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By Jr NeSmith

"Augered-cast-in-place (ACIP) pile installation technology has matured extensively since the first auger, pressure grouted pile was patented in 1959. The current technology allows for successful pile installation across a variety of stratigraphies to meet various project load resistance requirements. This paper presents an overview of current ACIP techniques by comparing a number of case histories in a variety of geologic settings from Eastern Pennsylvania, New York City and New Jersey to demonstrate ACIP pile constructability in soft soils as well as the penetration, and resulting significant loads resisted, of ACIP piles in dense soils and intermediate geo-materials. Geologic settings that will be discussed include the Piedmont and Coastal Plain geologic provinces as well as glacial till deposits. Keywords: Deep Foundations, Piles, Augercast, Augered-cast-in-place, Auger pressure grouted, ACIP, APGINTRODUCTIONThe author, along with two colleagues, published an article in Deep Foundations magazine (NeSmith et al, 2013) which described a number of the advances in equipment, techniques, installation monitoring and post-construction testing that have expanded the geologies in which Augered Cast-in-place (ACIP) piles are installed as well as increasing their efficiency in some traditional ACIP pile geologies. The author uses the term efficiency to refer to the load resisted by a pile of a certain diameter and the increased efficiency noted refers to increased allowable loads over those traditionally resisted by piles of certain diameter (or a reduction in pile diameter from that which was traditionally used to support a certain design load). The performance and installation of ACIP piles in a variety of geologies in the Northeastern U.S. are discussed herein.PIEDMONT PHYSIGRAPHIC PROVINCEThe Piedmont physiographic province stretches from Alabama to the east through Georgia and up the east coast, just west of the Coastal Plain to Pennsylvania and New York (Brown, 2002). It generally consists of soils weathered in place from the underlying bedrock, which is typically a combination of granite, schist and gneiss depending on the location within the province. The author’s experience in the Northeastern US has been on sites where alluvial or coastal plain soils overly the residual soils and partially weathered or intact rock of the Piedmont. The example presented here, from a site on Walnut St in Philadelphia PA, is representative of these projects."

Jan 1, 2016

By Takefumi Takuma, Hiroyuki Nishimura, Shigeru Kambe

"In order to achieve tubular pile driving with low noise and low vibration, the Press-in Piling Method has been adopted on many projects. The method utilizes reaction force derived primarily from previously driven piles to push in the next pile into ground. With attachments, the Press-in piling equipment can deal with hard soil as well as difficult site conditions. At West Toronto Diamond Rail Grade Separation Project in Toronto, Canada, the Press-in piling equipment drove more than 500 of 914 mm (36 inches) diameter tube piles in length of 12 to 25 meters (39 to 82 feet) to construct earth-retaining walls for railway grade separation. Myoshoji River Restoration Project in Tokyo, Japan drove some 600 of 1,000mm (39.4 inches) diameter tube pipe sections in length of 11 to 22 meters (36 to 72 feet) by the rotary Press-in piling equipment to increase the flood drainage capacity of an existing river in highly populated area of the city. Both projects exemplify the advantages of the method in urban settings.1. BACKGROUNDThe Press-in Piling Method was invented some forty years ago in Japan, where a very large number of construction projects were causing widespread construction pollution, especially by pile driving work in densely populated areas. The method has been providing solutions for piling projects which could not have been built otherwise due to the noise and vibration impact to the surrounding communities. The method can be used with various types of piles including sheet piles, tubular piles, concrete sheet piles and so on. With high pressure water jet and continuous flight auger attachments, the Press-in piling equipment can deal with dense sand, stiff clay, gravels, boulders and even soft rock without employing a different set of equipment."

Jan 1, 2015

By C. Dai, S Raathiv

The Waikato Expressway is one of the New Zealand Transport Agency’s (NZTA) seven roads of National Significance. Coffey is part of the City Edge Alliance engaged by NZTA for the Hamilton Section of the project. The 22km Hamilton Section is the largest and most geotechnically complex section of the Expressway. The Mangaonua gully in Sector 6 is the most challenging geotechnical area of the project for piling works. Together Coffey and Brian Perry Civil have carried out the temporary and permanent design and construction of embankments, piling works, retaining walls and soil improvement works for the bridge construction. The design and construction works were governed by weak alluvial layers and artesian pressure layers several meters beneath the ground level. This paper presents the action taken to improve the foundation of temporary platform, control the artesian pressure, prevent bentonite leakages into the highly permeable alluvial layer and challenges in the base grouting process. This paper summarises the key components in the construction and supervision of bored piling works and outlines innovative solutions for challenges which we faced during the construction.

