scholarly journals The Influences of Sand Content and Particle Size on the Desiccation Cracks of Compacted Expansive Soil

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Dongdong Li ◽  
Shaowei Zhang
Keyword(s):  
Particle Size ◽  
Soil Sample ◽  
Surface Crack ◽  
Expansive Soil ◽  
Natural Phenomenon ◽  
Sand Content ◽  
Surface Cracking ◽  
Desiccation Cracks ◽  
Size Groups ◽  
Sand Size

The desiccation cracks in expansive soil, which are a common natural phenomenon, have a significant negative impact on the engineering properties of the soil and are the direct cause of many engineering problems and geological disasters. This study aims to investigate the influences of sand content and particle size on desiccation cracks of the compacted expansive soil. First, samples of compacted expansive soil with five sand contents and four sand size groups were prepared. Then, a series of drying tests were performed. The dynamic variation of geometric parameters of the surface crack network during evaporation was quantitatively analyzed by using digital image processing technology and fractal theory. The results demonstrated that the increase of the surface-cracking areas in the early and later stages was manifested by the increase of the crack length and crack width, respectively. In the same size of sand particle group (0.15, 0.3 mm), as the sand content (dry weight ratio of soil sample) increased from 0% to 40%, the surface-cracking ratio (the ratio of the crack area to the total surface area of the soil sample) showed a decreasing trend (13.20%, 11.42%, 10.50%, 8.98%, and 7.71%, respectively). When the sand content (40%) was the same, as the sand size groups increased from [0.15 mm, 0.3 mm) to [1.18 mm, 2.36 mm), the surface-cracking ratio also presented a decreasing trend (7.71%, 7.69%, 4.35%, and 3.73%, respectively). The changing law of the fractal dimension of cracks was the same as that of the surface crack ratio. During the drying process, the deformation of the sample was characterized by centripetal shrinkage or cracking, which were mainly affected by the boundary conditions of the sample. This research’s results verify the effectiveness of sand to improve the dry-shrinkage characteristics of expansive soil, providing a reference for the improvement of roadbeds and the treatment of soil slopes in expansive soil areas.

scholarly journals Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. III. Distribution and kinetics of soil organic carbon in particle size fractions

Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 293 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Size Fraction ◽  
Organic C ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Clay Size Fraction ◽  
Sand Size

Distribution of soil organic carbon in sand-, silt- and clay-size fractions during cultivation for periods ranging from 20 to 70 years was studied in six major soils used for cereal cropping in southern Queensland. Particle-size fractions were obtained by dispersion in water using cation exchange resin, sieving and sedimentation. In the soils' virgin state no single particle-size fraction was found to be consistently enriched as compared to the whole soil in organic C in all six soils, although the largest proportion (48%) of organic C was in the clay-size fraction; silt and sand-size fractions contained remaining organic C in equal amounts. Upon cultivation, the amounts of organic C declined from all particle-size fractions in most soils, although the loss rates differed considerably among different fractions and from the whole soil. The proportion of the sand-size fraction declined rapidly (from 26% to 12% overall), whereas that of the clay-size fraction increased from 48% to 61% overall. The proportion of silt-size organic C was least affected by cultivation in most soils. It was inferred, therefore, that the sand-size organic matter is rapidly lost from soil, through mineralization as well as disintegration into silt-size and clay-size fractions, and that the clay fraction provides protection for the soil organic matter against microbial and enzymic degradation.

scholarly journals Plasticity and Swell-Shrink Behaviour of Electrokinetically Stabilized Virgin Expansive Soil using Calcium Hydroxide and Calcium Chloride Solutions as Cationic Fluids

2019 ◽  
Vol 29 (1) ◽  
pp. 128-146
Author(s):  
Jijo James ◽  
Archana James ◽  
Arun Kumar ◽  
Elumalai Gomthi ◽  
Karunakaran Kamal Prasath
Keyword(s):  
Soil Sample ◽  
Calcium Hydroxide ◽  
Calcium Chloride ◽  
Applied Voltage ◽  
Expansive Soil ◽  
Graphite Electrodes ◽  
Stabilization Process ◽  
Stabilized Soil ◽  
Free Swell ◽  
Different Levels

