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By Saba Mohan

This study presents results based on the Pile Installation Demonstration Project (PIDP) that was conducted as a part of the East Span San Francisco-Oakland Bay Bridge Seismic Safety Project. For the three full-scale pile installations, two different high-energy hydraulic hammers were selected for the installation. However, these hammers may not have sufficient energy to drive these large diameter piles at their ultimate capacity following long-term set-up. Nevertheless, these hammers were selected because, soil plug behavior, the generation of excess pore pressures and remolding of soil during driving were expected to reduce the shaft and end bearing resistance, and therefore reduce the energy required to drive these piles to design penetration. Data collected during continuous installation driving and after a series of re-strikes at different set-up times ranging from 1 to 33 days were used as input data for CAPWAP. These results were used to estimate the soil resistance along the pile length and at the toe of the pile, and the soil pile set-up behavior. Validity of the procedures used to predict the soil resistance to driving and predicted blow counts were verified with the field observed blow counts and the energy that was delivered to the pile. Based on combined CAPWAP analyses, the soil pile set-up with time was estimated and compared with results of other methods currently available in the literature for predicting the soil pile set-up rate.

Jan 1, 2002

By Davide Grassi, Joel Joaquin Cortez, Giovanni Spagnoli, Nick Chittenden

Grouting is a technique used to improve the engineering properties of soils and rocks. Grouting techniques are classified under different criteria: injection method used, type of grout material injected, typical application, and the sequence of construction. The best-known criterion is the mode of entrance or admission of grout into the soil or rock. It is possible to identify therefore several grouting techniques: compaction, fracture, jet/mixing and permeation. The function of penetration grouting is to reduce the permeability of the soil or rock and/or increase the strength and density. In order to avoid displacement, permeation grouting shall be carried out at carefully controlled pressures and flow rates, using appropriate grouts. Colloidal silica is an innovative binder which has low viscosity (about 5 m·Pas), it is not toxic (pH lower than 9) and it is workable between +5°C and +45°C. This paper presents several case histories: a consolidation job related to the installation of a new sewer in North Italy in cohesionless soils, water stopping injection in a weathered granitic bedrock in California, permeation works in the US in sandy soils to improve excavation and the installation of sheet piles in the UAE. Results show that the colloidal silica an innovative and robust technology to perform grouting in very fine soils where conventional binders or micro-fine cements cannot penetrate.

May 1, 2022

By Timothy Flaherty

We observed the boiling in the water very close to the water adjacent to where we were drilling. That only happened at the very beginning before it was switched to water flushing. Yes, it was performed with water flush.

Feb 10, 2003

By George Gazetas, Sissy Nikolaou, Fani Gelagoti, Irene Georgiou, Rallis Kourkoulis

"The need to shift geotechnical design from a “factor of safety” to a “performance based” design (PBD) approach has increased rapidly in the past years following examples from structural engineering. PBD supports sustainable engineered systems that target project-specific geotechnical behavior objectives and results in more rational and, in most cases, less conservative solutions. Resiliency, efficiency, risk optimization, and cost-effectiveness are key components of this approach. For design of retaining walls, the concept of mechanically stabilized earth (MSE) systems combines these attributes, while being environmentally friendly and adaptive to variable construction conditions. Natural hazards, such as earthquakes, may drive the design of MSE systems whose reliability depends on their performance under extreme events. In this paper, the authors compare the seismic response of an MSE steel-reinforced vs. concrete-reinforced retaining wall. The MSE system is composed of a grid of longitudinal and transverse ribs which internally enhances the capacity of the soil backfill. Results of fully non-linear twodimensional (2-D) numerical finite element analyses using two commercial programs with emphasis on the interface conditions are presented. The pull-out resistance of the grid used in the numerical simulation was evaluated from actual pull-out experiments. The results demonstrate a superior performance of the MSE system as compared to the concrete one, especially when subjected to strong seismic excitations.INTRODUCTIONThe idea of performance-based geotechnical engineering is not new, and has been evolving as our perception for ‘good’ performance has also evolved (Kramer, 2008). In early practice, the only criterion for achieving good performance was to avoid failure; designers had only to ensure that the available capacity of the geotechnical system is sufficiently higher than the expected demand (i.e. Load and Resistance Factor Methodologies). Yet, even when the key design requirements against collapse are satisfied, the system may still be placed into a condition in which the deformation constraints are not met (Bolton, 2012). To address these issues, geotechnical design has been developing into a predominantly performance-based approach that correlates deformation considerations to the severity of the experienced loading. As such, in earthquake-related problems, the definition of good performance of a geotechnical system is no more unique; for a low intensity earthquake the system should remain serviceable (i.e., the developed deformations should remain low), whilst for the design earthquake the maintenance of lifesafety is the single performance criterion."

