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By Ashraf M. Eid

Most research dealing with the problem of laterally loaded piles has been the response of individual piles subjected to lateral loads and/or bending moments. However, piles are seldom used individually but are normally constructed in clusters or groups. Little information is available of the effect of pile-soil-pile interaction (PSPI) on the performance of the group. This may be attributed to the difficulty of carrying out full-scale tests. Such tests are prohibitively expensive and require special installations to provide the required large lateral loads. The problem of laterally loaded single piles or pile groups involves the complexity of extending the theoretical solutions to the limits where the actual soil behaves nonlinearly. As the load increases, the elastic soil behavior cannot be adopted for design. Nonlinear soil behavior or the elasto-plastic behavior is evident. This research consists of experimental and theoretical models. The experimental work was conducted on models of free head pile groups in different configurations. The piles were in a sand formation and compared to the behavior of a single pile. The possible factors that influence the group behavior could be visualized. The experimental data was also compared to the widely used theoretical approaches to determine their adequacy. The analytical model makes use of the finite difference approach to calculate the soil non-linearity. A new approach equates the measured ground deflection and maximum bending moments of each row at every load level with the analytical model of single pile. This is the Deflection-Moment Fitting (DMF). The most suitable non-linear soil modulus modes and row contributions could thus be determined. Design of pile groups can be based on data pertaining to soil characteristics of the single pile. Results of the analysis were consistent with other approaches and proved to be adequate for design.

Jan 1, 2005

By Timothy Nelson, Simon Burnworth

"The University of California’s new Berkeley Art Museum and Pacific Film Archive will showcase a collection of art and film in a facility that pairs an existing 1930s-era printing press facility with a new, architecturally unique auditorium wing. The centerpiece of this adaptive-reuse project is the existing 3- story art-deco Administrative Building, which will be integrated into the new museum and provide approximately 18,000 square feet of usable space. Degenkolb Engineers, as the shoring engineer of record, along with Condon Johnson & Associates Inc., the shoring contractor, worked together with general contractor Plant Construction Company to design and build a temporary structure to facilitate the complex retrofit, renovation, and expansion of the Admin Building. This paper will discuss the challenges faced by the design and construction team, the sustainable solutions implemented on the project, and the collaboration between teams to meet the unique constraints of the project and the site.INTRODUCTION AND PROJECT BACKGROUNDThe Berkeley Art Museum and Pacific Film Archive (BAMPFA), which currently resides in a 1970s-era post-modern concrete structure just south of the University of California Berkeley (UCB) campus, was in need of a new home after an engineering evaluation revealed that the building possessed seismic deficiencies. Pressed for space, the University looked within its portfolio of properties and identified the site of the former University Printing Press facility as the place to build BAMPFA’s new home."

Jan 1, 2017

By Cen Guoji

The foundation of bored pouring concrete pile have been adopted in the bridge engineering of China since early in the sixties. They demonstrated tremendous technical advantage and achieved notable economic benefit. With improvement of bridge technique including construction technique work equipment, design theory, examination in quality and applicable range etc, the pile diameter became bigger and the foundation changed from shallow to deep-water. This paper examples Jiujiang Bridge of Guangdong in China, which is single-tower cable-staged bridge, total length of 1675m, and expouds adopted successfully the foundation of variable section large bored pile (upper part d=3m, central part d=2. 4m and lower part d=2m) on the conditions of complicated technique that the load is tremendous (it require specially to resist 12000 kN ship impact) and the piles have free length 30m. The paper will be to describle design project and construction practice of pile foundation with variable section, and to compare schemes of equal section pile and pile in sinking-well.

