Fill Placement Research Articles

Experimental Nailed Soil Walls

Abstract Normal gravity model tests were carried out in a trench to study the influence of several design parameters on the behavior of nailed soil-retaining walls. Six nailed walls were built by varying the nail length, nail inclination, and the method of nail installation. The construction of each wall involved gradual placement of 36 m3 of sand using a clamshell attached to an overhead traveling crane, followed by excavation (in front of the facing) and installation of model soil nails. Each completed nailed soil wall and its retained sand measured 3.0 by 3.0 m in plan and was 2.4 m high before placement of surcharge fill. This paper describes the method adopted for reducing side wall friction, the sand placement procedure, the checks on uniformity and reproducibility of the relative density of the sand, the instrumentation, and the stage-by-stage excavation and nailing process. A summary of monitored results of all the tests is presented, and the results of Test 1 are discussed in detail.

Field studies of the stress-strain state and consolidation of beds of the system of flood-protection structures in saint petersburg

Data on the soil beds of structures making up the Saint Petersburg flood-protection system and at test sites formed for field investigations of beds containing a thick layer of saturated clayey soils of highly plastic consistency are presented. Also cited are generalized results of multiyear measurements of strains, stresses, and pore-water pressure of the beds of the test sites during the installation of strip earth drains with subsequent loading by the layer-by-layer placement of sandy fills; these results are also analyzed.

No evidence of renal toxicity from amalgam fillings.

Dental amalgam continuously releases mercury. Studies of sheep [Boyd et al., Am. J. Physiol. 261 (Regulatory Integrative Comp. Physiol. 30): R1010-R1014, 1991] showed decreased renal function after placement of amalgam fillings. In this study, renal function was investigated in 10 healthy volunteers before and after amalgam removal. The subjects had an average of 18 tooth surfaces filled with amalgam, which was removed during one dental session. One week before and sixty days after removal, the glomerular filtration rate (GFR) was determined by 51Cr-EDTA clearance technique. Blood and urine samples were collected for analysis of mercury, creatinine, beta 2-microglobulin, N-acetyl-beta-glucosaminidase (NAG), and albumin 1 wk before and 1, 2, and 60 days after amalgam removal. The plasma mercury concentration increased significantly 1 day after removal. Sixty days later, significantly lower mercury levels were found in blood, plasma, and urine. The GFR values were similar before and after mercury exposure (mean 94 and 94 ml/min per 1.73 m2, respectively). No detectable effects occurred on excretion of NAG, beta 2-microglobulin, or albumin. It is concluded that no signs of renal toxicity could be found in conjunction with mercury released from amalgam fillings.

A MODEL SPECIFICATION FOR ENGINEERED FILLS FOR BUILDING PURPOSES.

Keywords SIR WILLIAM HALCROW, BUILDING RESEARCH ESTABLISHMENT, BRE FILL, MODELS, SPECIFICATIONS, BUILDING, CONSTRUCTION, GROUND, MOVEMENT, CONTROL, BEHAVIOUR, MATERIALS, DAMAGE, BUILDINGS, STRUCTURES, LOW RISE, SITE INVESTIGATION, SITES, PREPARATION, DISPOSITION, PLACEMENT, QUALITY, ASSURANCE, MONITORING, HAZARDS, SETTLEMENT, HEAVE, HOUSES, BENCHING, COMPACTION, TESTS, TESTING, PERFORMANCE... Show All

Application of geosynthetics in the construction of an overrun area at La Guardia Airport

Geosynthetic products were used successfully in the construction of a runway overrun area at New York's La Guardia Airport. A field fabricated geotextile sheet measuring 8.4 hectares was used to provide base reinforcement for the placement of approximately 400,000 m 3 of fill over a 23 m thick layer of normally consolidated clay. The inter-tidal nature of the site and its proximity to active shipping dictated that fill placement be performed using stringent lift and slope criteria. Prefabricated, vertical strip drains were used to accelerate subsoil consolidation. The performance of the drains was very good, back calculated Cv values were approximately 90% of the laboratory derived design value.

