Practical problems from surprising soil behavior
01 Mar 1986-Journal of Geotechnical Engineering (American Society of Civil Engineers)-Vol. 112, Iss: 3, pp 255-289
TL;DR: In this paper, the aging of quick clay after sampling, the remolded strength increases in samples maintained at constant water content, time effects in freshly densified or deposited sand, in which natural sand deposits can lose strength if disturbed but regain strength over time periods of weeks to months, and apparently sound lime-stabilized soil that swells and disintegrates starting a few years after construction.
Abstract: In spite of our present very advanced analytical capabilities, our present ability to predict actual field behavior is, in many cases, woefully inadequate. Four cases are described to illustrate one of the reasons why actual and predicted performances are sometimes so widely divergent—namely, failure to understand how a soil might respond over time to changed conditions. The four cases are: (1) The aging of quick clay after sampling, in which the remolded strength increases in samples maintained at constant water content; (2) time effects in freshly densified or deposited sand, in which natural sand deposits can lose strength if disturbed but regain strength over time periods of weeks to months; (3) apparently sound lime‐stabilized soil that swells and disintegrates starting a few years after construction; and (4) the failure of excess pore pressures to dissipate as predicted during the consolidation of soft clays. Study of each of these problems has led to an understanding of the responsible phenomena an...
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TL;DR: In this article, it is shown that microorganisms play an important part on the formation of many fine-grained soils, can alter the behavior of coarse grained soils (including hydraulic conductivity, diffusion and strength), accelerate geochemical reactions by orders of magnitude, promote both weathering and aging, and alter the chemical and mechanical properties of specimens after sampling.
Abstract: The understanding of soil behavior during the last 300 years has centered on mechanical principles, geological processes, and later on, mineralogy and the relevance of colloidal chemistry. More recently, research in biology and earth science has enabled important advances in understanding the crucial involvement of microorganisms in the evolution of the earth, their ubiquitous presence in near surface soils and rocks, and their participation in mediating and facilitating most geochemical reactions. Yet, the effect of biological activity on soil mechanical behavior remains largely underexplored in the geotechnical field. The purposes of this paper are to introduce microbiological concepts, identify and illustrate their potential roles in soils and rocks, and stimulate interest in seeking improved understanding of their importance and potential for advancing the states of knowledge and practice in geotechnical engineering. It is shown that microorganisms play an important part on the formation of many fine grained soils, can alter the behavior of coarse grained soils (including hydraulic conductivity, diffusion and strength), accelerate geochemical reactions by orders of magnitude, promote both weathering and aging, and alter the chemical and mechanical properties of specimens after sampling. While extensive research is needed to delineate the full impact of biomass and biomediated reactions on soil behavior, it is anticipated that a proper understanding of biological principles will lead to improved soil characterization, enhanced understanding of soil behavior, and even alternative geotechnical engineering solutions.
532 citations
TL;DR: In this paper, fly ash waste materials were used along with quicklime (CaO) to immobilize lead, trivalent and hexavalent chromium present in artificially contaminated clayey sand soils.
512 citations
Cites background from "Practical problems from surprising ..."
...Ettringite however, is known to be quite expansive when brought in contact with water, and its swelling could lead to catastrophic failures (Mitchell, 1984; Zhou and Colombo, 1987; Hunter, 1988; Dermatas, 1992; Mitchell and Dermatas, 1992), as well as possible releases of the previously immobilized toxic heavy metal components into adjacent water bodies....
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TL;DR: In this article, the authors found abundant thaumasite, a complex calcium-silicate-hydroxide-sulfate-carbonate-hyd rate mineral, forming a solid solution series with ettringite.
Abstract: Expansive reactions between lime and sulfate-bearing clay soils have attracted little attention until relatively recently. Lime treatment of Stewart Avenue in Las Vegas, Nevada, had induced heave in excess of 12 in. Heaved areas are found to contain abundant thaumasite, a complex calcium-silicate-hydroxide-sulfate-carbonate-hyd rate mineral. Thaumasite forms a solid solution series with ettringite, a calcium-aluminum-hydroxide-sulfate-hy drate mineral. In the presence of aluminum, ettringite forms first and is replaced by thaumasite only at temperatures below 15°C. The mechanism of heave is a complex function of available water, the percentage of soil clay, and ion mobility. Only the long-term possolanic chemistry of normal lime-soil reactions is disrupted. Cation exchange, agglomeration, and carbonation are unaffected. With the present state of knowledge, lime-induced heave is difficult to predict for all but most obvious conditions.
365 citations
TL;DR: In this article, a review of the triaxial IDS test and examples of its use to investigate the question of whether the aging improvements result from frictional or cohesive effects is presented.