Jan 1, 1991

By Shahid Islam, Lucian Bogdan

"The maintenance of infrastructures has been of particular concern to the engineering community. As the world’s infrastructure expands and existing infrastructure ages, monitoring and evaluation of the structures have become more critical than ever. A large number of retaining walls, tie backs, slope stabilizations and piles are designed using pre-stressing steel. Many piles and drilled shafts are designed using reinforcing steel. There are few testing methods available to assess these tension and compressive forces. High cost, complicated equipment and limitation of space often prevent these methods from being implemented. DYWIDAG-Systems International (DSI) has been involved in the development, testing and utilization of DYNA Force® sensors to measure the force in the anchors during construction and at any time during the lifetime of the structure. They can be used for bare, epoxy-coated, galvanized and greased-sheathed steel in the bonded, un-bonded, grouted or un-grouted length of the anchor. The sensor is robust and requires no maintenance. Sensors have received attention in terms of accuracy, performance, ease in installation, durability, and cost effectiveness. This paper describes its application in tie-back and anchor force monitoring of retaining walls and bridge abutment and compression forces in drilled shaft reinforcing steel where the data were collected manually, automated and remotely.INTRODUCTIONOur infrastructure is expanding and the existing infrastructure is aging. Some structures are expensive to maintain and some occasionally fail. There is a large demand for implementing health monitoring of structures. Many tie-backs, retaining walls, dams and other geotechnical structures are post-tensioned and many of them need repair using a post-tensioned system. On many occasions during construction and service life of the structure, it is useful to know the force in the post-tensioning and anchor system. Many piles and drilled shafts are designed using reinforcing steel and the compressive forces in reinforcement are unknown. Although there are many methods to measure the tendon force, most of them are cumbersome, expensive, and the accuracy varies depending on the method used.The elasto-magnetic (EM) technology is a novel approach to monitor forces in steel elements. The DYNA Force sensor is built based on EM technology (See Fig. 1). It is composed of a primary coil and a secondary coil (sensing coil). By passing current through the primary coil, ferromagnetic material is magnetized. The sensing coil picks up induced electromotive force that is proportional to change rate of applied magnetic flux (Faraday's law) and relative permeability. As permeability of core changes, output voltage changes. The output voltage is calibrated to measure the force. A readout unit is designed to magnetically energize the steel through the sensor and measure the response of the steel to the process. The readout unit then converts the response into a direct force reading. The sensor has an embedded thermistor which allows for temperature compensation. Due to the diversity of the magnetic property of steel, calibration is done for each type of steel allowing the sensors to perform at their highest accuracy."

Jan 1, 2017

By Patrick Wong

The design of piling platforms is addressed in BRE (2004) for both fine grained and coarse grained subgrades. However, for coarse grained subgrades, piling platform designs can often be overly conservative due to either conservative assumptions on soil friction angle, or concerns over density variations of granular fill, particularly for made-ground. This paper provides guidelines on economic design of piling platforms on coarse grained subgrade by providing recommendations on ground characterization, assessment of soil properties and the use of non-linear stiffness soil behavior. An innovative performance-based design approach is also introduced, utilizing proof rolling with associated testing and interpretation using small strain theory to overcome concerns regarding potential ground variability of made-ground. A case study is presented to demonstrate the successful application of this performance-based approach to avoid having to construct a new piling platform over a 2 ha area. Small strain, non-linear stiffness theory was used to enable a practical proof rolling pressure to be adopted without having to reach the design or ultimate operating pressure. The author considers that the performance-based approach adopted on the case study may be similarly applied to a range of other projects to derive economic solutions.

Nov 1, 2022

By Tracy Brettmann, Shailendra Endley, Jason Leary, Shashank Valluru

"Augered Cast-in-Place (ACIP) piles have long been used for deep foundation support in sands due to their high capacity and speed of installation. Very little information exists on the effects on capacity if the auger needs to be withdrawn from the hole prior to grouting. This condition can occur due to various reasons including grout plug ups, equipment issues, and grout supply delivery problems. It can become a major problem for the project team if this happens during production because the capacity of that pile is then in question, potentially resulting in re-design, installation of replacement piles and/or schedule delays. This paper compares the results of two high capacity test piles installed into a dense sand where one test pile was installed by first completely withdrawing the auger from the hole after drilling to the pile tip depth and the other test pile was installed utilizing conventional industry standard methods. Identical load tests were then performed on both piles to compare the effects of the two different installation procedures. The load test results were surprisingly similar in this case although the grout take required for the test pile installed in the pre-drilled hole was significantly higher to produce a similar grout return depth.IntroductionAugered Cast-in-Place (ACIP) piles are used extensively along the Texas Gulf Coast due to their combination of high capacity and speed of installation resulting in one of the most cost effective deep foundation systems relative to other options. Soil conditions in this region typically consist of alternating layers of sand and clay in the upper several hundred feet. ACIP piles are routinely installed to depths of over 100-ft to achieve the required capacity depending on the site specific soil conditions and therefore typically extend through and tip into sand layers. Occasionally, due to various reasons like equipment issues and plug-ups, the auger is withdrawn from the hole without grouting. Significant sand in the soil profile could lead to questions about the effect of the auger withdrawal on the pile capacity and load deflection relationship.This paper summarizes the results of two identical pile load tests performed on adjacent piles of the same length with the main difference being one was installed using the standard installation procedure and the other was installed by first completely withdrawing the auger from the hole after drilling to the pile tip depth. The load test results were then evaluated using load transfer analyses to estimate the effect of the withdrawal of the auger on the load-deflection characteristics and capacity."