Nov 1, 2022

By Inc. Pile Dynamics, Daniel S. Belardo, Marcus Galvan, George Piscsalko

Soil nails are often utilized as a temporary or permanent earth retention technique for slope stabilization and for excavation retention for existing or new structures. Soils nails are generally advantageous as installation is relatively rapid and they can be installed beneath existing structures and where site access for equipment is limited. Due to the typically small cross-section of these elements, the inability to inspect the holes prior to grouting/concreting, and the various installation techniques utilized, quality control for assessing the integrity along the entire length is limited. Currently, quality assurance is conducted by load testing to verify the pull out capacity after installation. The load testing is typically done on a small percentage of the total number of soil nails. This paper will provide the results of a demonstration where the new Non-Destructive Test (NDT) method Thermal Integrity Profiling (TIP) was used to access the integrity of several soil nails along their entire lengths. This TIP method has been successfully used for several years to assess the integrity in drilled shafts and ACIP piles. The TIP method assesses the integrity across the entire cross-section and can identify regions where bulges, necks, and insufficient grout/concrete are present. TIP testing can also help assure that the contractor's installation methods are adequate and consistent for the intended design. For the project presented, instrumented Thermal Wire were affixed to the centered tension bars prior to placement in the excavated shafts. Temperature measurements were recorded from the hydration energy generated after grout/concrete placement, capturing the entire heating cycle. Manufactured defects were installed on the center bar at multiple locations. The results and conclusion will be discussed as well as recommendations for future use.

Jan 1, 2017

By Sara Anderson, Rachel Nicholls, Tim Chapman, Janice Windle

"In city center sites around the world, and in particular in London, foundation reuse is becoming increasingly widespread as the ground is filled with detritus from previous developments. This paper sets out a systematic framework to consider the need for and benefits of foundation reuse and key issues to be resolved for foundation reuse to be successfully adopted on redevelopment projects. Once foundation reuse has been identified as a potential foundation solution there are several key stages in the design and construction process where the decision to reuse foundations needs to be assessed. The paper concludes by emphasising the importance of ensuring that the foundations being installed now can more easily be reused in the future.INTRODUCTIONThe concept of re-using foundations is not new, and has been adopted on an isolated project-byproject basis for many years. However, over the past decade, interest in the potential of reusing existing piles and caissons within Europe has increased significantly, with a growing interest in the United States of America and Japan. The need has been driven by necessity: on many urban sites the space available for new foundations diminishes with each new set of piles, and these problems can only grow in the future.Initiatives such as the European Union's RuFUS (Re-use of Foundations for Urban Sites) research project have resulted in identification of the key issues for technical viability and risk that have previously hampered potential foundation reuse projects.There is a need to define a systematic approach to the reuse of foundations so that the risks associated with reuse can be identified, managed and mitigated. This requires improvements in knowledge to provide confidence in the long term behaviour of the foundation support and address the risks involved in reusing existing foundations to overcome perceived obstacles in making foundation reuse a realistic option for many sites."

Jan 1, 2005

By Abdulazeez Rotimi, Barry Sheppard, Abid Adekunte

Good engineering practice is a function of sound theoretical knowledge, first-hand experience on previous projects of similar scope and scale, good acquaintance with case histories of similar projects completed by others in similar environmental conditions, as well as satisfactory degree of exposure to state-of-the-art methodologies. The four factors itemised above are typically interdependent. They amalgamatively influence the judgement of the Engineer and they ultimately result in the delivery of safe and cost-effective solutions by Professional Engineers. This technical paper presents detailed information on the ground engineering aspects of a large-scale housing development project located on a sloping site that had been presumed to be unstable in West Sussex, England. The ground engineering design package for the scheme comprised of temporary working platform designs & stability assessment for piling rigs and other construction machinery, geostructural designs for approximately 1km total run of permanent bored pile retaining walls to support the split-level construction on the sloping site and geostructural designs for the permanent foundation piles to support the housing units. The paper details how the four factors outlined above were amalgamated by the project’s foundation specialist consultants & piling contractors to deliver safe and practical solutions for the development, with significant savings in materials, cost and project completion time.

