Fill Layer Research Articles

Field study of set-up effect in open-ended PHC pipe piles

ABSTRACTLarge-scale field tests were conducted to study set-up effect in open-ended prestressed high-strength concrete pipe piles jacked into stratified soil. Four open-ended prestressed high-strength concrete pipe piles with 13 and 18 m in embedment depth were fully instrumented with fiber Bragg grating sensors and installed. Several restrike dynamic tests were performed on each test pile, with the time interval from 21.5 to 284 hours after installation. Static loading tests (SLTs) were later performed on each test pile at 408 hours after installation to substantiate the dynamic tests. Changes with time in pile bearing capacity and in the shaft and toe resistances were studied based on the results of the pile tests. The development of shaft resistance set-up in different layers was studied in particular. It was found that set-up effect in the shaft resistance is significant and the toe resistance increment was minor. The overall set-up factor of total bearing capacity was found to range from 0.09 to 0.53, and the set-up effect of friction pile is much larger than the end bearing pile. More significant set-up in shaft resistance was observed in fill and alluvium layer. The dimensionless set-up factor A for shaft resistance in marine deposits ranges from 0.5 to 1.43, and it contributes the most to the shaft resistance as the shaft resistance in marine deposits is higher.

Excavaciones arqueológicas en la Casa Bodega y Quadra en el Centro Histórico de Lima

This article addresses the principal results of the archaeological excavations at the Casa Bodega y Quadra, which uncovered a series of structures beneath the modern structure located on the site, below thick layers of fill. Archaeological excavations provide evidence that these earlier layers were buried in the wake of the earthquake that devastated the city of Lima in 1746. Comparison between these earlier structures and historical data demonstrates how space within the site was transformed from public to domestic – processes directly related to the evolution of the urban layout of viceregal Lima.

Three-dimensional numerical analysis of a DCM column-supported highway embankment

This paper presents a three-dimensional numerical analysis of a well-monitored DCM (deep cement mixing) column-supported embankment for a highway in Thailand. A coupled three-dimensional mechanical and hydraulic numerical model was used for this analysis, and the results are compared with the field measurements, including settlement, load distribution between soil and DCM columns, excess pore water pressure and lateral movement. The numerical model reasonably simulated the performance of the DCM column-supported embankment compared to the observed data. From the field measurements, the surrounding soils carried approximately half an embankment load, while the rest was transferred to the stronger soil layers below. The computed maximum bending moment in the column under the toe of the embankment was located at the interlayer between the fill material and soft clay due to the existence of thick fill material layer. A parametric study was conducted to investigate the influence of five key factors on the performance of the DCM column-supported embankment. The parametric study indicated that the factor of safety against bending moment failure (FSbending) seems to be the most important factor of safety to design in this study. The embedded column was more suitable than a fixed column to support high embankment load due to the higher moment capacity of the column with the same improvement area ratio ar, while the reduction ratios of settlement (Rs) and lateral movement (Rl) were not significantly different. If the floating column is chosen, sufficient improvement depth to produce the column tip laterally restrained is necessary to not only reduce the lateral movement but also increase the FSbending. The dr of greater than 0.7 is suggested in this study.

Implication of subsurface flow on rainfall-induced landslide: a case study

Post-failure field investigation, instrumentation, monitoring, and numerical simulation were performed to give insights into the failure mechanism of a 13-h-delayed rainfall-induced landslide. A conceptual hydrological model was postulated based on the findings obtained from the investigation works. The results showed that subsurface flow was recharged by intense and prolonged rainfall through outcrops of fissured bedrock. The recharged water was mounded in the moderately weathered granite layer and caused an increase in hydraulic head. The groundwater seeped gradually upward into the overlying fill layer even after the rain has ceased, and eventually triggered the landslide when the water table was raised to a critical state. As most of the existing hydrologic-slope stability models were developed on the basis of soil-impermeable bedrock model, this could result in great discrepancies between the simulated results and the real hydrological responses of the slope. The findings from the present study highlighted the importance of considering subsurface flow and hydro-geological features in assessing the mechanism of rainfall-induced landslide.

