Showing papers on "Settlement (structural) published in 1986"

Studies of the influence of non-linear stress-strain characteristics in soil-structure interaction

Abstract: Recent field and laboratory studies have shown that, even at very small strains, many soils exhibit non-linear stress–strain behaviour. Nevertheless, because of its convenience, linear elasticity will continue to play an important role in the analysis of such problems as settlement, deformation and soil–structure interaction. In this Paper the measured non-liqear stress–strain properties of a low plasticity clay are used in the finite element analysis of footings, piles, excavations and pressuremeter tests to assess the influence of small strain non-linearity in comparison with linear elastic behaviour. In all cases non-linear behaviour results in the concentration of strain and deformation towards the loading boundaries. This is shown to have important consequences for soil–structure interaction problems such as settlement profiles, pile group interaction and contact stress distributions. Small strain non-linearity also has a significant influence on the interpretation in terms of equivalent elastic modu...

The role of human water contact patterns in the transmission of schistosomiasis in an informal settlement near a major industrial area

Abstract: Human contact with schistosome-infested water was studied in a rapidly growing community near an industrial area: water-contact was observed and categorized; interviews concerning water usage were ...

Dilatometer to compute foundation settlement

Abstract: Sixteen examples demonstrate how the S. Marchetti dilatometer test (DMT) provides soil compressibility data for the rapid calculation of foundation settlements with an average ratio of predicted to actual settlement equal to 1. 18. The examples include sands, silts, clays and organic soils, with settlement magnitudes from 3 to 2850 mm. The settlement prediction method includes the use of the basic, 1-D vertical compression modulus M, with an example calculation using both an Ordinary Method and a Special Method that includes adjusting M for the magnitude of effective stress.

Effects of settlement and post-settlement mortality on the distribution of the ascidian Trididemnum opacum

Abstract: At Isthmus Reef, Santa Catalina Island, California, colonies of the colonial ascidian Triddemnum opacum occur disproportionately in cracks acd crevices on rock surfaces. Small colonies are found in the open, but large colonies occur only in crevices. Transplantation ot established colonies into unprotected open habitats showed that they are preyed upon intensively, probably by fish and urchins (up to 19 % mortality d.' and 80 % mo-l), with colonies of all sizes being eaten. Recruitment was primarily into pits in experimental substrata. A caging study of recruitment patterns suggested that the recruitment pattern results from disproportionate but not exclusive settlement of larvae into depressions, followed by differential mortality of colonies in the open during the first month after settlement. S a m p h g in 1985 suggested that changes during El Nido years of 1982-3 may have resulted in altered abundance and size-distributions of T. opacurn: Isthmus Reef lost its canopy of Macrocystis pyrifera; the abundance of urchms increased by almost an order of magmtude. T opacum colonies became an order of magnitude less abundant in unprotected habitats and showed a shift towards smaller colony sizes in all habitats.

Compressibility and Settlement of Compacted Fills

Abstract: Settlement predictions are necessary for compacted fills under a variety of circumstances (e.g., when fills are high, where major structural loads are to be supported, and when the fill materials are clays or weak rocks).As a result of an extensive testing program on both laboratory- and field-compacted materials, a systematic approach to this prediction has been developed. The recommended procedure involves one-dimensional compression testing in three parts. The initial vertical strains experienced by the compacted fill are those due to self-weight. The magnitudes of these are highly dependent upon the values of prestress established by the compaction process; however, they occur as rapidly as the fill can be built. The major vertical strains will probably occur as the fill becomes wetter and "softens" in service. The timing of this settlement is uncertain, because it depends upon climatic variables at the site. Materials in the upper portion of the fill will often swell under the low confinement, and the net movement is an appropriate summing of these events with the compressions that occur deeper in the fill. Assuming that the fill becomes essentially saturated in service, further settlements can be produced by loading of the saturated material. The latter response is conventional in nature. By testing a series of specimens, with a range of confinements which match those which will be imposed by the prototype fill, representative vertical strains are defined. Integration of these strains over the fill height produces the prediction of movement for the upper surface of the fill. The total testing and prediction technique is illustrated in the paper by example.

