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By Clif Kettle

The paper will detail the design and execution of passive and active settlement control measures, the means adopted to overcome the various physical and operational constraints, and to meet specified allowable settlement criteria. The paper will highlight the close integration between the tunnelling and geotechnical contractors, designer, and Client, and demonstrate how particular practical difficulties were overcome by both the design and the construction methods.

Jan 1, 2008

By Kelvin Lo, Erwin Oh, Darren Newel

The use of interface elements is widespread in most numerical methods to separate the structural elements from soil elements. It allows slipping and gapping or overlapping between the two media in contact with highly distinct deformability characteristics, such as piles and retaining walls. However, many existing analytical methods still assume no pile-soil slipping before failure in axially loaded piles. This paper attempts to compare the slipping and non-slipping analytical models by introducing an interface with a virtual thickness. Results show that both have different load-displacement characteristics when comparing to the measured data. The non-slipping model would result in a stiffer load-displacement curve if the same input stiffness parameters applied to both models. Different procedures to calibration the input stiffness parameters in slipping and non-slipping models are recommended.

By W. Morgan NeSmith

A drilled displacement pile program was utilized for the expansion of an existing power plant in Cohasset MN adjacent to the Mississippi River. The drilled displacement (DD) pile is an innovative foundation type that provides exceptional value in some geologies. In the U.S., DD piles have typically been used in coarse-grained soils due to the large friction capacities that can be generated by the piles in these conditions. This project was the first large scale experience for the project team where it was anticipated that significant portions of the DD pile capacity would be developed in primarily fine-grained soils. The project site consisted primarily of variable amounts of fill overlying predominantly low plasticity alluvial silts. In some cases, alluvial silty sand layers were encountered within the expected pile installation depths. Alluvial sands were typically encountered below the silts, in some cases within the expected pile installation depths. The project team developed a probe and pile load test program to address the variable subsurface conditions across the site. The program included monitoring various parameters (including applied torque and tool penetration rate) during the drilling portion of the pile installation using recently developed data acquisition techniques. This data was used to estimate the rig energy, or Installation Effort (IE), required for pile installation. IE profiles from the test and indicator piles were compared with subsurface data available from a number of previous site characterizations. Additionally, Cumulative IE values were compared to an in-house database of IE vs. DD Pile Capacity. Final production pile toe levels were based primarily on IE values selected from this comparison. The IE data collected during production was also used to address large variations in pile-cutoff elevation (relative to a fairly uniform ground surface elevation).

Jan 1, 2008

By Tony Amis

There is very limited information relating to the potential impact of temperature cycles, outside the variation that occurs naturally, on the behaviour of foundation piles. Such thermal loading occurs when piles are used as heat exchange elements within a Ground Sourced Heat Pump system, in addition to carrying building loads to competent strata. An investigation has been undertaken where a conventional load test has been extended to include a period in which the load is maintained and temperature cycles applied. Instrumentation was installed in the test pile, an adjacent borehole, two of the anchor piles and the heat sink pile in order to be able to develop an understanding of the temperature variation and associated strain changes within and between the various elements. Conventional electronic strain and temperature gauges have been used in conjunction with optical fibre sensors which also measure strain and temperature changes. The results have confirmed the validity of the assumption made in the thermo-dynamic design of the system, the compatibility of the differing measurement systems and differing installation methods for the optical fibres, and initial assessment suggests that the load-settlement response of the pile is not adversely affected by the temperature cycles applied.

