scholarly journals A Comparative Study On The Physical Properties of Natural Sedimentary Loess And Manual Filling Compacted Loess

2021 ◽  
Author(s):  
Linxin Zhang ◽  
Shengwen Qi ◽  
Yongtang Yu ◽  
Yaguo Zhang ◽  
Zhiqing Li ◽  
...  
Keyword(s):  
Clay Fraction ◽  
Strong Stability ◽  
Compression Modulus ◽  
Liquid Limit ◽  
Dry Density ◽  
Natural Water Content ◽  
The Difference ◽  
Exploration Well ◽  
Compacted Loess ◽  
Natural Loess

Abstract With the development of human society, mega engineering projects of removing the tops of hills to infill valleys began to appear in the loess region. The thickness of the manual filling compacted loess can reach tens of meters. For such large-scale construction projects, studying the properties of compacted loess is essential to ensure the safety and reliability of land creation and artificial infrastructure. In this paper, the specimens from two exploration well profiles were carried out to study the physical properties of natural loess and compacted loess from the Loess Plateau. Here the natural loess selected was deposited in old ages (Q2 and Q1) and had strong stability. The natural water content, dry density, specific gravity, liquid limit, plastic limit, plasticity index, clay fraction, silt fraction, sand fraction, compression modulus, and permeability coefficient have been determined. Statistical theories such as t-test and correlation coefficient checks were used to describe the difference between the two kinds of loess, and the degree of correlation among various indicators. Besides, 14 groups of exploration well data in 8 studies were collected. The variation of natural water content and dry density with well depth was analyzed to supplement the existing data. Results have shown that the manual filling compacted loess is significantly different from the natural loess. On the whole, the liquid limit, plastic limit, plasticity index, clay fraction, silt fraction, sand fraction and compression modulus of the compacted loess are smaller. And compared with the natural sedimentary loess with strong stability, it deforms more easily. The difference of compression modulus between the compacted loess and natural loess is mainly controlled by the dry density and the particle composition. Moreover, the heterogeneous level of the manual filling compacted loess is greater than that of the natural loess in the horizontal direction and smaller than that of the natural loess in the vertical direction. Under a combination of external hydrologic conditions and dead weight, the compacted loess will become more stable.

scholarly journals Experimental Study on the Dynamic Modulus and Damping Ratio of Compacted Loess under Circular Dynamic Stress Paths

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Liguo Yang ◽  
Shengjun Shao ◽  
Zhi Wang
Keyword(s):  
Principal Stress ◽  
Dynamic Stress ◽  
Dynamic Compression ◽  
Damping Ratio ◽  
Stress Path ◽  
Compression Modulus ◽  
Dry Density ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Compacted Loess

Dynamic loads such as earthquakes and traffic will simultaneously generate vertical dynamic stress and horizontal shear stress in the foundation soil. When the vertical dynamic stress amplitude is twice the horizontal shear dynamic stress amplitude, and the phase difference between them is 90°, a circular dynamic stress path is formed in the τ z θ d ∼ σ zd − σ θ d / 2 stress coordinate system. To simulate the stress state of soil in the area of the circular dynamic stress path caused by bidirectional dynamic stress coupling, a series of tests of compacted loess under the action of a circular dynamic stress path were carried out using a hollow cylindrical torsion shear apparatus. The effects of the mean principal stress, dry density, and deviatoric stress ratio (the ratio of deviator stress to average principal stress) on the dynamic modulus and damping ratio of compacted loess were mainly studied. The test results show that, under the action of the circular dynamic stress path, the larger the mean principal stress is, the larger the dynamic compression modulus and dynamic shear modulus are. The dynamic compression modulus increases obviously with increasing dry density, but the dynamic shear modulus increases only slightly. When the deviator stress ratio increases from 0 to 0.4, the dynamic compression modulus and dynamic shear modulus increase to a certain extent. In addition, the greater the dry density and deviatoric stress ratio are, the greater the initial dynamic compression modulus and initial dynamic shear modulus of the compacted loess. The dynamic compression damping ratio of compacted loess increases with increasing mean principal stress, but the dynamic shear damping ratio decreases with increasing mean principal stress. Dry density basically has no effect on the dynamic compression damping ratio and dynamic shear damping ratio of compacted loess. When the dynamic strain exceeds 1%, the greater the deviatoric stress ratio is, the smaller the dynamic compression damping ratio and the dynamic shear damping ratio are. The research results can provide reference for the study of dynamic modulus and damping ratio of loess under special stress paths.

scholarly journals Effect of clay content on strength and permeability of plastic loess-cement