Jan 1, 2017

By Vishal Pathak, Shailesh A. Godhuly

Ground Modification System in terms of Jet Grouting for soil strengthening and mass stabilization was engaged for a power plant project in an international power project, engineered by L&T-S&L. The site Geology consist of cohesionless type of sandy alluvial deposits (silty fine sand) as the main formation. Ground water table is encountered at shallow depth. Geological interpretation is done using soil investigation data along with CPT’s. This paper discusses design and implementation of jet grout technique to improve the mechanical behaviour of soil. To distribute load evenly from superstructure, a layer of growmast (drainage blanket) is laid above jet grout columns. Settlement evaluation is done using Finite element analysis with Plaxis 2D and Settle 3D. In the project, selected equipment foundations are resting on jet-grout columns including vibratory equipment like 144MW Gas Turbine etc. The project has been commissioned in September 2021 and operating with full capacity.

Sep 1, 2022

By Thomas L. Vande Voort

The strategic plan for bridge engineering issued by AASHTO in 2005 identified extending the service life and optimizing structural systems of bridges in the United States as two grand challenges in bridge engineering, with the objective of producing safer bridges that have a minimum service life of 75 years and reduced maintenance cost. Material deterioration was identified as one of the primary challenges to achieving the objective of extended life. In substructural applications (e.g., deep foundations), construction materials such as timber, steel, and concrete are subjected to deterioration due to environmental impacts. Using innovative and new materials for foundation applications makes the AASHTO objective of 75 years service life achievable. Ultra High Performance Concrete (UHPC) with compressive strength of 26,000 psi (180 MPa) and excellent durability has been used in superstructural applications but not in geotechnical and substructural applications. This paper explores the possibility of using precast, prestressed UHPC piles in future bridges. An H-shaped UHPC section, which is 10-in. (250-mm) deep with weight similar to that of an HP10×57 steel pile, was designed for constructability and economical reasons. Instrumented UHPC elements were cast to conduct large-scale field tests. In the field, two UHPC piles have been successfully driven in glacial till clay soil and load tested vertically. Test results, durability, drivability, and other material advantages over normal concrete and steel indicate that UHPC piles are a viable alternative to extend the life of bridge structures.

Jan 1, 2008

By Konstantin G. Ashkinadze

The paper considers performance of piles supporting transient pipe anchors in heavy industrial pipelines. Events such as pump trips or opening and closing of large valves produce short-term dynamic pulses in the pipeline with variable spectral characteristics. Their magnitude is large enough to cause major damage to the pipeline and its anchors, which face horizontal impact loads amounting to hundreds of kN. Design of pile foundations supporting these anchors is often governed by limitation of deflection of the support to prevent overstressing pipeline connections and equipment nozzles. The maximum deflection does not always correspond to the largest load because the stiffness of the soil surrounding the piles heavily depends on the rate of loading. Faster actions encounter stiffer soil response while loads of smaller magnitude applied slowly may be more critical for the deflection time history of the anchor. A typical transient action has both high- and low-frequency harmonics, which makes the response complex. Using load rate-dependent p-y curves published in literature, the paper develops methods of analysis of pile foundations for transient anchors. Pile displacement amplitude – input frequency – natural frequency correlations and time histories of pile response are constructed for typical profiles of transient actions, considering nonlinear soil response to large horizontal loads.

