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By Christopher R. Harris

"Considerations are presented for developing and implementing self-hardening slurry mix designs to be utilized in barrier seepage walls. Slag-cement-cement-bentonite (SCCB) slurries are the primary focus, with some comparisons referenced to the more traditional Portland-based cement-bentonite (CB) slurries. Field and laboratory mixing methods are reviewed, including 1) single sack – single mixer method; 2) bentonite slurry mixer – cementitious addition mixer method; 3) bentonite mixer – grout mixer – CB blending mixer method. Major phenomena associated with the dynamics of barrier wall excavation, such as loss of water from the in-trench slurry and consolidation of in-trench slurry are discussed. Other topics touched upon include sand content effects, fluidizers utilized, and chemical contaminants. The role of higher bentonite to water ratio is reviewed, with demonstration of improvement of filtration properties, and an increase of water retention of the final consolidated product.IntroductionSelf-hardening slurry has been utilized to construct barrier seepage walls for many decades. This is essentially a single-step slurry excavation and backfill process whereby the trench-supporting fluid gains strength over a short period during installation and maintains or develops low hydraulic conductivity. The resulting curing slurry becomes the actual barrier wall as the resultant cement-augmented clay slurry now fulfills the dual purpose of both temporary trench stabilization and final cured-in-place product. This eliminates the requirement and expense of subsequent backfill/slurry displacement operations required in traditional barrier wall installations.Self-hardening slurries have been fabricated using a number of various clays, most commonly sodium bentonite, calcium bentonite, attapulgite, and sepiolite. Perhaps due to plentiful high quality sodium bentonite deposits found domestically, the proven excavation stabilization properties imparted from sodium bentonite slurries, sodium bentonites are typically specified for formulating self-hardening slurries in the US. Cementitious materials utilized most commonly are Portland cement and slag (ground blast furnace slag or GBFS). For the purposes of this discussion, self-hardening slurry having a cementitious of Portland will be referred to as CB. Those having cementitious material of GBFS replacing Portland (partially or wholly) will be referred to as SCCB."

Jan 1, 2016

By Helen S. W. Chow, Harry G. Poulos

Most modern buildings involve the construction of a basement, often of several levels, to maximize the floor area ratio. The basement walls are generally designed for excavation retention purposes only, and are infrequently considered as elements which can help to support the structural loads from the superstructure. However, the basement walls can provide substantial stiffness and resistance to structural loads, and may contribute to the overall foundation capacity and stiffness. This paper presents a simplified approach to approximate the overall foundation capacity and stiffness considering the various components of the foundation system, including the foundation piles, the basement floor slab, the basement walls and interaction between each foundation component. The effect of the basement walls in enhancing the foundation stiffness values is examined by reference to the results of finite element analyses which consider a foundation subjected to vertical, horizontal and moment loadings. The approximate approach is found to give results that are adequate for a preliminary assessment of the effects of basement walls on the overall foundation response, without the need for detailed three-dimensional finite element analyses.

Nov 1, 2022

By Kenneth E. Henn, David B. Paul, John D. Rice, Brian H. Greene

"Several laboratory modeling programs have been conducted to investigate the mechanisms associated with internal erosion of dam embankments and foundations. The investigation consists of developing laboratory devices to model three separate mechanisms associated with process: 1) contact erosion along bedrock joints, and 2) piping into an open bedrock defect. The contact erosion device subjects the soil above a bedrock joint to high velocity flows in the joint. The erosion into a bedrock defect device examines a number of static and transient hydraulic conditions to study the mechanisms associated with this type of erosion. Numerous tests have been conducted using both devices. The results of the modeling will be discussed along with a discussion of how this information could be used in future dam design and risk assessment studies.IntroductionA series of laboratory modeling programs were performed to assess the seepage and internal erosion behavior of several man-made and natural structures within dams and their foundations. Each model was performed on a “bench scale” and depicted an isolated location where internal erosion was likely to occur. The models were subjected to hydraulic boundary conditions to simulate the in-situ conditions so that the processes of internal erosion could be observed. Two laboratory devices were developed to model conditions depicting 1) contact erosion along a bedrock joint in contact with a dam embankment, and 2) backward erosion (piping) into an open bedrock defect (joint, solution void, etc.).Embankment dams often have rock foundations containing defects which may detrimentally impact future performance. Further, there are existing foundations which contain rock defects that may already be detrimentally impacting the dams; however, due to the inherent aspects of the mechanism, the signs of distress may not have propagated to the surface and thus not observed during inspections. A better understanding of the mechanisms which are influenced by, and impose their influence upon, rock defects will enhance the ability of dam safety professionals to analyze the risks associated with internal erosion due to rock defects, increase our ability to monitor and successfully initiate earlier detection, and also increase our ability to design remediation methods to contend with rock defect failure modes."