Abstract: Soils age Their engineering properties often improve significantly during aging times of practical interest to engineers This paper provides examples from research and practice It includes a review of the triaxial IDS test, followed by examples of its use to investigage the question of whether the aging improvements result from frictional or cohesive effects Contrary to most current thinking, the soil stiffening and strengthening appears entirely frictional in effect The aging effects described appear mechanical, resulting from dispersive particle movements and internal stress arching under drained conditions The paper concludes with suggestions for using these mechanical aging effects in practice
355 citations
TL;DR: In this article, the authors review some of the key advances developed over the past 60 years in improving our understanding of the nature and methods of modifying and stabilizing expansive clay soils.
Abstract: Expansive clay soils—those that change significantly in volume with changes in water content—are the cause of distortions to structures that cost taxpayers several billion dollars annually in the United States. Much has been learned about their behavior over the past 60 years, and relatively successful methods have been developed to modify and stabilize them. This paper reviews some of the key advances developed over the past 60 years in improving our understanding of the nature and methods of modifying and stabilizing expansive clay soils. The state of the practice in stabilization is presented, and practical and research needs to help improve the state of the practice are discussed.
308 citations
References
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01 Jan 1976
TL;DR: In this paper, the authors developed an understanding of the factors determining and controlling the engineering properties of soil, the factors controlling their magnitude, and the influences of environment and time, and developed a two-part book which contains the following chapters: Part 1 - the nature of soils; bonding, crystal structure and surface characteristics; soil mineralogy; soil formation and soil deposits; determination of soil composition; soil water; clay-water-electrolyte system; soil fabric and its measurement; Part 2 - soil behavior; soil composition and engineering properties; effective, intergranular
Abstract: The book is intended to develop an understanding of the factors determining and controlling the engineering properties of soil, the factors controlling their magnitude, and the influences of environment and time. The two-part book contains the following chapters: Part 1 - the nature of soils; bonding, crystal structure and surface characteristics; soil mineralogy; soil formation and soil deposits; determination of soil composition; soil water; clay-water-electrolyte system; soil fabric and its measurement; Part 2 - soil behavior; soil composition and engineering properties; effective, intergranular and total stress; soil structure and its stability; fabric, structure and property relationships, volume change behavior; strength and deformation behavior; and, conduction phenomena. /TRRL/
3,283 citations
TL;DR: The sensitivity of clays is defined as the ratio of their undisturbed and remoulded strengths, and varies from about 1·O for heavily overconsolidated clays to values of over 100 for the so-called extrasensitive or quick clays.
Abstract: Synopsis The sensitivity of clays is defined as the ratio of their undisturbed and remoulded strengths, and varies from about 1·O for heavily over-consolidated clays to values of over 100 for the so-called extrasensitive or “quick” clays. As a result of experimental work it is shown that thixotropy can account for low or medium sensitivity but not for high sensitivity. Both laboratory and field evidence, however, show that a reduction in the salt concentration in the pore water, caused by leaching clays of marine or estuarine origin, can result in high sensitivities. Moreover, of the small number of clays so far investigated, those which have not been leached are found to exhibit only low or medium sensitivities of the order of magnitude explicable in terms of thixotropy. But it is, nevertheless, not suggested that leaching is the sole cause of high sensitivity and other possibilities are briefly discussed. Reasons are given, supported by experimental work, for the insensitivity of heavily overconsolidate...
439 citations
Book•
01 Jan 1957
TL;DR: In this paper, the authors investigated the relationship between shear strength and cone penetration in the fall-cone test and compared the results with a comparison of the fall cone test with the traditional cone test.
Abstract: (1) Region disturbed by the cone; (2) Study of the cone motion; (3) Relation between shear strength and cone penetration; (4) Precautions to be observed in the fall-cone test; (5) Comparison betwee ...
322 citations
TL;DR: The majority of the late glacial marine clays in Norway have been subjected to a leaching by fresh water due to a land elevation, resulting in a reduced salt concentration in the pore water as mentioned in this paper.
Abstract: Synopsis The majority of the late glacial marine clays in Norway have been subjected to a leaching by fresh water due to a land elevation, resulting in a reduced salt concentration in the pore wate...
272 citations
TL;DR: Sand deposits may undergo a significant loss in strength as a result of disturbance, thus behaving in some respects in a manner similar to sensitive clay as mentioned in this paper, and these phenomena appear to be related to solution and precipitation reactions involving quartz, amorphous silica, and other compounds and the formation of cementing bonds at interparticle contacts.
Abstract: Much evidence is now available that freshly deposited or densified saturated clean sand may exhibit substantial stiffening and strength increase with times up to several months. Sand deposits may undergo a significant loss in strength as a result of disturbance, thus behaving in some respects in a manner similar to sensitive clay. These phenomena appear to be related to solution and precipitation reactions involving quartz, amorphous silica, and other compounds and the formation of cementing bonds at interparticle contacts. The effects of these phenomena must be considered when evaluating the results of laboratory tests on reconstituted samples, in the assessment of ground improvement using deep densification, in the evaluation and interpretation of relative density measurements, and in the estimation of liquefaction potential.
229 citations