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By Gust Van Lysebetten, Monika de Vos

The objectives of monitoring geotechnical structures can be very diverse, including optimisation of the design, quality control, long term performance assessment, and approval of innovative execution techniques. In this context, new measurement techniques, based on optical fibres, offer the possibility of accurate strain and temperature monitoring with very small sensors and limited numbers of cables. This paper briefly presents optical fibre sensing techniques and illustrates their application to geotechnical structures by means of some projects, carried out by the Belgian Building Research Institute (BBRI).

May 1, 2022

Jan 1, 2005

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 Bernhard Bruggaier

Outside the oil and gas industry there is an increasing demand to install big piles for the foundation of ports, bridges, and wind-energy plants. This article introduces the design and techniques in using large MENCK pile driving hammers to install big foundation piles. Piles with a length up to 120 m, an outside diameter of 1.0 m to 3.15 m and weighing between 25t and 400t are being driven for these types of foundations. The required energy lies between 200 and 1700 kNm. Pile driving hammers that bring this amount of energy weigh from 38 to 300t and have a length between 10 and 20 m. Handling these big pile driving hammers requires a crawler crane on land or cranes on floating pontoons or jack-ups when working in water. Possible are either vertical or inclined piles, using a leader for inclinations up to 1:1.7 or up to 1:3 in a free riding version. Project descriptions demonstrate the versatility and practical use of the equipment under diverse operating conditions.

Jan 1, 2002

By Gang Guo, Zhong Liu

"In response to an increasing demand of anchored structures for underground space and transportation infrastructure in China, an innovative underreamed ground anchorage system was created. The novel anchorage system has provided more efficient functions with higher capacity at lower cost, because of the enlarged cylindrical body (known as ECB) sealed in capsule at bottom of anchorage. This paper presents the detailed structure of innovative anchorage system and its special features. To investigate the bearing mechanism of new anchorage, we evaluate its performance and failure mode based on the experimental results, and also indicate its strain-hardening load-displacement relationship. Unlike the shaft anchorages, it is identified no overall failure to be found in soil surrounding the underreamed anchorage. More importantly, the anchorage capacity is governed by the base resistance, which takes more than 80% of total pullout capacity resulting from the contribution of ECB. Finally a case history of anti-floating project introduces the new combined construction approach and procedure, which has provided the contribution to the quality control and cost efficiency.INTRODUCTION AND BACKGROUNDThe construction boom over two decades in China has resulted in an increasing demand for underground space and slope stability. The infrastructures market requires the more efficient anchorage systems for retaining structures, resisting uplift forces and slope protection. The major concern focuses on gaining higher capacity and lower cost resulted from perfecting anchorage systems. There are three main anchorage systems designed to achieve the above objectives: ? single bore multiple anchorage system (Barley 1997), ? regroutable anchorage system (Smoltczyk 1991), ? underreamed anchorage systems (Xanthakos 1991). Generally, the concept ? comparing with the other two, can be more competitive due to its distinct advantages. To improve the performance and durability of ground anchorages under the complex geological conditions and diversified engineering requirements, a number of different underreamed anchorage technologies had been used, which included cone - shape anchorage described by Liao, Wu and Shu (1997) in Taiwan, Soilex anchorage developed in Sweden (Massarsch et al. 1997), Soletanche anchorage proposed in France, blasting anchorage used in Czechoslovakia (Hobst and Zajic 1986), jet-grouting anchorage innovated in Europe (Anon 1988), as well as deep mixing anchorage created in Japan (Cheng et al. 2000).The underreamed anchorage systems have the remarkable advantages compared to the shaft anchorage system. However, there are also some weaknesses inherent in the underreamed systems. For instance, the mechanical underreamed anchorage is unsuitable in sand or waterbearing ground, because the enlarged hole is easy to collapse, and it is hard to ensure the quality of anchorages. On the other hand, relying on the blasting in deep hole, the geometrical space and dimension of enlarged hole is uncontrollable, meanwhile, the continuous blasting operations may easily cause the serious ground deformation and the negative effects to the completed anchorages."