Jan 1, 2016

By Yazen Khasawneh, Osvaldo P. M. Vitali, John E. Agee, Mohammad Nassim

A 3D FEM modeling of a ground improvement solution for an ice rink slab with stringent differential settlement limits is presented. Due to the complexity of the geotechnical conditions and strict deformation requirements, a structural slab supported by micropiles was initially proposed. However, this solution was costly and alternative solutions using ground improvement techniques were investigated. The proposed slab is supported directly on rock at one end and on approximately 45-ft deep cohesive soils on the other end. The numerical simulations show that differential settlement would be larger than allowable, if the ice rink slab is supported directly on the existing subgrade. The addition of the ground improvement scheme with compaction grouting demonstrated that the anticipated differential settlements are reduced significantly and would become less than the allowable magnitude. This study demonstrates that the use of numerical simulations to study complex loading and geological conditions will help to optimize designs and may result on significant cost savings.

Sep 8, 2021

By Tiruvengala Padma, Nilesh Naik

Piles are common type of deep foundation elements used for the special bridges, transmission towers, Jetties, and tall structures. Lateral loads on the structures can be due to either earth pressures, wind, waves, impact, moving vehicles and eccentric application of axial loads or in combination of the loads. Hence the lateral capacity of piles plays a major role in determining the pile dimensions. The laterally loaded pile analysis is a soil-structure interaction problem as the lateral capacity of pile depends on the soil strength and stiffness parameters and its reaction to the lateral load on pile. The common approach to determine the lateral load analysis of piles is the Beam on Lateral Springs Method also known as “p-y” method. In this method the pile is modelled as a beam and supporting soil is modelled as lateral springs. This study is focused on the comparison of output obtained from three geotechnical softwares namely FB-MultiPier, L- Pile and Wallap. L-Pile Software is based on Finite Difference Method, Wallap on Horizontal Subgrade Modulus Method and FB MultiPier on Finite Element Method. Pile response in terms of deflection, shear force and bending moments under vertical and horizontal loads from above three software are compared and concluded.

Sep 1, 2022

By Clarissa Aguiar, Seok hyeon Chai, Thamer Yacoub, Sina Javankhoshdel

Sheet piles are used as an excavation support for soil retention. They are interlocked systems to form a wall for earth support along with anchors to provide an extra lateral support in excavations. The earth pressure against a sheet pile structure is not unique for each soil, but rather a function of soil-structure system. Movements of the structure with respect to the soil are primary factor in developing the pressure and thus the problem becomes indeterminate. In order to model a sheet pile wall for the analysis, structural element/interface can be used for the sheet pile. However, the use of the structural element with soil model alone is insufficient to simulate this soil-structure system as it fails to capture the slip condition between the sheet pile and the retained soil. In order to capture this slip condition, an interactive element can be used between sheet pile and soil to allow slip to occur. There have been many case studies where this method was used to analyze the response of the retained soil. Numerical studies have shown a good agreement with experimental results, but this stiffness is often not a well-known parameter, due to its complexity in nature of interactive behavior between soil and sheet pile walls. Also, many case studies are carried out with twodimensional analysis of the foundation, where three-dimensional analysis may be more suitable in some practical applications. In this paper, the interactive behavior of the element between sheet pile and soil is investigated with case studies for staged excavation using sheet piles and anchors. Then, investigation of a three-dimensional model is carried out by comparing with two-dimensional analysis.

