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By Michael Frawley, Deana Ruud, Jessica Turner

Technology is allowing for new ways to mitigate risk associated with subsurface exploration and unanticipated subsurface conditions during construction. Unanticipated subsurface conditions have the potential to force delays and cost overruns on even the best-managed and well-executed projects. For more than a century, geotechnical professionals have documented the location and conditions encountered in hundreds of thousands of subsurface borings. Utilizing processes for compiling and managing data, owners can streamline site selection and receive access to a conceptual geotechnical model before field exploration takes place. Digitizing historical subsurface information allows for creation of an interactive, web-based platform combining publicly available information and culminating with the opinion of a local, experienced geotechnical engineer. This connectivity aids in the reduction of risks associated with unknown conditions on prospective project sites. Through this conceptual project study, we demonstrate how a project owner would be able to use a comprehensive desktop study to review the expected conditions prior to making a purchasing decision. Following the purchase, the expected conditions would be confirmed through traditional methods, confirming potentially problematic site conditions and the associated risks. INTRODUCTION Preliminary project planning is often based on assumptions made by the design team with regards to site suitability. After due diligence, site development is traditionally initiated by the owner or the owner’s representative when engaging a geotechnical engineer to perform a thorough subsurface exploration at a site. The data generated by the geotechnical engineer’s analysis of the site is required to design foundations, pavements and earth retaining structures and move the project from concept into design. This necessary, subsurface exploration can be time consuming, intrusive, and require significant resources, often when resources during construction seasons when resources are most limited. By leveraging historical data generated from previous subsurface exploration, a more thorough analysis of project risk can be developed prior to mobilizing a drill rig. Ultimately, preliminary budgets and designs are more accurate and geotechnical field exploration is more strategic. The geotechnical engineer’s role transforms from raw exploration and analysis to confirmation of anticipated conditions.

Jan 1, 2019

By Masaru Sakakibara, Ngo Tuan Anh, Mitsuo Nozu

"In the southern region of Vietnam and the southern United States, numbers of Deep Mixing (DM) columns have been installed to increase the stability of slopes and mitigate ground settlement. However, in some cases, there were some quality problems for in-situ cement mixing such as inclusion of unmixed lumps. According to the investigations by the X-ray diffraction analyses, electrical conductivity (EC) test, and careful observations of in-situ mixing quality, it has been observed that the existence of expansive soil and its high EC value cause the insufficient in-situ mixing. The countermeasures to address these problems have been taken.INTRODUCTIONIn South Vietnam, under the guidance of numbers of references and standards (Miki, 1998, JGS, 2000, Kitazume et.al., 2001, BS 2005), Deep Mixing (DM) has been used in recent years for soft clay improvement to increase the stability of slopes and to reduce consolidation settlement (Nozu 2005, Tung et.al., 2009, S. T. G. Peng et.al, 2009). However, at the initial phase of the DM operation, the authors have encountered some unusual phenomena such as (1) lower strength and inclusion of unmixed lumps (Figure 1), (2) less amount of up-heaved soil, and (3) sticking of large lumps of clay to the mixing blades. In regard to the above (3), Photo 1 shows one of the countermeasures against the sticking. By means of the placement of additional plates, the stuck clay has been reduced significantly.Subsequently, we have noticed that the quality of DM columns has not been so good, which meant that there have been some unmixed lumps in the column despite high cement dosage such as more than 300kg/m3. The authors also have encountered the similar incidents in Vietnam and United States during the deep soil mixing work. For example, Photo 2 is the core samples taken from the DM test column in northern Vietnam adopting cement injection during penetration (CIDP) procedure. To solve this problem, various tests and investigations have been performed so far (Nozu 2010, 2012)."