World's Largest In Situ Thermal Desorption Project: Challenges and Solutions

AbstractThis paper presents the largest In Situ Thermal Desorption (ISTD) project completed to date. The redevelopment of a former aerospace manufacturing facility adjacent to a commercial airport was the main driver, requiring relatively rapid reduction of several chlorinated volatile organic compounds (CVOC) in a 3.2‐acre source zone. The source zone was divided into four quadrants with differing treatment depths, heated simultaneously using a total of 907 thermal conduction heater wells. Five different depths were selected across the area, according to the depth of contaminant impact. Prior to implementation, a risk and optimization study led to placement of a vertical sheet‐pile wall around the treatment zone to minimize groundwater flow, and a pilot test of a novel direct‐drive method for installation of the heater casings. Because of a shallow water table, a layer of clean fill was placed over the treatment zone, and partial dewatering was necessary prior to heating. A network of vertical multiphase extraction wells and horizontal vapor extraction wells was used to establish hydraulic and pneumatic control and to capture the contaminants. The site was split into four decision units, each with a rigorous soil sampling program which included collecting a total of 270 confirmatory soil samples from locations with the highest pretreatment CVOC concentrations requiring reduction to below 1 mg/kg for each contaminant. Temperature monitoring and mass removal trends were used to trigger the sampling events. Eventually, a small area near the center of the site required the installation of four additional heaters before the soil goals were reached after 238 days of heating. The total energy usage for heating and treating the source area was 23 million kWh—slightly lower than the estimated 26.5 million kWh. Actual energy losses and the energy removal associated with the extracted steam were lower than anticipated. An estimated 13,400 kg (29,800 lbs) of CVOC mass was removed, and all soil goals were met. This paper presents the challenges associated with a project of this scale and describes the solutions to successfully complete the ISTD remedy.

Intentional Cooking Pot Deposits in Late Roman Jerash (Northwest Quarter)

Abstract – During the 2012 campaign of the Danish-German Northwest Quarter Project in Jerash, ancient Gerasa, three intentionally deposited cooking pots were found in a fill layer. Two of them were almost intact and discovered with ashes and other finds inside. Another one was fragmented and also held ashes inside. The cooking pot deposits are likely to have been termination deposits. It is the scope of this paper to discuss the context and function of these deposits and of comparable evidences. No completely conclusive explanation for the three deposited cooking pots from the Northwest Quarter can be given, but the context gives clear indications that they were deposited intentionally and were only in some sort of use for a short period of time. They were not part of an installation, such as a kitchen or production complex and they were not part of an ancient dump. The homogenous fill layers surrounding them indicate a rapid and intentional filling —a process in which these deposited pots played a role. We here suggest a possible ritual or magic function of these pots as termination deposits, but this can only be confirmed further by comparable finds excavated and documented in detail at other sites as well as better knowledge of the room that was backfilled and ritually closed with termination deposits. The main purpose of this article is to raise awareness of such deposits in archaeological contexts, which may too often be overlooked.

Building Scheme for an Ecological Slope Protection System of Three Gorges Reservoir Bank

Building an ecological slope protection system in the drawdown area of Three Gorges reservoir bank is imperative. Multiple anti-slide bearings were fixed on the riverside slope of the fluctuating zone of the reservoir area, and antioverturning boards were fixed on the bearings. All the anti-slide bearings, which were placed in the same height position in the transverse direction of the riverside slope, were connected by steel bars to form the backbone slip in the longitudinal direction. Two neighboring backbone slips in the transverse direction formed a groove. In the grooves, fill layer, water layer, fermented silt filling, and soil layer were paved sequentially from bottom to top. The results show that the slope protection system effectively manages the sludge, wastewater, and fluctuating zone treatments as one body; reduces energy consumption; saves energy; and benefits the environment.