Soil Reinforcement Practice for Fills Over Soft Ground in Japan

This paper summarizes the theory and practice of geosynthetic reinforcement of fills over extremely soft ground in Japan. Emphasis is placed on artificially reclaimed soft ground composed of marine soils which are characterized by high water contents and low shear strengths. The use of geosynthetics facilitates the movement of construction equipment and the placement of fill. The bearing capacity of the ground is improved by using high strength geosynthetics. Classical bearing capacity theory, cable theory combined with modulus of subgrade reaction theory, and plate theory are found to be useful in designing embankments on soft ground. The empirical parameters used in these theories are available for most projects. The unique geotechnical conditions of the soft ground typically inhibit the construction procedures specified in the design. The experience gained from past geosynthetic reinforced fill projects, one of which is highlighted in the paper, facilitates the improvement of fill placement and spreading techniques on soft ground.

Timing of first fillings on different permanent tooth surfaces in Finnish schoolchildren.

The timing of the placement of first fillings because of caries on different permanent tooth surfaces was determined at three health centers in Finland. The 927 subjects analyzed were born either in 1970-71 o4 in 1980-81. Basically, two different types of filling placement site were identified: 1) fissures and pits and 2) proximal and smooth surfaces. In some fissures and pits a 'post-eruptive'--that is, fillings placed in the year of emergence--was observed. This step had decreased markedly in the cohort born in 1980-81. The curves plateaued (retardation phase) at 50-60% for the occlusal surfaces in first molars for the children born in 1970-71 and at 20-30% for the younger cohort. The time without any filling varied from 1 to 7 years on smooth surfaces, and some surfaces remained totally filling-free. The filling placement curves followed the pattern of caries attack and can thus be used as an indicator of dental health.

Placement of calcium hydroxide in simulated canals: Comparison of glycerin versus water

Calcium hydroxide (Ca(OH)2) is an intracanal medicament used as an antimicrobial agent, temporary obturant, and for apexification. Placement should be controlled for the maximum biological effect. This study evaluated and compared the effectiveness of delivery of Ca(OH)2 mixed with water or with glycerin as to (a) length of placement and (b) density of fill at different levels. Fifty-six simulated canals with moderate curvature were prepared to #60 using the step-back technique. Ca(OH)2 was mixed with either water (28 canals) or glycerin (28 canals) into a thick paste and placed with lentulo spirals. Radiographs were made and blindly assessed. Results showed that glycerin was statistically significantly superior (p < 0.05) to water as to (a) length of fill and (b) density in the coronal, middle, and apical thirds. Of particular interest was the apical third, in which 0% of water and 50% of glycerin Ca(OH)2 pastes were completely dense.

Method of calculating pile fields and other vertically reinforced soil masses

A method is proposed for calculating the stabilization (reinforcement) of bases with layers of highly compressible soils by vertical strengthened elements in the form of ordinary, bored castin-situ, or auger-injected piles, punch holes, granular drains, etc. Such reinforcement reduces severalfold settlements and consolidation time of a weak base and also increases its resistance to horizontal (including dynamic) loads. The heads of the reinforcing elements can be embedded into the base as well as broadened (with “caps”) or joined by a ground beam. The soil deformation model in the ARM93 program takes into account nonlinearity under compression and shear as well as dissipation of the initial excess pore pressures initiated by the placement of fill and other preliminary loads. The authors developed “COMPGEO” applications programs for solving the main geotechnical problems on a computer. The programs realize adequate nonlinear models of soils and as a variant carry out the calculations according to the existing building codes SNiP.

Effect of thermal placement techniques on some physical properties of gutta-percha.