By Mohini Patel, Jahnavi Parmar, Pranav R. T Peddinti

Expansive clays pose a variety of geotechnical problems. Although the admixture stabilization is proven to address their problematic swelling and shrinkage characteristics, the influence of unsaturated condition on the engineering performance of these soils needs further research attention. In addition, highly saline soils with high organic content would further alter their performance. A similar soil stratum was encountered at the Gulf of Cambay, Bhavnagar district, India. High salinity in the in-situ expansive soil of basaltic origin and the prevailing unsaturated condition, enforces the engineers to look out for possible soil treatment methods. In this regard, the present work attempts to analyze the unsaturated behaviour of this soil when fly ash is used as an admixture. A comparative study for stabilized and unstabilized mixes is performed in terms of their unconfined compressive strength, electrical conductivity, swell characteristics and California Bearing Ratio.

May 1, 2022

By Liiban A. Affi

The most difficult task of designing multilevel tieback walls for deep excavation support is the determination of lateral stresses. These lateral stresses act not only on the shored height, but also on the embedded portion of the soldier pile, all the way down to the pile tip. Examples of lateral stresses include uniform surcharge load (soil spoils or equipment), strip load surcharge from Cooper E80 (train loads), line load surcharge (exterior footing or retaining walls), and point loads (cell tower). In this paper we will discuss the various surcharges, do step by step example calculations and show how to take the total lateral stress output and present the design pressures for direct use by the substructural designer. Included is a case study from a project Anaheim Hills, California, USA.

Jan 1, 2010

By Yazen Khasawneh, Osvaldo P. M. Vitali, Mohammad Nassim

The demand for renewable energy is growing as the conventional energy resources are becoming more limited and we are more conscious about the negative impact of conventional energy sources on the environment. Wind turbines technology is evolving in a fast pace, the towers are becoming taller, and the rotors are getting larger. The challenge is to maintain the Levelized Cost of Electricity (LCOE) as low as possible to ensure a sustainable and an economically feasible energy supply. Thus, the foundation systems for wind turbines should evolve to meet the increasing load demand, while reducing the LCOE. In this paper, an innovative foundation system for onshore wind turbines is presented. The new foundation system is the conventional P&H tensionless pier foundation (PHTP) with a reinforced concrete collar at the top of the pier. 3D FEM modeling was conducted to assess the benefits achieved by adding a collar at the top of the PHTP foundation. The numerical results show a significant performance enhancement of the proposed foundation system over the conventional PHTP foundation. The enhanced foundation system also has an economical advantage because the depth of the pier can be greatly reduced while maintaining a superior performance.

Sep 8, 2021

By A. David Miller, Chika Oya

"Field sampling and testing are part of the Quality Assurance/Quality Control (QA/QC) requirements for all Cement Deep Soil Mixing (CDSM) Projects. Field sampling and testing are also used for determining the performance and quality of soil mixing method(s) and are the primary basis for accepting or rejecting the soil mixing wall among all other QC testing. Two of the most commonly recognized and used sampling methods for CDSM walls are wet grab sampling and verification coring. Depending on the types of wall construction and project budget, one or both of these methods are normally used to help evaluate the in-situ matrix and quality of the mixed soils. Additional to ASTM strength and permeability testing from wet grab sampling and verification coring, more and more testing methods are being employed and accepted. However, these other testing methods tend to be unnecessary, lack consistency and repeatability, and are more subjective to manipulation and interpretation. In certain projects, there are also misconceptions involved with the results of wet grab sampling and verification coring, hence it is important to note how these wet grab sampling and verification coring work and represent the work in terms of quality of production.TYPES OF PROJECTSCDSM projects include (but not limited to) in-situ stabilization, liquefaction mitigation, excavation support, groundwater cutoff, and pollution containment. Although these projects use similar equipment on the jobsites, each project is treated differently in terms of catering to specification, uses of different mix designs, and emphasis on certain steps during production.Different types of projects with different specification changes the focus of quality, but soil types in jobsite also determine how to proceed with production. For example, a jobsite with predominate gravel layer must be treated differently as opposed to jobsite with clayey sand as the main soil type.WET GRAB SAMPLEWet grab sampling is one of the most used testing methods for QA/QC. The wet grab sample specimen is retrieved right after finishing the production of the desired element.Wet grab sampling equipment consist the use of 28 cubic inch (458.84 cubic cm) box attached directly to one of the auger stems. Hinges attached to the top and bottom of the box is fabricated to allow collection only during auger withdrawal. The collection box is strapped just above the mixing paddles on the auger stem and measured from the center auger head tip to confirm proper depth of collection. This box method has been used in Japan and U.S. for numerous projects."

