Clayey Silt Soil Research Articles

Effects of Microencapsulated Phase Change Material on the Behavior of Silty Soil Subjected to Freeze–Thaw Cycles

Freeze–thaw (F-T) cycles are one of the most important factors affecting the performance of silty soils with high kaolin content in seasonally freezing regions. This study investigates the improvement of a high-plasticity clayey silt soil (MH) with microencapsulated phase change material (mPCM) to prevent changes in mechanical properties when subjected to freeze–thaw cycles. Unconfined compression, one-dimensional compression, and freeze and thaw tests were performed to evaluate the behavior of treated soil under different freeze/thaw cycles and with different mPCM ratios. It has been observed that the mPCM additive decreased the unconfined compression strength (UCS); however, the strength of the soil held constant during the increasing F-T cycles, and the increase in the mPCM additive content increased the strength of the soil. The inclusion of mPCM affected the compression of the soil and increased settlement (∆H), although the settlement remained constant with increasing freeze–thaw cycles. It has been noted that the compression behavior, which is least affected by the unconfined compressive strength and freeze/thaw cycles, is achieved with the addition of 10% mPCM. As a result of the tests, it was determined that the most suitable additive mPCM ratio is 10% for the compression and strength behaviors.

Prediction of Smear Effect on the Bearing Capacity of Driven Piles

This paper deals with prediction the effect of soil remoulding (smear) on the ultimate bearing capacity of driven piles. The proposed method based on detecting the decrease in ultimate bearing capacity of the pile shaft (excluding the share of pile tip) after sliding downward. This was done via conducting an experimental study on three installed R.C piles in a sandy clayey silt soil. The piles were installed so that a gap space is left between its tip and the base of borehole. The piles were tested for ultimate bearing capacity according to ASTM D1143 in three stages. Between each two stages the pile was jacked inside the borehole until a sliding of about 200mm is achieved to simulate the soil remoulding due to actual pile driving. The results of the tests exhibited that the pile might loss 14% of its ultimate capacity when it is loaded immediately after installation. Also, it was concluded that the pile may regain of about 9% of its original capacity after 30days of its installation.

Exploration and isolation of indigenous arbuscular mycorrhizal fungi in post-landslide sandy and clayey silt for eco-friendly remediation

Critical lands are formed after landslides due to the erosion and stripping of the surface soil in the depletion zone and the formation of accumulation zones, requiring remediation efforts. Indigenous arbuscular mycorrhizal fungi help rehabilitate degraded lands, including post-landslide sites, by adapting to native soil conditions. This study investigates mycorrhiza’s presence in post-landslide areas with sandy silt in Cililin and clayey silt in Citatah. Soil samples are collected at 30 cm depth using a corer near Dysoxylum macrocarpum in Citatah and Gmelina arborea in Cililin. Mycorrhiza isolation involves wet sieving and centrifugation. Local mycorrhiza genera identified are Glomus, Gigaspora, Acaulospora, and Scutellospora. Sandy silt soil 2 exhibits the highest spore density of 178 per 100 grams, while clayey silt soil 1 has the lowest density of 148 per 100 grams. Glomus dominates in sandy silt with a 93 per 100 grams concentration and a 38–45 µm size. Scutellospora is scarce in clayey silt, with only 1 per 100 grams, 90-170 µm size. Isolated mycorrhiza can serve as compatible and adaptive inoculum. The discovery of mycorrhiza tolerant to post-landslide conditions is expected to play an important role in the remediation process of critical lands caused by landslides.

Assessment of Soil and Water Properties in the Central Marshes Southern Iraq

The Central Marshes are one of southern Iraq's most important wetlands and ecosystems. A study on evaluating soil quality and water quality in terms of chemical properties at certain sites in the southern Iraqi Central Marshes has been conducted to investigate their types and suitability for enhancing the agricultural reality of most field crops. Soil and water samples were collected from 15 sites and transferred to the laboratory. In the lab, the following parameters were determined: electrical conductivity (EC), total dissolved salts (TDS), organic materials (OM), pH, gypsum, and total sulfate content (SO3). The tests conducted on the samples indicated that it could be said that the soil of the Central Marshes is dark blackish-gray silty clay or clayey silt soil and revealed that most of the southern marshlands are suitable for planting different crops. Analysis of the results may have a role in designing and planning upcoming projects such as construction and agriculture, which would have to enlighten the decision maker.