Jan 1, 2008

By Hennie F. T. Barnard, Theodore E. B. Vorster

Where geotechnical designs are governed by settlement requirements, soil and rock moduli are important parameters for design. This paper reports on a method that was used to utilize dynamic modulus measurements in the field toward pile settlement designs for the proposed Square Kilometer Array (SKA) Project to be located near Carnarvon, South Africa. The project will comprise of over 3000 No. movement sensitive satellite dish structures. The method described in the paper utilizes strain-related modulus degradation across the complete ground profile, starting from measurements of peak particle velocity (and inference to dynamic modulus at small strain) as measured using Continuous Surface Wave (CSW) testing at individual dish positions. This is required due to the very small allowable foundation rotation of 5 arc seconds under the dishes’ operational conditions. The strategy of analysis was to conduct an iterative process starting from the measured small strain modulus profile of the ground. The likely maximum pile force for a specific piled foundation option was estimated and a single pile finite element analysis was performed using Plaxis 2D (Version 2010) to estimate the expected ground strain developing along the length of the pile. By assuming the shape of the shear modulus degradation curve with increasing shear strain, the iteration process then converged on a likely degraded modulus profile associated with the single pile and maximum load assumed. This process enabled identifying the pile cap size, pile configuration, pile sizes and pile lengths that would meet the operational movement limits. The chosen pile group configuration was then analyzed using the Repute 1.5 pile group analysis software. The design process and typical results are discussed in this paper.

Jan 1, 2017

By Ahmed H. Bukhary, Naser A. Al-Shayea

The objective is to assess the overconservatism in the parameters used for designing offshore piles. Methodology includes analysis of shaft friction data obtained from more than five different locations in the Arabian Gulf, consisting of 40 piles to depths up to 86 m. Reports were collected for both the dynamic pile monitoring system (DMS) and their corresponding geotechnical reports based on the American Petroleum Institute (API). The values of shaft capacity for the sand layers were analysed by comparing those based on API to the corresponding DMS values. Results of the comparison of the data from these reports showed that the pile design parameters obtained using API guidelines is generally smaller than that measured by DMS. The difference is presented in terms of an overconservative factor (OCF) which is adjusted based on statistical nonparametric test performed on the two data sets. The adjusted OCF were found to be 1.79 and 2.00 for carbonate sand at (loose to medium dense) and (dense to very dense) conditions, respectively. The corresponding values for silica sand were only 1.2 and 1.06. In conclusion, based on the evaluation conducted for data from these reports, the API shaft friction is overconservative for carbonate sand. The API shaft friction for piles in sand can be increased by multiplying it by the adjusted OCF.

By Massimo Poggio, Gabriele Balconi, Andrea M. R. Pettinaroli, Mario Ruggiero, Riccardo Castellanza

Grouting technologies are ground treatment techniques used for modifying the behaviour of a mass of soil or rock by injecting a mixture. The sleeved port pipes (also called Tube A Manchette) are highly diffused for grouting treatment of coarse soils and fissured rocks. This paper describes a combination of jet grouting and rock grouting with MPSP (multiple packer sleeve pipe) technique that has been used to realize waterproof curtains under fluvial structures for a cascade hydro-power plant. This is composed by five mini hydro-power plants, placed along the Iskar River, in Bulgaria, and composed by a penstock followed by the power house, a spillway, and an earth dam containing the reservoir. The geology of the site is characterized by an upper alluvial deposit lying over the bedrock. In each site, similar treatments were carried out: an impervious curtain along the plant section, obtained by executing jet-grouting columns in the surficial alluvial layers and grouting the underlying fractured rock by means of port pipes. The temporary embankment, built during the works for protecting each site from the possible river floods, has been waterproofed and stabilized by reinforced jet-grouting columns. The grouting processes have been controlled and monitored by a computerized system. INTRODUCTION The Iskar river cascade hydropower plant is situated northern of Sofia, Bulgaria, and it is composed by nine plants. Actually five of them have been built and produce energy. Each plant is composed by a penstock followed by the turbine building, a spillway, and an earth dam that contains the reservoir. The Iskar rivers runs in a narrow valley characterized by diorite or diabase rocks, with an upper deposit of alluvial soil, composed mainly by gravel and sand. Each plant requires an impervious curtain under the structures and in correspondence of the earth dam: this has been obtained by means of a jet grouting treatment of the alluvial coarse soil, and a grouting treatment with cement mixtures of the underlying rock using the MPSP technology. During the construction of the structures, the site has been shielded from the river water by a temporary earth embankment that has been statically improved and waterproofed by jet grouting columns reinforced with steel tubes; this allowed to work without interruption even in case of flood of the Iskar river.

