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By Frank Haehnig

Ground freezing is a technique which is used more and more in tunnelling under complex ground conditions. This paper will present three case studies which highlight different aspects of the ground freezing technique when applied in urban environment. The first project is the City-Tunnel in Leipzig, Germany, which is being built beneath the central station and which is the largest ground freezing project currently under construction in Germany. The second case study is part of the North-South-Line project in Amsterdam, Netherlands where ground freezing will be carried out to al-low the TBM drive through old wooden foundation piles. The freeze tubes for this project will be driven using Horizontal Directional Drilling (HDD). The last project is the Hallandsas Tunnel Sweden where the ground freezing equipment has to be installed against high water pressure. The paper illustrates that ground freezing can be implemented in difficult ground conditions such as soft ground, highly fractured rock and high water pressure. The case studies highlight the importance of good workmanship. With the increasing numbers of large tunnels being constructed in difficult ground conditions the paper concludes that the complex case studies presented will be-come more representative for future tunnel projects in urban environments.

Jan 1, 2008

By Marwa Nabil, Alaa A. Ata

"Recent developments in the analysis of piled rafts has incorporated the load sharing of the raft and the piles to support the superstructure. In the piled-raft system, piles are cast monolithically with the raft and the load is partly transmitted by the raft to the soil directly below it, and partly by the piles to more competent deep soil. While these piles are effective in increasing the bearing capacity and reducing the settlements, they often lead to significant straining actions at the pile head-raft connection which may constitute the weakest link. An attempt to provide a more economical solution, that at the same time overcomes this weak link, is to disconnect the pile heads from the raft and introduce an intermediate cushion of compacted fill. In this case, the piles are considered as reinforcement to the subsoil and will also act as settlement reducers. This paper investigates the load transfers mechanism of the unconnected piled raft with cushion using ABAQUS finite elements Program. The main objective is to provide an in depth analysis of the raft–soil–pile interactions in multi-layered soil under static and seismic loads. The investigated system provides an economical alternative for traditional connected piled raft foundation, where there is no need to reinforce the piles, no need for pile head demolition or expensive waterproofing of the pile head connection. Cost analyses of unconnected versus connected piled raft systems confirmed a cost savings in the construction that may reach from 50 to 70 percent.INTRODUCTIONDesigners around the world have gained more confidence to use the piled-raft as a more realistic system where the raft and the piles share transferring the superstructure loads to shallow and deep soil layers. A further advancement is to use unconnected piled rafts as another practical and economical alternative to the traditional piled rafts. Unconnected piled raft is also synonymous to settlement reducing piles; or simply, soil improvement piles. Liang et al. (2003) has extended the concept of pile-raft-foundation to a new type of foundation called composite piled raft foundation or unconnected piled raft foundation. The foundation is composed of a sand/gravel cushion sandwiched between the raft and piles. The piles group may contain short and long piles. The short piles are constructed of flexible materials such as soil-cement columns or sand-gravel columns, and are used mainly to improve the bearing capacity of shallow soft soil; the long piles, which are made of relatively rigid materials such as concrete, and their main function is to reduce settlements. The cushion plays an important role in mobilizing the bearing capacity of the subsoil and in modifying the load transfer mechanism of the piles. In Shanghai, China, this system of unconnected piled raft has proved to be quite suitable and effective in coastal areas, where deep soft soil deposits exist."

Jan 1, 2016

By K. E. Darnell

Drilled pier foundations have long been a favored foundation type for heavily loaded structures. Drilled piers derive their load-bearing capacity from end-bearing, and/or sidewall friction. This type of foundation is used in many geologic settings, including those areas underlain by hard carbonate rock, such as limestones and dolomites. When properly designed and constructed, drilled piers provide high load-carrying capacity in both compression and uplift. However, carbonate rock is often subject to intense differential weathering resulting in the formation of an irregular bedrock surface, sinkholes and caves; consequently, the investigation for, and the design of, drilled pier foundations is often complex. Further, the construction may be difficult and costly. This paper discusses geotechnical investigative procedures which can be employed to develop foundation design criteria and reduce the frequency of changed conditions. Finally, state-of-the-art construction practices and quality control techniques are discussed.