Jan 1, 2015

By Stephan Fisch, Franz-Werner Gerressen

"The use of cut-off-walls (COW) for the open pit coal mines has been used for decades. They have been used to reduce the negative hydraulic impact to the surrounding area caused by the open pit mining. The pile-guided trench cutting system is a worldwide unique technique, originally developed by the engineers of the mining companies themselves. It guarantees a continuous, joint free, COW during a continuous installation process. At this specific site in Welzow, this technique has been pushed to new limits in order to address the local lake region. Depth capability has been designed to about 430 ft (130m), proven are already depth of about 360 ft (110m) at a constant trench width of 39 inch (1000 mm). This project is approximately. 6.8 miles (11 km) long of COW, scheduled to be completed in 12 years period. About 2.05 miles (3.3km) have been installed, which is equivalent of about 3.5 Million ft² (330,000 m²). The system flushes special clay which forms a filter crust at the inner surface of the trench. Only natural clay resources used, in order to achieve the cut-off effect (colmation effect). The paper explains the installation process of the cut-off-wall as well as the equipment systems developed specifically for this project. After a successful start of the first phase of the project, the next step in the advancement of the equipment is already underway to enable the installation of greater depth to approximately 490 ft (150 m +) and beyond. The next generation equipment system is scheduled to start operation around 2018 INTRODUCTIONThis Serbian saying “Bóh je stworil Lužicu a cert je zaryl brunicu – God created Lusatia and the devil buried brown coal underneath it.” captures local communities’ ambivalence towards lignite.Lusatia is an almost entirely flat stretch of land between the Elbe and Neiße rivers dominated by glacial sands. On the surface, the heathland and woodland is hardly noteworthy. However, three large lignite mining regions, two in Brandenburg and one in Saxony, in the east part of Germany, divert the attention to underground level, down to depths of up to 120 meters. Here, seams crisscross the earth like ribbons. They were formed in the Tertiary around 17 million years ago.The mining of the lignite started almost 200 years ago. To enable open pit mining, a suitable dewatering system was required. At first, wells and drainage system were used. With the increasing demand to go deeper to enable full use of the existing resources with greater mining depth, a decision taken back in the 60th of the last century, the amount of water which had to be pumped increased dramatically. In peak times, approx. 1.57 Billion cubic yards per year (1.2 Billion m³/year) had to be pumped. This led to a lowering of the groundwater level for up to 230 ft (70 m), impacting the regional lake landscape. In order to reduce the influence on the water balance, and bring the water level back to pre1970th, a first development took place to implement the use of specific COW system to depth of about 147 ft (45m)."

Jan 1, 2017

By Nicolas Denies, Jeroen de Leeuw, Bart Lameire, Jan Maertens, André Vervoort, Flip Hoefsloot, Noël Huybrechts, Flor De Cock

"In recent years, the Deep Mixing Method has increasingly been applied for the construction of earth and water retaining structures. From practice, it has been experienced that there is a real need to develop execution and design rules adapted to the function of the soil mix wall (retaining wall, water barrier, foundation solution or a combination) including the temporary or permanent character of the application. Based on the results of the BBRI Soil Mix project (2009-2013), a design approach has been developed in collaboration with the SBRCURnet. The present paper briefly discusses the principles of this design approach which takes into account the function of the soil mix wall and the characteristics of the soil mix material. The interaction between the soil mix material and the steel reinforcement can be considered in the calculations depending on the function of the soil mix wall. Design and quality control requirements are given in function of the application and take the lifetime of the structure into account. Durability aspects of the soil mix material are therefore considered in the present design approach.INTRODUCTIONSince several decades, the deep mixing method is used for ground improvement works. A more recent application is the use of soil mix as structural elements such as in the case of the earth-water retaining soil mix walls. Since 2000, due to the economic and environmental advantages of the method, this particular application has shown an amazing growth in Belgium and in the Netherlands. A typical excavation (16 m depth), realized with CSM (Cutter Soil Mix) panels, is shown in Fig. 1. For temporary applications, the questions related to the mechanical characteristics of the material, its permeability and its adherence with steel have been investigated with success within the framework of the BBRI Soil Mix project (2009- 2013) (see Denies et al. 2012 for more details). The durability of the soil mix material remains a complex topic while permanent applications are more and more observed in practice. In order to define an obvious design approach, it was necessary to clarify the potential functions of soil mix walls and to establish the requirements related to their design and construction. The BBRI (in Belgium) and SBRCURnet (in the Netherlands) have therefore worked together to publish guidelines in the form of a handbook titled ‘Soil Mix Walls’ (publication foreseen in 2015). In this handbook, a methodology is proposed for the design of the soil mix walls for which the interaction between steel and soil mix can possibly be taken into account dependent upon the application. Each potential function of the soil mix wall is described (e.g. earth retaining wall, cut-off wall, etc.) and the temporary or permanent character of the application is always considered."