Jan 1, 2016

By Hubert Law, Dan A. Brown, Kyle M. Rollins

"Soil mixing and jet grouting provide a means to significantly increase the lateral resistance of pile group foundations with relatively little investment of time, effort, and expense compared to the cost for additional piles necessary to produce the same increased resistance. Comparative field testing conducted on full-scale pile groups before and after treatment of small soil volumes showed significant improvement in lateral resistance. The lateral resistance of the pile group increased by 60% due to soil mixing and by 180% due to jet grouting. To provide additional understanding regarding the influence of the soil mix strength, depth of improvement and width of improvement, a series of parametric studies were performed using a 3D finite element model. This set of “virtual load tests” was then combined with the results from the actual field tests to help develop a simplified model to account for observed behavior. In general, the testing and analysis indicate the pile group and the surrounding improved soil block generally act as an equivalent “super pile”. The passive force, side shear and base shear on the improved soil surrounding the pile group itself increased lateral resistance. This increase in resistance from the soil block can be added to the lateral resistance of the pile group.INTRODUCTIONThe lateral resistance of pile groups is often critical to the design of bridges and high-rise structures subject to seismic, wind, wave and landslide forces. Typically, when analyses indicate that the lateral resistance of a foundation is inadequate, additional piles, drilled shafts or micro-piles are added to increase the lateral resistance. Furthermore, an expanded pile cap or connecting beam is often required to structurally connect the new piles to the existing pile group. While this approach provides the required lateral resistance, it may also be relatively expensive and time consuming. An alternative approach is to use soil improvement techniques to increase the strength and stiffness of the surrounding soil and thereby increase the lateral resistance of the pile group. The improved zone could potentially be relatively shallow because the lateral resistance of piles is typically transferred within 5 to 10 pile diameters. For example, the soil around the periphery of the foundation could be relatively easily improved for an existing foundation as illustrated in Fig. 1(a) using a variety of soil improvement techniques. Alternatively, the soil under the foundation could be improved for a new foundation or even for an existing foundation with a technique such as jet grouting (see Fig. 1(b)). Improving the soil under the foundation would have the potential for producing greater increases in lateral resistance because the improvement would reach interior piles. In addition, the process of creating a cemented “soilcrete” zone around pile foundations could potentially produce a zone which would behave like a reinforced “superpile” with increased structural stiffness."

Jan 1, 2015

By Zhou Haizuo, Diao Yu, Zheng Gang

"The conventional design method for the embankment supported by DM columns usually assumes the simultaneous failure of all the columns. However, the progressive failure may occur in practice, especially considering that many researches have justified the critical load of DM columns is bending moment. In this study, a finite difference method was adopted to simulate the embankment on soft clay improved by DM columns. An increasing surcharge was applied on the embankment surface to investigate the mechanism of the progressive failure of columns beneath embankment. To capture the brittle bending failure of the DM columns, the model employed a cut-off method, in which the column was separated on failed section as long as the ultimate bending failure was reached. Furthermore, high-strength DM columns were used to enhance the global stability of embankment in this study. The numerical results showed that the ultimate bending failure was first reached at the column beneath embankment toe, and then a continuous collapse extended to the column beneath the embankment shoulder. It is found that the reinforcement could be obviously effective when the reinforced area of high-strength DM columns was extended to a certain area.INTRODUCTIONDeep mixed (DM) columns have been commonly used as a soil-improvement technique to increase stability and to reduce settlement of embankment. Research on failure modes of DM columns owing to embankment fill and surcharge has been the subject of interest for a number of investigators (Miyake 1991; Kitazume 2000; Han 2005; 2006).The potential failure modes of DM column include bending, inclination, shearing, rotating, soil flowing and a combination of these modes (Kitazume and Terashi 1991; Broms 1999). Many researchers have found that bending failure of DM columns was more critical than the shear failure. A centrifuge test was performed by Kitazume (2000) and the results showed that the columns failed in bending before shear failure. In addition, several numerical computations illustrated that design method using the shear strength overestimated the stability of embankment over DM columns (Han and Huang 2005; 2006; Navin 2006; Liu 2007; Wang 1996). In practice, an equivalent shear strength method based on bending failure could better reflect the stability of embankment (Zheng 2010; China Code JGJ79-2011)."

