scholarly journals Effect of Sand and Sand-Lime Piles on the Behavior of Expansive Clay Soil

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Mohamed Hussein
Keyword(s):  
Clay Soil ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Expansive Soil ◽  
Area Ratio ◽  
Engineering Properties ◽  
Chemical Stabilization ◽  
Expansive Clay ◽  
New City ◽  
Sand Piles

Expansive clay soil causes serious problems to many structures due to its swelling and shrinkage during wet and dry seasons. With the existence of expansive soil in Ahkmim new city, Sohag governorate, Egypt, some light buildings, road pavements, and buried pipelines have shown some damage. To avoid such damage, prior to construction, expansive clay soils should be stabilized. Different methods are available to improve the engineering properties of these soils such as densification, chemical stabilization, reinforcement, and techniques of pore water pressure reduction. The chemical stabilization of clay using lime is one of the widespread methods that can be used to improve the behavior of expansive clay soil. This study aims to investigate the effect of both sand and sand-lime piles on the behavior of expansive clay soil. A series of laboratory tests were carried out using the conventional Oedometer apparatus. Sand piles with different replacement area ratios (RARs) (4.68%, 10.16%, 24.6%, 35.84%, and 56.9%) were used. Also, sand piles stabilized with different percentages of lime (3%, 6%, 9%, 12%, 15%, and 20%) and with a replacement area ratio of 35.84% were used. The experimental results showed there is a significant improvement in reducing the swelling potential of expansive clay soil reinforced with sand or sand-lime piles. This improvement increases with the increase of both replacement area ratio and lime content.

scholarly journals Effect of Industrial Waste and Geopolymers on Stabilisation of Expansive Clay

2019 ◽  
Vol 9 (2) ◽  
pp. 5575-5577
Keyword(s):  
Shear Strength ◽  
Sodium Hydroxide ◽  
Clay Soil ◽  
Research Work ◽  
Expansive Soil ◽  
Industrial Wastes ◽  
Engineering Properties ◽  
Low Permeability ◽  
Expansive Clay ◽  
Strength Determination

Expansive clay soils are geotechnically problematic in nature as they possess less shear strength, high compressibility and low permeability. This research work was carried out with a view to improve index and engineering properties of expansive soil by stabilizing it with industrial wastes and geopolymers. The industrial wastes such as fly ash, silica fume and sodium-hydroxide were used for the stabilization of expansive soil. the virgin clay soil was tested for its index properties, compaction characteristics and shear strength determination. the stabilization of clay is made by adding and mixing those materials by varying its percentage. In the stabilization of soil with sodium hydroxide, an attempt has been made to study the effect of its molarity on the various properties of the soil. The clay soil stabilized with various materials was also tested for the same properties and that results were compared with that of virgin soil to find the effect of stabilization.

Static response of fly ash columnar improved ground

2001 ◽  
Vol 38 (2) ◽  
pp. 276-286 ◽  
Author(s):  
A Porbaha ◽  
T BS Pradhan ◽  
T Kishida
Keyword(s):  
Fly Ash ◽  
Stress Concentration ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Triaxial Compression ◽  
Area Ratio ◽  
Stress Redistribution ◽  
Soft Ground ◽  
Compression Tests ◽  
Composite Ground

This study presents the results of a series of monotonic undrained triaxial compression tests on clay specimens improved by columnar reinforcement. The process of loading and stress redistribution of a fly ash – clay specimen (FCS), in comparison with a sand–clay specimen (SCS), is examined in terms of stress–strain characteristics, generation of excess pore-water pressure, effective and total earth pressures, development of stress concentration, and the normalized undrained shear strength of the improved soil. It was found, predictably, that the deviator stress of the composite specimens was influenced by the consolidation stress, replacement area ratio, and properties of the column material. The stress concentration at the top of the composite ground which depends on the loading stage reaches a peak after the consolidation state and is reduced due to stress redistribution between the column and the soft ground. In terms of improvement effects, the mean shear strengths of FCS and SCS relative to the clay specimen are three and seven times greater, respectively, for a replacement area ratio of 49%.Key words: composite ground, fly ash, soil improvement, soft ground, triaxial test.

Improving engineering properties of mature fine tailings using Tubifex

2020 ◽  
Vol 47 (7) ◽  
pp. 812-821
Author(s):  
Xiaojuan Yang ◽  
Miguel de Lucas Pardo ◽  
Maria Ibanez ◽  
Lijun Deng ◽  
Luca Sittoni ◽  
...  
Keyword(s):  
Survival Rate ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Engineering Properties ◽  
Test Results ◽  
Sulfate Content ◽  
Mature Fine Tailings ◽  
Fine Tailings ◽  
The Mean ◽  
Solids Content