Some clinical techniques for the placement of gutta-percha root fillings involve the application of heat. This study was undertaken to assess the effects of intracanal heating techniques on the following properties of gutta-percha: coefficient of thermal expansion, softening temperature, phase transition temperature and organic content. Samples from each of four products were prepared by three different methods. The materials were studied by thermomechanical analysis, simultaneous thermogravimetry and differential thermal analysis, and by measurement of weight loss on ashing. It was shown that the techniques of gutta-percha placement involving heating in the root canal caused reversible physical changes in the materials without any apparent change in chemical composition. The average coefficient of thermal expansion was 137 x 10(-6)/degrees C, the softening temperature was 55.5 degrees C, there were two characteristic phase changes, and the organic content was 25%.

Use of drainage wicks for an embankment on slickensided clay

The 650-ha cooling pond for the Genesee thermal power plant near Edmonton required more than 15 km of earth-containment dyke up to 25 m high to be constructed on a high plastic clay foundation. Other embankment construction activity at the Genesee site indicated that there was very little dissipation of construction pore pressure in the foundation clay and that embankment heights of more than 6 m would require stabilization measures. The high portions of the cooling-pond dyke were built in three stages between 1982 and 1986. An extensive instrumentation monitoring program was established to control the rate of fill placement during construction. Counterbalancing earth berms were used to stabilize most of the high sections of dyke. During the later stages of dyke construction, lack of dissipation of high excess pore pressure in the foundation clay indicated that the sole use of counterbalancing berms might not provide sufficient stabilization. Prefabricated drainage wicks were used as an additional measure to lower the foundation pore pressures under the counterbalancing berms in these critical areas. Spacing of the wick drains was determined by applying Hansbo's wick-drain theory and from data collected from a wick-drain test section. Additional piezometers were installed prior to wick installation to assess the effectiveness of the wicks. Over 14 000 wick drains were installed at spacings of 2.5–2.75 m to a maximum depth of 26 m below the top of the berm. The installation procedures are discussed, along with difficulties of installation. The wicks were very effective in lowering the foundation pore pressures and improving dyke stability. Instrument monitoring data used to assess the wick-drain performance and to control the rate of construction during dyke completion are presented and discussed. Key words: drainage wick, high plastic clay, pore pressure, dissipation, deep, fill, dyke, instrumentation, monitoring.

Mercury from dental "silver" tooth fillings impairs sheep kidney function

In humans Hg vapor is released from "silver" amalgam fillings that contain 50% Hg by weight. Previous studies show that when 12 such fillings are placed in sheep teeth, the kidneys will concentrate amalgam Hg at levels ranging from 5 to 10 micrograms Hg/g renal tissue 4-20 wk after placement. In the present study 12 occlusal fillings were placed in each of six adult female sheep under general anesthesia, using standard dental procedures. Glass ionomer occlusal fillings (12) were inserted in two control sheep. At several days before dental surgery, and at 30 and 60 days after placement of fillings, renal function was evaluated by plasma clearance of inulin and by plasma and urine electrolytes, urea, and proteins. An average plasma inulin clearance rate of 69.5 +/- 7.2 ml/min before amalgam placement was reduced to 32.3 +/- 8.1 ml/min by 30 days and remained low at 27.9 +/- 8.7 ml/min after 60 days. Inulin clearance did not change in controls. After amalgam placement urine concentration of albumin decreased from 93.0 +/- 20.5 to 30.1 +/- 15.3 mg/l and urine Na+ concentration increased steadily from 24.8 +/- 7.7 to 82.2 +/- 20.3 mmol/l at 60 days. Concentrations of K+, urea, gamma-glutamyl transpeptidase, alkaline phosphatase, and total protein did not change significantly from 0 to 60 days in urine. Plasma levels of Na+, K+, urea, and albumin remained unchanged from 0 to 60 days after amalgam. Renal histology remained normal in amalgam-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Densification of Gravelly Sand Fill Using Intensive Surface Compaction

A case study is presented herein whereby a heavy vibratory roller was used to densify a 6-ft-(1.8-m) thick layer of gravelly sand fill located below ground-water level. Geotechnical engineering evaluations had concluded that the fill was susceptible to liquefaction during the design seismic event. Excavation and subsequent placement of the same fill in thin compacted lifts would have required a difficult and expensive dewatering effort. The layer was densified by repeated coverages of a heavy vibratory roller. Test borings with continuous standard penetration tests were performed to verify that the intended densification had been achieved.

