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By Craig M. Shillaber, Joseph E. Dove, James K. Mitchell

"This paper addresses two primary factors affecting the sustainability of Deep Mixing Methods (DMMs): construction materials and handling of the spoil from wet mixing methods. We examine these factors within a life-cycle embodied energy (EE) and carbon dioxide (CO2) emissions accounting framework, using the LPV 111 project in New Orleans, LA as a case history. The underlying assumption is that project planning and preliminary design have determined that a DMM is the best ground improvement alternative for achieving the broader aims of sustainable development. While EE and CO2 emissions are direct measurements of environmental impact alone, we illustrate how their minimization can also influence the social and economic consequences of the project. It is recommended that DMMs use lower energy and carbon material alternatives to Portland cement and lime in the binder whenever possible, with preference given to locally sourced materials. Currently available alternative cementitious materials include fly ash and slag, which are waste products from other processes. In addition, recycling the spoil material from wet mix methods on site is recommended. If the material cannot be recycled on site, transporting it to a processing and recycling center for later use as fill is preferred over landfilling. INTRODUCTIONWithin the geotechnical community there is an increased appreciation for sustainability considerations, which are an important component of the planning, design, construction, operation and maintenance of projects. An assessment of project sustainability includes holistic life cycle thinking, systems analysis, environmental impact assessment, use of safe and benign materials, awareness of local societies and cultures, social equity, protecting human health and well-being, and monetary costs (Abraham, 2006). Since ground improvement is a principal practice domain of geotechnical engineers, it is important that geo-professionals play a role in addressing the sustainability for these projects. In this paper, we illustrate by case history how different materials and methods associated with deep mixing projects can impact overall project sustainability through quantifying project embodied energy (EE) and carbon dioxide (CO2) emissions. EE is defined as all energy consumed to bring something into its present state (Chau et al., 2008; Inui et al., 2011; Soga et al., 2011; Chau et al., 2012). Recommendations are then made for how adverse environmental impacts of Deep Mixing Methods (DMMs) may be minimized, leading to more sustainable geotechnical construction."

Jan 1, 2015

By Michael Arnold, Bob Faulhaber, Joe Nichols

"Center Hill Dam is a critical part of the infrastructure controlling floods at the Caney Fork River and reducing flood levels at the Cumberland, lower Ohio and Mississippi Rivers. The Center Hill Dam Foundation Remediation Project was necessary to address Karst features in the foundation rocks and observed signs of distress of the dam. From 2011 to 2014 BAUER Foundation Corp. (BFC) performed deep foundation works for this project. The executed features of work include the installation of two walls. The first wall extends throughout the clay embankment into the underlying rock to provide encasement during the construction of the second wall. Its width of 7.4 feet makes it the widest diaphragm wall ever installed. The second wall is the actual seepage barrier and provides a continuous 2- feet wide wall. It extends through the first wall into the underlying rock and is up to 300 feet deep. The paper introduces the project, the requirements specified by United States Army Corps of Engineers (USACE) for encasement and barrier wall and the approaches taken by BFC. It discusses the ground conditions and describes the excavation equipment as well as the excavation methods used. A special focus is put on the steering capabilities of the hydrocutter equipment and the verticality performance.PROJECTBeginning in 2011, BFC was tasked by the USACE with the installation of a seepage barrier/cutoff wall at the Center Hill Dam Foundation Remediation project under a partially performance based specification. The remediation was necessary due to karst features in the foundation rocks and observed signs of distress, which led USACE to rate the dam with the most critical dam safety action classification (DSAC I). The executed features of work include the installation of two walls. The first wall, an encasement wall, extends vertically through the clay embankment and is embedded minimally into the underlying bedrock to provide embankment stability during the construction of the second wall, the barrier wall. The encasement wall is constructed of overlapping panels 7.4 feet (2.25 m) wide, which is the widest diaphragm wall ever installed, and up to 210 feet (64 m) deep. The second wall is the seepage barrier and provides a continuous 2 feet (0.6 m) wide wall consisting of overlapping panels. It extends through the encasement wall into the underlying bedrock and is up to 307 feet (93 m) deep. BAUER BC40 and BC50 hydrocutters mounted on MC96 and MC128 foundation cranes were used to perform the majority of the works (Figure 1). Excavations were performed under bentonite slurry (encasement wall) and water (barrier wall) and concrete was poured with the tremie method. Adding to the challenges, the project had to be executed in an environmentally sensitive area. Based on the high risk, a special focus was put on monitoring, quality control and geometric accuracy. The WallTracker information management system was used to share all relevant data between BFC and USACE (Roff et al. 2014)."