The effect of short fiber composite base on microleakage and load-bearing capacity of posterior restorations

Objectives: To determine the marginal microleakage of Class II restorations made with different composite base materials and the static load-bearing capacity of direct composite onlay restorations.Methods: Class II cavities were prepared in 40 extracted molars. They were divided into five groups (n = 8/group) depending on composite base material used (everX Posterior, SDR, Tetric EvoFlow). After Class II restorations were completed, specimens were sectioned mid-sagitally. For each group, sectioned restorations were immersed in dye. Specimens were viewed under a stereo-microscope and the percentage of cavity leakage was calculated. Ten groups of onlay restorations were fabricated (n = 8/group); groups were made with composite base materials (everX Posterior, SDR, Tetric EvoFlow, Gradia Direct LoFlo) and covered by 1 mm layer of conventional (Tetric N-Ceram) or bulk fill (Tetric EvoCeram Bulk Fill) composites. Groups made only from conventional, bulk fill and short fiber composites were used as control. Specimens were statically loaded until fracture. Data were analyzed using ANOVA (p = 0.05).Results: Microleakage of restorations made of plain conventional composite or short fiber composite base material showed statistically (p < 0.05) lower values compared to other groups. ANOVA revealed that onlay restorations made from short fiber-reinforced composite (FRC) as base or plain restoration had statistically significant higher load-bearing capacity (1593 N) (p < 0.05) than other restorations.Conclusion: Restorations combining base of short FRC and surface layer of conventional composite displayed promising performance related to microleakage and load-bearing capacity.

Consolidation Properties and In-Situ Stress of the Marine Clay in Southern Korea

A very soft ground constructed by dredging and hydraulic fill has characteristics such as high water content, high initial void ratio, and very little effective stress. Estimating, with thorough considerations about consolidation properties and the initial stress associated with each layer's distinctive stress history, is essential in order to predict a reasonable consolidation settlement of soft ground. By investigating a construction project for national industrial complexes at a coastal area in southern Korea that experienced reclamation and ground improvement adapting PVD, various laboratory tests to find consolidation properties were performed with undisturbed samples collected from the entire depth of the marine clay fill layer and original clay layer. Through the investigation, this report suggests relationships of heterogeneity of permeability in both vertical and horizontal directions, void ratio-effective stress, and void ratio-permeability. Considering the fact that the original clay layer was under the process of consolidation by load due to hydraulic fill from the top, estimating the appropriate initial stress of each layer is critical to predict the future process of consolidation settlement determined by time. In order to obtain the initial stresses of two layers with different stress histories related to consolidation, cone penetration and dissipation tests were conducted.

Study on thermal regime of roadbed–culvert transition section along a high speed railway in seasonally frozen regions

Harbin to Dalian passenger dedicated line (HDPDL) was the first high-speed railway in the moderately deep seasonally frozen regions in the Northeast China. The roadbed–culvert transition section (RCTS) was paid special attention, as it was prone to uneven deformation. In this paper, the temperature field and its changing process of a typical RCTS at Siping site along HDPDL were discussed based on monitoring data. The results showed that during the freezing period (from November, 2010 to March, 2011), the thinner of the fill layer on the culvert, the higher temperature amplitude appeared in the RCTS. Due to the solar radiation difference on the sunny and shady slopes, the temperature in the sunny-slope was 1–3°C higher than that in the shady-slope, and the difference increased as roadbed height increases. However, the culvert serves as a large ventilation duct, exchanging the amount of thermal rotation and weakening the temperature difference between the two sides. Numerical simulation of the temperature fields was carried out for discussing roadbed fill materials and culvert structures. The results indicated that, under the current design conditions, a pipe-style culvert shows a more stable thermal regime in the freezing period, while a box-styled culvert showed a more stable thermal regime in the thawing period. The anti-frost and insulation engineering measures were also discussed, and several critical design parameters were proposed and optimized. At last, it was found that the most suitable configuration was a box culvert with one section transiting to embankments, and this configuration was recommended for construction of high-speed railway in the seasonal frozen regions.

Mini-Pier Testing To Estimate Performance of Full-Scale Geosynthetic Reinforced Soil Bridge Abutments

The geosynthetic reinforced soil (GRS) performance test (PT), also called a mini-pier experiment, was developed by the Federal Highway Administration (FHWA) to evaluate the material strength properties of GRS composites built with a unique combination of reinforcement, compacted fill, and facing elements. The PT consists of constructing a 1.4-m square column of alternating layers of compacted granular fill and geosynthetic reinforcement with a facing element that is frictionally connected up to a height of 2 m, then axially loading the GRS mass while measuring deformation to monitor performance. The results can be directly used in the design of GRS abutments and integrated bridge systems. Considering that the geometry of the PT is square in plan, the equivalency of the results to a bridge application, which more resembles a plane strain condition, is evaluated and presented in this paper. The analysis indicates that the PT closely approximates the bearing resistance, or capacity, of a typical GRS abutment, and is a conservative estimate when predicting stiffness. These results indicate that the PT can be used as a design tool for GRS abutments at both the strength and service limit states.

