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By Lori A. Simpson

A high-rise building, consisting of two tower structures occupying the entire site, is in construction in San Francisco. The North Tower will consist of 12 and 35 stories above a one-level basement. The South Tower will consist of 9 and 22 stories over one partially below-grade level of common space; a portion of the South Tower will have a three-level basement. The towers will be supported on mat foundations bearing on native very dense sand in the footprint of the three-level basement and on ground improved with soil-cement mixed (SCM) panels that extend through loose sand and marsh deposits into very dense sand. Shoring systems for the basement excavations include cantilevered and tied-back soldier-beam-and-lagging systems and SCM cutoff walls. Subsurface conditions include loose fill and Dune Sand and loose and soft marsh deposits overlying very dense sand of the Colma formation. Groundwater is approximately 15 to 22 feet deep; the three-level basement extends below groundwater. The site is on Market Street in San Francisco, with SF Municipal Railway (MUNI) and Bay Area Rapid Transit (BART) tunnels running below Market Street approximately 45 and 36 feet north of the site, respectively. Both tunnels are 16.5 feet in diameter. The top of MUNI and BART tunnels are 25 feet and 63.5 feet below street grade, respectively. BART has stringent requirements regarding construction adjacent to their facilities, including disallowing adding pressure to their tunnel, lowering groundwater by more than two feet, and vibrations from construction activities. Design of the shoring and the foundations within the BART zone of influence were subject to their design requirements. The project was also subject to a peer review, as required by the San Francisco Department of Building Inspection. We used FLAC to evaluate stresses at the BART and MUNI tunnels and on the SCM panels. This paper will present the mitigations needed to address seismic hazards and BART restrictions and to provide adequate foundation support for a tall building with high seismic loads.

By Lorie M. Dilley

Alaska Village Electric Cooperative (AVEC), an electric utility cooperative providing power to 51 Alaska villages, has made a concerted effort to install wind turbines in the villages they serve in an effort to mitigate the growing costs of electrical power generation. The subsurface soils in several of these villages consist of sands and silts with ground temperatures of between 30°F and 32°F. The presence of warm, degrading permafrost in three of the villages has required innovative foundation designs, including the use of helical piers and piles to support steel and concrete wind turbine foundations. The design of the deep foundations had to account for the effects of degrading permafrost likely resulting from observed climate change patterns. Uplift forces imposed on the foundations were approximately 100 kips per pile. Uplift pile load testing was conducted on the installed piers and piles in order to determine the actual working load that each pier or pile could sustain. In addition, pile driving analyzer testing was conducted on several piles installed in the permafrost and compared to pile load tests. Results indicated that the installed piers and piles achieved the necessary capacity with sufficient factors of safety. Thermosyphons were installed near the foundations in order to limit the effects of climate change on the permafrost. The two to four wind turbines in each of the three villages are currently operational. Refinement of the design based on the pile testing from the first village to the third has decreased the cost of the tower foundations and improved our understanding of designing for warm, degrading permafrost.

Jan 1, 2010

By Vijaya Bhushan Rao, Jason Redgers

A substantial lifestyle destination in the United Arab Emirates, in the Emirate of Abu Dhabi comprising of 1315 villas, town houses and non-residential leisure facilities is built over an area of 280 hectares of former mangrove areas, natural sands and reclaimed lands. Large-scale subsoil investigations including field and laboratory testing carried out dividing the entire site in to 7 clusters. This investigation revealed alternating layers of loose sands and silty clays within the load influence zone of planned foundations, showing susceptibility to excessive settlements. Therefore, ground improvement works were undertaken using a combination of stone columns, Rapid Impact Compaction (RIC) and excavation and replacement of soils plus a 0.4m thick load transfer platform. This was necessary to limit the settlements, increase-bearing capacity and prevent long-term settlements. 30 no’s of full-scale Zone Load Tests, ZLT were carried out each for a duration of 30 days in order to ascertain the anticipated long-term settlements in the clay layers. In addition, further testing of electrical cone penetration tests, CPT, and Plate Load Tests, PLT. The use of Priebe and Asaoka’s observational procedure were applied to predict the final settlements and the use of back-analysis from the 30 days Zone Load Tests, ZLT results to establish the site-specific consolidation parameters in clay layers to optimize the design and ground improvement works.