Jan 1, 2017

By Ke Yang

Drilled shafts are widely adopted as the foundation for sound walls. However, there has been a lack of uniformity in design and analysis methods and design criteria, in terms of factor of safety against ultimate capacity failure as well as the allowable deflection. In order to establish a uniform design methodology for the drilled shafts supporting sound walls in cohesive and cohesionless soils, respectively, a database of full-scale lateral load tests on fully instrumented drilled shafts was collected. Based on the compiled database, existing design methods and design criteria of laterally loaded drilled shafts were evaluated. Broms method and COM624P (or LPILE) are suggested as the design methods for drilled shafts supporting sound walls in both cohesive and cohesionless soils. Additionally, the corresponding design criteria, including factor of safety and permissible deflection, for both design methods are recommended. Two full-scale lateral load tests on fully instrumented drilled shafts were subsequently conducted in Colorado to further verify the design recommendation. A comprehensive geotechnical investigation program was also carried out at the two new lateral load test sites that included pressuremeter test, SPT, as well as laboratory triaxial consolidated undrained tests and direct shear tests on the soil samples taken from the lateral load test sites. The test results obtained at these two load test sites were employed to validate the recommended geotechnical design and geotechnical testing methods for the drilled shafts supporting sound walls.

Jan 1, 2007

By Tony Amis

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

Jan 1, 2008

By Sushant Upadhyaya, Deniz Karadeniz, Ahmed Mohamed

Soil setup analysis provides opportunities for efficiencies in pile foundation design and installation. Soil setup gain with time was evaluated as part of the foundation design and installation for twelve bridges along the Interstate 64 corridor between York County and Newport News in Virginia. The substructure elements of the bridges consist of driven precast prestressed concrete piles or H-piles. This case study describes lessons learned to understand the soil setup phenomenon during the installation of the piles in coastal plain. We were able to make expedited decisions during construction by analyzing previously performed pile dynamic analyzer (PDA) test results within the project alignment. Data evaluation included analyses of PDA data obtained from initial driving and restrike after a few hours to 5 weeks. The test data showed pile resistance increase up to twice in most cases and as high as four times in some cases. Foundation design and acceptance based on soil setup can provide opportunities for cost savings and advanced scheduling during construction.

By Chetan D. Savani, Mike K. Muchard

The necessity to evaluate undocumented foundation lengths is essential in assessing the useable life, need for scour protection, retrofitting, or full reuse of existing bridge foundations. For this purpose, Parallel Seismic Testing (PST) has the best accuracy and is applicable to the widest range of foundation configurations used in bridge construction of any test method. Although not limited to bridges, PST case studies are presented involving two bridges. To preface the case study discussions, an overview of the PST method is given along with its results and analysis thereof. In one of the cases, we were afforded the rare opportunity to see the existing piles being extracted long after the PST testing program was completed. The resulting Class A prediction reaffirms the accuracy of the method. Versatility of the PST method is also exemplified in the two cases presented, where unique situations from complex foundation systems were overcome by analysis to provide successful results.