Jan 1, 2016

By P. Seethalakshmi, Yatakuri Yaswanth Naidu

The use of a single pile, group of piles with pile cap, piled raft foundation system, etc., are prevalent in transferring the superstructure load from the soft soil layers to the firm underground layers to reduce the settlement and improve the bearing capacity. The recent development of disconnected piled raft foundation has gained greater importance in improving the load transfer mechanism among the pile, raft, and subsoil by reducing the vulnerability of the greatest axial force on the pile head which leads to pile failure. The present study aims at analyzing the performance of unreinforced and Geogrid reinforced disconnected piled raft foundations under vertical loading using the commercially available finite element software PLAXIS-3D. A parametric study was conducted on unreinforced and reinforced disconnected piled raft foundations to explore the effect of varying pile stiffness as well as the inclusion of Geogrid layer on the load vs settlement, the load sharing ratio of piles and raft, and the distribution of axial load and bending moment along the length of the pile. The Mohr-Coulomb model was used for the granular cushion layer while the Modified Cam Clay model was used for soft clay underlain the sand layer. Raft and piles were assumed to be rigid and linear elastic. The results showed that axial force taken by piles with higher stiffness was maximum while settlement at the bottom tip of the pile with higher stiffness was maximum in both reinforced as well as unreinforced disconnected piled raft systems.

Sep 1, 2022

By Stefan Mewes

Europe’s second-largest seaport has installed a new combi wall consisting of pipe piles, sheet piles and inclined shaft grouted piles to support it. The new Liebherr piling rig with swinging leader was used to drive shaft grouted piles into a very dense soil layer of sand with glauconite. The 60 m Liebherr swinging leader was suspended at an inclination of 45° via a suspension frame and suspension ropes from the crawler crane. This inclined installation of shaft grouted piles via freely hanging swinging leader, as used for this project, is unique in Belgium. Moreover, the pile length of 43 m is a novelty for this type of pile. Shaft grouted piles consist of a steel profile with a separate box-like pile shoe with an open top. A thin grout is injected via an injection pipe during driving and emerges just above the pile shoe. As the pile is driven further down, so compressing the ground, the space above the pile foot is immediately filled with grout under pressure. This piling system is ideally suited for the transfer of high tensile loadings. It is a method to increase geotechnical load-bearing capacity and to reduce negative skin friction during pile driving.

Sep 1, 2022

By Alex Ryberg, Matthew L. Becker

Several integrity testing methods exist which may be used to evaluate drilled shafts. Each test method has advantages and limitations. On occasion, the results from different test methods may lead to conflicting conclusions, making it difficult to conclusively know which results more accurately represent the quality and integrity of a drilled shaft. This case study focuses on the integrity testing evaluation for two drilled shafts which were constructed using permanent casings and installed through flowing river water. Integrity testing was performed using Thermal Integrity Profiling (TIP) and Crosshole Sonic Logging (CSL) on each shaft. During testing, the influence of flowing water and soil layering needed consideration in the collected TIP data. Similarly, concrete curing time influenced the CSL test results and required the CSL tests to be performed multiple times with additional wait times following concrete placement. To aid in the shaft integrity evaluations, Low Strain Integrity testing via the Pulse Echo Method (PEM) was performed on several shafts and concrete coring was also performed to help further assess the acceptance or rejection of the questionable shafts. This paper presents an overview of the testing methods that were applied, their basic methodology, as well as potential limitations that should be considered when evaluating their results.