Jan 1, 2010

By Djk Arentsen

A new technique to drive tubular piles by impact hammer inside the pile has confirmed a dramatic reduction of noise and the opportunity to save steel. Also a reduction in driving time and a higher bearing capacity has been observed during a test program of this technique. As part of the so-called "Down-the-hole" driving technique, a wave equation analysis has been developed to calculate driveability and pile stress. The main feature of the new "Down-the-hole" technique is the development of a patented device allowing uncoupled penetration of pile tip and pile shaft, which makes it possible to drive both closed or open end piles and reduce the stress level induced in the pile wall. During a test program, a number of instrumented piles were driven and compared with traditional driving of the same pile with the same hammer on top (also instrumented). Also the stresses and performances were compared with precalculations. This paper, explains the technique and presents the test and noise results, in comparison with traditional top-pile-driving. The "Down-the-hole" driving technique is an interesting alternative for special applications where traditional pile driving requires a large wall thickness or in areas where noise is a hot item.

Jan 1, 1996

By T. G. Davies

The paper presents design equations for singly laterally loaded piles embedded in sand. These equations were obtained from a comprehensive nonlinear analysis of free and fixed head piles subjected to horizontal loads. The sand is modelled as an elastic-perfectly plastic material whose strength and stiffness are proportional to depth below ground level. The soil's response is described by means of a boundary element representation of the continuum while the pile itself is created as an elastic beam. Equations for the latter are derived directly from the Bernoulli-Euler theory and are coupled with those describing the non-linear soil response. The effects of bearing failure along the front, face of the pile, shear failure along its sides and tension failure at the back face are accounted for in the analysis. Simple equations are presented to describe both the elastic and inelastic responses. The only sol parameters required to use these equations are the angle of internal friction of the sand and a parameter characterizing the rate of increase of the sand's modulus with depth. The latter can be taken as equivalent to the modulus of subgrade reaction. The results of this analysis show that soil yielding is very significant at working load levels, resulting in substantial increase in bending moments and lateral deflection.

Jan 1, 2010

By Michael T. Lambert

The purpose of the this paper is to demonstrate the benefits of using additional instrumentation during load tests of auger-cast-in-place piles. Traditionally, only load and butt displacement are determined during load tests. The results from and methods used to instrument 15 auger-cast-in-place (ACEP) piles as part of six projects are included herein. By instrumenting the piles, the distribution of load along the pile length and load transfer can be determined, allowing the pile capacity to be adjusted or the length/diameter of the pile to be adjusted for the a given required load. The majority of the piles tested were designed as end bearing piles on either shale or limestone bedrock. No discussion of Geotechnical Instrumentation can be started without acknowledgement of the "Red Book." The actual title of the book is Geotechnical Instrumentation for Monitoring Field Performance, by Mr. John Dunnicliff, John Wiley and Sons, 1993. Anyone undertaking an instrumentation program should thoroughly review the Red Book, paying particular attention to Chapters 3 and 4. Instrumentation should not be done just because it can be done. There must be an unanswered question or questions that can be answered with measured data before instrumentation should be considered.

Jan 1, 2000

By Ed Kase

Cross-hole sonic logging (CSL) has become the universal standard, nondestructive testing (NDT) method used in evaluating the integrity of foundation structures to maintain quality assurance and quality control (QA/QC) of transportation facilities and infrastructures. Tomography, based on three-dimensional cross-hole sonic logging data processing technology, offers an improvement over the techniques currently used to characterize the interior structure of drilled shafts. The underlying concept for seismic tomography is based on the principle that acoustic waves propagate at different velocities through different types of material or the same material with different physical properties. Three-dimensional velocity tomographic images provide greater detail of the interior structure, making defects easier to classify with respect to size and location within the foundation structure. By accurately classifying these defects, an engineer has the information necessary to accurately assess whether these structures meet the applicable design requirements, allowing them to repair or replace inadequate foundation structures. The end result is that the foundation structures will meet the safety and service life requirements for their project. This paper will present applications of seismic tomography, illustrating how seismic imaging can provide accurate information regarding the integrity of foundation structures.