Jan 1, 2019

By Denton A. Kort

Historically the visual examination of drilled shafts to determine shape was typically done under dry conditions. Many engineers believe that by using a dry method of construction, the question of shape is minimized because they can visually examine the excavation. In fact, test data suggests that slurry stabilized shafts tend to perform better than similarly constructed dry shafts. Clearly, the uncertainty of the shaft shape is magnified when constructed under slurry. Recent advancements have allowed a mechanical caliper to determine shape in wet conditions, but can be limited by certain shaft anomalies. New sonar technology can determine shaft shape, volume and verticality. The value of sonar technology to the geotechnical and foundation industry at large in terms of quality assurance for clients/owners and quality control for drilled shaft contractors is significant. This presentation will discuss the development and process of sonar calipering technology as it relates to the geotechnical and deep foundation industry. Sonar calipering results presented may include images from the following types of projects: slurry walls, bridge piers, cofferdams and secant walls. The results identify shaft anomalies in a variety of slurry environments, from water and polymer mixes through mineral slurries. Real-time in-situ images and CAD drawings will be presented illustrating the advantages of good caliper data taken during construction. This presentation will appeal to the geotechnical and structural engineers, as well as those supporting the deep foundation industry at large.

Jan 1, 2007

By Andrew Cushing

This paper presents the design and construction of the foundation for a major high-rise real estate development on the west side of Manhattan. Arup was retained by Underpinning and Foundation Skanska to design a secant pile wall as excavation support for a proposed two-level basement of a new 23-story residential building located at 100 11th Avenue and West 19th Street. The secant pile wall will also act as the permanent basement retaining wall for the new building. The site is bounded on two sides by existing structures and is underlain by a thick deposit of very soft organic silt and clay. Therefore, the potential for ground movements and their impact on an adjacent structure bearing on shallow footings were of the utmost concern. This paper addresses the design and construction considerations associated with this secant wall, as well as installation details. Measured wall movements are also used to assess the validity of the pre-construction soil strength and stiffness design parameters.

Jan 1, 2008

By Maurice Guillaud

The most striking innovations on diaphragm-wall construction plant are those associated with continuous real-time trajectory monitoring of the excavating tool (either a grab or a hydro-cutter). The recent equipments are fitted with clinometers and gyrometers to control deflection, rotation or deviation from the vertical, thus allowing to install diaphragm-walls with a verticality accuracy of less than 0.3%. One of the greatest advantages of extensive use of on-board IT systems on the Hydrocutters and hydraulic grab machines is that it aids quality control by automatically producing complete real-time reports of all excavating data (verticality, depth, type of ground, rate of progress, stoppages, etc.). These reports are available to the Engineer, providing the total transparency required for Works Supervision and the Quality Assurance Plan. They also provide the Contractor with input data for databases used for optimising efficiency and progress criteria on future jobs.

Jan 1, 2002

By Cem Altuntas

This paper is the second in a series of two describing the design and construction of a foundation for a major high-rise real estate development on the west side of Manhattan, N.Y. The foundation members consist of large-diameter rock-socketed caissons, driven closed-end steel pipe piles bearing on rock, and a secant-pile retaining wall surrounding the entire site. This paper focuses on the Osterberg cell (O-Cell) load test completed for determining the allowable side-shear resistance between the concrete and the sides of the rock socket. Different qualities of mica schist bedrock, demonstrated by the penetration of rock with the soil auger or drill casing, were encountered. Accordingly, an additional subsurface investigation consisting of test borings at each caisson location was completed. Unconfined compressive strength tests were performed on representative rock samples. The ?soft? mica schist was observed to have vertical foliations and high mica content. For the first time in Manhattan, an O-Cell load test was performed to determine the allowable side shear resistance for both the soft and hard mica schist bedrock. The side shear resistance obtained from the O-Cell load test is compared with the side shear resistance allowed by the New York City Building Code and empirical correlations using unconfined compressive strength values for rock. The rock socket design for the caissons was refined based on the O-Cell load test results.