Sep 8, 2021

By Ryan Sullivan, Lisa Smiley, Jewels Stover

The Westerly Storage Tunnel (WST) Project is part of Project Clean lake, the North East Ohio Regional Sewer Dist years. When completed in 2020, WST will be nearly 2 miles of 25-ft diameter tunnel 200-250 ft below ground. The storage tunnel will manage higher flow volumes, keeping stormwater out of the combined sewer system reducing overflow occurrences. Three deep shafts provide access to the tunnel at the tunnel boring machine (TBM) launch and retrieval sites, as well as a vent shaft. Support of excavation for the access shafts was constructed utilizing unreinforced concrete diaphragm walls. This innovative, value-engineered alternate design significantly reduced risks associated with conventional secant piles combined with a rib and liner plate system. Implementation of the diaphragm wall technology resulted in a water tight, continuous shaft keyed into rock. This case study examines the design, methodology, and installation challenges unique to each shaft, as well as the benefits of the final product to the overall project.

By Abolfazl Eslami, Sepide Lotfi, Mohammad M. Eslami

"Via direct CPT methods for pile capacity prediction, correlation coefficients smaller than unity are used to relate cone tip resistance (qc) and sleeve friction (fs) to pile toe capacity (rt) and shaft capacity (rs), respectively. For linking CPT data to pile capacity, factors such as diameter, penetration rate, partial embedment of pile toe into a hard layer, mechanism of plunging, failure zone, data processing, and stress-strain conditions must be considered. The aim of this paper is to investigate the role and significance of scale effects and establish direct relation between CPT data and pile shaft capacity. A database has been compiled including 40 full scale pile load tests and CPT sounding records for calibration and validation of the proposed approach. Analytical studies demonstrate that differences between pile and penetrometer penetration rate, geometry, and stress-strain conditions influence the relation between fs and rs. By considering the determinants, a procedure is proposed from which the pile shaft capacity can be predicted. This approach demonstrates better agreement with measured capacity by static loading test and less scatter than other current CPT methods.IntroductionAmong different approaches for pile capacity prediction, in-situ tests such as SPT and CPT have been used as supplementary of static analysis. Due to similarities between CPT and pile, the measured cone tip resistance and sleeve friction can be employed for prediction of unit toe and shaft capacities, respectively.Determination of pile capacity from CPT data includes two main approaches: direct and indirect methods. Direct CPT methods apply the measured values of cone tip resistance (qc) for pile toe capacity (rt), and sleeve friction (fs) for pile shaft capacity (rs) with some modifications regarding scale effects. Indirect CPT methods employ friction angle and undrained shear strength values that have been estimated from CPT data.When using direct CPT methods to relate qc and fs to rt and rs, correlation coefficients smaller than unity are used. Factors such as diameter, penetration rate, mechanism of plunging, failure zone, data processing, and stress-strain conditions must be considered for correlation between CPT and pile capacity. The work presented in this paper aims toward ameliorating the situation in the area of pile shaft capacity prediction, based on cone sleeve friction.Case histories from full-scale tests are compiled and analyzed by means of six methods including five direct CPT methods for shaft capacity prediction and the proposed method."