Jan 1, 2017

By Alessandro Bertero, Manuel Toniolo, Vincenzo Tirozzi

"The installation of foundation elements (large-diameter Bored Piles or Diaphragm Walls) for the execution of underground works to be performed through the ""Top Down"" Technique (Stations, Car Parks, Subways, Artificial Tunnels) often requires the insertion, with pinpoint accuracy, of steel or prefabricated elements within the foundation system, to provide temporary and/or permanent support to the whole structure.The future high-speed railway station of Florence Belfiore (Italy) is a perfect example; the new station will be built in the Northwest area of Florence, about two kilometers far from the existing station of Santa Maria Novella. The project envisages installation of about 500 bored piles (1200-1500-2100 mm diameter), with lengths ranging between 50 and 70 m. In the upper inner part of 250 piles, a steel pipe (weight: 15-20 tons, length: 22-25 mt.) has to be inserted with pinpoint accuracy.The “TREVI-CALATORE” system allows to install the plunge columns and adjust their position and verticality.INTRODUCTIONThe execution of underground works via the ""Top Down"" technique, train or tube underground stations, parking shafts, tunnels, often implies the need to carefully insert steel or prefabricated structures, serving as provisional/definitive pillars, into the foundation elements.The future high-speed railway station of Florence Belfiore is a perfect example; the new station will be built in the Northwest area of Florence, located about two kilometers far from the existing station of Santa Maria Novella.The new Belfiore Station is part of the new European high-speed railway network. The works related to Florence urban penetration include (figure 1):•,a 6.5 km. twin tunnel excavated via TBM/EPB, that will run beneath Florence in a north-east direction,•,passing under more than 150 buildings, many of which can be considered historic buildings, with a soil•,coverage ranging from 6 m to 20 m;•,a North portal in Rifredi area, Firenze Castello Station;•,a South portal near Campo di Marte Station (which is also the launch shaft of the TBM)•,the new Underground Station in Belfiore area."

Jan 1, 2016

By Teresa M. Bodas Freitas, Arianna Lupattelli, Peter J. Bourne-Webb, Diana Salciarini, Martina Zito, Donatella Sterpi

The thermomechanical response of thermally-activated (TA) piles under monotonic thermal loads is quite well understood and the remaining uncertainties relate to the effect of long-term, cyclic loading of individual TA piles and pile groups. Recent studies undertaken by the authors have provided insights into the behaviour of TA pile foundations undergoing cyclic thermal loading. Despite their simplicity, the analyses show that key aspects of the observed response of piles in sand, under cyclic thermal loading can be reproduced, providing confidence in the outcomes of the analyses. The studies examined isolated piles and pile groups, and concluded that irrecoverable thermally-induced settlement may be mitigated through the choice of an appropriate margin of safety on the pile shaft resistance under service mechanical load conditions, and the maximum thermal stress can also be readily estimated. This paper consolidates these works and provides guidance regarding the safe geotechnical and structural design of the piles, then looks towards the remaining issues around the safe provision of thermally-activated pile foundations.

May 1, 2022

By Vladimir M. Korolev

The field studies conducted at the experimental-production sites allowed to develop the technology of arranging drilling piles in loess subsiding grounds over 25 m deep and over 250 mm in diameter, to select optimal compositions of flush fluids, to assess the carrying capacity and field of use of the piles under test and to produce a special equipment. The dependence of the ultimate axial pressing-in load on pile driving into the non-subsiding section, its diameter and method of fulfillment, as well as the ground moisture dependence of the specific ground resistance along the piles' side surface within the limits of the subsiding section were determined. The study results allowed to reduce the length of the work piles and the number of bars in the reinforcement frames. The obtained experimental data enable to give a preliminary assessment of the piles' carrying capacity under complicated engineering-geological conditions of subsiding grounds.

Jan 1, 2002

By Takefumi Takuma, Tsunenobu Nozaki, Masashi Nagano

The city of Naruto in the southwestern part of Japan is situated at the mouth of the mighty Yoshino River. An approximately 1,000m-long levee/bulkhead along one of the river’s tributaries in the city was raised with prefabricated steel panel walls on a concrete base bulkhead. Some sections of the walls’ foundations were combi-walls made of sheet pile cut-off walls and interspaced pipe piles; both of which were installed with press-in piling because the new wall alignment was very close to existing homes and businesses. A Clamp Crane, which clamped onto already installed piles and moved forward and backward on them, was utilized for a segment where the access to its piling location was too tight for a conventional crane or a track-mounted pile driver to maneuver.