Jan 1, 1900

By David A. Staab

Numerical modeling was used to investigate the feasibility of using two geophysical imaging techniques, cross-borehole ground penetrating radar (XBGPR) tomography and electrical resistivity (ER) tomography, for detecting and characterizing defects in deep-mixed soil columns. XBGPR modeling was accomplished with a three-dimensional numerical forward modeling code and a two-dimensional inversion routine. Spatial variations in apparent dielectric constant (Ka) and attenuation (a) were mapped. Electrical resistivity modeling was accomplished with a three-dimensional numerical forward modeling code and a three-dimensional inversion routine. Spatial changes in electrical resistivity were then mapped. Three different types of defects were simulated, in addition to a defect-free column. The computer simulations suggest that XBGPR tomography and ER tomography might be useful, non-destructive methods for detecting and estimating the extent of defects in deep-mixed soil columns. The results show that small, isolated defects might be difficult to detect, but defects approximately equal to or larger than the sampling interval (for XBGPR) or vertical electrode spacing (for ERT) should be detectable.

Jan 1, 2004

By Andrea Gambi, Giancarlo Olivucci, Maurizio Lenzi

"In the paper a criterion for the evaluation of the sharing of the lateral loads in a piled foundation is presented. It relies on the the compatibility condition between the rotation of the rigid pile cap and the rotations of the pile heads, following in that the criterion suggested by the Eurocode 8 - Part 5. This assumption leads to an analytical solutions which allows to deal with the sharing of the lateral loads and moments by means of two main interaction parameters only. A sharing domain is also derived and it shows the role played by the eccentricity of the lateral load on the values of the axial forces and of the bending moments at the head of the piles.INTRODUCTIONIt is well known that the interaction among soil, piles and foundation is one of the most complex subject to deal with in Geotechnical Engineering. Its rigorous study needs to employ suitable finite element software nowadays available and able to take into account the non linear behavior of the soil as a continuum and the inelastic response of the structure. A deep insight to the topic of the sharing of the loads cannot obviously renounce to this approach.On the other hand it is a daily need of the designers to have at their disposal simple tools that allow to make preliminary evaluations of the basic equilibrium conditions. To this purpose many methods of analysis have been developed in the past to face the sharing of the loads in a simplified version. The present contribution follows this way trying however to introduce some improvements that leads to find a solution that satisfies both the equilibrium of the forces and the compatibility of the movements (Lenzi, Gambi, Olivucci, 2002). The proposed model allows to identify the basic parameters which govern the sharing of the lateral load and it allows to perform also parametric analysis and quick checks that may be useful in the design of the piles."

Jan 1, 2005

The intent of this manual is to provide guidelines for inspectors of drilled shaft construction otherwise referred to as drilled piers, caissons or bored piles. It should also be helpful to train beginning geotechnical engineers with limited first hand experience or for geotechnical engineers who are training inspectors. It is expected that the general guidelines and procedures described here will be supplemented by local geotechnical engineers working in a particular region based on local practice and experience. Since drilled shaft construction procedures vary widely based on local geology and size of project, an all-inclusive manual is not considered practical. This manual focuses on traditional topside inspection for routine drilled shaft construction. Other inspection and evaluation methods that rely on electronic equipment are available, but these methods require extensive training and experience in the interpretation of results. These more sophisticated methods of drilled shaft inspection and evaluation are common in construction, but they are usually provided by specialty subconsultants. The subconsultant will typically submit a report for each shaft, which will be reviewed by the geotechnical engineer. Other manuals are available to describe the electronic methods of drilled shaft inspection.