The Analysis of the Effect of Fouling on the Performance of the Fill Layer

Based on that the film filling was simplified to the flat plate model, the heat and mass transfer of the filling zone with fouling in cooling tower were analyzed. The effect of fouling on the performance of filler was analyzed according to the dirt growth model. The work done in this paper can simply forecast changes in cooling tower performance caused by the filler fouling. It will lay a theoretical foundation for accurately calculating the performance coefficient of filler. And it is helpful to solving the problem of no the ripe empirical formula of filler performance with fouling for engineering applications.

Research on the Longitudinal Displacement between Track Plate and Filling Layer under the Influence of Temperature

In the construction process, it is not a one-time work to complete the track plates overall longitudinal connection of the CRTSII ballastless track structure. Moreover, due to the tracks longitudinal connection, temperature difference can form displacement accumulation in the whole structure. Under some serious circumstances, it may even produce excessive longitudinal displacement between track plate and mortar layer, and make mortar layer void. Based on the finite element method, a finite element model is built on the track plate and mortar layer. By targeting at the free end of the track plate, carry on a stress displacement analysis; study the influence of changeable temperature on motor layers relative displacement with track plate,the reasonable construction temperaturefor construction is put forward. The research results provide references for the ongoing ballastless track construction on the passenger dedicated line.

Historic Archeological Investigations at Roberts Cemetery Near Troy, Bell County, Texas

A preliminary archeological investigation was conducted in 2008 at Roberts Cemetery near Troy, Texas, as part of the Texas Department of Transportation’s planned expansion of Interstate Highway 35. Mechanical trenching discovered one unmarked grave near the highway right of way, and this led to an extensive mechanical search of the eastern edge of the cemetery in 2012. Following the removal of the southbound access road and thick layer of artificial fill, five additional unmarked graves were discovered. Of the six unmarked graves, two are located in the cemetery property and were left in place, but the four burials inside the highway right of way were exhumed. They were reinterred in a nearby plot in Roberts Cemetery.

Infinite beams on stone column reinforced tensionless earth beds under moving loads

In the present study, an analysis of a rail, idealized as an infinite beam, resting on a granular bed-stone column reinforced earth bed has been carried out under a load moving with constant velocity. The granular fill layer just below the rail has been modeled as the Pasternak shear layer, while stone columns as non-linear Winkler springs and foundation soil as non-linear Kelvin–Voigt body. As the load moves on rail, the rail tends to separate from the ground. This separation has been modeled (tensionless foundation) by means of appropriate deflection and soil reaction conditions. Governing differential equations of the soil–foundation system have been obtained and have been solved with proper boundary and continuity conditions. The Gauss–Siedel iterative method has been employed to obtain the solution of finite difference form of these equations. Detailed parametric study revealed that the velocity of load, the damping of the soil–foundation system, and the ultimate resistance of soft soil and granular fill layer has the least influence on the response of system. However, the magnitude of load, ultimate resistance of stone columns, diameter and spacing of stone columns, and degree of consolidation and relative stiffness of stone columns with respect to the surrounding soil have been found to significantly affect the response of the system. The influence of all these parameters has been quantified and presented in the form of readily usable non-dimensional charts.

Influence of Process Parameters on Surface Finish in Customized Bone Implant Using Selective Laser Sintering

Selective Laser Sintering (SLS) is a powder-based Additive Manufacturing process in which parts are built by sintering of selected areas of layers of Polyamide (PA12) powder using CO2 laser. The purpose of this work is to study experimentally the effect of orientation of the component, fill scan spacing and layer thickness on the surface roughness (Ra) of the customized bone implant fabricated through SLS technique. For this study computer tomography scan data was taken and converted to standard triangulation file (.stl) format using mimics software. Taguchis Design of Experiment approach was used for this study. An L27 Orthogonal Array (OA) of Taguchi design was used. Analysis of Variance (ANOVA) was then performed on S/N (Signal-to-Noise ratio) to determine the statistical significance and contribution of each factor on the surface roughness. The results indicated that orientation and layer thickness are significant parameters to cause appreciable improvement in surface finish.