Sep 8, 2021

By Glen R. Andersen

"Two of the greatest challenges we face in managing our aging infrastructure are to perform accurate condition assessments and to realistically predict the risk of non-action. The aim of this paper is to discuss common pitfalls we face in performing accurate condition assessments of our aging infrastructure using the case history of a recent near miss at the Lake Manatee Dam in Central Florida. The dam was placed into service in 1967 and was inspected every couple of years by dam safety engineers beginning in 1978. Although there was substantial and repeated evidence of a serious piping and internal erosion problem in each of these inspections, the problem was overlooked by most of the inspection teams. In 2012, the inspection team concluded that: “the Lake Manatee Reservoir Dam is well maintained and is in very good overall condition.” However, in 2013 a new team inspected the dam from an entirely different perspective, identified potentially serious conditions, performed an integration of the historical inspection data and concluded that: 1) the Lake Manatee Dam was in a severely distressed state; and, 2) without an immediate intervention there was a high risk of an uncontrolled release of the reservoir most likely following a large rainfall event and prolonged opening of the service spillway. This case history highlights human factors contributing to the near miss including group think and focusing on changes from prior inspections. The integration of historical inspection data is recommended for managing our aging infrastructure.INTRODUCTIONThe engineering analytical techniques most appropriate for assessing an aging infrastructure can be distinct from those used for the original design. To adequately manage our aging infrastructure it is necessary to change our perspective from anticipating failure mechanisms and designing to prevent them to assessing condition, detecting the presence of potential failure mechanisms, and assessing the potential risks. In many circumstances the failure mechanisms currently active may not have been anticipated by the original design team.We have developed a substantial body of experience in the design of our infrastructure. Full scale and laboratory testing coupled with the application of scientific principles to model behavior has led to many powerful design tools. The continued serviceability of our infrastructure as its elements reach their design lives stands as a legacy to our profession. However, under the sustained effect of limited resources for maintenance and rehabilitation parts of our infrastructure are in a highly deteriorated state. Unfortunately, the condition of some of these has not been properly assessed. This paper focuses on the Lake Manatee Dam in Central Florida and the process used to clearly identify its highly deteriorated state. While there are many factors that contributed to the lack of a proper assessment of its condition, the focus herein will be on human factors and in particular how “Group Think”, “Aversion to Bad News”, and “Condition Assessments Based on Changes to Prior Condition” may have contributed to not properly identifying the development of a serious failure mechanism."

Jan 1, 2017

By Tracy Brettmann

The Highway 146 Bridge Expansion Project across the Clear Creek Channel in Houston, Texas was designed on driven precast concrete piles. However, during construction, the piles along one side of the bridge along the main channel encountered obstructions and couldn’t be installed. These obstructions turned out to be the remnants of a previous bridge foundation at this location, which was unknown to the designers since that bridge had been demolished 40 years ago. Those old foundations were massive 20 ft by 40 ft (6 m by 12 m) pile caps 11 ft (3.3 m) thick supported on precast concrete piles 37 to 55 ft (11 to 17 m) long. The foundation re-design for these locations involved installing a single 78 inch (2 m) diameter drilled shaft up to 125 ft (38 m) long to replace the originally planned driven pile supported pile cap. The drilled shafts would need to be installed within very tight tolerances since they were supporting a single bridge column directly above it. In addition to drilling through the obstructions, this work would need to be completed from barges in 30 ft (9 m) of water capable of dealing with both the current and tides affecting this area. The shafts were installed using a multi-step process. The first step involved coring a larger diameter 100 inch (2.5 m) hole through the reinforced concrete pile cap and removing the concrete inside. This was followed by the installation of a 72 ft (22 m) long permanent casing to and removing the soil and existing precast piles inside. Finally, the drilled shaft excavations were advanced to the completion depths (uncased) using bentonite slurry as the support fluid.

May 1, 2022

By Matthew Janes

The installation of piles and casings is becoming increasingly difficult as restrictions on vibration become common in major urban areas. The use of high frequency, resonant excitation of a pile or casing permits ease of installation of sections to great depths with near imperceptible vibrations as close as 1 pile diameter. The new Resonant Driver is able to excite a pile at its resonant frequency (up to 150 Hz or 9000 VPM) to produce elevated levels of acceleration, force and displacement in the pile. The combination of extremely high acceleration and controlled levels of displacement allow the pile to slice through varied soil with almost no vibration translated into the ground. In direct comparisons between conventional vibrators and impact hammers the Resonant Driver produces less than 1/50th the vibration. The Resonant Driver results in ground vibration of between 1/20 and 1/40 of common limit levels (1 cm/s or 0.5 in/sec) as close as 1 pile diameter. At a distance of 5 m (16 ft) from the pile or casing vibration levels approach imperceptible levels. The Resonant Driver uses a proprietary algorithm to tune the drive vibration to the changing natural frequency of the pile as it is driven into the ground. By maintaining resonance the energy in the pile is built up like in a flywheel on an engine or a child on a swing. This build up of energy aids in driving and significantly reduces waste. Recent experience using the Resonant Driver is proving the technology can drive a variety of steel pile and casing sections through varied soils. Continued use of the Resonant Driver will create a data base of various pile and casing sections, soil types and achieved capacities.