Jan 1, 2004

By Chu E. Ho

Current methods of determining jet grout column diameters are highly empirical and site specific, and do not take into account the jet hydrodynamics and soil parameters explicitly. A theoretical model which describes the jet excavation mechanism is introduced in this paper, with the aim of providing an improved prediction tool that can be used in jetting design. The model is based on the assumption that the velocity distribution in the cutting jet is equivalent to that of a free jet with boundaries corresponding to the dimensions of the cavity excavated in the ground. The shape of the cavity formed depends on the erosional properties of the soil and jet expansion is limited by the resistance at the jet-soil interface. The model predicts that the limit of jet penetration is reached when the average dynamic pressure at the jet tip becomes equal to the ultimate soil bearing resistance. The reliability of the model, evaluated using results from four case histories of jet grouting field trials, is within ±15%.

Jan 1, 2006

Jan 1, 2002

By Tim Chapman

This general report considers what promoters of deep basement projects want from their teams and whether they get it often enough. Most large projects are based on complex financial models where the funding is related to a future income stream. Project delays and cost over-runs can critically affect the financial model. Too often, delays and cost over-runs originate in the substructure and foundations. We must take positive steps to improve our industry's reputation for reliability.

Jan 1, 2006

Jan 1, 1991

By Edmund J. Cardoza

WELCOME TO THE DEEP FOUNDATIONS INSTITUTE 26TH ANNUAL CONFERENCE AND WELCOME ESPECIALLY TO THIS SEMINAR ON NON-DESTRUCTIVE TESTING OF DRILLED SHAFTS, PRESENTED BY MEMBERS OF THE DFI DRILLED SHAFT COMMITTEE. MY NAME IS ED CARDOZA; I AM A VICE PRESIDENT WITH THE MILLGARD CORPORATION, A DRILLED SHAFT CONSTRUCTOR FOCUSING PRIMARLY IN THE EASTERN HALF OF THE UNITED STATES.

Jan 1, 2001

Jan 1, 1988

By Stephan Fisch, Franz-Werner Gerressen

"The use of cut-off-walls (COW) for the open pit coal mines has been used for decades. They have been used to reduce the negative hydraulic impact to the surrounding area caused by the open pit mining. The pile-guided trench cutting system is a worldwide unique technique, originally developed by the engineers of the mining companies themselves. It guarantees a continuous, joint free, COW during a continuous installation process. At this specific site in Welzow, this technique has been pushed to new limits in order to address the local lake region. Depth capability has been designed to about 430 ft (130m), proven are already depth of about 360 ft (110m) at a constant trench width of 39 inch (1000 mm). This project is approximately. 6.8 miles (11 km) long of COW, scheduled to be completed in 12 years period. About 2.05 miles (3.3km) have been installed, which is equivalent of about 3.5 Million ft² (330,000 m²). The system flushes special clay which forms a filter crust at the inner surface of the trench. Only natural clay resources used, in order to achieve the cut-off effect (colmation effect). The paper explains the installation process of the cut-off-wall as well as the equipment systems developed specifically for this project. After a successful start of the first phase of the project, the next step in the advancement of the equipment is already underway to enable the installation of greater depth to approximately 490 ft (150 m +) and beyond. The next generation equipment system is scheduled to start operation around 2018 INTRODUCTIONThis Serbian saying “Bóh je stworil Lužicu a cert je zaryl brunicu – God created Lusatia and the devil buried brown coal underneath it.” captures local communities’ ambivalence towards lignite.Lusatia is an almost entirely flat stretch of land between the Elbe and Neiße rivers dominated by glacial sands. On the surface, the heathland and woodland is hardly noteworthy. However, three large lignite mining regions, two in Brandenburg and one in Saxony, in the east part of Germany, divert the attention to underground level, down to depths of up to 120 meters. Here, seams crisscross the earth like ribbons. They were formed in the Tertiary around 17 million years ago.The mining of the lignite started almost 200 years ago. To enable open pit mining, a suitable dewatering system was required. At first, wells and drainage system were used. With the increasing demand to go deeper to enable full use of the existing resources with greater mining depth, a decision taken back in the 60th of the last century, the amount of water which had to be pumped increased dramatically. In peak times, approx. 1.57 Billion cubic yards per year (1.2 Billion m³/year) had to be pumped. This led to a lowering of the groundwater level for up to 230 ft (70 m), impacting the regional lake landscape. In order to reduce the influence on the water balance, and bring the water level back to pre1970th, a first development took place to implement the use of specific COW system to depth of about 147 ft (45m)."