2019 ◽  
Vol 48 (2) ◽  
pp. 25-30
Author(s):  
Boriana Tchakalova
Keyword(s):  
Water Content ◽  
Soil Stabilization ◽  
Clay Fraction ◽  
Clay Content ◽  
Loess Soil ◽  
Liquid Limit ◽  
Engineering Properties ◽  
Natural Soil ◽  
Dry Density ◽  
Maximum Dry Density

Plastic soil-cement is a type of soil stabilization used for the treatment of natural soil to improve its engineering properties. It is a hardened material prepared by mixing soil and Portland cement at a water content higher than optimum, usually near the liquid limit, without compaction at optimum water content to maximum dry density. In Bulgaria, this soil stabilization technique has been applied in foundation works in collapsible loess ground in order to replace a part of the collapsible layer, to increase the bearing capacity of the soil base and/or to isolate the geoenvironment from migration of pollutants. The aim of the current paper is to examine the effect of the clay content of the loess soil on the strength and permeability of plastic loess-cement. Results from the investigation indicate that the mechanical and hydraulic properties of the plastic loess-cement highly depend on the presence of clay fraction.

scholarly journals An investigation into the cause of road failure along Sagamu-Papalanto highway southwestern Nigeria

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ubido Oyem Emmanuel ◽  
Igwe Ogbonnaya ◽  
Ukah Bernadette Uche
Keyword(s):  
Construction Materials ◽  
Road Construction ◽  
Linear Shrinkage ◽  
Liquid Limit ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Southwestern Nigeria ◽  
Low Resistivity ◽  
The Road ◽  
Cause Of Failure

AbstractInvestigation into the cause of road failure has been carried out along a 60 km long Sagamu –Papalanto highway southwestern Nigeria. Geochemical, mineralogical, geotechnical and geophysical analyses were conducted to evaluate the cause of failure along the study area. The results of the laboratory tests showed that the percentage amount of fines ranges from 12 to 61.3%, natural moisture content from 6.8 to 19.7%, liquid limit in the range of 25.1–52.2%, linear shrinkage between 3.96 to 12.71%, plastic limit ranges from 18.2–35%, plasticity index ranges from 5.2 to 24.6%, free swell in the range from 5.17–43.9%, maximum dry density ranges from 1.51–1.74 g /cm3, specific gravity ranges from 2.52–2.64 and CBR between 3 and 12%. The Cone Penetrometer Test (CPT) shows a resistance value of 20–138 kgf/cm2. The major clay mineral that is predominant in the studied soil is kaolinite. The major oxides present are SiO2, Al2O3, Fe2O3, K2O, Na2O, MgO and CaO. The result of the 2D Electrical Resistivity Imaging revealed a low resistivity values for profile 2 and 3 ranging from 100 Ωm – 300 Ωm, between a distance of 20 m – 240 m along the profile to a depth of 7.60 m and a low resistivity value ranging from 50 Ωm – 111Ωm, between a distance of 80 m − 120 m along the profile to a depth of 15 m. It was concluded that the low CBR, low MDD and the class of subsoils namely A-26, A-7, A-2-7 (clayey soils) which were identified are responsible for the cause of failure experienced in the study area. These makes the soils unsuitable as road construction materials and hence, there is need for stabilization during the reconstruction and rehabilitation of the road.

Test Investigation on Mechanical of Unsaturated Loess

2012 ◽  
Vol 204-208 ◽  
pp. 22-27
Author(s):  
Yan Zhu ◽  
Yun Xu Chen
Keyword(s):  
Water Content ◽  
Horizontal Plane ◽  
Mechanical Characteristics ◽  
Loess Soil ◽  
Dry Density ◽  
One Dimensional ◽  
Test Investigation ◽  
Unsaturated Loess ◽  
Test Result ◽  
Compacted Loess

Compression and collapse of unsaturated compacted loess are studied by using dry density and water content which easily controlled in engineering, the controlling range of dry density and water content are confirmed respectively. Then the deformation of compression and collapse and the frequency of engineering damager occurrence can be decreased. In addition, the mechanical characteristics of loess in different directions may differ because the loess was consolidated only under the condition of its upper weight of soil and load. The conventional mechanical experiments, including one-dimensional compress and collapse test, were conducted with the specimen of loess soil in different angle from the original horizontal plane. The test result shows that the loess is anisotropic

scholarly journals Geotechnical properties of reinforced clayey soil using nylons carry’s bags by products

2018 ◽  
Vol 162 ◽  
pp. 01020 ◽  
Author(s):  
Nahla Salim ◽  
Kawther Al-Soudany ◽  
Nora Jajjawi
Keyword(s):  
Soil Stabilization ◽  
Clayey Soil ◽  
Ground Improvement ◽  
Soft Soil ◽  
Liquid Limit ◽  
Waste Material ◽  
Industrial Wastes ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Replacement Technique