Analysis of field performance—the Thunder Bay tunnel

Abstract: A numerical method for the calculation of the distribution of displacements for tunnelling in clays has been developed. The method employs an orthotropic elastic – perfectly plastic soil model that takes into account various sources of ground loss and soil–lining interaction. Both undrained and drained analyses have been carried out and the results are compared with the measured soil displacements of two instrumented arrays at the Thunder Bay tunnel. It is shown that the range of maximum settlements, the shape of the settlement troughs, and the pore pressure change, as well as the magnitude and direction of spatial displacements obtained from the analyses, compare reasonably well with the results of field measurements for both short- and long-term conditions. Key words: tunnelling, clays, anisotropy, elastic–plastic displacements, settlement trough, Thunder Bay tunnel.

Residual Soil Settlement From Pressuremeter Moduli

Abstract: The Menard pressuremeter test is briefly described, and practical drilling techniques are summarized for Piedmont residual soils. Applications and limitations of the pressuremeter are also briefly discussed. Two case histories are presented illustrating the use of the Menard pressuremeter and observed settlements are compared with predicted values. Two regression equations are given relating the pressuremeter modulus with SPT results for Piedmont residual soils based on 208 tests. Use of the Menard equations for predicting settlement is shown to give reasonably good agreement with observed settlement; other prediction methods are also briefly considered.

Stability and Change in Aboriginal Settlement within the Lower Little Tennessee River Valley

Abstract: Aboriginal settlement systems within the lower Little Tennessee River valley in southeast Tennessee are studied through analyses of archaeological data regarding regional land use patterns, the spatial distributions of settlements, and intrasite structure. These data derive from intensive archaeological survey, regional probabilistic sampling, and excavation, conducted by The University of Tennessee between 1967 and 198 1. Analyses of settlement data, representing over 12, 000 years of occupation, are preceded by the definition of a settlement typology, an evaluation of the spatial structure of environmental resources, and the development of chronological models of artifact variability for recognizing temporally specific site occupations. Regional land use patterns are defined through the spatial analysis of artifacts, employing a "non-site" sampling design, from a 34, 000-acre survey area. This analysis indicates a clear and continuous dichotomy in land use between alluvial valley and upland landforms that is best explained in terms of residential site maintenance versus resource extraction. Settlement patterns for each of 17 recognized cultural phases and four undesignated temporal units, dating from the Paleo-Indian to Historic period, are defined from a sample of 624 archaeological sites. These patterns are derived from site distribution data and syntheses of available information about intrasite structure and content. Evaluation of similarities and differences between phase-specific settlement patterns indicate four major diachronic trends: 1) the fluctuation of settlement intensity and distribution during the Archaic period, reflecting shifts in

Geotextiles eliminate approach slab settlement

Abstract: An innovative use of geotextile by the Wyoming Highway Department has significantly reduced bridge approach slab maintenance costs. Since 1983, 38 structures have been constructed or retrofitted with fabric-reinforced soil (FRS) walls beneath each approach slab. The FRS walls reduce settlement of the embankment soils and lower or eliminate lateral pressure against abutments, thereby maintaining approach slab support. Because the slabs remain positioned, expensive mud jacking and/or resurfacing programs have been reduced.

Prediction for the maximum settlements of ground surface by open cut

Abstract: The present paper is concerned with the prediction for the maximum settlements of ground surface adjacent to open cut. Using many field measurements, statistical analysis were made for the maximum settlement and the distance from wall where more than 2mm settlement occured. It became clear that those values are influenced considerably by the following factors; (1) ground type, (2) cutting depth H and width B, (3) deformation modulus of soils under excavated base, and (4) wall type. The parametric study by the FEM have confirmed the significance of statistically analized results. And it is shown that maximum settlements are influenced by the proposed cutting factor (BH/βDD). D is the wall length under excavated base and βD is coefficient related to the wall stiffness and deformation modulus of soil.

A Method for Assessing Relations Between the Physicogeographical Boundaries and Location and Growth of Settlement

Abstract: Positive correlation between the course of physicogeographical boundaries and location as well as growth of the settlements has 'been known from time immemorial. The highly diversified natural environment is often regarded as one of the main reasons why settlements lying close to such 'boundaries tend to develop (better than others. This standpoint seems to be greatly right and well justified, but owing to methodological hardships of which geographers are generally well aware attempts to undertake even a simplified measurement of the strength such bonds are likely to have appear extremely seldom. In Poland detailed cartometric and statistical research into some aspects of this area took effect primarily in the prewar time (e.g. on morphological and „fluvial\" boundaries). Later synthetic studies by M. Janiszewski having a much wider territorial extent (1968, 1973, 1982 etc.) contain, among other things, a pretty successful attempt to provide an overall evaluation of the strength the said bonds may exhibit by analysing the actual level of development of various towns against a background of their natural environments. Research by B. Dumanowski (1968, 1974, 1985) based on a specially designed method, cartometric and mathematical in its character, revolved about the effect mutability (i.e. differentiation) of the natural environment is likely to have on the density of population and settlements, taking Africa as an example.