Jan 1, 2017

By R. Paul De Bruyn

A. Crane Check List -- Make -- Model -- Year of Manufacture -- Where is load chart? Is it for this crane? -- Boom style and length -- Boom tip drawing (sketch) for fixed lead connection. Has the crane manufacturer been consulted on the point of attachment? -- How many drums; diameter and length of wire rope. -- Is the single part line pull enough to lift pile or hammer on single part line? -- What is the effective weight of the whole driving system - leads, pile, hammer, etc? -- Are there any auxilliary hydraulic systems? Are the line pulls on these adequate to lift the pile or hammer? -- What is the anticipated working radius? Will the spotter collapse to that length? -- Nature of foundation under crane - barge, marsh, unstable sand, etc. -- Does the crane meet OSAH and state regulations -current certification. Note - the operator is responsible for compliance with regulations. -- Is there any extra weight added to counterweight by compressors or hydraulic systems? What does crane manufacturer say? Consult factory before adding.

Jan 1, 1990

By Helene Kennedy, Josef Macsik, Yvonne Rogbeck, Gregory Makusa, Göran Holm

"Constructions activities in cities often imply large volumes of surplus material which could be treated by stabilization for re-use in new geotechnical constructions. Modification of dredged sediments by e.g. stabilization/solidification (s/s) is an example of sustainable handling option implying dredged contaminated sediments to become a potential resource for civil engineering constructions. The SMOCS project (Sustainable Management of Contaminated Sediments) within the Baltic Sea Region Programme 2007-2013 has developed a guideline based on a sustainability approach free to download at www.smocs.eu. The paper presents key issues in the guideline and highlights the importance of performing a field test as part of the design process. Two field tests with s/s-treated dredged sediments for new port areas are presented. Strength, permeability and leakage properties of s/s-treated contaminated sediments make beneficial use in geo-constructions possible. The influence of possible physical/chemical deterioration processes on the durability has been studied showing that freeze/thaw cycles might degrade the monolith of s/s-treated sediments. Consequently s/s-constructions shall be below freezing depth. Other deterioration processes such as salt and sulfate penetration were found of minor importance. Research is on-going to study the influence of and how to cope with freeze/thaw cycles on the long-term properties.BACKGROUNDConstructions activities in cities often imply large volumes of surplus material which could be treated by stabilization for re-use in new geotechnical constructions. The mechanical and environmental properties of the contaminated sediments could be modified through the stabilization/solidification method (s/s method) and provide a potential resource for civil engineering constructions. The SMOCS project (Sustainable Management of Contaminated Sediments) within the Baltic Sea Region Programme 2007-2013 has developed a guideline on management of contaminated sediments based on a sustainability approach. A field test on the application of the stabilization/solidification method for treatment of dredged soft contaminated sediments was implemented in the Port of Gävle, Sweden. The treated sediments were beneficially used as fill material in the new port area replacing ending natural resources."