By Dario Libano

"The Line 5 Extension, in Sao Paulo, Brazil, is currently the most important investment in public transportation by Sao Paulo’s state government. It will connect the south part of the city to the city center, crossing through four other major Metro lines and stations; all currently in operation. The total extension of the line is 11 km (6.8 mi), and includes a new parking yard for the trains and 11 new stations. The Brooklin Station, one of the new stations due to be open and operating in 2016, has a unique geometry of five secant shafts.The original design included constructing five secant shafts stabilized by two plastic slurry walls using conventional grab technology. One slurry wall, along the Santo Amaro Avenue, was to contain the contamination plumes, and another was for temporary support to enable the excavation of the shafts. The final retaining wall design was changed to a concrete structural diaphragm wall that reduced the construction time of the shafts by half, allowing the contractor to meet the construction schedule. This solution also avoided dewatering effects in a geological region characterized by Quaternary sediments and environmental contamination plumes. It was the first time that a hydromill was used in such a situation in Brazil. The hydromill, by overcutting the panels, increased the quality of the joints, and decreased the probability of having seepage into the shafts. The hydromill also created a seepage barrier and avoided movement of the contaminated plumes.The GeologyLocal geology is composed of a superficial Quaternary soil, basically soft organic clays and sands and gravels. From the depth of 8 m (26 ft) until 18 m (59 ft), geology is composed by tertiary medium compact sand with thin silt-clay layers. From 18 m (59 ft) down, there are alternations between compact silt-sands layers with very hard clays layers. Each is approximately 5 to 10 m (16.4 ft to 33 ft) thick.The Initial Basic DesignThe original basic design of the Brooklin Station was to be constructed from five 40 m (131 ft) diameter intersecting circular shafts, all in a line along the axis of the Metro tunnel, in 555 days. In the excavation sequence, the odd shafts were first excavated, waterproofed and had part of their inside cast-in-place structure built before the even shafts were excavated. During the excavation of the even shafts, part of the odd shaft’s support was demolished and connected with the even support. A 0.8 m (2.6 ft) thick plastic slurry wall, acting together with the wire mesh reinforced shotcrete support, ensured the excavation stability around the five shafts."

Jan 1, 2014

By M. Hesham El Naggar, Osama F. E. Drbe

"Abstract: The use of micropiles has greatly increased the last twenty years, including applications involving low capacity micropile networks, seismic retrofitting, underpinning of existing foundations and high capacity foundations for new structures. This paper presents a field study of the behaviour of single hollow core micropiles in firm to stiff lean clay. Eight micropiles were installed using hollow bars (76 mm OD and 48 mm ID) with air/water flushing technique and advanced to a depth of 5.75m: six micropiles were installed using 228 mm (9 in) drill bit and two micropiles were installed using 178 mm (7 in) drill bit. All micropiles were instrumented with linear potentiometers to measure the vertical displacement of the micropile head and vibrating wire strain gauges to measure the axial strain at three points along the micropile length. Twelve full scale tests were conducted on the eight micropiles, four monotonic compression, four cyclic compression and four tension tests. Only the results of micropiles tested under monotonic compression is presented in this paper. The full scale load tests and a comparison of the performance of the micropiles with 228 mm and 178 mm drill bit are presented and discussed in terms of load-displacement curves, bond strength and tip resistance. The results showed that the proposed values of bond strength in FHWA give a conservative design of the hollow core micropiles. The micropiles constructed with 228 mm drill bit performed marginallybetter than the micropile with 178 mm drill bit in terms of the ultimate capacity.IntroductionMicropiles have been defined in a variety of ways, but can universally be classified as small diameter (less than 300mm), bored, and grouted in place piles (FHWA, 2005; Bruce et al., 1999; and Scherer et al., 1996). They can sustain axial (compression and tension) and/or lateral loads. Dr. Fernando Lizzi used micropiles in 1952 for underpinning of historic buildings damaged during World War II (Bruce D. A., 1988). Since then, micropile applications have expanded rapidly to include underpinning for existing foundations, in situ reinforcement, and seismic retrofitting and foundations for new construction. In particular, micropiles have graduated from use in low-capacity micropile networks toapplications as single high-capacity foundation.Micropiles capacity is affected by the construction technique, which involves drilling, placing reinforcement, and placing or pressurizing the grout. For example, the drilling method influences the degree of bonding between the grout and the ground, and the placement of reinforcement and the choice of grouting method have an impact on the development of the bonding. Bruce et al. (1997) showed that grout/ground bond is most affected by the grouting method. Based on the type of pressure applied during the grouting process, micropiles are classified as follows (FHWA, 2005): Type A: grout is placed under gravity pressure only using either sand-cement mortars or neat cement grout. Type B: pressures typically in the range of 0.5 MPa to 1 MPa are applied in order to inject the neat cement grout into the drilled hole while the temporary drill casing is withdrawn. Type C: involves two-step process; neat cement grout is first placed in the hole under gravity pressure head only as in type A, and prior to the hardening of this primary grout, a similar grout is then injected via a preplaced sleeved grout pipe at a pressure of at least 1 MPa. Type D: like type C, this type is a twostep process: neat cement grout is placed in the hole under gravity pressure head only (but pressure could be applied in some cases), additional grout is injected via a sleeved grout pipe at a pressure of 2 MPa to 8 MPa once the primary grout has hardened. In some cases, a packer is used inside the sleeved pipe, enabling specific horizons to be treated. Recently, Type E micropile is proposed, which involves"