Jan 1, 2015

By Anthony T. C. Goh, Zhiye Zhao, Laddu B. Jayasinghe, Hongyuan Zhou, Yilin Gui

"Ground vibrations from blasting are undesirable and they are very short in duration with high principal frequencies and high amplitude. Structural response to that kind of excitations may differ significantly from that generated by lower-frequency earthquake vibrations. In practice, the damage to nearby structures to generated ground vibrations has been controlled by various codes and regulations available. However, the existing vibrations limits are not always applicable, as they depend on the geological conditions of the site and the dynamic characteristics of the structure. This paper investigated the influence of the rock-soil interface on the response of pile foundation to ground-borne vibration from rock blasting, through numerical simulations using finite element software LS-DYNA. It is found that the slope of the rock-soil interface greatly influences the location of damage and the extent of damage on the pile. The bottom of the pile is subjected to a larger blast pressure and stresses are highly concentrated at the pile bottom. Thus, the pile bottom can fail in shear before it reaches its plastic moment capacity.INTRODUCTIONDrilling and blasting is the widely accepted method to large-scale rock breaking activities in civil engineering constructions due to its cost effectiveness, higher efficiency and ability to break hard rock. However, ground vibrations from blasting are undesirable and it can cause damage to nearby structures. In practice, the damage to nearby structures to generated ground vibrations has been controlled by various codes and regulations available. The existing vibration limits are not always applicable, as they depend on the geological conditions of the site and dynamic characteristics of the structure.Pile foundations are commonly used as foundations of high-rise buildings and bridges to transfer the heavy loads from the superstructure above through weak compressible soil strata into deeper, competent soil layers which have adequate capacity to carry these loads. In engineering practice, many piles are normally designed to carry mainly vertical loads and very little lateral loads, as typically the vertical loads (the gravity) are significantly larger than the horizontal loads such as wind loading. However, in recent years, there have been a number of reported case studies of translational soil movements that have induced stresses and bending moments that have damaged pile foundations and in some cases resulted in collapse of the superstructure. Typical lateral load include nearby construction activities such as an excavation for a basement or slope, the construction of a road embankment or a tunnel, as well as earthquakes (Abdoun 1997; Goh et al. 1997; 2003; Chen et al. 1999; Dobry et al. 2003; Boulanger et al. 2007; Black et al. 2007)."

Jan 1, 1900

By Stephan A. Jefferis

I presume that the questioner is not asking about the reduction of sulfate in groundwater to hydrogen sulfide as a result of biological activity promoted by organics in the grout hardener and that the question relates to sulfate attack on cementitious grout systems. For the project in Spain presented in my paper, we used a very high pulverized fuel ash (PFA) content in the cementitious material. This gives good sulfate resistance and indeed the chemical interaction will actually cause the permeability to drop for about 50 years without any question of sulfate attack and damage to the whole thickness of the grout - of course there will be attack at the exposed face of the grout where it is in contact with the contaminated groundwater. The mix had over 75% PFA, and also a very high overall cementitious content. The mix was the contractor's design and showed excellent behavior in laboratory proving trials. In grouts as distinct from concrete, PFA gives significantly better sulfate resistance than ground granulated blast furnace slag which is often used in Europe as a component of bentonite-cement mixes for slurry trench cut-off walls.

Feb 10, 2003

By James L. Christensen, Gregory Sanchez, Michael P. Walker

The Fogg Museum expansion project required excavation and construction in a congested urban area in Cambridge, Massachusetts. A soldier pile tremie concrete (SPTC) wall provided the support of excavation and now serves as the permanent basement wall of the new expansion of the museum. The existing Fogg museum had a single basement level. The new expansion has a two-level basement for new exhibit space and an amphitheater. The east side of the site is about 20 feet above the basement level of the existing Fogg structure which resulted in a significant unbalanced load that needed to be resolved without damaging the original Fogg structure. The SPTC wall was supported with a combination of tiebacks and internal bracing. The final depth of the excavation was about 40 feet below street level. Strict movement control was imposed because the existing museum contained an Italian Renaissance-style courtyard. The southeast corner of the SPTC wall had to accommodate underpinning of an historic concrete ramp which was ultimately incorporated into the expansion. Challenges during construction included excavating the SPTC wall panels up to 12 feet into argillite bedrock which had occasional diabase dikes and sills. The following topics are discussed in more detail after a general project.