Jan 1, 2015

Jan 1, 1997

By Robert Bachus, Jamey Rosen, Fabio Santillan, Georgette Hlepas

"A seepage barrier of length 4,800 feet and maximum depth 144 feet is being installed at Bolivar Dam in Ohio. This project is owned by the United States Army Corps of Engineers and contracted to Treviicos South. Many data types are being collected, synthesized and analyzed on a nearly real-time basis to monitor and track dam construction using several technologies including an enterprise relational database and web-based Geographical Information Systems. These data are being collected by both the owner and contractor and managed by the data subcontractor, Geosyntec Consultants. Each of the owner and contractor brings their own list of goals and desires to the data management program, and the subcontractor’s duty is to address these goals with minimal compromise by either party. The owner requires comprehensive, transparent and timely access to data in both “executive summary” and detailed formats. The contractor requires immediate analysis of disparate data to determine (for example) if a given excavation meets the specified tolerance and continuity requirements. This paper will describe the tools and methods used to store, analyze and visualize these data and discuss how each party’s needs were met in a collaborative system.INTRODUCTIONThe 4,800 foot long seepage barrier under construction at Bolivar Dam requires the collection, organization, and sharing of several types of data. These data include drawings and borehole logs that existed prior to construction; data collected during construction (seepage barrier panel composition and verticality data, slurry quality control and quality assurance data, grouting records, etc.); and instrumentation data collected and reviewed throughout and beyond construction. Each of these data streams require input and review from the Owner (United States Army Corps of Engineers (USACE), responsible for quality assurance and the ultimate consumer of the data), the Contractor (Treviicos South, responsible for the construction of the seepage barrier, its quality control and analysis of the data per the Contract Specifications), and the Data Management Subcontractor (Geosyntec Consultants, responsible for organizing and presenting the data to meet the needs of the Owner and Contractor). While all parties work with the same common goal, i.e.: producing a high quality product in an efficient manner making dam safety paramount during construction, and require immediate and comprehensive access to these data, the needs and desires of the parties differ. The challenge presented to the Data Management Subcontractor is to synthesize these data into a series of tools and reports that meet each of these needs."

Jan 1, 2017

By Jim Slatter, Ben Collingwood

"It is well known that the adoption of an appropriate construction methodology is critical to quality outcomes for bored piles (drilled shafts). Many case studies have been published documenting quality issues that have arisen due to a range of causes involving ground conditions, ground support, drilling and cleaning techniques, groundwater, concrete properties and concreting methods, amongst other things. Despite the body of published information, pile defects remain common in practice. The authors share over 40 years’ experience in the Australian piling industry and have participated in many hundreds of projects involving bored piles in design, construction and testing roles. It is the authors’ experience that many defects are caused by conditions or practices that are known to be problematic, but that are often not recognised or addressed at the time of the works. This paper provides an overview of industry practices and key factors relevant to quality outcomes. The authors draw upon their own construction experience, published case studies and guidelines, and observations from independent pile testing activities they have been involved in across the Australian piling industry. The intent of the paper is to provide a consolidated review of typical industry practices and to highlight key areas in which construction quality can be enhanced.INTRODUCTIONThere are many published studies of cases where bored piles have been constructed and found to have concrete defects. The authors have had personal involvement in many cases where the outcomes and learnings are not publically available. The nature and cause of defects is always dependent on site and project specific factors, and therefore methodologies and materials that produce satisfactory outcomes in certain circumstances may be problematic elsewhere. The process of bored pile construction encompasses the following key areas:??excavation and ground support;??pile preparation and cleaning;??pile reinforcement and fitments.??concrete supply and mix performance;??concrete placement methodology;Each of these elements is equally important and can influence construction quality in completed piles. In the authors’ experience, it is often a combination of seemingly minor issues that leads to significant defects in piles. Conversely, attention to detail in all aspects of bored pile construction is required to produce outcomes of a consistently high standard."