Jan 1, 2015

By Jeffrey Goodwin P. E., Melih Demirkan Ph. D. P. E., Kevin Tehansky P. E.

Just an hour drive down MD 301 from National Harbor, construction to replace the Governor Harry W. Nice Memorial/Senator Thomas ‘Mac’ Middleton Bridge (HNB) began in spring of 2020. The Maryland Transportation Authority (MDTA) contracted with Skanska-Corman-McLean (SCM) to deliver a new US 301 bridge spanning 1.9 miles from Maryland to Virginia over the Potomac River aiming to improve capacity, safety, and access of the roadway. The project area presented a geotechnical design challenge due to the installation of new bridge foundations in the problematic soils of the Atlantic Coastal Plain alluvial deposits. With the existing bridge remaining in service during construction, and the site’s logistical constraints placing new pile driving operations near existing abutments and piers, a complex instrumentation and monitoring plan was developed to ensure public safety throughout the project. This paper discusses the geological conditions of the project area, the collaborative approach of various design team members to develop an appropriate monitoring plan utilizing various instrumentation, an understanding of baseline conditional movements of the existing bridge, and impact response of adjacent construction activity to help deliver effective new bridge foundations while protecting the old ones.

Oct 1, 2022

By Tomohiro Yamasaki

"At the pre-construction foundations of the controlled waste disposal site built at the Port of Kinuura, the clayey soil account for the most, and with lesser amounts of sand compaction piles and sand mat. The cement deep mixing method (CDM) was used to improve ground impermeability and to reinforce the foundations on the seawall. Laboratory mixing and testing was performed to determine the appropriate quantities of cement additive for clayey soil, SCP sand, and sand mat. The test results indicated that maintaining the design strength of qu = 1,550 kN/m2 would require C = 100 kg/m3 of cement additive for all three soil types (clayey soil, SCP sand, sand mat). The permeability performance needed to improve ground impermeability assumes a permeability coefficient of K = 1.0×10-6cm/s. And the clayey soil satisfied the performance requirements at C = 100 kg/m3. However, to improve grand impermeability of the SCP sand and sand mat required more than 5% of particles having diameters of less than 75 µm. Thus, in the latter two cases, the required cement adding quantity was C = 250 kg/m3. The test specimens at one to two weeks after the created with a permeability coefficient of K = 10-6cm/s became permeability coefficient of K = 10-7cm/s six week later due to the effects of cement solidification. So the permeability coefficient declined about one order. The permeability coefficient three months later tends to decline continued with a somewhat lower.INTRODUCTIONBetween 2008 and 2011, the Aichi Seaside Environment Center constructed the Kinuura No. 3 offshore controlled waste final disposal site at Taketoyo in Aichi prefecture. (see Figure 1). The disposal site offers a landfill capacity of 5.21 million m3 and measures 472,000 m2 in area, of which some 344,000 m2 is a managed controlled sector enclosed within an impermeable seawall."