Jan 1, 2008

By Don W. Dotson

In 1962, Kondner prepared several papers dealing with hyperbolic stress-strain response of cohesive soils. The following year, Brinch Hansen proposed 80% and 90% failure criteria for stress-strain behavior of cohesive soils. Fellenius was instrumental in popularizing these failure criteria for pile load tests and offered a direct solution equation for the failure load according to the 80% failure criterion. Since the 90% Criterion has been incorporated into the International Building Code, equations for the direct solution of the failure load at the 90% Criterion would be useful to practicing engineers. This Technical Note supplies the derivation methodology for the 80% Criterion and provides expressions to determine the load and deflection at failure for the 90% Criterion.

Aug 1, 2013

By Ryan P. Sullivan, G. Alan Klevens, Jian Huang

"BACKGROUNDLake Hamilton in Hot Springs, AR was created in 1932 when the Arkansas Power and Light Co. completed Carpenter Dam on the Ouachita River to generate electricity. Today, the 7,200-acre (2,914 hectares) impoundment is one of Arkansas’s most popular recreational and residential lakes.U.S. 70 crosses Lake Hamilton by means of a seven-span bridge featuring nine steel girders per span. Constructed between 1982 and 1984, the 1,410-foot long (430m) bridge carries four lanes of traffi c across the lake. The bridge is supported by six intermediate reinforced concrete piers composed of hammer heads, stems, footings and seals, which sit on the underlying rock. (See Figure 1). The bridge rises to a maximum of 33 feet (10m) above the surface of the lake and the footings and seals extend a maximum of 29.5 feet (9m) below the surface of the lake. The seals are situated on hard, fractured sandstone and shale.Routine underwater inspections in 1993 revealed large cracks in the lean seal concrete and refl ective cracks in the reinforced concrete footings. Infrastructure Engineers, Inc., The Arkansas State Highway and Transportation Department’s (AHTD) design consultant, then conducted an in-depth underwater inspection of the pier foundations. The investigation included cross-hole sonic logging, singlehole sonic logging, visual examination and strength testing of core samples, and petrographic analysis.The investigation revealed extensive cracking and low-strength concrete within the seals of all intermediate pier foundations. Many voids within the seal concrete had become fi lled with silt. There was evidence of continued seal deterioration between underwater inspections.AHTD and its engineers considered three rehabilitation solutions in the preliminary engineering stage: micropiles, a cofferdam supported concrete jacket, or a pile supported concrete jacket. The three alternatives were estimated to cost $1,250,000; $4,320,000; and $3,030,000 respectively. All three options would transfer the loads from the pier footing directly to the rock below, bypassing the seal concrete."

Jan 1, 2007

By Ryan P. Sullivan, G. Alan Klevens, Jian Huang

"BACKGROUNDLake Hamilton in Hot Springs, AR was created in 1932 when the Arkansas Power and Light Co. completed Carpenter Dam on the Ouachita River to generate electricity. Today, the 7,200-acre (2,914 hectares) impoundment is one of Arkansas’s most popular recreational and residential lakes.U.S. 70 crosses Lake Hamilton by means of a seven-span bridge featuring nine steel girders per span. Constructed between 1982 and 1984, the 1,410-foot long (430m) bridge carries four lanes of traffi c across the lake. The bridge is supported by six intermediate reinforced concrete piers composed of hammer heads, stems, footings and seals, which sit on the underlying rock. (See Figure 1). The bridge rises to a maximum of 33 feet (10m) above the surface of the lake and the footings and seals extend a maximum of 29.5 feet (9m) below the surface of the lake. The seals are situated on hard, fractured sandstone and shale. Routine underwater inspections in 1993 revealed large cracks in the lean seal concrete and reflective cracks in the reinforced concrete footings. Infrastructure Engineers, Inc., The Arkansas State Highway and Transportation Department’s (AHTD) design consultant, then conducted an in-depth underwater inspection of the pier foundations. The investigation included cross-hole sonic logging, singlehole sonic logging, visual examination and strength testing of core samples, and petrographic analysis.The investigation revealed extensive cracking and low-strength concrete within the seals of all intermediate pier foundations. Many voids within the seal concrete had become filled with silt. There was evidence of continued seal deterioration between underwater inspections.AHTD and its engineers considered three rehabilitation solutions in the preliminary engineering stage: micropiles, a cofferdam supported concrete jacket, or a pile supported concrete jacket. The three alternatives were estimated to cost $1,250,000; $4,320,000; and $3,030,000 respectively. All three options would transfer the loads from the pier footing directly to the rock below, bypassing the seal concrete."