Abstract This investigation focussed on the plasticity and swell-shrink behaviour of an expansive soil that was stabilized using electro kinetic stabilization (EKS) techniques with cationic fluids for enhancement of stabilization. 0.25 M solutions of calcium hydroxide and calcium chloride were used as cationic fluids. An electro kinetic (EK) cell of dimensions 500 mm x 150 mm x 160 mm with inert graphite electrodes of size 140 mm x 160 mm x 5 mm was adopted for the stabilization process, carried out at an applied voltage of 40 V over a period of 6 hours. After the duration of the test, stabilized soil sample was subjected to Atterberg limits and free swell tests to determine its plasticity and swell-shrink characteristics. The results of the investigation found that both fluids were capable of reducing the plasticity and swell-shrink behaviour of the soil with different levels of effectiveness.

scholarly journals Physical and Chemical Characteristics of Oil Palm Plantation Soil: A New Lead in Forensic Investigation

2021 ◽  
Vol 19 (01) ◽  
pp. 97-105
Author(s):  
RUS DINA RUS DIN ◽  
SERI MIRIANTI ISHAR ◽  
HEMANANTHINI NAGANATHAN
Keyword(s):  
Particle Size ◽  
Soil Sample ◽  
Soil Ph ◽  
Oil Palm ◽  
Reference Sample ◽  
Chemical Components ◽  
Chemical Characteristics ◽  
Forensic Investigation ◽  
Physical And Chemical Characteristics ◽  
Physical And Chemical

Soil sample is one of the important evidence that can be found in crime scene. Unknown soil sample can be analysed and compared with reference sample in order to determine the origin as its physical and chemical components possess unique characteristics. The purpose of this study is to determine the physical and chemical characteristics of soil from oil palm plantations in Perak, Malaysia to assist forensic investigation. Total of 97 topsoil samples were collected from three different oil palm plantations in Perak. Particle size distribution was obtained using dry sieving technique and colour of soil sample was examined under three conditions that are dry, moist and ashed. Soil pH was measured using pH meter and percentage of composition of soil organic matter (SOM) was determined by weighing the sample before and after ignition. Result showed that the composition of particle size <0.18mm was within the range of 5.57-21.11% whereas for particle size between 0.18mm - 0.6mm was within 31.62 - 52.96% and 25.78-66.86% for particle size >0.6mm. The color mode of soil after oven dried, moistened and ashed was greyish brown (10YR 5/2), very dark greyish brown (10YR 3/2) and light yellowish brown (10YR 6/4) respectively. Soil pH was in the range of 5.79 – 6.70. The percentage of SOM was between 3.29 - 20.48%. The physical and chemical characteristics of soil analysed in this study from three different locations of oil palm plantations varied and it is possible to discriminate these locations based on the analysis highlighted in this study.

scholarly journals Study on Crack Development and Micro-Pore Mechanism of Expansive Soil Improved by Coal Gangue under Drying–Wetting Cycles

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6546
Author(s):  
Hongxing Zhu ◽  
Yan Zhang ◽  
Zhuhan Li ◽  
Xiaoyu Xue
Keyword(s):  
Soil Sample ◽  
Pore Volume ◽  
Pore Diameter ◽  
Expansive Soil ◽  
Soil Samples ◽  
Coal Gangue ◽  
Pore Density ◽  
Pore Characteristics ◽  
Average Pore ◽  
Road Engineering

Expansive soil is prone to cracks under a drying–wetting cycle environment, which brings many disasters to road engineering. The main purpose of this study is use coal gangue powder to improve expansive soil, in order to reduce its cracks and further explore its micro-pore mechanism. The drying–wetting cycles test is carried out on the soil sample, and the crack parameters of the soil sample are obtained by Matlab and Image J software. The roughness and micro-pore characteristics of the soil samples are revealed by means of the Laser confocal 3D microscope and Mercury intrusion meter. The results show that coal gangue powder reduces the crack area ratio of expansive soil by 48.9%, and the crack initiation time is delayed by at least 60 min. Coal gangue powder can increase the internal roughness of expansive soil. The greater the roughness of the soil, the less cracks in the soil. After six drying–wetting cycles, the porosity and average pore diameter of the improved and expanded soil are reduced by 37% and 30%, respectively, as compared to the plain expansive soil. By analyzing the cumulative pore volume and cumulative pore density parameters of soil samples, it is found that the macro-cracks are caused by the continuous connection and fusion of micro-voids in soil. Coal gangue powder can significantly reduce the proportion of micro-voids, cumulative pore volume, and cumulative pore density in expansive soil, so as to reduce the macro-cracks.