Jan 1, 2015

By Paolo Cavalcoli, Federico Pagliacci, Marco Chiarabelli

"The Sheikh Jaber Al-Ahmad Causeway Project in Kuwait is estimated at approximately $US3.7 billion and consists of constructing a causeway across the Kuwait Bay, connecting the Shuwaikh Port with the northern Subiyah area, where the new “Silk City” will be established. The $US77 billion Silk City will revive the ancient “Silk Road” trade route and will become a major free trade zone linking central Asia with Europe. The new city will be completed in 2030, it will house about 700,000 people and, furthermore, it will include the tallest tower in the world. The Causeway will stretch approximately 23.3 miles and will be composed of a combination of low-level bridges, embankments and transition islands. A bridge of about 16.8 miles in length will span the navigation channel and a free flow interchange at the Shuwaikh Port will connect the causeway to the main road network in Kuwait City. The geo-construction portion of the project involves the execution of 1,200 drilled shafts with diameters of 98 inches and 118 inches embedded to a maximum depth of about 276 feet. Details are provided concerning the subsurface conditions, the geotechnical characteristics and the strength parameters, illustrating, as well, the installation technique implemented for the construction of the drilled shafts. In addition, particular attention is paid to the description of the challenges faced while constructing the drilled shafts at a distance of about 10 miles from the shore, such as the depth of the water above the midline (more than 160 feet), an underwater current and the tidal variation.INTRODUCTIONThis paper presents an overview of the foundation works executed for a 37km causeway across the Bay of Kuwait, connecting Shuwaikh Port with Subiyah New Town Development. The project, in which Trevi is actively engaged, includes a 27 km low-level bridge across the bay, a main bridge with a span of 200 m, an overpass and a 5 km approach road onshore in Subiyah.The main purpose of this report is to provide information about the nature and features of the applied technique of bored piles, including a description of each work phase and other related details, in order to aid in the design of the foundations for the proposed construction.Works for the soil investigation were carried out in accordance with accepted geotechnical standards/guidelines. Brief descriptions of the methodology of the field are also provided in this report."

Jan 1, 2016

By Viswanadham B. V. S., Babu K. V

Many refineries are in the process of revamping and expanding their existing facilities. Most of the refineries are located in coastal areas due to ease of transportation and storage of crude oil. Considering the criticality of structures as well as prevailing soil conditions, most of the structures are supported on pile foundations. In depth review of sub-surface investigations data followed by liquefaction assessment of the site, it is noticed that site is prone to liquefaction during the seismic event. Among various techniques, driven cast-in-situ piles were selected to mitigate liquefaction. Static cone penetration tests were conducted during the pre and post installation of driven cast-in-situ piles at identified locations. Analysis of cone penetration test data shows that considerable ground improvement has been achieved post-installation of driven cast-in-situ piles.

Sep 1, 2022

By Mark Zablocki, Dakarai McCoy

Ground vibrations are an unavoidable effect of driving piles and may pose a risk to nearby infrastructure and the comfort of adjacent occupants. Driven-pile-induced ground vibrations are known to vary widely based on ground conditions, pile material, and installation means and methods. A monitoring sensor to record ground vibrations during pile driving is necessary for understanding potential impacts to sensitive infrastructure and should be considered when implementing a monitoring program anticipating ground vibrations. The implementation of a vibration monitoring program historically relies on experiential-based decision-making, which may result in the costly vibration monitoring of low-risk infrastructure. Prior understanding of anticipated ground vibrations is necessary to create an appropriate monitoring program. A framework is proposed for organizing data from past monitoring programs and quantifying the anticipated risk of driven-pile-induced vibrations. An example of risk quantification from data imported to ]a cloud database is presented by comparing driven steel H-pile and prestressed precast concrete vibration monitoring measured and collected by Haley & Aldrich between 2010 and 2020. The methods presented within the example can be applied to quantify a first order approximation of risk for ground vibrations at proposed driven pile sites based on the measured performance of previous sites with similar ground characteristics and pile installation methods. The presented novel data managements tools allow for a quick aggregation of vibration data with similar site conditions.

Sep 8, 2021

By Adel Hanna

Earth pressure acting on piles driven in sand is playing a major role in estimating pile capacity. In literature, researchers entertained simplifying assumptions in estimating the earth pressure acting on the pile's shaft, ignoring the effects of pile installation and pile size. Empirical formulae were introduced based on laboratory or field test results, where major discrepancies can be found among these formulae. In this paper, the theory of cavity expansion and the finite element technique will be used to establish the effects of pile installation technique and pile's diameter on the earth pressure acting on the pile's shaft and accordingly on the values of the existing coefficient of passive earth pressure and overconsolidated ratio. It is of interest to note that pile driven technique and pile's diameter have significant increase on the earth pressure acting on the pile's shaft and accordingly on the overconsolidation ratio in case of loose or medium sands, while they may cause crushing and dilation in case of dense sand. Keywords: Single pile, Cavity expansion, Cohesionless soil, Driven piles, Numerical modelling, Finite element technique, Earth pressure.