Sep 8, 2021

By Robert C. Simpson, Ghada S. Ellithy

"There are several methods for estimating the axial capacity of drilled shafts installed in coarse-grained soils. Most methods estimate the ultimate capacity for side friction and tip resistance. Design capacity is then calculated by applying a resistance factor to the ultimate capacity. In reality, however, ultimate resistance may not be mobilized except after a significant displacement that is not structurally tolerated in either compression or tension modes.A full- scale load test is the best way to obtain the load settlement curve for a drilled shaft, especially in soil formations where accurate estimation of soil frictional properties from a field investigation may be difficult. This paper presents the results of a static, axial, compressive bi-directional load test, using the Osterberg method (O-cell test). The test was designed so that the shaft above the O-cell would move up and the shaft below it would move down when loaded. At the start of the test the concrete around the O-cell is fractured generally on a plane near the bottom of the cell.The test was designed to validate the design capacity of drilled shafts embedded into the Vashon recessional outwash (Qvro), which is a glacially derived sediment consisting of thick deposits of cobbly sand and gravel relatively free of silt and clay found in the Seattle, WA area. The test shaft consisted of a 2.5- feet (0.75 m) diameter drilled shaft. The test shaft was installed to a depth of about 47 feet (14.3 m) into this formation. A maximum load of 437 kips (1.95 MN) was applied during the test, in each direction. The maximum load was attained at upward and downward displacements of less than 0.1 inch (2.5 mm), respectively.Although the load test did not yield ultimate values, the results are compared to the design assumptions using methods adopted in the FHWA and AASHTO guidelines, which verified the adequacy of the design assumptions. We conclude that more emphasis is needed in the prediction of the service loads and corresponding mobilized displacement that may lead to a more cost effective design. It is also clear that more testing to higher loads could lead to more efficient designs on specific projects and generally as data is added to the local knowledge base."

Jan 1, 2015

By Adnan A. Malik, Tadashi Maejima, Jiro Kuwano, Shinya Tachibana

"The helical piling system provides solution to many geotechnical related problems due to its quick installation, higher compressive and pullout resistance, no wastage of material, workable in limited areas and reusability. However, its use as a foundation for bridges and high-rise buildings is still limited as compared to other piling methods. In the present study, the performance and load settlement behavior of screw and straight pile is investigated under cyclic compressive load in dense ground conditions. To achieve the set objectives, pile load tests were conducted in a cylindrical steel container. The model ground was compacted with dry sand at relative density of 80%. It is observed from the test results that screw and straight pile resistance reduced when the cyclic load is applied at allowable pile resistance state. The reduction in the ultimate pile capacity is more in straight pile than in screw pile. However, straight pile showed higher ultimate pile capacity than screw pile under similar pile tip diameter. The effect of helix bending deflection on load settlement behavior and ultimate pile capacity increases under cyclic loading.INTRODUCTIONScrew pile is one of the new developments in deep foundation, which is growing tremendously fast because of its quick installation technique, less noisy operation, no wastage of material and involvement of minimum manpower. Screw piles have an edge on straight pipe piles due to its high bearing capacity and uplift resistance. The installation mechanism of screw pile is different from straight pile. Torque and pressure is required to install the screw pile whereas hammering, pressure and vibration is required to install straight pile. As the installation mechanism is different between screw and straight pile, therefore, the ground disturbance that is produced during their installation is also different. The ground disturbance produced during the installation also depends upon the pile tip condition i.e. open or closed ended. Sakr, (2009) stated that the compressive capacity of screw pile in 3 to 5 times higher than driven piles having the same shaft diameter and length. The reason for this increase in pile capacity is due to helix, which is generally 2 to 2.5 times the pile shaft diameter. Larger helices can give higher end bearing capacity but it requires very powerful machinery to install in dense grounds. For instance, if large helix screw pile is installed in a dense ground then helix-bending deflection will start affecting the end bearing capacity (Yttrup and Abramsson, 2003; Malik et al. 2013 and 2015). According to Malik (2015), the equations of thin plate (Young and Budynas, 2002) with uniformly distributed load on the plate can give reasonable estimation of helix deflection due to dense ground conditions."