Jan 1, 2015

By Paul Doherty

It is known that the axial capacity of a displacement piles installed in clay varies with time. Consolidation theory suggests that dissipation of porewater pressure set-up during pile installation would lead to increased effective stress and hence higher pile resistance. In recent years a number of case histories have reported time dependent capacity increases for piles installed in sand. Although there is some debate regarding the physical mechanisms controlling this phenomenon, known as ageing, it is unrelated to pore pressure dissipation as piles in sand are installed in primarily drained conditions. A series of field tests designed to investigate ageing effects in soft clay are presented in this paper. Full-scale load tests on 6m long 250 mm square concrete piles, which were driven into soft clay are described. The piles were first tested approximately 100 days after installation, at which stage full equalization of the excess pore pressures had occurred. Static load tests were then performed up to 10 years after pile installation. The piles exhibited significant ageing, with their shaft resistance increasing by up to 66% over a 10 year period. Possible mechanisms for such aging characteristics are explored.

Jan 1, 2011

By Alper Turan

The use of aggregate pier foundation systems has become widespread as the engineering practice moves towards cost-effective ground improvement solutions that provide accelerated construction schedules. Increased bearing capacity, effective settlement control and potential for liquefaction mitigation are commonly acknowledged benefits of aggregate piers. This paper studies the mechanisms by which aggregate piers interact with each other and with the surrounding ground when excited by seismic loads. A particular emphasis was placed on the response of a raft foundation supported on a site improved using aggregate piers. Three-dimensional nonlinear finite element analyses were conducted using commercial software package, ABAQUS. Non-linear soil behaviour is modelled using a three-dimensional total stress-based bounding surface plasticity model, which is able to simulate stiffness degradation and damping increase in the soil. The soil stratigraphy considered in this study was a 30 m deep soil deposit that comprised a very stiff base layer and a shallow soft surficial clay layer. Ricker Wavelet time histories with different frequency contents are used as the excitation force in the analyses. Various area replacement ratios (ARR) for aggregate piers are studied for a square plan layout. The results presented in this study are considered to be of interest to researchers and designers in evaluating the seismic ground response of the sites improved using aggregate piers.

By Alper Turan, Hesham El Naggar

"The use of aggregate pier foundation systems has become widespread as the engineering practice moves towards cost-effective ground improvement solutions that provide accelerated construction schedules. Increased bearing capacity, effective settlement control and potential for liquefaction mitigation are commonly acknowledged benefits of aggregate piers. This paper studies the mechanisms by which aggregate piers interact with each other and with the surrounding ground when excited by seismic loads. A particular emphasis was placed on the response of a raft foundation supported on a site improved using aggregate piers. Three-dimensional nonlinear finite element analyses were conducted using commercial software package, ABAQUS. Non-linear soil behaviour is modelled using a three-dimensional total stress-based bounding surface plasticity model, which is able to simulate stiffness degradation and damping increase in the soil. The soil stratigraphy considered in this study was a 30 m deep soil deposit that comprised a very stiff base layer and a shallow soft surficial clay layer. Ricker Wavelet time histories with different frequency contents are used as the excitation force in the analyses. Various area replacement ratios (ARR) for aggregate piers are studied for a square plan layout. The results presented in this study are considered to be of interest to researchers and designers in evaluating the seismic ground response of the sites improved using aggregate piers. INTRODUCTIONThe schedule and cost limitations imposed by the traditional over-excavation and replacement method for the stabilization and settlement control for poor soils resulted are underlying factors for the significant increase in the use of aggregate pier foundation system, particularly in the last two decades. Various well known advantages of aggregate pier systems including increased bearing resistance, settlement reduction, and increased uplift capacity have been studied by various authors. The use of aggregate pier systems for settlement control in soft soil deposits was studied by various researchers including Lawton and Fox (1994), Lawton et al. (1994) and Wissmann et al. (2001). Lien and Fox (2001) studied the behaviour of aggregate pier systems supporting embankments and retaining walls. The stabilization of slopes by means of aggregate piers was studied by Lien and Fox (2001), Wissmann et al. (2002). Thompson et al. (2009) reported on a performance monitoring study of aggregate pier systems supporting MSE walls. The interaction mechanism between the aggregate pier system and the surrounding soil attracted attention of various researchers. Handy and White (2006a) and (2006b) studied the changes that occur less than 2 m from centers of the piers, and further away, respectively. The support mechanism of aggregate pier systems subjected to compressive loading were studied experimentally and numerically by White et al. (2007) and Pham and White (2007), respectively."