Jan 1, 2003

By Fred Fuchs

"Most deep foundation work is either unseen by the general public or viewed as an inconvenience in their daily lives. Hurricane Katrina changed that perspective for everyone in New Orleans — and many other people in the U.S. and abroad. The public and the government of south Louisiana, and the U.S. Army Corps of Engineers (USACE), all needed to restore trust in the system that protects their property and, more importantly, their lives. While much has been written about the failures of government agencies, in this case incredible solutions were devised and implemented despite daunting schedules and arduous conditions. These solutions were achieved through collaboration, and through the efforts of USACE, where the goal was to fi nd the most expeditious and effective design/build solutions. This disaster thrust the pile driving industry into the national spotlight. Boh Bros. Construction Co., L.L.C., along with numerous local and national heavy construction companies, subcontractors, material suppliers and government agencies, take pride in the milestones reached after Hurricane Katrina.The majority of New Orleans’ population lives below sea level. Historically, the city has been protected by a fl ood control system consisting of earthen levees and I-walls (steel sheet pile topped by vertical concrete wall). Rainwater is pumped out of the city over this protection system and into canals that feed into Lake Pontchartrain. On August 29, 2005, when Hurricane Katrina made landfall just east of the city, the levee system experienced a major failure of several I-walls lining the outfall canals, causing flooding of 74% of the east bank of the city. The counterclockwise rotation of the wind pushed the lake water onto the south shore, raising the level of water more than 10 ft (3 m). A failure of 450 ft (137 m) of floodwall lining the east side of the 17th Street Canal caused extensive damage. This breach prevented the use of the pump stations that outfall into the 3-mile (4.8 km) long 17th Street Canal."

Jan 1, 2008

By Hayel M. El-Naggar, Marawan M. Shahien

"Large capacity piles are important type of foundation elements that are needed in case of high column loads such as in tall buildings with large span between columns. In many projects, especially if the designer uses the concept of one pile supporting one column (Hamza, 2003a & b). The axial capacity of the large bored deep foundations can be further increased by grouting the shaft skin and the base of the pile. The increase in the capacity of the piles due to grouting can be tremendous. Thus grouting appears as an ideal solution for achieving more reliable foundation and greater savings (Littlechild et al., 2000). A data base of pile load tests of instrumented grouted piles is under development in a major study aiming to propose a simple method to estimate the axial capacity of large bored grouted piles. The data base include pile load tests from projects constructed in Egypt and abroad. The main goal of this paper is to analyze pile load test(s) from one project. The tested deep foundations included 1.2 m diameter and 1.5 m diameter piles and a barrette of size 1.0mx2.8m. The instrumentation of the tested piles and barrette allowed for the separation of skin friction and base contributions to the axial load. Further, the contribution of the skin friction of every layer along the pile shaft could be identified. The results of the analysis clarified how base and shaft grouting increased the axial capacity of the pile and decreased the settlements for certain load level compared to conventional un-grouted piles installed under similar conditions.INTRODUCTIONIn recent years, significant research has been carried out to develop new techniques which are suitable to withstand problems in major projects such as high applied loads in high rise building, large spans structures projects and structures designed using the concept one pile supporting one column (Hamza, 2003a & b). Base and shaft grouting of piles are one of these new techniques which aim at decreasing the settlements and increasing the capacity of the pile under axial load that became major requirements in large projects (Stocker, 1983; Mullins et al., 2001; and Hamza, 2015).Base grouting consists of injection grout under pressure at the base of the pile after the concrete is sufficiently hard. Field evidences showed that the ultimate end bearing of base-grouted piles could be as high as 1.5 that of non-base-grouted bored piles (Suckling and Eager, 2001). Further, field evidences was provided by Shahien and El-Naggar (2015) that showed an increase in end bearing resistance due to base grouting reached to 2 to 3 times that of non-base-grouted bored pile. On the other hand, shaft-grouting causes increase in the soil density in the zone which had been disturbed by the pile construction and thereby improves the shaft resistance of the pile. Field measurements by Gouvenot and Gabaix (1975), Stocker (1983), Robson and Wahby (1994), Troughton and Stocker (1996), Byrne et al. (1998), Joer and Randolph (1998), Hamza and Leoni (1998), Littlechild et al. (2000), Hamza and Ibrahim (2002), Hamza (2003 a&b), Hamza (2015) and Shahien and El-Naggar (2015) showed that the shaft resistance of grouted piles could be nearly 1.5 to 5 times that of non-grouted piles."