Jan 1, 2008

By Ivan Hee

The 2.5km long bridge over the Beauharnois Canal and St. Lawrence Seaway is a major structure in the new Autoroute 30 project near Montreal. Foundations for the bridge consist of footings on bedrock, driven piles, and drilled shafts. This paper describes the design, verification, and construction of 1.85m diameter drilled shafts socketed into very strong and abrasive dolomitic sandstone. Two loading tests on sacrificial, heavily-instrumented, 1.18m diameter test shafts using Osterberg load cells were performed, with telltales installed to monitor a possible rock cone failure mechanism. The loading tests resulted in a revision to the initial design and provided a greater understanding of the cone uplift mechanism in rock. Insights gained are discussed and economies of the load testing program presented. Construction methodologies are also presented.

Jan 1, 2011

By KeerthiRaaj Subrmanian, Muthukkumaran Kasinathan

"A railway embankment is under construction between Nagapattinam to Thiruthuraipoondi covering 36.5 km. The sub-soil strata comprises of soft clay extending up to 10 m below existing ground level, which is subjected to stability and settlement problems. A trial stretch covering about 5 kilometer was improved using Prefabricated Vertical Drains (PVD) with surcharge was recommended to accelerate the consolidation settlement. The geotechnical characteristics of the subsoil are examined through laboratory tests on representative soil samples. Recent improvement in the finite element analysis has facilitated modeling of PVD in finite element software for computing the settlement magnitude and time rate of consolidation. In this study the theoretically predicted settlement magnitude and time rate of consolidation from Terzaghi.s vertical consolidation, Barron's radial consolidation are compared with the analyzed FEM results for both the cases with and without PVD improved embankment. The comparative analysis between FEM and predicted data hold good for stresses and the associated deformations. The excess pore water pressure was significantly lower and their dissipation was faster in case of embankment with vertical drains. Thus PLAXIS 2D tool shows fairly convincing results in comparison to the theoretical solutions.1. INTRODUCTIONFrom the earlier times civilization has been developed in a fashion either at the banks of river or near to the shore region, because of the easier availability of food and water. This over centuries made them as huge cities, consequently population rise made the increased necessity of highway, railways, port and even more ground for construction. As a stake researchers are pushed to make a low bearing ground into a massive carrier of skyscrapers, embankment, bridges etc. These low bearing ground suffers from total and differential settlement, slope instability. Hence, numerous ground improvement techniques were followed to eradicate these concerns which include preloading, piling, stone column, vertical drains and geosynthetic reinforcement. Among them Prefabricated vertical drain (PVD) are often used to accelerate consolidation of soft subsoil and has been the main soil improvement method used in improving the soft marine clay deposit (Chu et al.(2004); Chai (2001) and Arulrajah et al.(2003)). Literature review of embankment over soft clay deposit reveals that combination of PVD with preloading is widely considered as an economical and less time consuming ground improvement technique."

Jan 1, 2015

By Thomas M. Caruso

Construction of a new ship dock at a major Philadelphia area refinery required geotechnical design and field consultation. The new dock, which consists of a system of mooring dolphins and platforms, will be capable of docking the Stena V-MAX Oil Tanker (V-MAX). The 1100 ft long V-MAX is currently the largest tanker to travel the Delaware River and will induce significant lateral loads on the new ship dock. Lateral loads induced on the dock will be resisted by over 200 pipe piles installed on a batter. The piles used for support of the dock included 20 and 30 in. diameter reinforced, concrete filled pipe piles. Complete construction of each pile included driving of the pile to the design ultimate capacity, flushing the pipe pile casing clean of overburden materials followed by drilling rock sockets into the underlying Wissahickon Formation. Variations in depth to bedrock, rock quality and degree of weathering and presence of very hard quartzite lenses created a complex geologic environment that presented challenges for the pile/rock socket design and installation. The design of the pile system, installation methods, QA/QC and testing (Pile Dynamic Analysis), as well as the challenges that were encountered through the duration of the project are presented and discussed.