Development of an improved pile design procedure for single piles in clays and sands. final report. appendix p

Abstract: This report deals with the prediction of the axial load carrying capacity of single piles in various soil conditions The purpose is to evaluate thirteen selected prediction methods using a 100 pile data base which was obtained from the Mississippi Highway Department The selected methods include SPT/Su methods, cone penetrometer methods, a pressuremeter method and a dynamic formula method The data was organized on paper files and then on an IBM-PC diskette Computer programs were then written to perform the selected methods The methods were analyzed by comparing the predicted response to the measured response for each pile load test A detailed analysis of each method was performed by analyzing piles in different soil conditions separately and using limiting values for the point resistance Five methods which predict the entire load-settlement behavior were analyzed for predicted settlement at working loads A risk analysis method is presented to show the importance of properly selecting safety factors Appendices A through O are bound in a separate volume These include pressuremeter data for eight sites, all measured and predicted load-settlement curves, separate plots of predicted versus measured loads for each soil category and for each prediction method, predicted versus measured settlement for each soil category and for each prediction method and plots of risk values versus factor of safety for each predictive method Appendices P and Q are each bound separately Appendix P is the user's manual for COYLE, a computer program that computes ultimate capacity versus depth and load versus settlement for axially loaded piles using H M Coyle's method Appendix Q is the user's manual for PILECPT, a computer program that computes ultimate capacity versus depth and load versus settlement for axially loaded piles using the Laboratoire des Ponts et Chausees cone penetrometer method

Moccosin Confluence: Occupation ovel Settlement in the Lower Fredericksburg Basin of the Edwards Plateau

Abstract: AND MANAGEMENT SUMMARY During the summer of 1982 the eastern half of Lyndon B. Johnson State Historical Park was surveyed and sites tested. The work was sponsored by the Texas Parks and Wildlife Department and performed by Center for Archaeological Research and the Division of Behavioral and Cultural Sciences, The University of Texas at San Antonio. The Principal Investigator was Joel D. Gunn. The field work was conducted by the field course in archaeology from the University of Texas at San Antonio. Members (listed in the Acknowledgments section) of the Anthropology Laboratory class assisted the Principal Investigator with laboratory analysis. Most of the sites were shallow or deflated and of limited information value except for their location in the overall settlement pattern. Excavation of 41 GL 21, Hop Hill (Gunn and Mahula 1977a), was completed. An old stream channel was found in the bedrock under the site. It was filled with occupation debris from the Late Archaic. The site may have been used as an overlook to an adjacent ford in the Pedernales River. At the confluence of the Pedernales River and Williams Creek (Moccasin Confluence) at the east end of the park a very important site was found. Moccasin Confluence consists of two segments divided by Williams Creek. The west segment (41BC71) is a deeply stratified alluvial site with a Holocene sequence. Whether the sequence is continuous through the Holocene remains to be determined. The levels are extremely thick in the Middle and Early Holocene. The location, at three sources of varying sediments, indicates that the site could be a very sensitive geological barometer of Holocene climate, a hypothesis that seems to have merit based on analysis of sediment grain size composition and IPF analysis of sediment chemistry. The site is very rich in chronological diagnostics and is of great potential for studying environmental and cultural process in the Edwards Plateau region. Analysis of artifact wear patterns, points, flake size and frequencies, and mollusks indicates the site was inhabited over long periods of time, sometimes with a fair amount of intensity. Nomads apparently visited the site at the beginning of each cultural period and eventually settled there until their culture was disrupted. The site is recommended for nomination to the National Register of Historic Places. The site (41BC63) on the east bank of Williams Creek outside the park, considered to be the eastern segment of Moccasin Confluence, was tested enough to show that it has a dense burned rock midden. It is assumed to represent a shift of occupation locus to the east side of the creek during the Middle Archaic.