Jan 1, 2017

By Alexander Ciccone, John H. Gill

Jet grouting is a highly versatile ground modification technique that can offer significant commercial and technical advantages over traditional concrete pit underpinning applications. Despite these advantages, jet grouting remains an underutilized technique in the construction industry due to its perceived complexity, cost, and risk. When performed thoughtfully, underpinning by jet grouting offers significant safety and schedule advantages over traditional underpinning approaches. The New England construction market has seen a recent acceptance in the use of jet grout underpinning on congested project sites across a variety of subsurface conditions. The reduction of the cement batch plant footprint due to equipment advances has allowed the use of this technique in urban sites where its use would be previously infeasible. Furthermore, jet grout underpinning has been utilized for support of historic and sensitive structures with generally lower tolerance to settlement than is typically feasible with conventional pit underpinning. Robust, real-time geotechnical instrumentation monitoring systems have helped reduce the uncertainty and further expand the feasibility of jet grout underpinning applications. When properly designed and constructed by qualified and experienced jet grouting contractors, the flexibility of soilcrete for design and construction may be utilized to overcome the many inherent challenges which complicate underpinning and earth retention systems. INTRODUCTION The construction of buildings and infrastructure in our increasingly dense urban spaces often requires excavations below the elevation of existing structures immediately adjacent to the proposed work. Where a proposed excavation system encroaches into an existing structure’s zone of influence, additional measures, such as the construction of an underpinning or excavation support system, are required to safely excavate and minimize the impacts on the adjacent structures. Jet grouting is one method of underpinning that offers significant commercial and technical advantages over many other techniques. Though it was first used to the United States in the 1980s and has grown in popularity elsewhere, jet grout underpinning remains underutilized domestically due to its perceived cost and risk premium. Jet grouting has significant technical advantages over other underpinning methods due to its applicability in a wide range of soil types and its flexibility of design and installation. The jet grouting process is capable of limiting the movement of foundations during construction and excavation to lower thresholds than most traditional underpinning methods (Droof, Furth, & Scarborough, 1995). Its use for underpinning historic and sensitive structures with lower settlement criteria provides additional evidence to its technical utility. Through thoughtful design, adequate planning, and experienced installation, jet grouting can be an appropriate underpinning solution that can provide significant cost and schedule savings.

Jan 1, 2019

By Dale Berner, Michael O’Sullivan

"This article focuses on lessons learned from innovative designs including in-the-wet construction methodology and modified foundation conditions, for two United States Army Corps of Engineers (USACE) megaprojects. Olmsted Dam FoundationThe over $2 billion Olmsted Dam on the Ohio River is currently under construction 16 mi (29.6 km) upstream from the confluence with the Mississippi River. The project is under the jurisdiction of the Louisville District of the USACE. It will consist of an 800 ft (244 m) long tainter gate section, a 1,400 ft (427 m) navigable pass, two boat abutment sections, a fixed weir section, and upstream and downstream scour protection. The Olmsted Dam and its two 1,200 ft (366 m) locks, which were built in 2002, will eventually replace both Locks and Dam #52 and #53, both built in 1929, and thereby bring significant benefits to the Ohio River navigation system.In 2002, the Jacobs/COWI JV completed the design of the dam; which was an engineering challenge for several reasons. A significant consideration was its proximity to the New Madrid Fault, which could impose an 8.4 Richter scale seismic event on the structure, which is located in an area of potentially liquefiable alluvium. The extensive seismic analysis performed by the designer included a response spectra analyses, lateral pushover analyses of pile foundations, hydrodynamic added masses, pile group effects, and the development of kinematic motions as a result of the soil-pilestructure interaction."