Jan 1, 2008

By Emad Farouz, Ehab S. Shatnawi, Charles Winter

The increasing demand for small deformations and high-capacity drilled shafts without enlarging drilled-shaft diameters has motivated the development and increased use of a base grouting (BG) technique. This technique has been demonstrated to improve drilled-shaft axial capacity, especially for shafts tipped into loose cohesionless soils. To date, there are a couple of documented design methods for estimating the axial geotechnical resistance of base-grouted shafts. However, there is no or lack of research that addresses the lateral response of such shafts. A base-grouted drilled shaft test program was carried out during the design phase of the Wisconsin I-94 Zoo Interchange reconstruction project. The test program included installing and testing one base-grouted shaft and one ungrouted shaft under both lateral and axial loading. Based on test results, it was concluded that the lateral behavior of the BG drilled shaft is significantly stiffer than conventional drilled shaft . Hypothetical method was developed to account for potential increased, however, the method should be verified with more lateral load test.

By Ilhan Chang, Ernest Nsabimana, Kiseok Kwak, Juhyung Lee, Young-Hoon Jung

"Numerical analyses were performed to analyze the behavior of two different type of suction piles (mono type and group type) under various soil layer conditions (uniform silty clay layer, uniform silty sand layer, and two-layer deposit consisting of clay and sand layers) and lateral loading locations (top, middle, and bottom of the suction pile). According to the results, mono suction pile shows maximum resistance when load is applied on its middle, regardless of the soil layer conditions, while group suction piles varies significantly according to the allowance on head rotation. When head rotation is allowed, the behavior of group type piles become similar to the behavior of mono suction pile. Whereas, when rotation is prevented, resistance is maximized when load is applied on the top head. Moreover, group suction piles show higher efficiency regardless of the ground condition and geological stratum. For further advances, concrete block on the top of group suction piles are suggested as an effective alternative method to prevent partial rotation and maximize ground resistance for group suction piles.IntroductionWith the development of offshore technology, applications and real site installations of suction piles are increasing significantly nowadays. They are generally used as mooring anchors in various floating structures, marine platforms, and offshore wind turbines. According to its convenience in installation and removal, suction type foundations are becoming good alternatives for deep ocean support systems. The bearing capacity is similar to the bearing behavior of ordinary offshore structures (piles or drilled shafts). The most common use of suction caissons is anchors for catenary mooring lines, where the chain angle at the mudline is close to zero (Randolph, 2002; Sharma, 2004).Recently, it is reported that a huge isolated single suction pile can be replaced by a group of moderatesized suction piles (Randolph et al. 2004). A single monopile is easy to be produced and installed in site. It is expected that monopile foundation is not applicable for deep depths because it has a limitation on penetration according to its huge side skin area (i.e. friction). Moreover, stiffness requirements sometimes render thicker pile wall conditions which are impractical to be produced."