Jan 1, 2016

By Monica R. Garcia, Antonio Alberto S. Correia, Paulo J. Venda Oliveira

"The aim of this paper is to analyze the creep behavior of a Portuguese soft soil stabilized with binders in one-dimensional conditions, based on oedometer creep tests. The study focuses on the analysis of the effect of the binder content and binder type on the creep behavior of a stabilized soil. The results show that the best binder type for this soil, in terms of creep behavior, is composed of Portland cement and fly ash with a dry weight proportion of 75/25, as this promotes the development of secondary pozzolanic reactions. The results also show the decrease in the secondary compression index with the increment of the binder content, since it promotes an increase in the cementation bonds between soil particles. The general analysis of the results shows a clear dependence on C??and qu, until values of qu of 1500 kPa; after that this relationship is negligible.INTRODUCTIONThe geotechnical structures (such as embankments, dams and buildings) built on organic soils exhibit notable creep deformations, which increase the maintenance and exploitation costs and can even compromise their functioning. To attenuate the creep effects of the soft ground, some improvement techniques are frequently used, such as preloading or reinforcing the soil foundations with vertical rigid inclusions, like concrete piles, stone columns or deep mixing columns (DMCs). However, the installation of DMCs in the soft ground induces (via the arching effect) a transfer of stresses from the soft soil to the DMCs, which causes an increase in the creep settlement on the DMCs (Venda Oliveira et al. 2011).Notwithstanding the fact that the creep behavior of clays has been the object of several studies (Leroueil et al. 1985; Mesri and Castro 1987; among others), the study of the creep behavior of soil-binder admixtures has been practically ignored by the scientific community. The few studies on this theme have revealed that a stabilized soil’s creep behavior is dependent on: the type of binder (Venda Oliveira et al. 2013), the binder content (Correia 2011; Bobet et al. 2011; and Venda Oliveira et al. 2013), the stress level applied during the creep phase (Venda Oliveira et al. 2013), the organic matter content of the natural soil (Venda Oliveira et al. 2012; 2014), and the curing conditions (humidity, vertical stress applied during curing, and curing time) (Correia 2011; Venda Oliveira et al. 2012).The aim of this paper is to contribute to a better understanding of the creep behavior of a soil-binder admixture, by examining the results of oedometer creep tests. The study focuses on the analysis of the effect of the binder content and binder type on the creep behavior of a stabilized soil. Additionally, the creep behavior is correlated with the effective vertical yield stress and the unconfined compressive strength (UCS)."

Jan 1, 2015

By Racquel Nottingham, Marc Mastrantuono, Freddy Lopez

In the digital era that we live in, connectivity and mobility play a decisive role in our daily activities. In this context, insufficient telecommunication infrastructure gives origin to the so called “dead zones” (areas with poor or non-existing cell phone reception), which hinder economic development in small communities and in many rural areas, since they remain invisible to a larger marketplace due to the inadequate cellular coverage. Several countries are working to identify these dead zones and with this information, establish strategies together with mobile providers in order to improve the existing mobile networks by expanding the coverage areas. As a result of the analysis, it is expected that thousands of telecommunication towers for 4G and 5G networks will be erected in the coming years. Telecommunication towers are slender elements that require large shallow foundations to verify primarily the safety against overturning. However in remote areas, it can be advisable to consider alternatives to the conventional shallow foundations, in order to optimize the use of materials (concrete, reinforcement steel, etc.). The following article presents an overview of intervention projects, where telecommunication towers were founded on micropiles. The micropiled foundations allowed to reduce considerably the dimensions of the originally planned shallow foundations. Furthermore, the use of micropiles allows for additional optimization, in combination with pre-fabricated foundations (i.e., precast concrete elements, etc.). This paper will focus mainly on the design and the execution of the micropiled foundation.

Sep 8, 2021

By Tara Schenk-McFarland, Mark Bliss

Echo Dam, located near Coalville, Utah, is a facility that provides storage for irrigation and municipal use. Original construction of the dam was completed in 1931. Because of seismic concerns, the spillway crest structure and upper chute section, founded on old landslide and colluvial material, were recently replaced. Prior to replacement of these structures, jet grouting of a block of the loose and potentially liquefiable soils, directly beneath the spillway crest structure was selected as the preferred alternative to address the potential for settlement and cracking of the spillway crest structure. The replacement or alteration of the in-place soil reduces the likelihood of seismic-induced excess pore pressure development and subsequent settlements. Core drilling and sample recovery of the production jet grouted columns was completed to verify compliance with the specifications. It was recognized that due to the larger rock sizes within the deposits that full homogeneity of the jet grouted zone was unlikely to be achievable. However, the purpose of this jet grouted section was to strengthen enough of the soil so that widespread liquefaction does not occur. During the jet grouting production many instances of ground fracturing occurred. Fracturing was evident based on grout/air bubbles exiting the surface near some of the grout holes during jet grouting, air bubbles appearing in the spoil pits, and lifting of the ground surface in the vicinity of the monitor during the jet grouting process while the system was pressurized. In one instance, a section of the upstream spillway slab, which was left in place, was cracked due to pressurized grout escaping beneath the slab. The overall results of the jet grouting were satisfactory despite difficulties encountered. The cause of the fracturing is hypothesized and a recommendation is included to reduce the likelihood of this occurring on future jobs.