Jan 1, 2014

By M. Hesham El Naggar, Yasser Abdelghany

"ABSTRACT: The axial and lateral monotonic and cyclic behavior of helical pile foundations was investigated and new innovative helical screw systems suitable for seismic loadings were developed and patented. More than one hundred full scale field load tests were conducted on instrumented helical screw piles installed in cohesive soil. The piles included: plain helical screw piles (P-HSP); grouted (G-HSPs); fiber reinforced polymer FRP-G-HSPs; and reinforced grouted RG-HSPs. The RG-HSP piles axial capacity was more than twice that for P-HSP, with minimal reduction after cyclic loading, and their lateral capacity was more than 3 times the P-HSPs capacity. A 3-D finite element model was established. The results of 3-D finite element modeling were used to establish the load transfer mechanism and a design methodology for the considered piles.INTRODUCTION AND LITERATURE REVIEWHelical (screw) anchors have been utilized in tension loading and have gained popularity for bearing load applications. Helical piles represent an overall cost effective alternative to conventional piles for new construction and repair applications. The helical piles speed and ease of installation, less noise during installation added advantage with regards to their efficiency and reliability for underpinning including re-support and reconstruction of distressed and damaged foundations for either stabilization or rehabilitation. The “square shaft” SS175 pile is a segmented deep foundation system with helical steel bearing plates (helices) welded to a central steel shaft. Load is transferred from the shaft to the surrounding soil through these bearing plates. Segments or sections are joined with bolted couplings. Practically installed depth is limited only by soil resistance and economics. A helical bearing plate or helix is one pitch of a screw thread. All helices regardless of their diameter have a standard 75 mm pitch (Figure.1). The performance of single helical anchors and group action were studied experimentally and theoretically by several researchers, the researches focuses on the installation torque and uplift resistance. Some researches focus on the load carrying capacity with little pile response to cyclic loading effects or to instrumented full scale field testing. Helical piles axial compressive or lateral loading still is not well characterized and needs more analyses and their seismic performance was not investigated. For such this research was initiated to investigate the helical piles monotonic and cyclic performances under axial and lateral loadings to consider their usage in different applications in seismic zones. Among the several researchers, Clemence (1983); Mooney et al. (1985) conducted field and laboratory testing; Hoyt (1989), Hoyt et al. (1995), and Ghaly and Clemence (1998) conducted theoretical and experimental testing, Puri and Vijay (1984), Huang et al. (1995), Perko (2000), and Pack (2000) conducted theoretical analyses. Rao and Prasad (1993), Prasad and Rao (1994), conducted experimental testing; Vickars and Clemence (2000) studied the performance of helical piles with grouted shafts."

Jan 1, 2014

By Stephan Jefferis

It is my understanding that the Scandinavians have done some fundamental work on durability. I have seen a study published whereby the author, Helen Anderson, comments on the durability of polyurethane grouts and there was -if I am not mistaken- a reference made to another Scandinavian testing institute comparing durability of the polyurethane to cement grout under the same type of circumstances. Circumstances are important so we should actually ask the gentleman to shed some light on this particular method because apparently Scandinavia is the place where durability has been taken very seriously and has been well researched.