Jan 1, 2017

By Bo Westerberg, Mattias Andersson, Yvonne Rogbeck

"Deep stabilisation has been used in Sweden for decades. The method has been improved to allow it to be used in different types of soils and with new binders. One challenging soil type in Sweden is so-called sulphide soil, a fine-grained soil which contains organic material and iron sulphides. There have been some cases in Sweden of problems when using deep stabilisation in this type of soil, and in one case a slope failure occurred. This paper shows that it is possible to achieve good results with deep stabilisation in sulphide soils. Laboratory and field studies from a test site along the Botniabanan railway line in Sweden are presented. Geotechnical and chemical properties of the natural soil were investigated in the laboratory and one or more of these properties may explain the differences in the stabilising effect of sulphide soils. The strength of the laboratory samples and the columns in the field were tested and compared. It is shown that a satisfactory stabilisation effect can be achieved with the proper choice of binder, amount of binder added, curing time and mixing energy. In sulphide soils, more binder additive is needed than in “ordinary” inorganic clays.1. INTRODUCTIONThe term sulphide soils is used in this paper to refer to the unique types of sulphide soil commonly found in the coastal areas along the north-eastern coastline of Sweden between the cities of Gävle and Haparanda, a distance of about 900 km. Sulphide soils are in general very compressible, susceptible to creep deformation and normally show low undrained shear strength. A sulphide soil may have a negative environmental impact through acidification and chemical action if it is subjected to oxygen, for example during excavation or lowering of the ground water table, Mácsik (1999). In foundation engineering works, efforts are made, for environmental or/and economic reasons, to use the sulphide soil as the foundation instead of excavating it. Deep stabilisation by means of columns is a potential method for use when sulphide soil needs to be improved in order to reduce settlements or/and increase the stability of embankments.Sulphide soils were formed as sediments at river mouths and off the coast in the special environment prevailing at the time of sedimentation, Mácsik (1994). The water in which the sulphide soil was sedimented was brackish/sweet and the environment was typically deficient in oxygen. The environment prevented complete decomposition of the organic material in the sediments. As a result, sulphide soils were formed primarily in the form of a fine-grained composition of clay and silt minerals, iron sulphides and organic matter. Such environments still exist today and new sulphide soil sediments continue to be formed."

Jan 1, 2015

By Mark R. Svinkin

"Construction equipment and operations usually produce soil and structural vibrations which may harmfully affect various structures and also the content of buildings and houses. The level of structural vibrations depends on a number of factors such as characterized sources of vibrations, soil conditions, and susceptibility of structures. There are certain knowledge and experience for managing the effects of construction vibrations which require implementation of condition survey of structures, information on construction dynamic sources and soil conditions at a site, evaluation of possible vibration effects on structure, calculation of ground vibrations before construction, use mitigation measures to decrease vibrations, and a choice of appropriate vibration limits. The paper presents the application of known concepts for assessment of vibration effects on structures from bridge constructions.INTRODUCTIONVibrations producing by construction activities such as pile driving, dynamic compaction of loose soils, demolition work, heavy construction equipment and trucks can affect adjacent and remote structures. Vibration effects on structures, sensitive devices and processes may create significant practical problems. Legal actions are often required for solutions of vibration consequences. The level of construction vibrations depends on dynamic sources, soil conditions at a site in particularly availability of soils with settlement potential, distances from the sources, parameters of waves propagating at a site and susceptibility rating of adjacent and remote structures. It is likely that intolerable structural vibrations from direct vibration effects of impact pile driving and resonant floor vibrations from vibratory pile driving may be induced in adjacent structures to construction sites.Foundation settlements resulting from soil vibrations in loose soils usually occur in the proximity of dynamic sources, but it is important that dynamic settlement may happen at various distances from the source. There are such examples. First, Kaminetzky (1991) mentioned a case history of building settlements developed at a distance of about 305 m (1000 ft) away from a pile driving site. Foundations of the buildings were underpinned on piles down to the tip elevation of the new driven piles to prevent building settlements. Second, Lacy and Gould (1985) shows that the peak particle velocity (PPV) of 2.5 mm/s (0.1 in/s) of ground vibrations could trigger dynamic settlements at distances up to 30.5 m (100 ft) from driven piles."