Jan 1, 2007

By George Burke

"Many soil mixing methods have evolved over the years, but the Trench Cutting Re-mixing Deep method (TRD) was developed in Japan, circa 1993, to construct continuous uniform cutoff walls, without the need for an open trench. TRD mixing has been used on over 300 projects in Japan for excavation support, groundwater barriers, liquefaction mitigation, soil improvement and pollution containment. To date, TRD mixing has been used on only three projects in the United States: a test cell in Long Beach, Calif., for seawater intrusion barrier in 2004; a groundwater barrier at a wastewater treatment plant in Lincoln, Calif., in 2005; and presently at Herbert Hoover Dike surrounding Lake Okeechobee in southeastern Florida.The most notable benefits of TRD are its abilities to overcome difficult geology, such as layered rock and dense cobbles and gravels that hinder other soil mixing methods, and to create extremely high-quality walls. The method is ideal for situations in which access precludes the use of more traditional methods due to spoil control, such as waterways and congested urban environments or subsurface obstruction/difficult ground. Spoil disposal is minimized since TRD mixes the soil in place.TRD mixing has a horizontal continuity advantage over traditional multi-auger deep soil mixing (DSM) systems. Because DSM systems create walls by overlapping soil-cement columns, the auger may be deflected by difficult ground, and gaps are possible. Gaps may also occur when constructing an exceptionally deep wall due to the possibility of auger deviation from its required vertical alignment.The method also has a homogeneity advantage in layered soils. Because DSM constructs columns by rotating the defined length mixing tools up and down the soil profile while injecting binder, strength and permeability in each layer will vary. The TRD method vertically mixes the entire profile and core samples show highly uniform strength. It is most cost-effective in deep difficult ground such as layered rock or dense cobbles and gravels."

Jan 1, 2009

By Damien Enright, Franz-Werner Gerressen

CFA/ACIP pile is the most used single pass drilling method for deep foundation installations. It is constructed by rotating and driving a Continuous Flight Auger (CFA) into the ground at a controlled speed to the specified pile depth. Concrete is then pumped under continuous positive pressure through the hollow stem of the auger to fill the borehole as the auger is withdrawn. CFA/ACIP piles are preferred due to their high daily production capacity when used in suitable soil conditions. CFA/ACIP piles have been installed in the United States for decades and the industry has seen a huge development in equipment, installation process, monitoring and more. Nowadays, CFA/ACIP piles are installed using fully computer monitored drill rigs rather than a bulky crane and lead setup. Because of the torque and crowd offered by these rigs, piles can be installed to depths of more than 100 feet and diameters up to 48 inches. New age crane-based equipment with leader systems are than welcome to substitute old fashioned bulky cranes These new age crane-based systems combine the benefits of sufficient hydraulic power, fully equipped software, etc. with the additional benefits that they can do single pass drilling without extension systems, even when drill depths of more than 100 feet are required. The paper will explain the construction process and will discuss some jobsite references and experiences made using the new age crane-based equipment.

Oct 1, 2022

By Tsunenobu Nozaki

"Basically, the “Press-in Piling Method” was invented to eliminate construction nuisances, such as noise and vibration which have been serious unsolved problems for advancing societies over a long time. In the construction industry, piling works have been a major cause of noise and vibration, because most piling methods utilize dynamic load to install piles into the ground. The secret of the Press-in Piling Method is to utilize static loading to install pre-formed piles rather than dynamic load. The piles are hydraulically gripped and jacked into the ground by the special piling rig known as the “Silent Piler”. Therefore, the piles can form a robust and firm foundation, which is another advantage of the Press-in Piling Method.The Press-in Piling Mechanism and Implant Foundations The basis of the Press-in Piling Method is simple. The Pres-in Piling Machine installs a preformed displacement pile into the ground by static jacking force. The reaction for the Press-in Force is generated by gripping previously installed piles, which are called “Reaction Piles”. Due to this, the Press-in Piling Machine can produce a powerful piling force whilst only requiring minimal machine size.With the Press-in Piling Method, as piles are pressed into the ground, they are incorporated with the surrounding soils, which provides a large bearing capacity and passive horizontal resistance. These embedded foundations which are firmly anchored into the ground are known as “Implant Foundations”. Being embedded into the ground, the foundations are resilient and maintain their serviceability even in the worst credible design conditions."