Feb 10, 2003

By Kenneth R. Chadwick, Thomas J. Tuozzolo, Terence P. Holman

"Micropiles are often installed to retrofit existing foundations that experience distortion and to underpin structures prior to future construction. The Dublin Road Pump Station project is an example of retrofitting due to a basal failure during construction that compromised the bearing capacity of the soils. A completed pump station settled and had to be restored to its original position, and work could not proceed until a new support system for the partially completed wet well could be designed and installed. The project involved the construction of three below-grade structures for a new pump station in a growing area of Jackson Township, N.J. The general contractor constructed three pump station structures consisting of a pump chamber, wet well and an inlet chamber in early 2006.The geologic conditions beneath the project site (Figure 1) consisted of loose/soft to medium dense/stiff sand, silt and clay to a depth of 40 ft below ground surface, underlain by medium dense to dense glauconitic silty fi ne sand. When the general contractor was constructing the wet well, which involved an internally supported sheet pile excavation 32 ft below the ground surface and 28 ft below the static groundwater level, basal failure, boils and ground loss occurred. Driven piles were installed to support the wet well structure, but additional ground loss was observed within and outside the sheet pile excavation, followed by settlement of the adjacent pump chamber structure. Post-failure investigations were conducted by Mueser Rutledge Consulting Engineers, N.Y. (MRCE), a geotechnical and foundation engineering consultant. Their investigation concluded that the ground losses around the pump station structures had compromised the supportive capabilities of the natural subsoils.The owner engaged Moretrench, a geotechnical specialty contractor, to work with MRCE to develop a constructible solution to support the pump station structures in general and to restore the pump chamber to its original position. Knowing that ground loss had already occurred as a function of the initial basal heave and subsequent pile driving, the team selected micropiles as the preferred foundation element, primarily due to their flexibility in bypassing these disturbed zones and generating capacity as a function of grouting volume and pressure. Drilled piles were also recommended due to concerns about causing additional settlement of the pump chamber if driven piles were used."

Jan 1, 2008

By Masaki Kitazume

Deep mixing method, in-situ admixture stabilization technique, has been developed and adopted for on land and marine construction works in Japan. The geotechnical design procedure of the method has been standardized in Ministry of Land, Infrastructure and Transport Government of Japan for port and harbor facilities, which includes the block type and wall type improved grounds for foundation stability, settlement reduction purpose. This procedure is based on the allowable stress concept, in which the induced stresses within the improved ground are confirmed to be lower than the allowable strength in the internal stability calculation. This procedure has been cited by several organizations to establish their standards. The Ministry has a plan to introduce a reliability based design for marine construction works in 2006, in which the design procedure on DM improved ground will also be modified to the reliability based. In the new design procedure, the average and variation of soil parameters and external loads are incorporated by partial safety factors to investigate the stability of improved ground. According to the plan, the author has been studied the design procedure and the magnitude of partial safety factors, and has established a preliminary draft of the standard. This draft will be brushed up through comparing the current design procedure. In this article, the design concept and design procedure of the method are briefly described.

Jan 1, 2004

By Scott M. Mackiewicz

This project includes replacement of the historic vertical-lift span Meridian Bridge (U.S. Highway 81 over the Missouri River) that connects Yankton, South Dakota with rural Cedar County, Nebraska. The new 76-foot wide, 1,590-foot long steel plate girder structure required the use of drilled shaft foundations that extended into the underlying Carlile Shale formation. Designers indicated that an individual drilled shaft capacity of about 2,000 kips will be needed at each of the river piers, and based on the subsurface information, 8 to 10-foot diameter drilled shafts extending to about 115-foot would be required for support of the bridge structure. An Osterberg Load Test was performed on one test shaft to determine the ultimate skin friction and end bearing of the Carlile Shale. This paper describes the design and installation of the load test drilled shaft as well as presents the load test results as compared with predicted design values determined using FHWA methods.

Jan 1, 2008

By R. J. Yan

There was a plant equipped with a 32000t Hydraulic Press to be built, under which a box foundation of 22.5m x 15m x 14.25m (depth) with a base slab of, varying thickness was proposed. The subgrade reactions, bending moments and settlements needed to be determined by means of in-situ model test. A model of the same materials as the prototype scaled to l/10 was embedded in-situ with simulated depth in the bedrock. A lot of data obtained from 39 bench marks, 32 elongation measuring points, 30 couples of electric resistance strain gauges and 24 pressure cells attached to the model foundation enables all the quantities required to be found out. Since it was put into operation, the settlements measured has reasonably agreed with the test results and the foundation has been in good condition.