Strength and Deformation Characteristics of Dune Sand Earth Blocks Reinforced with Natural and Polymeric Fibers

In this paper, we present a strength and deformation evaluation of earth blocks reinforced with different types of fiber. A natural palm tree fiber and two other types of synthetic polyolefin fibers were used to improve earth blocks’ strength and stiffness. The soil used to cast the earth blocks was composed of dune sand, which is extensively available in the United Arab Emirates and most Gulf Cooperation Council (GCC) deserts, and clayey silt soil acquired from Al-Ain city, UAE. Sixteen different mixes were prepared for this study. Two identical earth blocks were cast in a wooden mold from each mix to form a total of 32 blocks. After compaction, the blocks were consolidated under pre-specified pressure, air dried, and tested to failure in the compression machine. The main parameters investigated in this study were clay content, fiber types and percentages, and cement content. The results indicate that the addition of natural or polymeric fiber to cast earth blocks significantly improved their compressive strength. The maximum compressive strength of improved blocks showed an increase of more than 30% above the maximum compressive strength recorded for identical soil blocks without fiber. In addition, the post-peak and pre-peak strength behaviors of the earth blocks are different with different fiber contents. Finally, the addition of 0.5% cement to the fiber-reinforced blocks showed a negligible effect on the peak compressive strength. However, cement content improved the early stage (small strain) stiffness of earth blocks.

RELATIONSHIP BETWEEN SOIL ENGINEERING PROPERTIES AND CORROSION RATE IN ANDESITIC VOLCANIC SOILS, WEST LAMPUNG, SUMATRA, INDONESIA

Soil is the most diverse environment that can cause metal corrosion. Many researchers claim that soil is a corrosive environment that has complexity compared to other environments. With a background knowledge of soil engineering properties in a specific area and their effects on the metal corrosion process then corrosion problems can be prevented. This paper presents the relationship between andesitic volcanic soil engineering properties with an average corrosion rate based on geotechnical and statistical methods. In this paper, we propose a new average corrosion rate per year on that soil. The study area took place on the Sekincau-Way Tenong Transect Road, West Lampung, Sumatra, Indonesia. This area was composed of silty clay to clayey silt soils which weathering products from andesitic-basaltic volcanic breccia. This soil can store water that is moderate to high and has high plastic properties. Based on the statistical approach, it can be concluded that the corrosion rate in andesitic volcanic soils is 1.132 mm/yr. Soil engineering properties (water content, index plasticity, and clay content) simultaneously affect the average corrosion rate. The effective contribution of each independent variable (soil engineering properties) to the corrosion rate is a plasticity index of 39.5%, the water content of 24.79%, and clay content of 26.04%. Index plasticity and water content were found to raise the average corrosion rate at the soil samples, while clay content was on the side that lowered the average corrosion rate.

WITHDRAWN: Effect of coal ash on strength characteristics of clayey silt soil treated with cement

Coal-based thermal power plants produce coal ash as a by-product and the major concern is for handling and disposal of coal ash without adversely affecting the environment. There is a feasibility to utilize the coal ash in an environmentally safe manner in geotechnical engineering applications. To achieve this objective, an experimental investigation was conducted in which coal ash was used as replacement material in soil mixtures. A clayey silt soil was used in this study and class F type coal ash (CA) was blended in different proportions up to 50% by mass of the soil. The testing program comprised characterization of soil and coal ash, compaction tests and California bearing ratio (CBR) tests. The stress–strain and strength characteristics of compacted soil with coal ash and cement were analyzed. The test results showed that all the mixes achieved a higher CBR value than the control specimen. The optimum coal ash contents for clayey silt–coal ash mixes were found as 20% and 50% which showed higher CBR value, it could be due to the packing effect and imparting cohesion, respectively. The minimum cement content of 1% to the optimum mixes provided a significant improvement in CBR values of 25.19% and 29.14% as compared to the control specimen of 4.72%. These results are acceptable values and hence, the coal ash blended soil is found to be suitable for pavement subgrade and embankments constructions.

Development of Practical Correlations Between Cone Penetration Resistance and SPT Values for Various Types of Soils

A suite of relationships has been developed between cone penetration resistance (qc) and SPT values of clayey and sandy soils. The major difference between these relationships and those of previous studies lies in the range of data and variety of soils. Most studies with the same scope of research since 1959 have been considered herein, and their practical data have been collected. Then, by means of statistical analyses and data refinement, a database was provided for diverse types of soils (including silty sand, clayey, sandy and sandy silt soils). Accordingly, for each soil type, the data were classified as either regression or test data. The regression data were applied to develop the correlations between qc and SPT value (N60). The test data were employed to examine accuracy of the correlation compared to the available relationships for the same soil type. The results indicate that the proposed relationships between qc and N60 for silty sand, sandy and sandy silt soils are simple with RMSE values equal to 0.078, 7.012 and 7.498, respectively, whereas in the case of clay, the relationship becomes more complex (accuracy of 0.248). Based on the results derived herein, it can be concluded that all relationships proposed in this study are of greater accuracy compared to the previous relations.