Sep 8, 2021

By N. V. Nayak

Konkan Railway Project is one of the most ambitious railway construction projects in India, involving construction of a 760.km long, Broad Gauge (1676 mm), single track railway line, connecting Roha in Maharashtra State with Mangalore in Kamataka State. The railway line travels along the Western Coast of Indian subcontinent, through states of Maharashtra (382 km), Goa (105 km) and Karnataka (273 km) (Fig.1). The project alignment traverses through one of the most formidable terrains ever encountered, in the history of railway construction in India. In the State of Goa only, railway alignment is crossing 6 major rivers Terekhol, Chapora, Mandovi, Zuari, Sal and Talpona. Zuari Railway Bridge (1305.6 m), Mandovi Railway Bridges (I and II) (1182.7 m) rank as 2nd and 3rd long bridges, (first longest bridge being Sharavati Bridge (2.2 km} at Honavar) which have been constructed on Konkan Railway. All these three bridges have been constructed by M/s.Asia Foundations and Constructions Ltd. (AFCONS). This paper presents, case history of construction of pile/caisson foundations for Zuari and Mandovi Bridges.

Jan 1, 1996

By Emad Farouz

This paper compares the predicted axial capacity of driven Pre-cast Pre-stressed Concrete (PPC) piles for the Lake Gaston Water Treatment Plant (LGWTP) using several design methodologies versus the axial capacity measured from dynamic and static load testing. The LGWTP site is located in Chesapeake, Virginia and is part of the Great Dismal Swamp. The subsurface investigation included soil borings, in-situ dilatometer (DMT) tests, and in-situ piezocone (CPTu) tests. The axial capacity predictions of the PPC piles were performed using the computer programs DRIVEN and FB-DEEP which are based on SPT N-values. Additionally, an empirical method proposed by Martin, et al. (1987) based on local experience with PPC pile design in the Yorktown formation in the Tidewater area of Virginia was also evaluated. Finally, the ?Laboratoire Central des Ponts et Chausées (LCPC)? method developed by Bustamante and Gianeselli (1982) based on CPT measurements was also used to develop the axial pile capacity of the piles. This paper shows that the FB-DEEP computer program and the LCPC method provided a reasonably good prediction of the pile axial capacity measured from PDA, CAPWAP, and Static Load Tests in comparison with the other design methods used. The soils in this area develop significant setup over time and it was found that FB-DEEP and the LCPC method are capable of incorporating this setup in the prediction of the long-term axial capacity of driven piles in this area.

Jan 1, 2007

By Jorj O. Osterberg

The practice of using side shear resistance in the design of drilled shafts socketed in rock is discussed. In the absence of field test data for the particular rock involved, the designer often neglects the side shear altogether or uses an extremely conservative value. The uncertainty of using strength data from compression tests on rock cores is discussed. Examples of full scale load tests are given which illustrate that even in the weakest of rocks, considerable side shear resistances are obtained, enabeling reductions in the depths of the sockets and consequent savings. Existing Practice. The existing design practice in using side friction/bond between a drilled shaft in rock or hard soil varies very considerably in different areas of the U.S., in different areas of the world, among different Geotechnical Engineers, and in the requirements of different building codes. In fact, the variation is so great that it is inconsistent and contradictory. For example, in Florida where fairly weak coral limestone and sandstone is prevalent, the general practice is to use side friction only and to allow no end bearing. In Chicago, Detroit, Boston and other areas where soft clay overlies stiffer clays, hardpan and limestone or other hard rock, the common practice is to allow for no friction and to use end bearing only, even though the lower portion of a shaft frequently penetrates stiff to hard clays and hardpan (glacial till) before bearing on hardpan or rock. In Hong Kong, if the hole is stabilized with drilling mud, no end bearing is allowed. In Boston (Thompson, Erikson, and Smith, 1989), two tests at two sites on 18 inch pipe piles penetrating 100 feet of soft clay and driven only inches into an argillite, tested 140 and 210 tons in ultimate side shear resistance. Certainly, with long drilled shafts, no matter how soft or weak the soil or rock is, some if not considerable side friction occurs, and where drilling mud is used, there must be considerable end bearing.