Jan 1, 2016

By Jerold Bishop, Grant Bearss, Aleksey Egorov

"When a shock wave is released in the bottom of a drill hole filled with wet concrete slurry, the result is called an electrohydrodynamic effect, or EHDE. The energy is carried through the fluid with minimal loss because the slurry is an incompressible medium. Repetitive discharges provide a series of energy pulses that compact the soil along the pile shaft and at its base. The process is analogous to repeated applications of low-energy blast densification or to dynamic compaction. In general, the process is not depth dependent. EHDE was identified in the 18th century by an American scientist who observed that a spark between two electrodes placed under water induced a burst of pressure. In 1957, two Russian engineers formulated a process and received a patent for a method of creating a pressure wave by transforming power from an electrical discharge to a mechanical impact. They derived more than 200 applications for technical and industrial processes.In the 1970s, civil engineers at the Engineering and Building Institute in St. Petersburg, Russia, began to look at EHDE to improve the capacity of drilled piles. Early experiments showed that electric discharges in a wet concrete slurry mix could create a pressure wave of up to 26 MPa (3700 psi). Later tests demonstrated that this pressure level could be created in a drilled pile hole. The researchers devised equipment and in the early 1990s began to study pulse technology as applied to drilled piles.This application was accepted into the Russian Federation Building Code in the 1990s. The code treats “regular” drilled piles with equivalent bearing area as having roughly half the capacity of a driven pile. However, the code considers drilled piles treated with the EHDE technique a direct “one for one” substitution for driven piles and allows higher values if the capacity is established by static load testing. Hundreds of projects have been completed in Russia using this technology to value engineer drilled pile projects. In several instances, the number of drilled piles installed was fewer than half of the number originally planned for due to the capacity increase that EHDE-treated piles provided.Drilled PilesIn drilled pile construction, the EHDE process creates a mechanical pressure wave that impacts the base and sidewall of a drilled pile shaft. Soft, poorly consolidated or loose soil is compacted by successive pulses of pressure created by electrical discharges. These mechanical impulses are made by inserting a discharge probe into the wet concrete slurry. A discharge across the tip of the probe creates the pulse that travels outward to the sidewall and base of the drilled pile through the incompressible medium of the slurry. The power pack ratings for equipment presently in use are 35 and 50 kJ (kilojoule).Each pressure wave strikes the soil, causing compaction and expanding the hole. Workers apply the pulses until the size of the hole stops increasing. They watch the slurry level during pulsing. When the level quits dropping, further soil compaction in the drill hole sidewalls and base is not possible. After the pulse process is complete, workers insert a rebar cage and the pile is finished.The process does not alter the soil mineralogy. The electrical discharge is internally grounded and does not arc to the sidewalls of the drill hole. Soil is not scorched or altered in any manner; it is only compacted by the pressure wave. This technique has been used in urban areas with no effect on electrical or electronic equipment."

Jan 1, 2009

By Jeremy G. Kress

We propose the discrete element method (DEM) as a complimentary alternative to analytical solutions and FEM models for the analysis of pile response. DEM is a novel approach to the engineering design of deep foundations which can be used to provide insight into the mechanics of soil-soil and soil-structure interaction. It is common to use analytical, empirical, and semi-empirical methods to predict pile behavior, where if granular properties, pile length, or load orientation change, then significant adjustments are made in the design sequence. DEM provides a more uniform approach in granular soils. Based on constitutive force-displacement relationships and laws of motion in rigid and elastic bodies, few changes must be made for a wide variety grain types, pile types, embedment, and load orientation. Preliminary results for simulation of a single pile are qualitatively consistent with results from conventional design procedures and also provide significant information not available from other analyses (e.g., local information about interface failure during shear). Importantly, these analyses are portable to a variety of pile types and installation procedures, which may not be the case for empirical approaches. Given consistent increases in computing power and rapid advances in model speed and sophistication, the DEM should prove to be a robust method for design and the analysis of pile response in granular soils.