A Study on the Behaviour of Stone Columns in a Layered Soil System

Stone columns are one of the cost-effective and efficient methods for improving the ground which strengthen the soil and reduce the settlements. The study of the behaviour of stone columns in layered soils is of great importance. In this paper, results obtained from the experiments done on the stone columns with varying thickness of clayey silt soil (lithomargic clay) at bottom and the lateritic soil at the top are discussed. The lateritic layers are varied from top for a depth of 1D to 5D where D is the stone column diameter. Experiments were performed on untreated soils alone, soil with the ordinary stone column, geogrid encased stone column with and without additional horizontal reinforcement called basal layer to geogrid encased stone column in lithomargic clay. Similar experiments were conducted using lateritic soil. By considering layered combination of these two soils, experiments were also performed on ordinary stone column, geogrid encased stone column and geogrid encased stone column with basal layer. Laboratory tests were conducted in a unit cell on the floating stone column of diameter 60 mm. The load capacity of the stone column and bulging characteristics are significantly affected with the increase in the layers of lateritic soil. The encasement of stone column enhances the stone column’s capacity and reduces the bulging. The additional horizontal reinforcement layer also showed a significant impact on the load capacity of the stone column. Experiments conducted were modelled and analysed using PLAXIS 2D software package.

The relationship between sea-level change, soil formation and stress history of a very soft clay deposit

The paper addresses the relationship between sea-level change, soil formation and stress history of a very soft clay deposit close to the city of Rio de Janeiro (Sarapui II), permitting some conclusions on hypotheses discussed over time. Dating samples throughout the very soft organic clay profile provided values between 8590 and 2300 cal. yr BP. The average rate of deposition is 0.9 mm/yr. The very soft clay overlies a yellow clayey silt soil of Pleistocene origin (12,630–12,240 cal. yr BP). The combination of geological and geotechnical data indicates that the paleo-sea-level highstand in the Rio de Janeiro area (and possibly in the region between 8°S and 26°S in the Southern Hemisphere along the Brazilian coast) occurred around 7000 cal. yr BP. These sets of data also indicate that the lower part of the Sarapui II deposit was formed during transgression and the upper part during regression. The overconsolidation of the deposit, excluding the top 2.5 m, could be attributed to secondary consolidation.

Model Development for Computing Cracking in Soil Reinforced with Fibers from Three Different Bioresources

Abstract The study explores the effects of three different lignocellulose fiber-reinforced (jute, coir, and water hyacinth [WH]) soils on the desiccation potential of compacted clayey silt soil. A new model was developed using artificial neural networks (ANN) for estimating cracking in soil reinforced with different fibers as a function of suction and water content. The program for ANN was developed in house using C++. Before model development, suction and water content were simultaneously monitored for 105 days along with the crack intensity factor (CIF). After model development, relative significance of each parameter (suction and water content) on the corresponding CIF was estimated. Adding lignocellulose fibers significantly increased the water retention capacity in the soil and reduced the CIF significantly as compared to unreinforced soil (almost half the amount). Obtained ANN models were efficient in predicting the CIF. The CIF is inversely proportional to water content and directly proportional to suction. The CIF value in bare soil, jute, and WH composites primarily depends on suction. Because of the increased water retention capacity of coir, the value of CIF depends equally on both suction and water content values. The log normal distribution of CIF was found in soil–jute composites.

A Theoretical Study of Some Unsaturated Properties for Different Soils

Soil–water characteristic curves (SWCC) can be defined as the relationship between the water content and suction of an unsaturated soil. It considered a basic relation to explanation of the engineering behaviour of unsaturated soil such as hydraulic conductivity and shear strength, So the study of SWCC is useful to reduce the time and cost of unsaturated soil testing for different engineering purposes. An approach model has been used to predict the SWCC for different soils. The influence of the soils on SWCC shape, the unsaturated hydraulic conductivity and shear strength parameters have been studied in this paper using mathematical models. The results of SWCC show that suction of clay soil is bigger than sandy soil, while the clayey silt soils exhibit an intermediate behaviour at same water content. The values of unsaturated shear strength are increasing while the unsaturated hydraulic conductivity is decreasing with increasing soil suction. This behaviour of the last two parameters with soil suction should be taken in consideration for engineering purposes.