All structures built on soft soil may experience uncontrollable settlement and critical bearing capacity. This may not meet the design requirements for the geotechnical engineer. Soil stabilization is the change of these undesirable properties in order to meet the requirements. Traditional methods of stabilizing or through in-situ ground improvement such as compaction or replacement technique is usually costly. Now a safe and economic disposal of industrial wastes and development of economically feasible ground improvement techniques are the important challenges being faced by the engineering community. This work focuses on improving the soft soil brought from Baghdad by utilizing the local waste material for stabilization of soil, such as by using “Nylon carry bag’s by product” with the different percentage and corresponding to 1 %, 3% and 5% (the portion of stabilizer matters to soil net weight) of dried soil. The results indicated that as Nylon’s fiber content increases, the liquid limit decreases while the plastic limit increases, so the plasticity index decreases. Furthermore, the maximum dry density decreases while, the optimum moisture content increases as the Nylon’s fiber percentage increases. The compression index (decreases as the Nylon’s fiber increases and provides a maximum of 43% reduction by adding 5% nylon waste material. In addition, the results indicated that, the undrained shear strength increases as the nylon fiber increases.

scholarly journals Technical and Environmental Impacts of Coal Waste Used as a Soil Stabilizer in Construction Projects of Forest Roads

2021 ◽  
Vol 42 (3) ◽  
Author(s):  
Sara Mansouri ◽  
Mehran Nasiri ◽  
Amir Modarres
Keyword(s):  
Environmental Analysis ◽  
Soil Stabilization ◽  
Liquid Limit ◽  
Soil Conditions ◽  
Coal Waste ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Forest Roads ◽  
Waste Products ◽  
Soil Stabilizer

Many pozzolans are waste products from industrial processes. Every year a huge amount of coal waste is gathered from the coal washing plant in the Hyrcanian forests of Iran. These materials can be used for soil stabilization in construction and maintenance projects of forest roads. This paper aims to (a) investigate the role of coal waste (CW) as a soil stabilizer and (b) determine the changes in soil specification regarding the environmental pollution in different combinations of materials (soil, lime (4 and 6%) and CW (3, 6, 9 and 12%)). For this purpose, different technical and environmental analysis and laboratory tests were performed. Technical tests showed that the soil liquid limit and maximum dry density decreased with an increase in lime and CW contents. Addition of CW could increase the soil CBR, UCS and OMC. According to XRD test, the addition of CW and lime can increase the size of crystals in stabilized soil samples. Environmental analysis showed that the use of stabilizer significantly reduced the concentration of heavy metals such as Cd, Cr and Pb. Also, all of the metal concentrations leached from samples satisfied the required criteria, but the addition of lime and CW increased the concentration of N, P, and K. These changes can increase the invasive species consistent with calcareous soil conditions along the roads. According to the results, the combination of coal waste and lime can be one of the best methods for in situ remediation. It would, however, be better to use a minimum amount of stabilizer in pavement layers of access roads due to environmental sensitivity.

scholarly journals Relationship between consistency parameters and granulation of fen soils

2013 ◽  
Vol 12 (3) ◽  
pp. 121-128
Author(s):  
Krzysztof Wilk
Keyword(s):  
Complex Analysis ◽  
Linear Equations ◽  
Clay Fraction ◽  
Building Design ◽  
Liquid Limit ◽  
Soil Parameters ◽  
Geotechnical Parameters ◽  
Substrate Quality ◽  
Liquidity Index ◽  
Clay Fraction Content

Determination of bearing capacity requires knowledge of the ground strength parameters. The best way to appreciate soil properties is the use of the direct research methods. In the case of less responsible buildings, projected on the simple ground structure, it often seems reasonable to adopt conservative soil parameters without performing a complex analysis. The base for determination the values of the geotechnical parameters is the estimation based on the correlation between the mechanical and geotechnical parameters of soil. It is important not only for the new building design, but also to facilitate the verification of the substrate quality during the execution of the work. This paper presents the relationship between granulation (clay fraction content) and soil consistency parameters (plastic limit, liquid limit, plasticity index and liquidity index). The analyzed values are determined as a result of alluvial ground studies. These soils were consequent upon the accumulation of river. The founded relationships were described by linear equations and were compared with the results presented in the geotechnical literature. These comparisons often show a significant effect of regional ground forming  conditions on the parameters of consistency.