Jan 1, 2017

By Brian Wilson, Franz-Werner Gerressen

"Cutter Soil Mixing, also known as CSM, was developed in Europe as an alternate method of Deep Mixing to the more traditional single and multiple auger techniques, and brought to market by Bauer Maschinen GmbH (Bauer), towards the end of 2003. Initial development of the technique had been completed in a joint venture between Bauer and Bachy Soletanche. In 2004 the concept was introduced to the North American market. Continued development of the method and demonstration of its versatility, both in terms of applications and applicable soil types has seen a steady growth in the number of designs incorporating the approach, and contractors offering the technique. This paper provides a brief overview of the variety and size of projects and applications where the method has been adopted, discusses some lessons learned with respect to equipment operation as well as the improvements that have been introduced to the equipment, and briefly reviews the current state of practice, as well as some of the associated on-going research and development.BACKGROUNDCutter Soil Mixing (CSM) is a technique for deep soil mixing that was initially developed as a collaborative effort between Bauer Maschinen (Bauer) and Bachy Soletanche, but which ultimately resulted in the separate development of two somewhat different brands of CSM tool. The Bauer brand of CSM entered the European market in 2004, and was first promoted in the North American market in late 2004, with the first project starting in 2005. The Bachy Soletanche brand, sometimes referred to as “Geomix” was first marketed in Europe in 2005 and the first model introduced in North America in 2007.The development of the Cutter Soil Mixing technique utilized the experiences gained from Trench Cutter/Hydrofraise equipment, developing a technique that incorporates two cutting wheels rotating about a horizontal axis as opposed to the more conventional deep soil mixing approach which utilizes augers and mixing paddles rotating about vertical axes. Whereas the Trench Cutter/Hydrofraise technique excavates the soil from within a panel, and supports the open hole using a bentonite slurry, the CSM technique cuts and displaces the soil whilst pumping a slurry/grout directly into the soil through a port located between the wheels. The combination of cutting the soil while introducing an appropriate volume of slurry effectively fluidizes the column of soil around and above the cutter head. While this process achieves a high degree of mixing, even on the downward cutting stroke, thorough in-situ mixing typically occurs on the withdrawal stroke, when most of the slurry is added."

Jan 1, 2015

By Brian E. Ladd

"A load test program was performed on two auger cast piles constructed in the Inner Coastal Plain geology of North Carolina. Both test piles were installed through Coastal Plain deposits and into underlying Piedmont residual soils; one test pile was embedded into partially weathered rock (PWR). The recommended 100-ton design load was confirmed by a test program that included instrumenting the piles with strain gages. The two piles performed differently during the load tests due to the effect of embedment into PWR. Loading Test Pile No. 1, which was not embedded into PWR, to failure at about 230% of the design compressive load allowed for evaluation of the mobilization of the ultimate shaft and end bearing resistances. Mobilization pile resistance was evaluated by comparing shaft and end bearing resistances to top of pile deflection (d) normalized by the pile diameter (D). For Test Pile No. 1, the ultimate average shaft resistance was achieved at d /D of about 7.5% and ultimate end bearing resistance at d /D of about 9.5%. Test Pile No. 2, embedded into PWR, achieved a d /D of only about 4% at 200% of the design load and was not loaded to failure. Shaft resistance was mobilized at a different rate within each individual geologic layer, i.e. ultimate shaft resistance did not occur simultaneously for all geologic layers. As the available total shaft resistance was exceeded and end bearing mobilized, the unit shaft resistances reduced from the peak values. A modified Davisson offset using d /D of about 6.5% appears applicable for evaluating the ultimate capacity of auger cast piles in the Inner Coastal Plain.INTRODUCTIONAuger-cast-in-place (ACIP) piling was developed in the 1940’s and patented in 1956 (Neely, 1991). Since patent expiration in 1973, ACIP piles are abundantly used in the United States, particularly in the southeast. However, most literature addresses driven piles constructed in sand and clay with lesser discussion of drilled piles. Conventional design methodologies (a- method, ß-method, SPT or CPT correlations, etc.) are based on data derived from numerous projects in a great variety of geologies. O’Neil (2001) notes that there are significant levels of uncertainty in the “universal” databases as evidenced by coefficients of variation of 0.35 to 0.40 for geotechnical parameters (su, SPT-Nvalue, etc.) used to estimate pile capacities.There is a need to develop local databases developed from data obtained from load tests that measure shaft resistance and end bearing. This paper presents the results of load tests conducted on axially loaded auger-cast-in-place piles constructed in the Inner Coastal Plain geology of North Carolina. Shaft resistance, end bearing, and movements that initiated mobilization of these resistances are described. The information presented herein can be used to refine geotechnical correlations and parameters applied in auger cast pile design methodologies."