Jan 1, 2003

By John S. Pack

The application of square shaft helical piers in expansive soils is a standard of practice in many areas of the United States. Over 20 years of performance monitoring show exceptional performance and economy will result if proper design procedures, specification requirements and installation procedures are followed. This is true for new foundations and the repair of existing foundations, including lightly loaded wood-frame structures on expansive soils. Proper design includes: 1) site geotechnical characterization, 2) pier layout such that each pier is loaded to its maximum design capacity, 3) maximize spans between piers, 4) minimize the number of piers, 5) isolate the structure from the expansive soil with an appropriate void zone below all grade beams, slabs or other components that would otherwise be in soil contact and 6) utilize only single helix piers. Proper specification employs a performance specification that specifies: 1) the design load on each pier with a suitable safety factor, 2) the minimum installation torque, typically 4,000 ft-lbs (5.4 kN-m), or refusal, 3) a minimum pier shaft steel Fy = 70 to 90 ksi (483 to 621 Mpa) and pier helix steel Fy = 80 ksi (552 Mpa), 4) 1.5 to 1.75 inch (38.1 to 44.5 mm) square shafts, 5) smooth shaft surface, 6) the ICC Evaluation Report (ER) number of the manufacturer and 7) the manufacturer ISO 9001 certification for material quality control. Proper installation requires: 1) equipment with sufficient axial compression force (crowd) on the pier shaft so the helix engages the soil and advances to the specified minimum installation torque or refusal, 2) additional specialized techniques for expansive soils and 3) qualified specialty helical pier installation contractors experienced in expansive soils who submit and utilize pier configurations, techniques and equipment that will most effectively and economically meet the specified performance.

Jan 1, 2007

By Sam X. Yao

In construction of drilled shafts under water, placing concrete in the shafts is technically demanding and involves complex construction logistics. Past construction experience has demonstrated that high quality concrete can be placed in drilled shafts under water with a proper concrete mix and proper placement techniques. However, a significant number of failures have occurred which have resulted in excessive cost overruns and delays. These problems may have occurred because proper underwater concrete construction techniques have not been widely disseminated within the industry. This is a technical area where competent design and sound construction planning can achieve a significant reduction in both risk and cost. This paper will discuss some key technical issues in the concrete mix design, concrete production and placement for the drilled shaft construction. The paper also describes two lesson-learned case histories from drilled shaft construction projects.

Jan 1, 2013

By Ali S. Fayad

"In June 2014, Orange County Flood Control District (OCFCD) completed construction improvements of the East Garden Grove-Wintersburg Channel for a price of $42 million. Instead of the pre-existing traditional trapezoidal levee, the channel was improved with a vertical compact levee. Dubbed Soil-Mix-Sandwich (SMS), this geo-structural and environmental solution for coastal channel improvements, underlain by liquefiable soil strata, was both a design and construction innovation. It employed Deep Soil Cement Mixing (DSCM) within the confines of a hydraulically-pressed (Giken Method) sheet pile duo. SMS was unique because it incorporated both subterranean and supra-dredge-line soil mixing within a very narrow workspace. Its DSCM pattern aimed at optimum densification of the workspace and was confirmed during the construction process. It availed the DSCM sub-contractor (Hayward Baker Inc.) the opportunity to demonstrate the fitness of their huge wet-mixing machinery within a very confined access-area and introduced approximately 70,000 cubic yards of DSCM within a limited 15 foot workspace width that stretched for a mile. The sheet pile duo created a construction-enclosure that became a stay-in-place load resisting system. PROJECT CHRONOLOGY AND LOCATIONAn Orange County Flood Control District (OCFCD) project-report was commissioned to study the East Garden Grove Wintersburg channel (OCFCD facility # C05). The report examined the hydraulic conveyance of the C05 channel and was concluded in 1994 by Williamson & Schmidt. The project-report did not encompass extensive geologic studies; but it provided several alternatives for channel improvement. It recommended a single row of sheet piles as the preferred alternative for the downstream reach.The most downstream reach of the C05 channel is located in an environmentally sensitive area, in City of Huntington Beach, California, USA. Its site includes seismic chasms that surface within the C05-footprint (the Newport- Inglewood tectonic fault). Extensive deposits of liquefiable soil exist beneath the channel. Furthermore, tidal-influence prevails against the channel levee. Implementation of a successful design for channel improvement emerged after several traditional concepts were deemed unacceptable by geotechnical consultants. OC Public Works (on behalf of OCFCD) was in need of a design and construction technique that mitigated many associated risks. From these circumstances, Soil-Mix-Sandwich was born and was referred to in the rest of this discussion as SMS. OC Public Works required the SMS design concept to undergo verification by independent geotechnical consultants. SMS chronology from conception to construction can be summarized as follows:"