The present study investigated the effects of Tubifex (Oligochaeta: Tubificidae) treatment on the dewatering process of mature fine tailings (MFT). Experiments testing the survival rate showed that Tubifex can survive at 20 °C and 4 °C. MFT with initial solids content (Sc) of 30% of total mass were treated in 11 settling columns by three Tubifex densities, 1400, 2000 and 4200 individuals·m−2. Test results showed that the mean survival rate at 20 °C and 4 °C on the 28th day stayed around 85%. Tubifex enhanced MFT dewatering by providing compacted tailings with 11.6% and 66.7% higher Sc and undrained shear strength compared with nontreated tailings. Tubifex accelerated pore water pressure dissipation. Tubifex did not affect the chemical composition of tailings except for a decrease in sulfate content. The Sc of tailings treated by Tubifex increased by 67.4% within nine months, which was 129% greater than the Sc increase of the nontreated tailings after 11 months.

scholarly journals Numerical Simulation Of The Treatment Of Soil Swelling Using Grid Geocell Columns

2015 ◽  
Vol 23 (2) ◽  
pp. 9-18 ◽  
Author(s):  
Mohammed Y. Fattah ◽  
Raid R. Al-Omari ◽  
Haifaa A. Ali
Keyword(s):  
Finite Element ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Expansive Soil ◽  
Matric Suction ◽  
Degree Of Saturation ◽  
Axial Forces ◽  
Column Material ◽  
Cap Model

Abstract In this paper, a method for the treatment of the swelling of expansive soil is numerically simulated. The method is simply based on the embedment of a geogrid (or a geomesh) in the soil. The geogrid is extended continuously inside the volume of the soil where the swell is needed to be controlled and orientated towards the direction of the swell. Soils with different swelling potentials are employed: bentonite base-Na and bentonite base-Ca samples in addition to kaolinite mixed with bentonite. A numerical analysis was carried out by the finite element method to study the swelling soil's behavior and investigate the distribution of the stresses and pore water pressures around the geocells beneath the shallow footings. The ABAQUS computer program was used as a finite element tool, and the soil is represented by the modified Drucker-Prager/cap model. The geogrid surrounding the geocell is assumed to be a linear elastic material throughout the analysis. The soil properties used in the modeling were experimentally obtained. It is concluded that the degree of saturation and the matric suction (the negative pore water pressure) decrease as the angle of friction of the geocell column material increases due to the activity of the sand fill in the dissipation of the pore water pressure and the acceleration of the drainage through its function as a drain. When the plasticity index and the active depth (the active zone is considered to be equal to the overall depth of the clay model) increase, the axial movement (swelling movement) and matric suction, as a result of the increase in the axial forces, vary between this maximum value at the top of the layer and the minimum value in the last third of the active depth and then return to a consolidation at the end of the depth layer.

scholarly journals Swelling phenomena and effective stress in compacted expansive clays

2016 ◽  
Vol 53 (1) ◽  
pp. 134-147 ◽  
Author(s):  
David Mašín ◽  
Nasser Khalili
Keyword(s):  
Pore Water ◽  
Effective Stress ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Swelling Pressure ◽  
Constitutive Modelling ◽  
Dry Density ◽  
Expansive Clay ◽  
Experimental Database ◽  
Clay Aggregates

The central aim of this paper is to discuss the applicability of the effective stress principle as defined by Terzaghi (total stress minus pore-water pressure) to predict the behaviour of expansive clay aggregates. Phenomena occurring between individual clay minerals are reviewed first at the molecular level obtained in the colloid science research. In particular, it is noted that, for interparticle distances higher than approximately 1.5 nm, the pore-water pressure in the bulk equilibrium solution forms an additive component of the interparticle disjoining pressure. It is concluded that for these distances Terzaghi’s effective stress principle should be adequate to describe the clay behaviour. To support these developments, an extensive experimental database of nine different sodium and calcium bentonites available in the published literature was analysed. With the aid of double structure constitutive modelling, procedures were developed to extract information about the behaviour of clay aggregates from the experimental measurements. It was then shown that unconfined water retention curves, swelling pressure tests, swelling under constant load tests, and mechanical unloading tests are all uniquely related in terms of the dependency of dry density (or void ratio) of clay aggregate versus mean effective stress. By considering reversibility of aggregate behaviour and full saturation of aggregates, this implies that the effective stress principle is a valid way of predicting expansive clay aggregate volumetric deformation.

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.

scholarly journals Bio-desaturation and bio-sealing techniques for mitigation of soil liquefaction: a review

2018 ◽  
Vol 250 ◽  
pp. 01018
Author(s):  
Muttaqa Uba Zango ◽  
Khairul Anuar Kassim ◽  
Abubakar Sadiq Mohammed
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Improvement ◽  
Soil Liquefaction ◽  
Engineering Properties ◽  
Calcite Precipitation ◽  
Nitrogen Gas ◽  
Liquefaction Resistance ◽  
Cyclic Shear ◽  
Soil Behaviour

Biogeotechnology is a recent area of study that deals with the improvement of engineering properties of soils in an eco-friendly and sustainable approach through the use of microorganisms. This paper first, reviewed the concept of bio-mediated soil improvement technique, components involved and the roles they played. Two processes of bio-mediation soil improvement techniques i.e. microbial-induced calcite precipitation (MICP) for producing bio-cement via ureolysis and bio-desaturation for generating specifically biogenic nitrogen gas via denitrification, their mechanisms of occurring and factors influencing them were described in details. An overview study was done on soil liquefaction. Conventional methods employed for mitigations of liquefaction hazards were reviewed and their limitations were drawn. The use of the de-saturation process for mitigation of soil liquefaction was adequately addressed. Mitigation of liquefaction using biological processes, in particular, MICP and/or bio-desaturation were introduced. The findings from the previous works have shown that both the two techniques are capable of improving liquefaction resistance of soils. Most of the results have shown that presence of biogenic nitrogen gas in soils treated with denitrifying bacteria is able to induce partial desaturation in the soil which consequently increases the cyclic shear strength, reduces pore water pressure and changes the soil behaviour from compressive to dilatant. Finally, potentials, challenges, and recommendations for future studies were identified.