Construction of rock-earth dam of the Hoabinh hydraulic development

1. The adopted design and construction schemes for the dam made it possible to place, under complex geologic and hydrologic conditions, the dam fills without trench construction or drainage, which permitted starting sooner the fill placement work and sharply reduced the construction cost. 2. For the dam engineering work, use was made of national and foreign experience in construction of high rock-earth dams -the dam core was constructed using clay-skeleton soil fills; the developed transition zones were made using fills consisting of inexpensive natural soils, which made it possible to eliminate the use of artificial mixes; and zoned placement of soils in the dam shells was carried out. 3. The construction method and sequence made it possible to build the dam under complex climatic conditions within the established period and to use soils from useful excavations almost exclusively.

Fluidization technique for mine backfill with slurry of high density

Fill placement using a very concentrated slurry for underground mines has been recognized as a favorable approach to improve backfill quality and economy. For this reason much effort has been devoted to preparation of high density slurry. This paper introduces the fluidization technique as a more effective and economic technology for producing tailing slurry of a high density and describes the fluidization mechanism, experimental system and results obtained during backfill. Test runs were carried out both in the laboratory and at a mine site with tailings of different size, which were allowed to settle down in a silo. A water jet was used to disperse solid particles and keep them in suspension and flowable under the action of gravity. The main factors affecting slurry density are fluid velocity, pressure and discharge. The technique introduced here has been used in backfill preparation and the density of slurry formed by fluidization has reached 75–80% solids by weight.

The Portuguese bend landslide

The Portuguese Bend landslide, in coastal southern California, is an active, slow-moving mass of blocks and debris that extends from the shoreline to moderate altitudes along part of the southerly margin of the Palos Verdes Hills. These hills form a peninsula that is underlain by Cenozoic sedimentary and volcanic rocks draped anticlinally over a core of Mesozoic schist. In the southerly parts of the peninsula, inherently weak units in the Altamira Shale Member of the Miocene Monterey Formation dip seaward in general concordance with the ground surface. Ground failure has been widespread in this area. It evidently began in mid- to late-Pleistocene time, and it has continued intermittently to the present. The Portuguese Bend landslide represents a reactivation of movement of the eastern part of a complex of prehistoric landslides occupying an area of approximately two square miles. This latest episode of movement began in 1956, presumably in response to placement of fill during a road construction project. The active slide subsequently was enlarged by sequential failure of adjoining blocks of ground, and by September 1969 about 54,500,000 metric tons of debris was slowly moving downslope in an area of approximately 104 ha. Movement has been continuous since recent failure began in 1956, although the velocity of the active slide decreased markedly after that year. Between 1962 and 1972 the velocity fluctuated only slightly about an average value of about 1 cm per day. The active slide is an irregular prism, roughly triangular in plan view. The southern side of the triangle trends approximately 1100 m east-west along a stretch of shoreline that essentially coincides with the toe of the slide. The other two sides of the triangle trend northeast and northwest from the ends of the toe and meet about 1200 m north of the shoreline. The thickness of the moving mass differs considerably from one place to another, reflecting both topographic irregularities and major undulations in the underlying surface of movement. The maximum thickness is approximately 75 m. Movement is occurring along a distinct basal failure surface. The eastern part of the slide is underlain by bedrock, and is bordered by bedrock with a general structure that limits further deep-seated propagation of failure to the east and northeast. In contrast, the western part of the slide is underlain and bordered by extensive ancient landslide deposits that are marginally stable. Further encroachment of the active slide westward and northwestward into these materials was viewed as a distinct possibility at the time the dissertation was prepared and has occurred since then. Continued movement of the Portuguese Bend landslide since 1956 has been due to four main factors. A rise in the water table during the period 1957–1968 has been documented in the northwestern part of the moving mass and is attributable mainly to infiltration of surface runoff entering numerous open fissures that cut the surface of the slide. The toe of the active slide daylights along the shoreline and is subjected to storm-wave erosion, so that any natural build-up of resisting forces is prevented in this area. The redistribution of mass as the slide has moved along an undulatory failure surface has been responsible for local fluctuations in the driving and resisting forces. Finally, smoothing of irregularities in the failure surface by the moving slide mass must have decreased some of the forces resisting movement.