Jan 1, 2015

By Michael A. McNicholas

"Deep foundations utilize the varying soil conditions to provide the most cost-effective or practical scope for a given jobsite. Once the scope has been determined and the engineering applied, the element can be installed and tested to determine if it is suitable. QA/QC programs are vital for the assurance that the element designed by the engineer has not only been properly constructed but that the design assumptions are confirmed. The two deep foundation elements referenced are drilled displacement piles (DDP) and micropiles. Each of these elements allows for large loads to be distributed deep into the subsurface geology. Having the technology and ability to monitor the tests in real-time can be beneficial to a contractor in determining if the design is adequate or if adjustments need to be made on future piles. The proper QA/QC guidelines for installation and monitoring need to be in place to ensure that an accurate interpretation can be made on the pile. This paper discusses the typical testing and the positive results that the author has encountered using the latest advances in strain analysis.KEY TERMSDrilled Displacement Piles:A deep foundation system that has the ability to shed load into the geology through shaft resistance as well as tip resistance, similar to drilled shafts. This pile element is unique in that it has a consistent pile section and thus a consistent modulus of elasticity.Micropile:A deep foundation system used in applications where the foundation lies over material not suitable for a spread footing and the ideal soil stratum is deep below the foundation. Micropiles will have two different cross-sections consisting of a cased section and an uncased section. For this reason, this pile type requires additional analysis when computing stress-strain relationships.Geokon Strain Gauges:Instrumentation such as Models 4911A-4911 Vibrating Wire Strain Gauges ( known as Sister Bars) are designed to be embedded in grout and calculate loads based on the change on grout strain over a period of time.Stress:A pile element is under a compression (axial loading) load when a force acts along its axis and is normal to the plane of the section. The corresponding stress the pile is experiencing is described as a normal stress. The stress is obtained by dividing the magnitude of the load distributed over the cross-section by the area of the pile cross-section, as shown in Eq. 1."

Jan 1, 2017

By Ramanathan Ayothiraman, Anurag Singh

"An experimental program was undertaken to investigate the effects of randomly distributed basalt fibre on the index and engineering properties of Dhanori clay and to compare its performance with the properties of soil reinforced with polypropylene fibre. In the present investigation, 7 groups of soil samples were prepared at four different percentages of basalt fibre and polypropylene fibre content and tests were done for measuring their consistency limits, compaction characteristics, unconfined compression strength and consolidation properties. The test results indicate that the inclusion of basalt fibre in Dhanori clay resulted in significant improvement in properties. The improved properties are not comparable with polypropylene fibres, nevertheless, the improvement by basalt fibres is able to meet the typical design target values and the cost is very much less than synthetic fibres. More importantly, basalt fibres are environment friendly.INTRODUCTIONConstruction of buildings in low lands with engineered filling, flexible and rigid pavements for highways/airfields, and embankments for highways/railways are also part of major infrastructural development in addition to construction of tall buildings, bridges/fly overs, major dams and underground structures. The later projects require different improvement techniques than that is adopted in the former projects. Ground improvement techniques such as use of reinforcement inclusions within soil found as an effective and reliable technique. Especially such modification by fibre reinforcement, is primarily possible in engineered filling, pavements subgrade and embankments, where surface mixing is easier; and may not be feasible when stabilization/modification is required for deeper depths. In comparison with conventional reinforcement using geosynthetics (strips, geotextile, geogrid, etc.), there are some advantages in using randomly distributed fibre as reinforcement. In past few decades, the discrete fibres are simply added and mixed randomly with soil, in much the same way as cement, lime, or other additives.There are several studies (Ziegler et al. 1998; Puppala et al. 2000; Bei-xing et al. 2004; Cai et al. 2006; Tang et al. 2007, 2012, 2016; Abdi et al. 2008; Viswanadham et al. 2009; Le et al. 2015) that investigated the behaviour of polypropylene fibre-reinforced soil and reported that an increase in fibre content caused an increase in strength and shrinkage potential but brought on the reduction of swelling potential. The length of fibres had an insignificant effect on soil characteristics, whereas fibre contents proved more influential and effective. A study on rubber fibre conducted by Hambirao and Rakaraddi (2014) mentions that tensile cracking of clays can be improved with the inclusion of short rubber fibres, optimum fibre content was about 15 % of weight of soil. Several experimental studies (Babu et al. 2008; Chaple and Dhatrak 2013; Vibhakar and Nahta 2014; Soundara and Senthilkumar 2015; Goyal et al. 2015; Jayasree et al. 2014, 2015) were conducted on coir fibre-reinforced soil and concluded that it helped in reducing the swell potential and 1% fibre by weight of the soil almost doubled the CBR value. Martins et al. (2015) found that 4% of sisal fibre by weight of the soil reduced the visibility of cracks. Pillai and Ayothiraman (2012), Ayothiraman et al. (2014) and Sahu et al. (2016) have demonstrated that human hair fibres can be used to improve the properties of both fine grained and coarse grained soils."