Genetic programming for soil-fiber composite assessment

Unconfined compressive strength (UCS) of soil is one of the basic index parameters for representing the compressive bearing strength of soil. Fiber reinforced soil is one of the most popular and practical ground improvement approaches used in geotechnical infrastructures. Analytical models for estimating UCS of soil-fiber composites have been developed in the literature. However, these models rarely incorporate the combined effects of dynamic field parameters such as fiber content, soil moisture, and density. These effects can be studied by the development of a holistic model based on a dimensionless strength improvement factor (SIF), which is defined as the ratio of UCS of reinforced soil to the unreinforced UCS. The current model estimating SIF indicates the improvement expected in UCS of soil-PP fiber composite based on the three design conditions such as fiber content, soil density, and moisture content. For this purpose, a series of 108 laboratory tests were first conducted to measure UCS of both fiber-reinforced soil and unreinforced soil under different fiber contents, soil density, and soil moisture content. Clayey silt soil and commercially used polypropylene (PP) fibers were selected in this study as soil and fiber material respectively. Genetic programming (GP) approach was then used to formulate models based on the measured data. The hidden non-linear relationships between SIF and the three inputs were determined by sensitivity and parametric analysis of the GP model. It was found that the moisture content in the soil has the highest influence on the strength factor that accounts for the change in strength. Coupled effects of soil parameters (soil moisture, soil density) and fiber content have been studied using parametric analysis which includes different possible field conditions (parameters). The results have been discussed along with the reinforcement mechanism of PP fiber for different soil conditions. It is believed that the robust GP model developed will be useful to determine optimum input values for designing safe bearing foundation soils which are reinforced with PP fibers.

Stabilization of Clayey Silt Soil Using Small Amounts of Petrit T

Effects of using small amounts of a Petrit T, a by-product of manufacture sponge iron, to modify clayey silt soil were investigated in this study. Petrit T was added at 2%, 4% and 7% of soil dry weight. A series of unconfined compressive strength tests, consistency limits tests and pH tests were conducted at 7, 14, 28, 60 and 90 days of curing periods to evaluate the physical and mechanical properties of treated soil. Results indicated improving in the unconfined compressive strength, stiffness and workability of treated soil directly after treatment and over time. Increasing in soil density and decreasing in water content were observed, with increasing Petrit T content and curing time. The pH value was immediately increasing after treatment and then gradually decreased over time. Failure mode gradually changed from plastic to brittle behavior with increasing binder content and curing time. The outcomes of this research show a promising way of using a new by-product binder to stabilize soft soils in various engineering projects in order to reduce the costs which are associated with of excavation and transportation works.

The Behaviour of Laboratory Soil Electrical Resistivity Value under Basic Soil Properties Influences

Electrical resistivity method (ERM) was a popular indirect geophysical tools adopted in engineering, environmental and archaeological studies. In the past, results of the electrical resistivity value (ERV) were always subjected to a long discussion and debate among the related parties such as an engineers, geophysicists and geologists due to its lack of clarification and evidences in quantitative point of view. Most of the results produced in the past was always been justified using qualitative ways which difficult to be accept by certain parties. In order to reduce the knowledge gap between those parties, this study has performed a laboratory experiment of soil box resistivity test which supported by an additional basic geotechnical test as referred to particle size distribution test (d), moisture content test (w), density test (ρbulk) and Atterberg limit test (LL, PL and PI). The test was performed to establish a series of electrical resistivity value with different quantity of water content for Clayey SILT and Silty SAND soil. It was found that the ERV of Silty SAND (600 - 7300 Ωm) was higher than Clayey SILT (13 - 7700 Ωm) due to the different quantity of basic soil properties value obtained from the basic geotechnical test. This study was successfully demonstrated that the fluctuation of ERV has greatly influenced by the variations of the soil physical properties (d, w, ρbulk, LL, PL and PI). Hence, the confidence level of ERV interpretation will be increasingly meaningful since it able to be proved by others parameter generated by laboratory direct test.

