Introduction in many areas of telangana the main problem in construction is the poor bearing capacity of the soil. Expansive soils are fine grained soil or decomposed rocks that show huge volume change when exposed to the fluctuations of moisture content. Expansive soil stabilization using plastic fiber waste. The moisture variations in expansive soils cause shrinkswell behaviour, resulting in distress to the structures founded inon problematic soils. These limits distinguish the boundaries of the several consistency states of cohesive soils. Paper open access expansive clay soil stabilization using. Such soils contain clay particles of one or more minerals which have a strong affinity for water. Tables 3 and 4 present the schemes available to recognise the swell potential of finegrained soils based on shrinkage limit. Atterberg limit of soil is the main parameter in indirectly identifying expansive soils 12. Increase in moisture content in expansive soils causes the following effects. The main objective of this paper is to understand the. The effect of variation index plasticity and activity in. Water can also be introduced into the soil through people, or their infrastructure.
The plasticity index is a useful measure to verify the suitability of clay for potteries, for the construction of the clay core in an earth dam, and for the construction of a clay liner to contain a polluted material. Introduction expansive soils pose a severe threat to civil engineering infrastructure worldwide. Expandable soils, expansive clays, shrinkswell soils and heavable soils are some of the synonyms used for these soils. Expansive soils occurring above water table undergo volumetric changes with changes in water content katti 1979, nelson and miller 1992. Kaolinite exhibits a shrinkage limit of 25% to 29% depending on particle sizes, while its plastic limit is typi cally 30% to 40%, and its liquid limit is typically 35% to 72%. Depending on its water content, a soil may appear in one of four states. A study of the atterberg limits of different clays has shown that the ratio of liquid limit to plastic limit defines the type of clay present in a soil. When soil starts losing moisture, it changes from liquid state to.
Identification of expansive clay by indirect method is an empirical relationship on experience and identification of atterberg limit, clay content, initial moisture content, dry volume weight, and shrinkage limit 11. Expansive soils also have low values of shrinkage limit. This research focuses on the understanding of swelling and shrinkage phenomenon in the surface layer of expansive soils. Soil engineers did not recognize the problem of expansive soils until 1930. Maximum swell occurs at some point between the plastic limit and liquid limit. Index properties of expansive soil like liquid limit, plastic limit and shrinkage limit with and without flyash have been compared. Swellingshrinkage behaviour is likely to take place near ground surface where it is directly subjected to seasonal and environmental variations. Where w 1 is the initial total weight of soil in stagei, w d is the dry weight of soil, v 1 is the initial volume of the soil in stagei, v d is the volume of soil in dry state stage iii. The main objective of this paper is to understand the engineering properties of regina clay using in situ and. Alternate heave and settlement due to seasonal climatic variations result in distress and damage in civil infrastructure systems.
Various aspects of expansive soils relevent to geoengineering practice simple correlations between soil plasticity and expansion potential soil expansion potential astm d4829 this test was developed in orange county, california in the mid1960s and introduced in the 1973 uniform building code as ubc test standard 292. Influence of soil structure on the shrinkage behaviour of a soil irrigated with salinesodic water. Swelling shrinkage behaviour is likely to take place near ground surface where it is directly subjected to seasonal and environmental variations. Expansive soils as used in this manual also include marls, clayey siltstones, sandstones, and saprolites. Swellingshrinkage behavior of natural expansive clays. Shrinkage, from the reduction of moisture caused by evaporation or the evapotranspiration of vegetation, and the subsequent increase in soil moisture content has caused heave in expansive soils. Snethan 1984 based on field and laboratory studies on expansive soils of united states of america used liquid limit and plasticity index as criteria for identifying expansive soils. Swelling pressure and retaining wall design in expansive soils. Index termsexpansive clay, soilstructure interaction, shrinkswell of clay. Expansive soils expand and contract due to change in moisture content of the soil. Expansive soils identification, detection and remediation strategies emilio m.
Standard test method for shrinkage factors of cohesive soils. In 1911, the swedish agriculturist atterberg divided the entire range of soil state from liquid to solid state into four stages, which is known as atterberg. Environmental conditions of a particular area in which expansive soils are located play an important role in the behaviour of such soils. Compacted, expansive soils 253 ll liquid limit a dry density of soil sample in kgm 3 w water content. It represents the lower bound water content for any volume reduction of a soil mass and hence, regarded as a measure of volume stability of the in situ soil. The test results indicate that, the free swell index linear variation with the non swelling residual soil.
Expansive soil, soil stabilization, polypropylene, atterbergs limit, cbr. The expansive soils due to their large water holding capacity are highly difficult material to be handled in construction sites. Determination of shrinkage limit of remoulded soil equipment for shrinkage limit test shrinkage dish having flat bottom, 45mm diameter and 15 mm height. Many criteria are available to identify and characterize expansive soils, such as liquid limit table 1, plasticity index table 2, shrinkage limit table 3, shrinkage index a. The oedometer based tests can be used to determine swell behaviour of soil. Professor emeritus civil engineering, university of pretoria, specialist consultant. Dec 18, 2016 expansive soils and stabilization 3 introduction expansive soils could be defined as soils whose volume changes with introduction of moisture i. These water contents distinguish the boundaries of the several consistency states of cohesive soils. In a second stage, after desiccation cracks were closed, soil volumetric expansion is only. Linear shrinkage abbreviated name ls test number p6 test method type a version number 1 scope this test covers the determination of the linear shrinkage of a disturbed soil sample. Expansive soils and stabilization 3 introduction expansive soils could be defined as soils whose volume changes with introduction of moisture i. Expansive soils exhibit large volume changes when their water content changes.