Jan 1, 2016

By Haijian Fan

Currently, deep foundation designs for the service limit state are deterministic in nature. The settlements and lateral deflections of deep foundations are calculated by means of numerical techniques whereby the foundation-soil interactions are characterized by discrete load transfer curves such as t-z or p-y curves. The noted deficiency of the deterministic approach is that the uncertainties arising from various sources, such as soil properties and model errors are not considered. To address this deficiency, a performance-based reliability design methodology is developed using Monte Carlo statistical methods. The performance based design criteria are defined in terms of the specified allowable displacement. The input to the numerical solution techniques, including the soil strength parameters, unit weight of the soil are relevant to the generation of the load transfer curves are treated as random field. The well established random field generator algorithm, local averaging subdivision, is used to generate random samples of input, where the mean values, variances, the probability distribution, and correlation structures are required statistical parameters for these random variables. The objective of the performance based reliability design is to determine the optimized foundation dimensions so that the probability of failure is less than the target probability of failure. The probability of failure by the Monte Carlo approach is simply the ratio of the number of unsatisfactory performance to the sample size. A numerical example for laterally loaded drilled shaft is given to illustrate the application of the methodology. The incorporation of the correlation length is shown to be critical for properly accounting for the site soil spatial variability.

By Thai Nguyen Ph. D

Dynamic Load Test (DLT) on driven piles has been performed routinely all over the world. In several recent projects, even 100% testing has become a norm where every single pile is dynamically load tested. In these cases, most piles are of uniform sections, making the field analysis (CASE method) straight forward. The CASE method, which has been used for the last 50 years, however, is only applicable to uniform piles to monitor pile driving stresses as well as pile capacities. Signal matching analysis can handle different configurations. However, the analysis used to require user inputs (i.e., non-automatic). Manual signal matching analysis, which can solve non-uniform solutions, traditionally takes hour(s) to complete for one blow. As such, the real-time pile driving stresses and resistances had traditionally been relying upon the CASE method, using typical range of CASE damping (JC). Until 2021, due to the lack of a rigorous instant signal matching analysis for non-uniform piles, no tool was available to help engineers evaluate non-uniform piles in real-time. An inexperienced field engineer may overlook this shortcoming when evaluating peak driving stresses. Furthermore, ultimate bearing resistances for non-uniform piles may require further evaluation to account for the non-uniformity of piles if relying on the CASE method. This paper highlights recent advances in instant Signal Matching Analysis on non-uniform piles, allowing field engineers to monitor stresses and resistances of non-uniform piles during driving.

Oct 1, 2022

By Haijian Fan

Currently, deep foundation designs for the service limit state are deterministic in nature. The settlements and lateral deflections of deep foundations are calculated by means of numerical techniques whereby the foundation-soil interactions are characterized by discrete load transfer curves such as t-z or p-y curves. The noted deficiency of the deterministic approach is that the uncertainties arising from various sources, such as soil properties and model errors are not considered. To address this deficiency, a performance-based reliability design methodology is developed using Monte Carlo statistical methods. The performance based design criteria are defined in terms of the specified allowable displacement. The input to the numerical solution techniques, including the soil strength parameters, unit weight of the soil are relevant to the generation of the load transfer curves are treated as random field. The well established random field generator algorithm, local averaging subdivision, is used to generate random samples of input, where the mean values, variances, the probability distribution, and correlation structures are required statistical parameters for these random variables. The objective of the performance based reliability design is to determine the optimized foundation dimensions so that the probability of failure is less than the target probability of failure. The probability of failure by the Monte Carlo approach is simply the ratio of the number of unsatisfactory performance to the sample size. A numerical example for laterally loaded drilled shaft is given to illustrate the application of the methodology. The incorporation of the correlation length is shown to be critical for properly accounting for the site soil spatial variability.