IMPROVEMENT OF SELECTED PARTS OF BASRAH GOVERNORATE SOILS USING A MIXTURE OF CEMENT AND NOVOLAC POLYMER

A weak clayey silt soils from Garmmat Ali and a sandy soil from AL-Nashoa region were used from different sites and depths and mixed with (0.2%,0.4%,0.6 w/W) of Novolac polymer with (2%,4%,6% w/W) of Cement to know the profitable amount of Novolac, and improving some of engineering properties of the soils that include: the plasticity and compacting. A noticeable improvement in the plasticity of these clayey soils as result of adding a mixture by the rise in their plastic limit, dry densities, lowering in their optimum moisture contents, and increase in tensile strengths as compared with crude soils. There are also an improve in treated sandy soil properties. The cost of using this polymer as a soil binder was reduced by about 50% as compared to the usual practice which involve removing the clayey silt soils and replace them by sand or other materials.

Soil Resistivity Measurements to Predict Moisture Content and Density in Loose and Dense Soil

In the past, most of the soil electrical resistivity charts were developed based on stand-alone geomaterial classification with minimal contribution to its relationship to some of geotechnical parameters. Furthermore, the values cited a very wide range of resistivity with sometimes overlapping values and having little significance to specific soil condition. As a result, it created some ambiguities during the interpretation of observations which were traditionally based on qualitative anomaly judgments of experts and experienced people. Hence, this study presents soil resistivity values based on laboratory experiment with a view to predict the soil moisture content and density in loose and dense soils. This study used a soil box and a resistivity meter to test a clayey silt soil, increasing its water usage from 1-3% based on 1500 gram of dry soil. All the moisture contents and density data were observed concurrently with 25 electrical soil resistance observations being made on the soil. All testing and formula used were in accordance with that specified in BS1377 (1990). It was apparent that the soil resistivity value was different under loose (L) and compact (C) condition with moisture content (w) and density (ρbulk) correlations being established as follows; ρbulk(C) = 2.5991ρ-0.037, ρbulk (L) = -0.111 ln (ρ) + 1.7605, w(L) = 109.98ρ-0.268, and w(C) = 121.88ρ-0.363 with determination coefficients, R2 that ranged between 0.69 0.89. This research therefore contributes a means of predicting these geotechnical parameters by related persons such as geophysicist, engineers and geologist who use these resistivity techniques in ground exploration.

Case Study of St. Louis, Missouri: Comparison of Bioretention Performance to the Runoff Component of a Restored Water Balance

AbstractRunoff has important meaning in the context of the performance of post-construction best management practices (BMP) and compliance with National Pollutant Discharge Elimination System (NPDES) storm water permits. To illustrate, this work uses continuous simulation modeling to estimate water balance components from bioretention and compares the results to those of a representative natural condition for the St. Louis, Missouri, area. Three different bioretention scenarios were modeled, each with different capture volumes and design features. The water balance of the representative natural condition is based on a prairie landscape in clayey silt soil over limestone bedrock. If runoff is defined as all discharge originating from the BMP, then none of the scenarios achieved the target natural condition. This is because evapotranspiration (ET) is the dominant process removing runoff in a natural condition, deep infiltration (deep recharge) in the St. Louis area is limited by geology, and ET is a small p...

Influence of Waste Tire Chips on Strength Characteristics of Soils

An experimental study was conducted to investigate the effect of waste tire chips on the strength characteristics of two soils. A cohesive clayey silt soil and a cohesionless fine sand soil were used. A program of standard Proctor tests, unconfined compression tests and California bearing ratio tests was carried out on specimens of the cohesive soil-tire mixtures, by varying tire chips content from 5% to 20% by weight of the soil. Vibratory compaction tests and direct shear tests were conducted on the cohesionless soil-tire mixtures by adding tire chips varying from 10% to 50% by weight. The results showed that 13% and 30% chip contents, respectively by weight, were optimum for composite strength of the two reinforced soil mixtures.

Underground pollution travel from leach pits of on-site sanitation facilities: a case study

A long-term field study was undertaken under different hydro-geological conditions at some locations of the state of West Bengal (India) to understand the phenomenon of underground pollution movement, and to assess safe horizontal distance of water sources from on-site sanitation leach pits. The study showed that pollution travel from leach pits, both in horizontal and vertical directions, is dependent on soil type, permeability, hydraulic gradient, grain size, and position of groundwater table with respect to the leach pits. A minimum travel of pollutant of 2.055 m was found in clayey silt soil, whereas a maximum travel of 10.20 m was observed in gravel–sand composition of soils in 10-day period. The study also demonstrated that clay envelop around leach pit arrests the movement of pollutant (both chemical and bacteriological) to a considerable extent. In the present study, graphical technique has been suggested for estimating underground travel of bacteriological contamination under given soil composition.