Jan 1, 2015

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

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

Jan 1, 2017

By Ronnie W. Sisk

1. Troubles start early - Inadequate Geotechnical Data A. Owners think they are saving money by allowing limited soil borings at their site. This places a high gamble on the bidders and the Lump Sum Price will be higher. B. Inaccurate elevations on soil reports. a. Surprises in depths - over or under design bid bottom elevations. 1. Requires backfill and extraction of casing that is too short for the greater depth of the drilled shaft. 2. Redrill utilizing longer casings. 3. Softer earth (backfill) can cause difficulties in redrilling such as less quantity extracted on the auger and maintaining plumbness. 4. Greater concrete overrun. b. Extreme under depths. 1. Excessive concrete is placed as a result of planning for a deeper shaft. c. Geotechnical report that does not supply a layout of boring locations. d. Design Engineer does not have a basic knowledge of how a caisson is installed.

Jan 1, 1988

By Garland Likins

High strain PDA testing has become common for verification of capacity of both driven and bored piles. It is equally applicable to Augered-Cast-in-Place (ACIP) Piles. It also evaluates other aspects of the installation such as integrity. The benefit of high strain dynamic test results for the relatively low cost of the tests compared to conventional static testing has resulted in widespread use. The method is described and specific procedures for testing ACIP piles are outlined. Example results demonstrate the application.

Jan 1, 2000

By Julie H. N. Hampden, Per G. Reinhall

"Executive summary: Impact pile driving of steel piles is a common construction practice in freshwater and marine environments for the building of structures and foundations. This practice produces extremely high sound levels underwater that have proven injurious to aquatic fish and wildlife. To limit impacts to sensitive species, resource management agencies employ a variety of different strategies including timing restrictions to limit in-water construction windows to those months when there are low flow conditions in lakes or rivers, to those hours when tides are low, or to periods of the year when species of concern are least likely to be present in the project vicinity. In addition, permitting agencies have identified noise thresholds above which sensitive species could be injured, resulting in additional project conditions to curtail the extent of project noise impacts including: limiting the number of piles or pile strikes per day, requiring biological monitoring, and mandating the use of noise attenuation techniques, such as bubble curtains and cofferdams. Numerous studies have shown current noise attenuation techniques are costly and provide limited or variable noise reduction [1-3]. This is because the noise from pile driving is not only transmitted through the water column, it is also transmitted through the sediment back into the water column [1, 4-8]. Though these protective measures may help to reduce project impacts, they also result in additional complexity, expense, and potential risk for project delivery. Marine Construction Technologies, a Public Benefit Corporation, in collaboration with University of Washington and Washington State Department of Transportation, has developed a pile that can be installed with standard pile driving technologies (vibratory or impact hammers) and consistently decreases the total noise transmitted into the water. The double-walled pile is relatively quiet in comparison to unattenuated piles or existing noise attenuation techniques. This technology not only reduces the risk to sensitive species by minimizing the extent of potential impacts, it also reduces potential risks to project delivery by limiting the size of monitoring areas, minimizing the need to cap daily production rates, and eliminating the need for deployment of additional noise attenuation devices. Results from finite element modeling of the pile, scaled prototype testing, and full scale field testing in Commencement Bay (October 2014) and Vashon Island (October 2015) in Puget Sound, Washington indicate a reduction the peak sound pressure between 14 and 20 dB relative to single walled piles at a range of approximately 10 meters. These tests also confirm that the double-walled piles provide drivability similar to standard steel piles. In addition, preliminary calculations for capacity and structural characteristics demonstrate that double-walled piles provide equivalent or better performance than same-sized standard piles."

Jan 1, 2017

By J. G. La Fonta

The rapid development of real-time monitoring technology for the construction of large underground structures in urban areas can be attributed to: the zero-risk objective, the need for transparency between all parties involved and the control of real cost within the budget. Real-time monitoring can be an integral part of the construction contract (for example when compensation grouting is required) or independent, in particular when measurements of existing structures and buildings bordering the project are to be taken before construction starts. Three examples of extensive field instrumentation schemes are described: a large road tunnel in the Moscow suburbs, a new metro line in Amsterdam and major redevelopment works at a busy Central London rail interchange.