Jan 1, 2015

By Robert C. Simpson, Ghada S. Ellithy

"There are several methods for estimating the axial capacity of drilled shafts installed in coarse-grained soils. Most methods estimate the ultimate capacity for side friction and tip resistance. Design capacity is then calculated by applying a resistance factor to the ultimate capacity. In reality, however, ultimate resistance may not be mobilized except after a significant displacement that is not structurally tolerated in either compression or tension modes.A full- scale load test is the best way to obtain the load settlement curve for a drilled shaft, especially in soil formations where accurate estimation of soil frictional properties from a field investigation may be difficult. This paper presents the results of a static, axial, compressive bi-directional load test, using the Osterberg method (O-cell test). The test was designed so that the shaft above the O-cell would move up and the shaft below it would move down when loaded. At the start of the test the concrete around the O-cell is fractured generally on a plane near the bottom of the cell.The test was designed to validate the design capacity of drilled shafts embedded into the Vashon recessional outwash (Qvro), which is a glacially derived sediment consisting of thick deposits of cobbly sand and gravel relatively free of silt and clay found in the Seattle, WA area. The test shaft consisted of a 2.5- feet (0.75 m) diameter drilled shaft. The test shaft was installed to a depth of about 47 feet (14.3 m) into this formation. A maximum load of 437 kips (1.95 MN) was applied during the test, in each direction. The maximum load was attained at upward and downward displacements of less than 0.1 inch (2.5 mm), respectively.Although the load test did not yield ultimate values, the results are compared to the design assumptions using methods adopted in the FHWA and AASHTO guidelines, which verified the adequacy of the design assumptions. We conclude that more emphasis is needed in the prediction of the service loads and corresponding mobilized displacement that may lead to a more cost effective design. It is also clear that more testing to higher loads could lead to more efficient designs on specific projects and generally as data is added to the local knowledge base."

Jan 1, 2015

By Raymond E. Sandiford

"The redevelopment of the World Trade Center (WTC) provided an opportunity for the Port Authority of NY and NJ to complete a long sought underground connection between all of Lower Manhattan’s transit lines, the World Trade Center and the World Financial Center (WFC) (Figure 1). Creating this connection was a challenge because the WFC lies west of the heavily trafficked Route 9A, also known as West Street. The previous connection was a bridge that required pedestrians to make significant level and directional changes to navigate the crossing. The positioning and elevation of the Route 9A pedestrian tunnel was established to provide pedestrians with a clear, single level, climate controlled corridor from the new WTC Transit HUB to escalators leading into the WFC Winter Garden.As the most direct link to the WFC, tens of thousands of people a day will use the pedestrian corridor. To accommodate this large number of pedestrians and provide an obstruction free passage, the tunnel has a clear width of 50 ft (15.2 m). Although only 250 ft (76.2 m) long, that short length presented many technical challenges.Here I describe how the challenges were overcome during the construction. However, some of the truly problematic issues arose from coordinating the phasing of this project with adjacent construction activities at the WTC, the reconstruction of Route 9A, and the WFC’s redevelopment program. The limited access to the excavation areas and confined site logistics were further complicated by having to maintain six lanes of traffic on Route 9A at all times. The efforts were so intertwined that, well into the underpass construction, the Port Authority Construction Department decided to merge a portion of that work into the WFC redevelopment."

Jan 1, 2012

By Mahesh Hingorani

Integrity issues for bored cast-in-situ piles have raised the need for the use of non-destructive tests to verify pile integrity and detect possible anomalies in installed pile sections that could adversely affect their serviceability. Integrity inspections performed after installations are often the most reasonable alternative available to assess the shaft quality. The two most common methods are pulse-echo from a small hand held hammer at the pile top, and cross-hole ultrasonic transmissions along the shaft between parallel sonic pipes. While different in technique, each method has its advantages and limitations. This paper emphasizes more on the degree of accuracy of low-strain pile integrity test by comparing the results with cross-hole sonic logging. Reliable data collection and interpretation by an experienced test engineer will reveal the integrity of the pile. Cross-hole sonic logging and low-strain pile integrity testing were both specified as quality control measures for a metro rail project in India. Both cross-hole sonic logging and low-strain pile integrity testing indicated defects in several bored piles. Also minor imperfections recorded by cross-hole sonic logging were observed in low-strain results. The observations of the two test methods are presented and compared for a better understanding of the importance of low-strain test results for any project. INTRODUCTION Cast-in-situ concrete piles are often chosen as a deep foundation alternative where challenging soil conditions exist. Although quality control measures are almost always taken during the installation of the piles, it is often difficult or impossible to confirm the integrity of the pile at this stage, particularly in wet conditions. Because of the relatively high probability of bored piles having anomalies, quality assurance of each bored pile is essential for each project.

Jan 1, 2019