THE EFFECTIVE STRESS RESPONSE OF A SATURATED CLAY SOIL TO REPEATED LOADING

1969 ◽  
Vol 6 (3) ◽  
pp. 241-252 ◽  
Author(s):  
D. A. Sangrey ◽  
D. J. Henkel ◽  
M. I. Esrig
Keyword(s):  
Pore Water ◽  
Effective Stress ◽  
Critical Level ◽  
Clay Soil ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Triaxial Tests ◽  
Repeated Loading ◽  
Repeated Stress ◽  
Saturated Clay

The results of a series of tests designed to examine the behavior of saturated clay soil under repeated loading are reported. Triaxial tests, under conditions of axial symmetry, were used and the rates of deformation were chosen so as to permit the accurate measurement of pore water pressure at all stages of the tests.It was found that, for any particular consolidation history, a critical level of repeated stress existed. Below this critical level, a state of nonfailure equilibrium was reached in which the stress-strain curves followed closed hysteresis loops. Above the critical level of repeated stress, effective stress failure occurred; and each cycle of loading produced cumulative increases in deformation.An interesting feature of the test results was that a linear relationship between the magnitude of the applied repeated stress and the increase in pore water pressure was found for stress levels below the critical value.

Research study of the hydraulic behaviour of the Po River embankments

2013 ◽  
Vol 50 (9) ◽  
pp. 947-960 ◽  
Author(s):  
Giovanni Calabresi ◽  
Francesco Colleselli ◽  
Domenico Danese ◽  
Gianpaolo Giani ◽  
Claudio Mancuso ◽  
...  
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Engineering Properties ◽  
In Situ Tests ◽  
Po River ◽  
Fine Grained ◽  
Hydraulic Behaviour ◽  
Two Dimensional Flow ◽  
Atmospheric Variables

To investigate the hydraulic behaviour of the fine-grained embankments along the mid-course of the Po River, research was carried out on a full-scale physical model, built on the floodplain along the existing embankment and forming a pond. The pond was filled to reproduce historical floods. The prototype was built according to recommendations formulated by the Po River Management Authority. The engineering properties of the foundation soils were investigated by in situ tests and complemented by some suction-controlled laboratory tests. Pore-water pressure was measured in the embankment and in its foundation before, during, and after the experimental reproduction of two floods that occurred in 1976 and 2000. Atmospheric variables were monitored at the prototype site. Monitoring data refer to 6 months of experimental activities. Pore-water pressure measurements were first presented and subsequently interpreted through an isothermal two-dimensional flow approach where boundary flow rates express the evolution of atmospheric variables. The distribution of the pore water provided by this interpretation was used for stability analyses of the prototype. Results from the experimental activities and their interpretation indicate that the river embankment remains extensively unsaturated during floods. Typical suction trends within the embankment, suction-associated soil strength, and the resulting slope stability safety factors are also shown.

scholarly journals Investigation on the Failure Mechanism of Rainfall-Induced Long-Runout Landslide at Upputhode, Kerala State of India

Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1212
Author(s):  
Rajkumar Andrewwinner ◽  
Sembulichampalayam Sennimalai Chandrasekaran
Keyword(s):  
Shear Strength ◽  
Failure Mechanism ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Pressure Ratio ◽  
Simulation Software ◽  
Engineering Properties ◽  
Antecedent Rainfall ◽  
Landslide Mass

The main objective of the study is to estimate the shear resistance mobilized on the slope surface under large deformation and to identify the failure mechanism of the landslide through the simulation model. The field investigations were carried out using Geophysical tests, and the laboratory tests were conducted to identify the engineering properties of the soil with weathering characteristics of the parent rock. The residual shear strength parameters from Torsional ring shear tests were used in LS-RAPID numerical simulation software to study the mechanism of the landslide. The critical pore water pressure ratio (ru = 0.32) required for the initiation of a landslide was obtained. The increase in pore water pressure reduces the soil matric suction and thereby results in the reduction of the shear strength of the soil. The progressive failure mechanism and the three landslide processes (initiation, run out and deposition) are investigated. The velocity of the moving landslide mass in the role of demolishing the building is studied and helps in finding suitable remedial measures for the nearby building. The empirical rainfall threshold based on the antecedent rainfall was developed and revealed that either a high daily rainfall intensity of 142 mm without any antecedent rainfall, or an antecedent rainfall of 151 mm for a cumulative period of 5 days with even continuous normal rainfall can initiate landslide.

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