Jan 1, 2006

By Andrew Higgins, Jamey Rosen

This presentation will demonstrate some recent advancements in the applications of Project Information Systems (PIMS) technology to seepage barrier walls in the context of evolving Owner Specifications. The use of geospatial technology in particular is used to track, visualize, and analyze data from a variety of sources and serve those data to contractors and owners via dashboards and as-built drawings. Data describing the geometry of construction elements (including diaphragm panels, secant piles, and jet grout columns) is of particular importance on these projects, and this presentation will include case studies in the United States of how these data are used to determine if a barrier wall is constructed as designed and if it meets the owner specifications with respect to tolerance (i.e., if each element is sufficiently close to vertical) and overlap (i.e., do adjacent elements overlap sufficiently to prevent leakage).

May 1, 2022

By Rangaswamy. K, Naga Sivaji

A stone column is one of the most commonly employed methods of ground improvement techniques. This method used to increase the strength, decrease the compressibility of loose granular and finegrained soils. Also, it accelerates the consolidation in clays and reduces the liquefaction potential of sands and silt soils. In general, the stone column contains 15 to 75mm stone aggregates. In reality, it is not easy to avail the natural stone aggregates due to unavailability in locally nearby places. Present work aims to replace the stones partially or entirely by scrap tyre chips as an alternative material. The utilisation of recycled tyre chips in ground improvement is an environmentally friendly solution and avoid the disposal of tyre chip waste in large pits. Model tests conducted on marine clay with encased end bearing stone columns (ESC) constructed with a mixture of stone aggregate and tyre chips with sizes 4.75 to 10mm. The column diameter is 75 mm, L/d ratio maintained to 5.3. Non-woven geotextile wrapped encased stone column has introduced in the soft marine clay model. Encasement prevents the lateral squeezing of aggregates into the surrounding clay and protects the drainage function of the stone column. A set of load-settlement tests were conducted on both the clay model and clay model treated with the stones-tyre chips column. The model was loaded by the tri-axial loading frame. Shear strength parameters of stones and tyre chips were determined by large size direct shear tests. Model test results are concluding that the load-carrying capacity of the clay is improved significantly after installing the stone column in it. The encasement increases the load-carrying capacity and stiffness of the ordinary stone column. It is also proved that the stone aggregate could be replaced partially by tyre chips up to 60% without a significant reduction in its performance.

Nov 1, 2022

By Andrzej Tejchman

A method of improvement of a subsoil under bored pile base by injection is presented. The method employs a special chamber attached to the reinforcement at the bottom of the drilled borehole. The chamber is made of semi-permeable textile bag. The injection entered under high pressure into the bag, causes prestressing of subsoil under the pile base. The results of load tests of piles improved in this manner have shown a substantial increase of their capacity together with simultaneous reduction of settlements. This technology has been implemented for four constructions such as trestle bridges in Gdynia and Warszawa and the bridges in Szczecin and Gdansk. The injection effects are shown based on the load test results.

Jan 1, 2002

By Jamey B. Rosen

As Project Information Management Systems (PIMS) technologies develop, the range of projects to which one can apply these technologies grows while the cost to apply them shrinks. In recent years, technologies previously limited to large “megaprojects” (e.g., major dam rehabilitations) owned by major entities (e.g., the United States Army Corps of Engineers) with large budgets have been applied to smaller projects with less stringent specifications and more modest budgets. This paper will describe applications of PIMS technologies to small projects with limited budgets, including examples from levee construction, small-scale grout curtain installation, and diaphragm and secant pile cut-off walls. We will include a demonstration of how PIMS technologies can effectively analyze verticality data from koden and hydromill data streams to automatically generate models and as-built drawings showing overlap and deviation along the depth of the foundation. INTRODUCTION This paper discusses the application of Project Information Management Systems (PIMS) technologies to geo-foundations projects, with a focus on technologies and examples that are in a lower cost range. PIMS technologies allow contractors and other stakeholders to perform efficient quality control on their data, generate quick or automatic reports and as-built drawings, perform analyses to better understand their construction, and ultimately use their data to increase the quality of their construction. As PIMS technologies are relatively new to the deep foundations industry, and owner specifications on their use are generally viewed as complex and limited to large scale projects, PIMS technologies are frequently viewed as an expensive component that is beyond the scope of a smaller or simpler project. However, the same principles and techniques generally associated with large projects can be applied to projects at smaller scale. Furthermore, as these technologies develop both in the deep foundations and other industries, the cost of application is decreasing quickly making them even more affordable for smaller projects. The remainder of this paper provides some justification for applying PIMS technologies, describes some scalable data management concepts and workflows and then provides some examples of “low cost” applications of these technologies.

Jan 1, 2019