Jan 1, 1900

By Paolo Cavalcoli, Federico Pagliacci, Marco Chiarabelli

"The Sheikh Jaber Al-Ahmad Causeway Project in Kuwait is estimated at approximately $US3.7 billion and consists of constructing a causeway across the Kuwait Bay, connecting the Shuwaikh Port with the northern Subiyah area, where the new “Silk City” will be established. The $US77 billion Silk City will revive the ancient “Silk Road” trade route and will become a major free trade zone linking central Asia with Europe. The new city will be completed in 2030, it will house about 700,000 people and, furthermore, it will include the tallest tower in the world. The Causeway will stretch approximately 23.3 miles and will be composed of a combination of low-level bridges, embankments and transition islands. A bridge of about 16.8 miles in length will span the navigation channel and a free flow interchange at the Shuwaikh Port will connect the causeway to the main road network in Kuwait City. The geo-construction portion of the project involves the execution of 1,200 drilled shafts with diameters of 98 inches and 118 inches embedded to a maximum depth of about 276 feet. Details are provided concerning the subsurface conditions, the geotechnical characteristics and the strength parameters, illustrating, as well, the installation technique implemented for the construction of the drilled shafts. In addition, particular attention is paid to the description of the challenges faced while constructing the drilled shafts at a distance of about 10 miles from the shore, such as the depth of the water above the midline (more than 160 feet), an underwater current and the tidal variation.INTRODUCTIONThis paper presents an overview of the foundation works executed for a 37km causeway across the Bay of Kuwait, connecting Shuwaikh Port with Subiyah New Town Development. The project, in which Trevi is actively engaged, includes a 27 km low-level bridge across the bay, a main bridge with a span of 200 m, an overpass and a 5 km approach road onshore in Subiyah.The main purpose of this report is to provide information about the nature and features of the applied technique of bored piles, including a description of each work phase and other related details, in order to aid in the design of the foundations for the proposed construction.Works for the soil investigation were carried out in accordance with accepted geotechnical standards/guidelines. Brief descriptions of the methodology of the field are also provided in this report."

Jan 1, 2016

By Dennis Wrixon

It was a little bit exceeded. The decision was the uniform settlement is measured at each one corner and the highest one corner is the important one. And in addition there is a differential settlement of 2.1 mm allowed. So we reached about 7.8 or 7.9 mm with the highest corner and in addition 2.1 so it was a little too much. But behind there is a very difficult calculation of the authorities where all of the displacements are combined together and there are of course some more factors of safety in these settlements.

Feb 10, 2003

By Jamey Rosen, Georgette Hlepas

Verticality data collected from panel and pile elements of seepage barrier walls describe the shape and position of those elements in three dimensions. 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). Contractors use verticality data to confirm that their work matches the design, and owners use verticality data to verify the contractor’s work and confirm that specified criteria were met. Project Information Management Systems (PIMS) technology has been applied to the management, visualization, and analysis of verticality data. This paper will provide examples of how contractors and owners have used a PIMS to compile and synthesize data collected during excavations (e.g., from Cutter Soil Mixer and Hydromill drill rig telemetry), and from measurements of completed excavations (e.g., using the Koden ultrasonic tool), and used those data to model excavation geometry. We will present case studies of using these models to estimate backfill placement volumes, and to evaluate the verticality tolerance and overlap between elements.

Sep 8, 2021