Jan 1, 1991

"Every year during the Transportation Research Board (TRB) Annual Meeting in Washington D.C., the Federal Highway Administration (FHWA) National Geotechnical Team (NGT) takes time to talk about what we are doing in research, training development and policy support. At times, I have jokingly referred to it as the State of the Program Address, but we do see it as an important opportunity to update our transportation partners on priorities and needs for the program.This update is really a snapshot of the program during the previous year, with a look at projects that are currently active. Activities undertaken by the NGT are funded from multiyear roadmaps maintained by the FHWA program and research offices, and reflect trends and opportunities affecting and influencing transportation geotechnics now and in the future. The roadmaps identify activities in research, development, guidance, technology transfer and training that will be accomplished by the NGT through and beyond FY 2020 in eight broadly-defined focus areas: • Extreme events, geohazards and sustainable geotechnics• Performance management• Reliability-based design and construction• Advanced geotechnical modeling• Alternative delivery methods• Design and construction optimization• Site characterization• Quality assuranceThe process to identify focus areas and to develop activities that will be addressed by the NGT is guided and informed through input from the FHWA NGT members, and considers feedback and input from State Departments of Transportation (DOTs), FHWA Division offices, industry and academia. This process is revisited annually to review not only the activities that are currently funded, or will be funded, but also to review the relevance of the focus areas with respect to the future needs of the FHWA, State DOTs and the transportation community.In 2016, the NGT was successful in delivering several products that will advance the state of the practice and that better support policy. Products developed included research reports, design and construction guidance, and training courses. In 2017, the research and program offices will continue to work on projects that fit within our prioritized plan and that positively impact the geotechnical community as a whole. A listing of recently completed and currently active projects is provided below."

Jan 1, 2017

By Ross Cutts

As a public servant geotechnical engineer, I observed how costly and valuable geotechnical field explorations are to the success of every project. Often however, the field exploration is a long and complex process that is made less efficient by the difficulty of retrieving and utilizing nearby internal or external historic geotechnical datasets. As an employee of a public agency, we would often start our investigations for every project from scratch, given the difficulty of locating and utilizing historic geotechnical data. This is an ethical and technical failing of our profession. When we start subsurface explorations from scratch, not only do we often duplicate investigations, we are also likely defaulting to reapplying tradi- tional test methods that yield con- servative geotechnical parameters, resulting in overly conservative and potentially costly construction. To address this issue while working as a public servant, I started a research program with Yunfeng Zhang, Ph.D., of the University of Maryland, to build a tool that could compile internal historic geotechnical data and extract additional value from it, using machine learning. This tool was able to provide, upon request, nearby historic geotechnical data, estimated soil parameters and recommendations for geotechnical test methods best suited for a given project site. This prevented common field ex- ploration problems such as, requesting duplicate data, requesting test methods that were not applicable for the project geology, not realizing presence of karsts, missing permits for wetlands, private property and others. This tool allowed for more efficient field investigations with regards to time and money saved. There was one problem with this tool: it could only be used by internal employees of a single state's depart- ment of transportation (DOT) for which this data was compiled. I realized at that point that it would be of tremendous value to make this concept universally accessible to the geotechnical engi- neering profession. I left public service to devote time to building a platform that would host historic geotechnical data from publicly funded sources throughout the country. The tool I helped build as a public servant was the foundation of Geosetta, a nonprofit company dedicated to serving the geotechnical profession. The nonprofit structure was adopted to prevent acquisition by a for-profit company and to ensure that Geosetta remains an independent steward of our profession's valuable data. Geosetta provides a GIS (geographic information system) platform that enables users to view historic geo- technical data and extract value from it with machine learning-based predictions and visualization tools. This data is provided in an open and interchangeable format called DIGGS, which stands for Data Interchange for Geotechnical and Geoenvironmental Specialists, making it easy for users to integrate it into their workflows. Geosetta is collaborating with the American Society of Civil Engineers' Geo-Institute and other sponsors to extract public data at no cost to the agency and provide the profession with free access to the existing data and access to advanced tools through a subscription to support the nonprofit mission.

Nov 1, 2023