Jan 1, 2010

By Hector Simchas

"1. BENTONITE: THE CRUCIAL CONSTITUENT OF SLURRYSuspensions of bentonite and water are used in a variety of applications in underground engineering. For the construction of underground elements like slurry walls or piles, bentonite slurries offer support to the excavation of loose soils and counter pressure against hydrostatic pressure of ground water, especially where soil permeability is high. In addition, for the construction of tunnels by the slurry-shield method or when hydromills are used for excavation, bentonite suspensions transfer the loosened soil to the surface. In applications like pipe jacking and microtunneling, or where high revolution drilling is required, bentonite also provides lubrication and cooling.To fulfill these functions, the properties of a bentonite slurry need to remain stable, or at least predictable, during the course of construction. Unfortunately, when a suspension mixes with earth, ground water and/or impurities, its properties may be compromised resulting to reduced performance, which would in turn lead to increased construction costs and the risk of the excavation collapsing. Our experience in the lab and onsite is presented herewith.2. MOST USUAL FACTORS OF PERFORMANCE FAILUREWater and soil quality are important factors defining the behavior of suspensions. In an extensive program of measurements in our technical laboratory, the effect of frequently encountered harmful substances on bentonite suspensions has been examined and the results are summarised in Table 1.Some tests show that the conductivity of water has a direct relationship with Marsh Viscosity. For example, we have seen that if the quantity of bentonite required to achieve a 40s Marsh Time ranges between 50-52 kg/m3 at water conductivity below 100 µS/cm; when conductivity is increased to 1,400 µS/cm, we need 65-68 kg/m3 in order to achieve the same property."

Jan 1, 2015

By Evangelia Ieronymaki

Civil engineering education relies on traditional methods of teaching, comprising mostly of deductive instruction by presenting the theory, followed by applications. This paper presents an alternative way for teaching foundation design to senior students, introducing a more inductive approach. The students are presented with a project/game adapted to a real-world problem at the beginning of the course. They are asked to identify the correct steps and methods throughout the lectures, for reaching an appropriate solution that they document and present at the end of the course. To make the project more enjoyable, the project has the format of a game where the students compete with each other on completing the task faster and more efficiently. The goal of this teaching approach is to enhance the ability of the students for problem solving and the engineering way of thinking, while playing a game. In the end, the students were requested to respond to a survey regarding the efficiency of this project/game on their learning. The results showed that students prefer more inductive methods for a design course, feeling that this project made them think more like engineers, while the ‘game’ twist of it made the whole course more fun. INTRODUCTION Most civil engineering courses are taught in 2019 the same way they used to be taught 40 years ago in the 80s. Classic methods are mostly deductive, where the instructor presents the theory first and then applications of that theory follow. Little or no attention is given initially to why the theory was developed or what are the problems it solves. The applications of the theory, and thus the purpose it serves, come only in the end and after methodologies have been presented, leading the students to show low interest in the material. As Albanese and Mitchell (1993) have reported, people are mostly motivated to learn things when they clearly see the need to know them. This explains the students’ little motivation that, if any, comes mainly from the fact that the material may be useful either in other courses or in their future careers. On the other hand, there are alternative inductive methods of teaching, where the role of the students is more active. A lot of researchers have highlighted the benefits of inductive methods in teaching engineering courses. Based on Prince and Fedler (2006), inductive methods include; a) inquiry-learning, b) discovery learning, c) problem and project-based learning (PBL), d) case-based teaching, and e) just-in-time learning. Inquiry-learning is maybe the most traditional method of inductive teaching/learning methods, where the instructor asks questions or poses problems and the students need to apply the theory they have learnt in order to find the solution (Bateman 1990; Prince 2004; Lee 2012). Similar to inquire-learning is the discovery learning, where students have to find the solution to a problem or answer to a question, while the instructor simply provides feedback to the students without guiding their efforts (Leonard 1988; Westbrook and Rogers 1994).