Jan 1, 2017

By Michael Arnold

"BAUER Foundation Corp. was one of three contractors awarded with the installation of a cut-off wall at the Herbert Hoover Dike Rehabilitation project. The cut-off wall was constructed up to 84 feet deep and 25 inches thick. It extended from the crest through the middle of the existing dike into the underlying peat, sand, and rock layers. BAUER used the cement deep soil mixing method of Cutter Soil Mixing (CSM) to install the wall. Soil mixing was facilitated by first removing the peat layer in the wall alignment using Kelly drilling and replacing it with suitable backfill, resulting in a secant pile wall arrangement of replacement columns. BAUER successfully finished four task orders with a total length of just over 10 miles. Up to six rigs of the types BAUER BG 28, BAUER BG 40 and RTG RG 25 were concurrently used to perform the replacement columns and the cut-off wall installation.The paper introduces the project, the geotechnical site conditions, and the requirements specified by USACE. It focuses on the specific adaptation of the CSM method to the site conditions and on the equipment used. Strength and permeability results obtained from an extensive testing program are presented. The impact of the curing conditions on lab and in-situ test results is studied, and test results are related to soil conditions.PROJECTThe Herbert Hoover Dike is a 143-mile-long dike encircling Lake Okeechobee in south central Florida. When it was constructed in the 1930s and 1960s, the purpose of Herbert Hoover Dike was flood protection from hurricanes. However, during the 1970s a higher lake level was maintained permanently to provide local agriculture with water. Later, damage became apparent during two nearly back-to-back high water events in the 1990s, when numerous sink holes, seeps, pipes, and boils were observed (Fig. 1). In 2000, the Congress approved USACE to propose rehabilitation measures. The installation of a cut-off wall into the existing dike was chosen during the initial design process as the preferred measure to improve the safety of the dike (Davis et al. 2009).The first section of the dike to be rehabilitated was Reach 1 located along the southeast side of the lake between the towns of Port Mayaca and Belle Glade. An indefinite delivery indefinite quantity (IDIQ) multiple award task order contract (MATOC) was issued for this 22.4-mile-long stretch by USACE in 2007. BAUER Foundation Corp. (BAUER) was one of the three contractors that succeeded in the qualification process. Each of the three successful contractors had their own novel construction techniques. In the years 2008 to 2012 BAUER executed four task orders totaling over 10.0 lineal miles of cut-off wall with 3.3 million square feet of design surface area."

Jan 1, 2015

By Arash Khosravifar, Ali N. Ibrahim

"Large areas of Iraq are covered with collapsible soils namely gypsiferous soil which is often used as the foundation soil for structures. In particular, the Mosul Dam foundation is comprised of high contents of gypsiferous soils. Intrusion of water through the foundation soil dissolves gypsum which acts as the binding material between soil particles. This phenomenon results in the formation of collapsible soils which can cause serious damages to the dam structure. The failure of Mosul Dam, with a reservoir as large as 11 billion cubic meter of water, can be catastrophic. In the past, Mosul Dam Authorities have been remediating the soil foundation by injecting cement mortar. This method has been proved not economic; therefore, new, more efficient, methods are desperately needed.This research study focuses on finding practical methods to remediate collapsibility of gypsiferous soils by improving their geotechnical properties. This study presents remediation of collapsible gypsum-rich soil by grouting. Three types of stabilizer materials were used to make the grout; (1) sodium silicate (Na2 O3 Si) which is a well-known chemical soil stabilizer, (2) bentonite slurry, and (3) silicone oil. The purpose for using these stabilizer materials is to provide an impermeable layer (waterproofing coat) around the gypsiferous soil particles and to fill the voids that may occur in the soil as a result of gypsum dissolution when subjected to water.A series of double oedometer (collapse) tests and direct shear tests were carried out on gypsiferous soils before and after remediation by grouting. The results show that the soil compressibility decreases in the grout-treated gypsiferous soil by reducing volumetric strain. Consequently, the potential for collapsibility decreases too. It was also shown that grouting, increases the shear strength of the soil at confining stresses smaller than 250 kPa by increasing the cohesion combined with a slight reduction in the internal friction angle.INTRODUCTIONGrouting is one of the ground improvement techniques which is often used to improve the loose foundation soils. Bruce (2003) provides step-by-step procedures on using grouting techniques for sealing dams and other water reservoirs. Grouting can be classified as permeation grouting, compaction grouting or hydraulic fracturing. Permeation grouting is an effective way to send the grout into the ground without disturbing the soil structure, i.e. free flow of grout into the soil voids where grouting is accomplished by injection of a fluid-like material that is capable of forming a gel and binding the soil particles together. Grout materials may be solution grouts or suspension grouts. The permeation grouting technique is generally used to minimize ground permeability and to control ground water flow, but it can also be used to strengthen and harden the ground (Raman et al., 2012)."