Reclamation of Exxon Ray Point Tailings Basin

This paper outlines key items for reclamation of uranium tailings impoundments, using the reclamation of Exxon Coal and Minerals Company's (ECMC'S) Ray Point (or Felder) uranium mill site and tailings impoundment as a case history. ECMC's Ray Point is the first Title II site for which a final reclamation plan has been approved and constructed. Initial reclamation work of the Ray Point Site consists of mill decommissioning, mill site cleanup, and initial tailings impoundment cover placement. The licensing process in Texas consists of submitting the reclamation plan documents to Texas Department of Health (TDH), with subsequent discussion of the plans and submittal of additional data, analyses, and clarification. Following approval of the Ray Point reclamation plan, final reclamation work is carried out, and consists of random fill placement, compacted soil cover construction, topsoiling, and revegetation. The Ray Point site is currently monitored for specific performance criteria. After these performance criteria have been achieved, ownership of the property will be transferred to the state.

Bulkhead Failure Investigation and Redesign

A 300‐ft‐long anchored bulkhead at Kake, Alaska, failed following placement of fill behind the bulkhead wall. The entire wall rotated outward at the toe and moved downslope 40 to 60 ft. No on‐site over‐water borings had been made, but local geologic investigations and pile driving resistances noted during construction suggested that a 5‐ to 20‐ft‐thick zone of soft marine clay overlying relatively dense offshore sloping soils and shallow bedrock lay beneath the project site. The failure is believed to have resulted in the displacement of the soft clay down to the surface of the competent soils. After the failure, the granular fill originally placed behind the bulkhead lay immediately over competent soils along the bulkhead alignment. Observations from onshore borings, dredging, and offshore test pile driving after the failure support the conclusion that the clay was removed from the bulkhead and till area by the failure. The bulkhead was redesigned with its alignment about 24 ft inland, and with a higher ...

An Experimental Study of the Influence of Confining Pressure on Permeability Coefficients of Filldam Core Material

ABSTRACT During construction period of a filldam the soil medium is subjected to varied confining pressues by the placement of the additional fills due to step by step construction of the dam. Therefore, it is necessary to evaluate the influence of the confining pressure on permeability coefficients of the core material. This has been accomplished by developing a permeability testing apparatus, making use of a triaxial cell. A series of permeability tests were carried out on filldam core material and the corresponding results are presented in this paper. The test results showed that the confining pressure has a significant influence on the permeability coefficient of the compacted cohesive soil. Thus, it is very important that the influence of the confining pressure on the permeability coefficients should be considered by the construction engineers while they construct the embankments.

フィル堤体の盛土に伴う基礎岩盤の変形と透水性の変化

The fill placement works on the dam foundation as overburden loading. This loading would influence the stress states in the foundation resulting in the change of strain and permeability in the underground. Therefore, the authors actually measured the deformation of dam foundation and the change of permeability due to the fill placement at two damsites. The results measured at both damsites indicate that the fill placement causes the compression of dam foundations accompanying the decrease of permeability. The authors feel that these results are very helpful for the determination of effective grouting design for the foundation of filldams. Furthermore, the authors theoretically try to explain the relationship between the compressive strain of the foundations and the decrease of permeability due to the fill placement by using the simple models.