Jan 1, 2017

By Morris J. D, Baldwin Z., Wiltcher P. M

21 Moorfields is an oversite development in central London spanning Moorgate tube station. It required the installation of both the highest loaded bearing piles and the highest top loaded static pile test ever undertaken in the UK, at 50.5MN (5,680 tons). The 17-storey building is founded on only 15 large diameter bored piles installed through the roof of the live station. The piles are located in two parallel rows 50 m (164 ft) apart, bridging the underlying train lines and the Crossrail tunnel below. This unique project required a diverse cross-section of skills and experience from the Project Team as we not only pushed the boundaries of design but also those of construction practices. Our team therefore needed to be made up of members from multiple businesses and disciplines. The team worked together, in a highly collaborative environment, for around two years before any work started on site. A key challenge for this project was that there was only one opportunity to construct each pile. If a position had to be abandoned there were no alternative locations and the impact on the project would have been catastrophic. It was therefore vital that all events that may have led to the abandonment of a pile were investigated ahead of commencement on site. Risk elimination and mitigation strategies were developed for all eventualities whether they be associated with the design or construction processes. The successful pile load test, coupled with all contract piles being fully instrumented with state-of-theart fiber optic (CemOptic) cable along their full length, has improved our understanding of the performance of such large and heavily loaded piles. The works piles will all be monitored during the construction of the new building, providing new insight into their real-world performance. Such groundbreaking work has never been undertaken before in the UK and has the potential to significantly influence the industry’s understanding of pile behavior, and design, in the future. This paper will discuss the challenges the team encountered during the design and construction of this highly complex urban project, particularly when adopting, by necessity, a pioneering approach.

By James S. Graham

Marine design and construction methods are presented on the caisson foundations for the tower piers at the Brooklyn, Ben Franklin, Delaware Memorial 1st, Tappan Zee, Walt Whitman, Throgs Neck, Verrazano Narrows, Delaware Memorial 2nd, and Newport Bridges. All of the bridges are founded on caissons, bearing on bedrock, soil, or piling. Caissons at the Tappan Zee Bridge are partially supported by piling and partially by buoyant forces. General subsurface conditions for each are provided. The purpose of this paper is inform engineers how bridge foundations using caissons were built over major waterways in the Northeastern USA in the past, anticipating a surge of new bridge construction in the near future.

Jan 1, 2005

By Artak D. Mirzoyan

Pile foundations near the edge of a slope are often required to resist lateral loads. This is particularly important for piles at abutments of bridges. However, very few full-scale tests are available that compare the effect on lateral resistance of piles installed in sloping ground to piles installed in horizontal ground. To investigate the effect of a slope on lateral pile resistance, three full-scale lateral load tests were performed on an instrumented steel pipe pile. For the first test, the pile was laterally loaded in horizontal ground; in the second test, the pile was at the crest of a 30º downward slope; and for the third test, the pile was located three pile diameters from the crest of a 30º slope. The soil around the pile consisted of well-graded clean sand (concrete sand) and was compacted to 95% of the modified Proctor maximum unit weight in all three tests. Lab and in-situ direct shear tests indicated that the friction angle of the sand was approximately 39 degrees. The pile was instrumented with strain gauges so that the bending moment versus depth profile could be determined. Pile head load, deflection and rotation were also measured. Based on the load versus deflection curves, the presence of the slope resulted in a decrease in lateral resistance of about 20% for the pile at the crest of the slope and 8% for the pile at 3D from the crest of the slope relative to the pile in horizontal ground. The presence of the slope also resulted in an increase in the maximum moment of 29% and 20% for the piles at the slope crest and at 3 pile diameters from slope crest, respectively. Analyses using LPILE with the measured friction angle significantly underestimated the lateral resistance for the horizontal soil profile. After calibrating the model with the response of the pile in horizontal sand, analyses including the slope still underestimated lateral resistance by about 20%.

Jan 1, 2007

By Jorj O. Osterberg

This paper is for presentation at the 14th Annual Members Conference of the Deep Foundations Institute held at the Hyatt Regency Hotel, Baltimore Maryland on October 10, 1989. This is an introductory presentation of a one hour symposium on the applications of a new testing device. This paper discusses how the device works and its uses. Papers following this describe: - How the cell is constructed and calibrated - Two projects on which the device was used on long driven piles to determine the frictional capacity - A bridge project on which the device was used on an instrumented test drilled shaft and a working drilled shaft

Jan 1, 1989