Jan 1, 2010

By Waddah Akili

At an offshore site along the Red Sea coast of Saudi Arabia, marine structures were supported on tubular steel piles driven into coral and coral contaminated sands and silts. Surprises and disappointments faced during the installation of the piled foundation were, to a large measure, due to inappropriate design methodology and absence of proper soil information. The paper describes the design evolution process, highlights the static pile test program conducted to verify design parameters, and amplifies the need to prepare for worst possible scenario when coral deposits are encountered. Despite corrections made to the design, based on site-specific insitu parameters (skin friction, end bearing) perceived from load tests conducted on site; the final design adopted overestimated capacities in over 50 percent of total piles driven. The paper describes the changes introduced to the design during the execution of the project, highlights the pile test program conducted to verify the design, and compares pile design penetration with actual penetration depth. The unpredictable and erratic pile behavior observed, ascertains the need for more appropriate pile design and installation guidelines for driven piles in coral and coral contaminated formations.

By Yoshio Mitarai, Takeshi Nagatome, Yosuke Tanaka

"This paper describes an application of lightweight soil in a deep water area to stabilize an existing quay wall at the Port of Tokyo. Super Geo Material, abbreviated SGM, is a type of lightweight soil, which consists of dredged cohesive soil, cement and air foam, and is applied in coastal development work, such as port and airport construction. This paper reports a SGM construction project at the Port of Tokyo by using a SGM special plant vessel, which was deployed for the Tokyo International Airport (TIA) Expansion Project in order to achieve large-scale and rapid construction. The key issue in SGM construction is quality control. One key quality issue is control of the mix proportion of SGM in consideration of volumetric changes due to air foam-breaking during pumping and air foam shrinkage due to water pressure when SGM is placed in deep water. A smart technique for placing SGM is also necessary to prevent quality deterioration when SGM is placed in deep water, for example, increased bulk density and decreased shear strength due to water absorption. This paper introduces an actual case of SGM construction with a particular focus on quality control of SGM during construction.INTRODUCTIONSuper Geo Material, abbreviated SGM, is a lightweight stabilized soil which is used in coastal development work in Japan (CDIT 2008). SGM is applied as a backfilling material behind existing quaywalls or above underground structures in order to reduce earth pressure on the existing structure and improve seismic resistance. SGM has been applied in many coastal development projects. In particular, SGM was used at the Tokyo International Airport (TIA) Expansion Project (Haneda Airport) as the backfilling material at a quay wall at the joint between the reclaimed area and pier part in a new runway (Nagatome et al. 2010a & 2010b, Yamatoya et al. 2010, Mitarai et al. 2011). In this project, large-scale and rapid SGM construction was implemented by the special SGM plant vessels within 6 months under the condition of limited construction period.This paper introduces a new SGM construction project at the Port of Tokyo in 2011. This project employed the special SGM plant vessel, “Ryujin Mark II”, to achieve large-scale and rapid construction within a limited period. SGM was also placed in a deep water zone at the maximum water depth of approximately 15 m. Thus, quality control of SGM was a key issue for meeting project requirements. This paper describes the actual SGM construction in the Tokyo Bay area and quality control techniques for SGM, considering volume changes due to pumping and placement below water."