Overall, a generalized theoretical framework is developed to understand the behavior of expansive soils. Expansive soils present significant geotechnical and structural engineering challenges the world over, with costs associated with expansive behaviour estimated to run into several billion annually. The increasingly extensive use of concrete slab on ground construction after 1940 has further increased the damage to the structure caused by expansive soils. Excessive cost of damages to infrastructure mainly due to expansive soils is reported each year. During the course of experiments, four samples of different soils are used with plasticity indices of 20, 30, 35, and 40. Mar 01, 2000 shrinkage limit, one of the atterberg limits, is widely linked with many plasticitybased soil behaviors. However, in a great majority of these cases, such correlations have been found to exhibit. If soils dry out more intensely, the residual shrinkage zone from air entry to shrinkage limit shows a smaller soil volume decrease compared with water loss. Expansive soils are the most problematic in regions with very defined wet and dry periods, as opposed to areas that maintain a certain level of moisture throughout the year, as this annual cycle causes the soils to expand and swell every year. Undisturbed field samples were used to capture the effect of in.
The differential movement caused by swell or shrinkage of expansive soils can increase the probability of damage to the foundation and superstructure. Various aspects of expansive soils relevent to geoengineering practice simple correlations between soil plasticity and expansion potential soil expansion potential astm d4829 this test was developed in orange county, california in the mid1960s and introduced in. Oedometer based estimation of vertical shrinkage of expansive. Based on the laboratory tests, a new methodequation is developed for the prediction of the lateral swelling pressure of unsaturated expansive soils behind of retaining walls. Every soil present on the earth tends to lose its moisture due to either natural or artificial reasons.
The phenomenon of swelling soils in the country is now only slowly being recognized, and oftentimes only when this has manifested itself in the form of extensive damage to the structures or pavements. Christensen department of engineering mechanics, engineering building, the university of wisconsin, madison, wisc. The atterberg limits are a basic measure of the critical water contents of a finegrained soil. Shrinkage limit, one of the atterberg limits, is widely linked with many plasticitybased soil behaviors. Upon absorbing water, their particles grow, resulting in expansion of the. Pre and post stabilized results are compared to arrive at conclusion that can thwart expansive soil problems. The shrinkage limit can be reasonably approximated as the plastic limit pl. Water can also be introduced into the soil through people, or. Kamel, et al, treatment of expansive soil with chemical a dditives, pp. The atterberg limits are found for remoulded soil samples. To simulate drying temperatures typical of site conditions, two shrinkage schemes were adopted, partial and full shrinkage.
It is the maximum water content at which a reduction in water content will not cause a decrease in volume of the soil mass. Clyde armstrong natural hazards cause billions of dollars of damage to trans portation facilities each yearonly flooding causes more dam age than expansive soils. In this study, a series of conventional oedometer tests were conducted to investigate the. Published laboratory test results indicate that the liquid limit ll of such soils is 5070, and the plasticity index pi ranges from 2545. This problem can be overcome by altering the soil through addition of non expansive soil and chemicals such as lime, cement etc. This paper is a brief research summary of the special topic on the engineering geological characteristics of expansive soils in china, including the geological origin, composition, fabric, physical and chemical characteristics, and engineering properties of six types of expansive soils. Nearly all types of transportation facilities have been affected by expansive soil behavior and, as.
It is the lowest water content at which soil can still be saturated. Two large evaporating dishes about 120mm diameter with a pour out and flat bottom. Here, the plasticity properties including liquid limit, plastic limit, shrinkage limit, and plastic index of clay soils in the region will be examined and compared before. Engineering geological characteristics of expansive soils in. This paper presents swelling behaviour of soils with wide range of plasticity characteristics i. Determination of swelling and shrinkage properties of. Potentially expansive soils can be found almost anywhere in the world. Content, ii plasticity index, iii shrinkage limit can be qualitative indicators of expansive characteristics. A common way to describe expansive soils is through plasticity index values. In each state, the consistency and behavior of a soil is different and consequently. Soil shrinkage characteristics in swelling soils 475 types of soil swelling when a dry soil wets, during the first stage it undergoes three dimensional 3d volumetric expansions, because its desiccation cracks are still opened figure 6. Vi mechanics of expansive soils expansive soils are those that exhibit unusually large volume changes as a result of moisture variations and environmental changes 4.
Astm d427 04 test method for shrinkage factors of soils by. These soils are generally described as dark grayish brown to very dark grayish brown clay, with a high shrinkswell potential. The swellshrinkage behavior of expansive clays was investigated in four soils of different plasticity cyclic swelling. The effect of variation index plasticity and activity in swelling vertical of expansive soil agus tugas sudjianto1, kabul basah suryolelono 2, ahmad rifai and indrasurya b mochtar3 1 civil engineering departmen, widyagama university, malang, east java, indonesia 2 civil engineering departmen, gadjah mada university, yogyakarta, indonesia. In 1911, the swedish agriculturist atterberg divided the entire range of soil state from liquid to solid state into four stages, which is known as atterberg limits or consistency limits.
Behaviour of expansive soils stabilized with hydrated lime. Shrinkage limit article about shrinkage limit by the free. As the factors governing the shrinkage limit are entirely different from those controlling the swelling of soils, the. Most of these areas are covered with clay of very soft consistency. An experimental study for identification and comparison of.
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