Effect of the Length of Geogrid Layers in the Bearing Capacity Ratio of Geogrid Reinforced Granular Fill-soft Subgrade Soil System

In the present study, blast furnace slag in granulated form has been used as a granular fill overlay on soft subgrade soil. The effectiveness of geogrid-reinforced granular fill overlay on soft subgrade soil has been assessed by small scale model tests in the laboratory by evaluating two parameters bearing capacity ratio (BCR) and reduction factor. The effect on BCR of strip footing for various lengths of geogird layers in the best performing thickness has been observed. Best performing thickness of the granular fill layer has been found by the parametric study which is not included in this paper. Parametric study has been performed to observe the effect of length of geogrid layers in granular fill overlay on soft subgrade soil. The test results indicate substantial improvement in terms of increase in bearing capacity and reduction in the footing settlement due to provision of geogrid in the granular fill overlay on soft subgrade soil. It has been found that b/B ratio of 4 gives substantial improvement in BCR and beyond b/B ratio of 4, there is no significant improvement in BCR.

Beams on extensible geosynthetics and stone-column-improved soil

In the present study the response of rails, treated as infinite beams, resting on geosynthetic-reinforced granular fill on top of stone-column-treated soft soil, was studied under the action of moving loads. The granular fill layer was modelled as a Pasternak shear layer and the extensible geosynthetic layer as a rough elastic membrane. The stone columns and soft soil were idealised by non-linear Winkler springs and a Kelvin–Voigt body, respectively. Due consideration is given to the range of parametric values that are normally found to be valid in the case of railway tracks. A detailed parametric study revealed that the magnitude and velocity of a moving load, viscous damping, the diameter and spacing of stone columns, the ultimate bearing resistance of stone columns and the soft soil, tensile modulus of geosynthetics, relative compressibility of stone columns and average degree of consolidation significantly affect the response of the soil–foundation system.

Experimental and numerical analyses of circular footing on geogrid-reinforced granular fill underlain by soft clay

Experimental and numerical investigations into the bearing capacity of circular footing on geogrid-reinforced compacted granular fill layer overlying on natural clay deposit have been conducted in this study. A total of 8 field tests were carried out using circular model rigid footing with a diameter of 0.30 m. 3D numerical analyses were performed to simulate soil behavior using finite element program Plaxis 3D Foundation. The results from the FE analysis are in very good agreement with the experimental observations. It is shown that the degree of improvement depends on thickness of granular fill layer and properties and configuration of geogrid layers. Parameters of the experimental and numerical analyses include depth of first reinforcement, vertical spacing of reinforcement layers. The results indicate that the use of geogrid-reinforced granular fill layers over natural clay soils has considerable effects on the bearing capacity and significantly reduces the lateral displacement and vertical displacement of the footing.

Influence of inclusion of geosynthetic layer on response of combined footings on stone column reinforced earth beds

The present paper deals with the analysis of combined footings resting on geosynthetic reinforced granular fill overlying stone column improved poor soil. An attempt has been made to study the influence of inclusion of geosynthetic layer on the deflection of the footing. The footing has been idealized as a beam having finite flexural rigidity. Granular fill layer has been represented by Pasternak shear layer and stone columns and poor soil have been represented by nonlinear Winkler springs. Nonlinear behavior of granular fill layer, stone columns and the poor soil has been considered by means of hyperbolic stress strain relationships. Governing differential equations for the soil-foundation system have been derived and solution has been obtained employing finite difference scheme by means of iterative Gauss Elimination method. Results of a detailed parametric study have been presented, for a footing supporting typically five columns, in non-dimensional form in respect of deflection with and without geosynthetic inclusion. Geosynthetic layer has been found to significantly reduce the deflection of the footing which has been quantified by means of parametric study.