Jan 1, 2015

By Andrew Z. Boeckelmann, David S. Graham, Paul J. Axtell

In the last fifteen years, several research studies have evaluated the ability to detect various types of deep foundation concrete integrity flaws with crosshole sonic logging (CSL) and thermal integrity profiling (TIP). This paper synthesizes the findings from the research, focusing on two studies that included CSL and TIP testing of drilled shafts with various types of flaws. The first, a 2016 research study of test shafts for the Wisconsin DOT, included inclusions inside and outside the reinforcing cage, intentional tremie withdrawal during concreting, and soft bottom flaws. The second, a 2021 study of production shafts for the Missouri DOT, included one shaft with and another without soft bottom conditions. After synthesizing the ability of each test method to detect each type of flaw, the paper presents recommendations for improving how CSL and TIP results are evaluated in practice. The recommendations highlight DFI‟s CSL interpretation protocol as well as the importance of evaluating TIP data versus time, not just depth. The paper includes example temperature-versus-time plots for various types of flaws and emphasizes how temperature-versus-time evaluation can be used to distinguish soft bottom conditions from standard bottom-of-shaft temperature roll off.

Oct 1, 2022

By Osamu Taki

The innovative Soil-Cement Mixed Wall Technique emerged in Japan and obtained recognition in the engineering and construction communities in the 1980's. This technique was introduced to the United States in 1986. It was accepted as the most credible construction technique by the U.S. Bureau of Reclamation for ground stabilization and cutoff wall work in the Jackson Lake Dam Project, Wyoming in 1987 and 1988. It was also accepted as a remediation technique by U.S. EPA for a Superfund Innovative Technology Evaluation (SITE) demonstration on in-situ solidification/ stabilization. The Soil-Cement Mixed Wall Technique consists of mixing in-place soils with cement grout or other reagent slurries using multiple axis augers and mixing paddles to construct overlapped soil-cement columns. The overlapped column panel is then extended to form an underground continuous soil-cement wall for use as a cutoff wall or a structural diaphragm wall for groundwater control and excavation support. By arranging the column panels in various configurations, the technique becomes a versatile tool for stabilization of soft or liquefiable soils.

Jan 1, 1990

By Nils Schneider, Marc Peters, Stefan Frey, Andrea Fluck

Due to the worldwide population growth, the development of sustainable infrastructure and the exploration of renewable energies plays a key role to handle the rising megacity trends and to limit carbon footprint. Herrenknecht AG is a leading manufacturer of Tunnel Boring machines and has constantly endeavored through its extensive Research and Development programs to address limitations faced by the civil engineering industry as regards to construction equipment capabilities. New mechanized technologies, mainly coming from the tunnelling industry, have been developed by Herrenknecht AG as an efficient alternative to conventional civil engineering, where tailor-made concepts are required to comply with restricted conditions onsite. Very often this innovation led technology capability has meant making construction processes safer due to minimal human intervention and also far more productive due to higher performance as compared to other latest or conventional methods of construction. The rising need for even higher building structures and large-capacity bridges involve the development of innovative deep foundation technologies for on- and offshore operation. Conventional methods like bore piles reach their technical and economic limits under certain conditions. For building shafts and foundations, the mechanized Vertical Shaft Sinking Machine technology (VSM) from Herrenknecht AG is a proven innovation and has now been used in various onshore infrastructure projects worldwide to construct a total of 94 circular shafts in depths of up to 115 meters. It operates below the groundwater level, completely remote-controlled from the surface in a diameter range from 4.5 to 18 meters. Subsequently Herrenknecht noted that Offshore foundations, especially in non-drivable ground conditions such as soft and hard rock (e.g. limestone, sandstone, mudstone, granite etc. or soft soil with high density) and shallow continental shelf (water depth approx. 20-60m), presented construction challenges and equally an opportunity for building high performance equipment. The latter construction conditions usually requires drilled installation methods for applications such as harbor enlargements, bridge foundations and foundations for offshore wind turbines. The Offshore Foundation Drilling technology (OFD®) is Herrenknecht’s latest innovation, incorporating our learnings from the VSM and full-face Tunnel Boring machines, and the OFD® enables a rapid and economical offshore installation in such variable ground and rock conditions. This paper will discuss the technology behind the new mechanized technology of VSM and Herrenknecht’s latest innovation of the OFD® along with their respective application fields in foundations construction. The paper will further present in details, their range of benefits to the construction industry.

Nov 1, 2022