swelling problem of expansive clay that is why the main reason to select lime and fly ash in this project, both are good binding material to increase the cohesion force and shear strength of soil and assured to established rigid pavements and foundations. The mixing proportion of lime, fly ash and combination of lime and fly ash are (0%, 2 %, 4 % ), (10%, 15% ,20% ), (2 %+10 %, 2 % +15 %, 2 % +20 %) and (4 %+10 %, 4 % + 15 % , 4 %+ 20 %) with expansive soil respectively and then explored how much it modify the characteristics of soil like maximum dry density moisture content, consistency limits, FSI, UCS and CBR value which compare to untreated soil. Lime and fly ash treated soil carried out various tests Such as Moisture content test, consistency limit, compaction test, Unconfined Compression swelling index test and California bearing ratio test then after justify weather the bearing capacity of soil is good or not . Classification of soil was determined by conducting plasticity index and swelling index tests. Effect of lime and fly ash on soil index properties were assessed by conducting Atterberg limits test, strength of soil were assessed by conducting compaction test, UCS tests and CBR test and swelling properties were checked by conducting swelling index test. Expansive clay soil were mixed with lime, fly ash and combination of lime - fly ash by replacement process of soil and then cured for 7, 14 and 28 days.

Increasing Density and Cement Content in Expansive Soils Stabilization:Conflicting or Complementary Procedures for Reducing Swelling?

2020 ◽  
Author(s):  
Nilo Cesar Consoli ◽  
Mariana Tonini de Araújo ◽  
Suéllen Tonatto Ferrazzo ◽  
Vinícius de Lima Rodrigues ◽  
Cecilia Gravina da Rocha
Keyword(s):  
Moisture Content ◽  
Portland Cement ◽  
Significant Influence ◽  
General Equation ◽  
Cement Content ◽  
Expansive Soils ◽  
Dry Density ◽  
Loss Of Mass ◽  
Porosity Index ◽  
Swelling Model

Present study makes three contributions to the literature of expansive soils: (i) it proposes equations to predict soil swelling based on dry density and cement content, (ii) it checks the developed general equation by predicting the swelling of different expansive soils from literature and (iii) it designs experiments that investigate factors that have a significant influence on swelling. An experimental programme was carried out to analyse the expansion of bentonite-kaolin-cement blends. Different proportions of bentonite-kaolin, cement content, dry density and moisture content were evaluated. A unique relation of the cement/porosity index was obtained for cement stabilized expansive soils swelling; this index has been used before to portray strength, stiffness and loss of mass of stabilized soils and is now shown to be applicable to describe swelling of expansive soils treated with Portland cement. In the present research, cement content and dry density are seen as conflicting parameters regarding the swelling of expansive soils, since increasing Portland cement amount reduces swelling and increasing density (through compaction) causes higher expansion. A general swelling model was proposed and successfully checked with data from the literature, being able to predict the swelling of expansive soils with different densities, expansive mineral, moisture and cement contents.

DETERMINATION OF EXPANSIVE SOIL STRENGTH USING A FRACTAL MODEL

Fractals ◽  
2001 ◽  
Vol 09 (01) ◽  
pp. 51-60 ◽  
Author(s):  
YONGFU XU ◽  
DE'AN SUN
Keyword(s):  
Shear Strength ◽  
Soil Sample ◽  
Expansive Soils ◽  
Triaxial Compression ◽  
Expansive Soil ◽  
Fractal Model ◽  
Dry Density ◽  
Compression Tests ◽  
Surface Fractal ◽  
Strength Formula

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.

The Tests on the Lime-Treated Expansive Soils Compaction Characteristics

2013 ◽  
Vol 405-408 ◽  
pp. 548-553
Author(s):  
Xin Zhong Wang ◽  
Rui Liu ◽  
Shu Jun Peng
Keyword(s):  
Water Content ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Compaction Characteristics ◽  
Lime Content ◽  
Compaction Energy ◽  
Wetting Time ◽  
Lower Height

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.

Sign in / Sign up

Export Citation Format

Share Document