Jan 1, 1900

By Meeok Kim, Paul Beljan, Gordon Chen

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

Jan 1, 2015

By Lance Rasband, Richard Hanke, John Starcevich

"The 17.4 meter (57 ft) diameter tunnel boring machine (TBM), the world’s largest at the time of her launch in 2012, locally referred to as “Bertha,” is stuck. Incapacitated due to mechanical failure approximately 36 meters (120 ft) beneath downtown Seattle, situated precariously between the deteriorating Alaskan Way Viaduct and the failing Seattle Seawall. Accessing Bertha with a vertical shaft provides the best approach to address all facets needed for repairs and will allow the full removal of Bertha’s cutter head and related inner workings. Limited area above the tunnel alignment and the physical restrictions of existing infrastructure, create significant challenges for the design of an otherwise symmetrical shaft, requiring special attention to design and layout. Consequently, the access/recovery shaft design required a combination of 3m, 2.5m, 2.2m, 1.5m and 1m diameter unreinforced drilled secant piles coupled with various ground improvement techniques and dewatering, to fully satisfy the shoring design requirements. This paper will describe the shaft installation procedures, equipment used and pitfalls encountered while undertaking access shaft construction of this magnitude.INTRODUCTIONTunneling on Seattle’s SR99 tunnel project began in July of 2013. After slowly mining through a 4.5 m (14.76 ft) thick fiber-reinforced concrete headwall and the first of three stabilized “safe havens,” Bertha would proceed along the proposed alignment through 122 meters (400 ft) of jet grout improved soil at a rate of slightly over 1.6 m (5.25 ft) per day. Once past the improved area, it was planned that “Bertha” – would be moving at a rate of about 11 m (36 ft) per day. By the end of October 2013, Bertha had mined roughly 131 m, (430 ft) averaging 1.4 m (4.6 ft) per day and had begun mining within native soils. By December 2013, tunneling had reached the 244 m mark and Bertha was averaging 3.6 m (11.8 ft) per day, achieving as much as 12.8 m (42 ft) of progress on given days. Unfortunately, on December 6th, 2013, Bertha began to stumble and all progress quickly came to a halt.It was initially reported that an obstruction had stopped Bertha in her tracks. The preliminary investigation involved installation of 10 deep dewatering wells to reduce the hydrostatic pressure around the TBM, and allow visual inspection of the cutter head from within the TBM, and also to investigate for the presence of obstructions at the face of the cutter head. During this inspection, fragments of steel pipe were discovered entangled in the cutter head. The fragments were apparently from an abandoned 254 mm (10 in.) diameter monitoring well casing, previously installed by WSDOT to monitor ground water conditions for the design and planning of this tunnel project. After the steel was removed from the cutter head and cleared from Bertha’s path, tunneling resumed. It was then discovered that Bertha was only able to generate a slow crawl."

Jan 1, 2016

By Arash Khosravifar, Ali N. Ibrahim

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

Jan 1, 2017

By Shawna Munn, Nadir Ansari, Toben Jerry

With ever increasing demands on space in urban environments and smaller available footprints, buildings are being designed to increasing heights to meet the need. This case study discusses the increasing challenges in developing projects within urban environments with smaller available footprints and increasing building heights. The One, Canada’s tallest residential building under construction will stand at 85 storeys and is located at one of the most prominent and built up intersections in Toronto, Yonge Street and Bloor Street. This led to many challenges in design and construction of the shoring and foundation work, including the required design capacity of the foundations for the supertall building and proximity of the large diameter drilled shafts to the excavation shoring wall. This case history describes the shoring design option evaluation, performance, and lessons learned to date throughout construction of the building foundations within a small congested site. PROJECT OVERVIEW The One, Canada’s tallest residential building under construction by Mizrahi Developments, is a supertall building that will stand at 85 storeys and 306 m (1005 ft). The first 18 floors will be comprised of retail, restaurants, and hotel with luxury residential condominium units in the tower above. The project is located on the Southwest corner of Yonge Street and Bloor Street, one of the most prominent and built up intersections in Toronto. The L-shaped excavation measures 58 m by 47 m (190 ft to 154 ft) and ranges from 22 m to 28 m (72 ft to 92 ft) in depth with one internal corner projecting 11 m (36 ft) into the site.

Jan 1, 2019

Jan 1, 1993

By E. W. Raabe

The paper discusses the increasing role of specialist grouting techniques to form water seals or cut-offs for deep basement construction. Raabe and Toth discuss the various grouting methods available for sealing applications and then concentrate on the use of Soilcrete Jet Grouting, a system particularly well suited to ground water control. The Soilcrete processes, suitable soil types and quality control methods are fully described, particularly with regard to the formation of cut-off walls and sealing slabs to prevent the progress of ground water or leachates. The authors have included case histories detailing their experience on designing and installing Soilcrete seals for various projects in West Germany. These include an underground rail project in Dortmund and a discharge structure for the Alz Canal at Burghausen.

Jan 1, 1989