Jan 1, 2017

By Brain E. Ladd

A load test program was performed on two auger cast piles constructed in the Inner Coastal Plain geology of North Carolina. Both test piles were installed through Coastal Plain deposits and into underlying Piedmont residual soils; one test pile was embedded into partially weathered rock (PWR). The recommended 100-ton design load was confirmed by a test program that included instrumenting the piles with strain gages. The two piles performed differently during the load tests due to the effect of embedment into PWR. Loading Test Pile No. 1, which was not embedded into PWR, to failure at about 230% of the design compressive load allowed for evaluation of the mobilization of the ultimate shaft and end bearing resistances. Mobilization pile resistance was evaluated by comparing shaft and end bearing resistances to top of pile deflection (?) normalized by the pile diameter (D). For Test Pile No. 1, the ultimate average shaft resistance was achieved at ?/D of about 7.5% and ultimate end bearing resistance at ?/D of about 9.5%. Test Pile No. 2, embedded into PWR, achieved a ?/D of only about 4% at 200% of the design load and was not loaded to failure. Shaft resistance was mobilized at a different rate within each individual geologic layer, i.e. ultimate shaft resistance did not occur simultaneously for all geologic layers. As the available total shaft resistance was exceeded and end bearing mobilized, the unit shaft resistances reduced from the peak values. A modified Davisson offset using ?/D of about 6.5% appears applicable for evaluating the ultimate capacity of auger cast piles in the Inner Coastal Plain.

By Paul R. Lear

Sustainability continues to be an important aspect of remediation and infrastructure projects. Deep soil mixing (DSM), a common construction and remedial technology, can easily incorporate the following sustainability best management practices (BMPs), including Minimizing Total Energy Use and Maximizing Use of Renewable Energy; Minimizing Air Pollutants and Greenhouse Gas (GHG) Emissions and Maximizing Use of Machinery Equipped with Advanced Emission; Minimizing Water Use and Impacts to Water Resources; Beneficial Reuse of Materials/Reduction of Materials and Waste Reduction; Use of Local Labor and Supplies. This paper focuses on the sustainability of DSM treatment and provide carbon footprint calculations at least one completed DSM project which used these sustainability BMPs to demonstrate the environmental impact of the sustainability.

Sep 8, 2021

By Chris Normand, Paul Volpe, Eric Wey, Howard Perko, Burt Ogilvie, Patrick Murray

"A refinery expansion project for Marathon Petroleum Company in Southern Louisiana required existing medium to large pipe racks to be expanded for additional capacity. Foundation modifications were necessary in order to add levels to the existing pipe racks. New piles were added and existing pile cap foundations were expanded. Several different pile types were considered. Custom designed large diameter helical piles were chosen, because they can be installed quickly with low overhead restrictions, produce minimal soil spoils, and are cost effective. The load capacity required for piles was higher than typical, off-the-shelf helical piles. In particular, the lateral load capacity demand was high due to wind loads of a hurricane prone region. Methods used to design and size helical piles are summarized including capacity to torque ratio estimation for composite helical piles. Pile load testing was performed in order to confirm design capacities of the helical piles under axial and lateral loading. Measured axial and lateral deflections compared well with predicted values. This case history evaluates the effectiveness of modern helical pile design methods within the context of a real and practical example.INTRODUCTIONAs the capacity of modern installation equipment increases, large-diameter helical piles are being used to support higher loads in more diverse applications. Currently, large-diameter high-capacity helical piles are used for electrical power transmission, power generation, high-rise buildings, bridges, and industrial applications. This case study regards a 2.5-mile pipe rack modification project within an existing refinery. One of the many challenges for engineering and construction of refinery revamp projects is determining how to effectively expand the capacity of existing foundations for additional equipment, piping, and other facilities. Custom designed large-diameter helical piles provided an effective solution to the challenges faced when expanding the capacity of existing pipe racks."