Jan 1, 2017

By Raffaella Granata, Daniele Vanni

"This paper presents the drilling and grouting program performed at two abandoned landfills located into former calcarenite rock quarries in Manfredonia, Italy. Tests performed after the abandonment of the landfills detected leachate infiltration into the groundwater, which required the implementation of a remedial program. In order to seal the rock fissures and create an impervious basin at the base of the two landfills, sub-horizontal boreholes were drilled and grouted into the rock under the waste deposits. At the same time, sub-vertical boreholes were drilled and grouted along the perimeter, to laterally confine the landfills. Finally, the landfills were properly capped with an HDPE membrane, geogrid, geotextile and topsoil. The methodology implemented to create a watertight barrier under the two landfills was innovative and cost-effective. Moreover, the drilling and grouting minimized the environmental impact of the remedial work, since the waste remained in their original location and were not affected by the remedial process.IntroductionThe two landfills, “Pariti-1 RSU” and “Conte di Troia”, are located approximately 6 km (4 miles) southwest of Manfredonia, a small town close to Foggia, Italy (Fig. 1). These landfills are located into two rock quarries, formerly used for the extraction of calcarenite (i.e., a weak calcareous sandstone, in tuff facies), and were abandoned in the early 90s. The two landfills cover a total area of about 45,000 m2 (11.2 acres), and mainly include urban solid waste with a depth of up to 25 m (82 ft). The main characteristics of the two waste landfills are listed in Table 1."

Jan 1, 2016

By Robert B. Bittner

The Sutong Bridge across the lower Yangtze River in China will have, when completed, the longest span (1,088 m) and the highest towers (306 m) of any cable stayed span in the world. The foundations for this record setting span will also be record setting. They are located in water depths exceeding 30 m with maximum flows exceeding 3 m/sec. The soil at the site of the main pylons consists of layers of silty sands and silty clays extending to bed rock at 270 m below river elevation. This paper describes the innovative methods used by the team of foundation designers and constructors to support this record setting bridge at this very challenging site. This paper covers three specific topics related to the foundations of the Sutong Bridge: ? Design and construction of the 131 drilled shaft (2.8/2.5 m diameter and 114/117 m long) under each of the two main pylons, including the post-grouting of all drilled shaft tips. ? Design and construction of the scour protection for the two main pylons, ? Construction methods used to construct the waterline pile caps (113.8 m by 48.1 m by 13.3 m deep) under each pylon.

Jan 1, 2013

By Meeok Kim, Paul Beljan, Gordon Chen

"Clinton combined sewer overflow storage (CSO) facility project developed by the Department of Water Environment Protection of Onondaga County, New York, is to improve sewer facilities and infrastructure in Syracuse, New York. The below grade facility will provide a storage of untreated stormwater during highflow periods to be treated later, thus reducing CSO discharges to Onondaga Creek.The CSO system consists of three parallel storage tunnels and two end chambers (west and east chambers) as main underground structure. The storage tunnels are about 850 ft. long, 55 ft. wide, 24 ft tall and located 20 ft deep below grade. The chambers, include above access and operation structure, are about 40 to 55 ft. deep and approximately 60 to 100 ft. wide.Kiewit Infrastructure and Weidlinger Associates Inc. developed an alternative approach for the tunnels to meet the facility completion schedule, strict design guide lines and quality control as an environmental and water tight concrete structure for the project. The original design anticipated use of a TBM machine to bore three parallel tunnels between two previously constructed chambers.The alternative design used a three barrel culvert cast-in-place structure in a cut and cover excavation supported by a soil bentonite wall. The SOE along the jet grouted bottom seal provided a ground water cut off as well.The SOE system is specially designed to enhance the quality of culvert CIP structure construction by providing enough space for a full height construction. Also it further reduces the construction time by having the less squarefootage of jet grout installation. The design of tunnel systems is accomplished effectively through the utilization of soil structure interaction using a finite element methodIntroductionTo avoid construction of an additional treatment plant to handle increases in combined sewage flows, the Department of Water Environment Protection of Onondaga opted to construct the Clinton combined sewer overflow storage (CSO) facility.The Clinton CSO facility provides an environmental friendly mitigation method for combined sewer overflows on Onondaga lake which is located in northwest of Syracuse."

Jan 1, 2015