Jan 1, 2019

By Fred C. Schmednecht

For years, the strategy was to contain waste and in many applications, is still the recommended method. Recently, it has become acceptable to create filters below ground for the in-situ treatment of waste. Consequently, in lieu of the waste being contained, it is desirable that the waste flow through a pervious treatment zone. For instance, subterranean pervious walls comprised of iron sand are particularly useful in treating chlorinated solvents in contaminated groundwater. The iron acts as a corrective filter to treat the contaminated groundwater. How are these impervious and pervious walls being constructed? One effective means of constructing an impervious barrier is the vibrated beam method. This method, in brief, involves the use of a fabricated steel beam, a vibrator, a pile driving crane, and a mixing plant. This method results in a 4-6" wide wall with depths up to and exceeding 100'. Over one hundred slurry walls have been installed using this method in the United States. The need for the vibrated beam method continues to escalate due to its reduced health and safety considerations, high level of quality control, lack of excavation, narrow working area, and ability to achieve depths greater than 100'. A recent project was in Marinette, Wisconsin at the ANSUL facility. The project consisted of a 28,000 square foot slurry wall and was completed in January of 1999. Another effective means of creating an impervious barrier, where structural support from the barrier is needed, is the Waterloo® Barrier System. This system involves the use of a pile driving crane, Waterloo® steel sheet piles which are patented steel sheet piles due to their groutable interlocks, and a grout plant. This system results in a water-tight barrier due to the grouted interlocks and provides structural support. A project was completed at Beta Steel in Portage, IN for a retention pond to protect Lake Michigan. Due to the new concept of "filtering", there are few accepted construction techniques available. One effective field proven construction technique is the patent pending mandrel emplacement technique. This technique involves the use of a fabricated hollow steel mandrel with a shoe, a vibrator, a heavy duty crane, and a material feeder. This technique results in a pervious wall which may be comprised of pure iron sand or any other flowable media. Using this technique, the pervious wall may be constructed in varying widths to depths in excess of 100'. A successful installation occurred in October 1997 at Cape Canaveral Air Station in Florida.

Jan 1, 1999

By Z. Q. Zhou

It is the first worke in design of pile foundation to determine the carring capacity of single pile, and a static loading on site is considered to be the lost derect and reliable way. All values P and settlements S induced can be plotted as a broken-line. Since soil is a kind of elasto-plastic and cohesive material, the increasing of settlements is generally greater than that of loads. Different value Pu nay be given by different tester on his P-S diagram, because of erroys in the test and complicated, characteristics of soil. The analytical method of exponential equation shown in this paper derives a specified solution. After using an exponential curve to regress values of loads P and corresponding settlements S from on-site test, coeficients A and B of exponential equation can be obtained. With this curve an ultimate carrying capacity of single pile can be determined. The resistant forces of pile shaft and pile tip can also be defined by the tangent of the calculated knee point, as it is called (tangent method). At last, an example is given to show how the ultimate carrying capacity of f 500mm bored pile is obtained with this method for a project in Kunming.

Jan 1, 2010

By Hal W. Hunt

Heavier loading and more efficient equipment is helping to keep driven piles competitive in America. Better Knowledge and testing of soils and support materials make it practical to use higher stresses; this is being strongly promoted by those directly concerned with timber, steel and concrete piles. Readily available point protection is increasingly used to assure penetration of piles without damage to full load bearing capability. Fabric drains are being installed with pile equipment to speed consolidation of soils. Sheet pile configuration has changed; production has been reduced largely because of imports. Dynamic checking of representative piles for load carrying capability is replacing conventional load testing of just a pile or two ? at much lower cost.

Jan 1, 1987

By S. Merjan

Three papers were presented for discussion at the conference: 1) Instrumented driven steel tube piles at Canary Wharf; author: A. R. Gaba, United Kingdom. The author described the Canary Wharf development in the London Docklands, and in particular, the decision to build over the water by driving open-ended steel piles 25m in length into the sands below the soft estuarine deposits. The tubes were then filled with concrete above the sand plug (usually 17m below pile head). Three trial piles were instrumented with: a) resistance strain guages on the inside of the tubes; b) vibrating wire guages on the re­inforcement of the concrete. The trial piles showed elastic behaviour in five cycles of lateral loading, while the verticle load tests showed a definite bi-linear load-settlement behaviour. The initial stiff portion was a result of frictional staff resistance, both inside and outside the tube, with the soil at the base contributing at higher settlements. Loads were taken to three times working load, with no imminent signs of failure.

Jan 1, 1991