Evaluation of Suitability of Red Clay from Selected Areas of Gercus Formation, Sulaimaniyah, North Iraq, for the Construction of Embankment Dams

2021 ◽  
pp. 3417-3427
Author(s):  
Amera I. Hussain Hussain ◽  
Ibraheem I. Ibraheem
Keyword(s):  
Ph Value ◽  
Soil Classification ◽  
Liquid Limit ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Red Clay ◽  
Embankment Dams ◽  
Filling Materials ◽  
The North ◽  
Geotechnical Assessment

      In this research, a geotechnical assessment was conducted for clay of the Gercus Formation to determine its suitability for embankment dams. The selected area is located in the north of Iraq. Six samples were collected from two sites in Dokan (Sulaimaniyah) and Haibat Sultan mountain (Koysinjaq), three samples each. Various geotechnical (physical, mechanical and chemical) tests were conducted based on standard specifications.      The results of the grain size test of clay samples showed their conformity with Zone C curves and their suitability for the construction of embankment dams, according to the Iraqi standard for roads and bridges.  The results of the plasticity limits test showed that the soil is made of fine, low plasticity silt (ML), and low plasticity clay (CL), according to the unified standard soil classification. The water content and plasticity limit tests (liquid limit, plastic limit, and plasticity index) demonstrated that these clays are conformable with the limits of the Iraqi standards. The results of the modified compaction test found a maximum dry density value of 1.962 g/cm3 with an optimum moisture content of 11.5%. The results of the permeability index (K) revealed low permeability according to the Das classification and, therefore, showed the suitability of the samples as raw filling materials in the construction of dams. Chemical tests (sulfate content, organic materials content, total dissolved salts, gypsum content, and pH value) showed compatibility with the requirements for the use in dams construction under the Iraqi standard (SoRB/ R5).

Analysis of Tyrrell Sea Deposits from the Vicinity of the Victor Diamond Mine: Comparison of Three North American Clay Deposits

2018 ◽  
Author(s):  
Jean Holloway
Keyword(s):  
Hydraulic Conductivity ◽  
Clay Fraction ◽  
Liquid Limit ◽  
Open Pit ◽  
Open Pit Mining ◽  
High Plasticity ◽  
Lake Agassiz ◽  
Clay Deposits ◽  
De Beers ◽  
Limestone Aquifers

he De Beers Victor Mine is an open pit diamond mine, and is located in the James Bay lowlands. The lowlands are characterized by extensive peatlands overlying Tyrell Sea sediments. One of the potential impacts of open pit mining, and the focus of the current work, is the potential for differential subsistence in the Tyrell Sea sediments owing to continuous groundwater withdrawal from the underlying limestone aquifers. To fully understand the potential effects of subsistence, a better understanding of the nature and properties of the Tyrell Sea sediments is needed. This will be achieved by analyzing various properties of samples collected from the Victor Diamond Mine, and comparing those properties with values from Lake Agassiz sediments and Bearpaw Shale. Properties such as hydraulic conductivity, grain size, plastic and liquid limit, and mineralogy will be compared. It is expected that the samples from the Victor Mine are a rock flour dominated by clay fraction, composed mostly of finely ground carbonates. The sediments are expected to have high plasticity, low hydraulic conductivity, and moisture content too low for that of true clay.

Dry Density Based on Soil Index Properties by Using Expert System

2020 ◽  
Vol 857 ◽  
pp. 266-272
Author(s):  
Bushra S. Albusoda ◽  
Dhurgham A. Al-Hamdani ◽  
Mohammed F. Abbas
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Multiple Linear Regression ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Liquid Limit ◽  
Dry Density ◽  
Great Success ◽  
Ann Model ◽  
Model Liquid

Dry density modeling is a valuable issue. Artificial neural networks (ANNs) have been used in many problems in geotechnical engineering and have demonstrated great success. In this paper, the ANN model is proposed to predict the dry density of the soil. The developed model is managed by the Matlab Neural Network Interface (R2016a). To create the ANN model, liquid limit, plastic limit, plasticity index, moisture content, specific gravity, finer accuracy than sieve 200, total suspended solids, organic and SO3 were selected and used as input parameters. There are (9, 6,5 and 3) nodes, (10) nodes and (1) node used for input, hidden layers and output layers, respectively. The value of dry density obtained from three sources was sympathetic. The first source is the experimental results of 99 soil samples conducted in Al-Najaf Institution laboratory for this study. The second source was to propose the expected dry density using multiple linear regression analysis (MLRA) on the samples used in the first source; The results show, that the prediction of the use of ANNs was closely consistent with the experimental data. Correlation coefficient (R2) and mean square error (MSE) were 0.97368 and 3.19474 10-3, respectively. The observed results of the proposed system were very comparable with those obtained from empirical analysis and the prediction obtained from multiple linear regression analysis, where the advanced ANN approach is applicable.

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