Jan 1, 2017

By Peter Middendorp, David J. Tara, Gerald E. Verbeek, Jan Fischer

"For pile driving simulation the model used must be accurate for the entire process, i.e. from the start of pile driving until the pile has reached its target depth. Of the various model components (hammer, pile and soil), the soil is the most difficult to characterize accurately. This is well known, but the aspect that is not as well understood (and therefore commonly misapplied) is the fact that the soil properties and thus the soil parameters do not remain constant during the pile driving process. Furthermore, this phenomenon of soil fatigue, mainly for skin friction, as a continual change of soil resistance during pile installation, is not implemented into all commonly applied pile driving simulation software and could therefore not be taken into consideration. In this paper the effect of soil fatigue will be described by numerous research results, showing that this effect will occur regardless. Different methods to consider the change of soil resistance during pile installation will be presented, some applying soil fatigue while others merely reduce soil resistances. Using currently available wave equation software that can take soil fatigue into consideration, the importance of doing so will be shown on the basis of the back calculation of a monopile installed offshore in Germany.THEORY BEHIND SOIL FATIGUESkin friction and toe resistanceTo simulate pile installation as accurately as possible, detailed geotechnical knowledge about the mechanical behavior of the soil surrounding the pile is necessary during each step of the installation process. Therefore, to ensure ""geo-mechanical correctness"" of a pile driving simulation, the shaft friction and the toe resistance have to be recalculated at each penetration level. For the skin friction parameters this is especially important since they change significantly during pile installation because of soil fatigue. Depending on the pile and soil type, the toe resistance can experience changes as well due to soil fatigue during to pile driving. However, in this paper the toe resistance values were kept constant over the entire penetration depth.In general, the unit skin friction can be derived from measured values (CPT, qs) or calculated as a function of the horizontal effective stresses dh acting perpendicular to the pile wall of a vertically driven pile. The horizontal stresses can then be converted into the unit skin friction qs using the Mohr-Coulomb failure criterion:"

Jan 1, 2017

By Kevin Green, Iván Contreras, Aaron Grosser, Jon Ausdemore, Rachel Leier, Amr Ragy

"Construction of a new tailings dam was required to increase tailings storage capacity at a trona mine near Green River, Wyoming. The new dam was founded on overburden soils underlain by both fractured and competent bedrock. The stored tailings and water had high salt content, resulting in salty seepage water. To reduce the impact of the salty water on groundwater and the Green River, the design of the new tailings dam included a 257,260 SF (23,900 m2) seepage cutoff extending into competent rock.An extensive subsurface characterization was performed prior to completing the design and suitable seepage cutoff methods were evaluated. The approach selected was a full replacement panel using hydromill and clamshell for construction and self-hardening slurry (SHS) for the wall material. Laboratory testing was performed and ongoing monitoring has continued to evaluate the hydraulic conductivity and seepage cutoff performance in the briny environment.The paper includes project background, the collaborative approach and outcomes of the QA/QC program, and the monitoring results for the seepage cutoff wall.PROJECT BACKGROUNDCiner Wyoming, LLC (formerly OCI Wyoming, LLC) owns and operates the Big Island Mine facility near Green River, Wyoming. This underground trona mine has produced soda ash since 1962. The Greater Green River Basin covers much of southwestern Wyoming and extends into northeastern Utah and northwestern Colorado. The Ciner facility is located in the Green River Basin, which is part of the Wyoming Basin physiographic province. The Green River runs to the west and the south of the Ciner facility.Beginning in the early 1990s, Ciner primarily disposed tailings underground in mined-out panels. However, in recent years, underground storage has become limited and some disposal has transitioned to the ground surface. Long-term planning revealed a need to expand Ciner’s surface tailings disposal capabilities. Pond 2, a previously permitted disposal area, was identified as the most viable location for a storage facility. The Pond 2 site is directly north of the Ciner plant facilities, northwest of the active Upper Delta tailings storage facility, and northeast of the Green River (Fig 1)."

Jan 1, 2016