Influence of particle-size distribution homogeneity on shearing of soils subjected to internal erosion

2020 ◽  
Vol 57 (11) ◽  
pp. 1684-1694
Author(s):  
Shijin Li ◽  
Adrian R. Russell ◽  
David Muir Wood
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Soil Sample ◽  
Size Distribution ◽  
Fine Particles ◽  
Internal Erosion ◽  
Triaxial Tests ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Homogeneous Particle

Internal erosion (suffusion) is caused by water seeping through the matrix of coarse soil and progressively transporting out fine particles. The mechanical strength and stress–strain behavior of soils within water-retaining structures may be affected by internal erosion. Some researchers have set out to conduct triaxial erosion tests to study the mechanical consequences of erosion. Prior to conducting a triaxial test they subject a soil sample, which has an initially homogeneous particle-size distribution and density throughout, to erosion by causing water to enter one end of a sample and wash fine particles out the other. The erosion and movement of particles causes heterogeneous particle-size distributions to develop along the sample length. In this paper, a new soil sample formation procedure is presented that results in homogeneous particle-size distributions along the length of an eroded sample. Triaxial tests are conducted on homogeneous samples formed using the new procedure as well as heterogeneous samples created by the more commonly used approach. Results show that samples with homogeneous post-erosion particle-size distributions exhibit slightly higher peak deviator stresses than those that were heterogeneous. The results highlight the importance of ensuring homogeneity of post-erosion particle-size distributions when assessing the mechanical consequences of erosion. Forming samples using the new procedure enables the sample’s response to triaxial loading to be interpreted against a measure of its initially homogenous state.

Potential for using soil particle-size data to infer geological parent material in the Sydney Region

Soil Research ◽  
2013 ◽  
Vol 51 (4) ◽  
pp. 301 ◽  
Author(s):  
Margaret R. Donald ◽  
Pamela A. Hazelton ◽  
AnneMarie Clements
Keyword(s):  
Particle Size ◽  
Soil Sample ◽  
Soil Texture ◽  
Compositional Data ◽  
Size Fraction ◽  
Parent Material ◽  
Ecological Communities ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Statistical Classifiers

Ecological communities are more than assemblages of species. In assessing the presence of many ecological communities, interpretation of soil properties and associated parent material has become a definitive component under environmental legislation worldwide, and particularly in Australia. The hypothesis tested here is that the geological parent material of a soil sample can be determined from particle size fraction data of the Marshall soil texture diagram. Supervised statistical classifiers were built from data for four particle-size fractions from four soil landscape publications. These methods were modified by taking into account possible autocorrelation between samples from the same site. The soil samples could not be classified with certainty as being derived from Wianamatta Group Shale or Hawkesbury Sandstone parent material. The classification of alluvial/fluvial-derived soils was no better than chance alone. A good classifier using four-fraction compositional data could not be built to determine geological parent material. Hence, the three size fractions of the Marshall soil texture diagram are insufficient to determine the geological parent material of a soil sample.

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.

scholarly journals Effect of wetting-drying cycles on surface cracking and swell-shrink behavior of expansive soil modified with ionic soil stabilizer

2020 ◽  
Vol 61 (6) ◽  
pp. 1-13
Author(s):  
Huan Minh Dao ◽  
Anh Thuc Thi Nguyen ◽  
Tuan Manh Do ◽  
Keyword(s):  
Moisture Content ◽  
Crack Length ◽  
Surface Crack ◽  
Crack Width ◽  
Relative Rate ◽  
Linear Shrinkage ◽  
Image Processing Technique ◽  
Overburden Pressure ◽  
Area Density ◽  
Surface Cracking

This paper presents the results of an experimental investigation of the effect of wetting-drying cycles on the surface cracking and swell-shrink behavior of modified expansive soils. An image processing technique was employed to understand this effect by quantifying the surface crack area density, crack number, crack length, mean crack width, and absolute shrinkage. Parameters such as height, the relative rate of expansion, and linear shrinkage were used to characterize the effect of wetting-drying cycles on the swell-shrink behavior of the specimens subjected to various overburden pressures. The results showed that the increase in the number of wetting/drying cycles accelerated the crack growth and led to the increased crack number, total crack length, and surface crack area density. Moreover, as the number of wetting/drying cycles increased, the absolute shrinkage to be on the rise, and the mean crack width exhibited fluctuation characteristics. Furthermore, the moisture content was inversely related to the crack extent. For the specimens subjected to various overburden pressures, the height and the moisture content showed a good linear relationship. With the increase in wetting/drying cycles, the relative rate of expansion of the specimen decreased. Additionally, a larger overburden pressure resulted in a lower relative rate of expansion; however, as the number of wetting/drying cycles increased, the relative rate of linear shrinkage increased and then decreased.

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