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By Thomas Lardner

Excavation for The Bow, EnCana, in downtown Calgary, occurred between May 2007 and September 2008. A monitoring programme was used to determine the behaviour of the shoring wall, soil and bedrock during the excavation for the 21 metre (69 ft) deep excavation with a footprint of approximately 17,000 m2 (183,000 sq ft). Results from the inclinometer readings indicated that significant horizontal movement due to a weak rock layer and shear band effect. These modes of movement account for up to 100 mm (4.0 in) and 45 mm (1.8 in) of lateral deflection, respectively. Based upon the results of the monitoring programme, rock samples were collected from the weak mudstone bedrock, with great difficulty, to determine the strength and deformation parameters. Results from the uniaxial compression tests indicate a UCS around 830 kPa (120 psi) and elastic modulus between 80 and 180 MPa (11 and 26 ksi). Mohr-Columb parameters were determined to be c' = 340 kPa (49 psi) and f' = 24°. Residual strengths were determined to be c'r = 0 and f'r = 15°. Using the results of the laboratory tests and field investigation records, an initial finite element analysis was conducted. Results of the analysis show good correlation when compared with the observed monitoring deformation, indicating accurate portrayal of rock parameters. Additional analysis and investigation is required to determine the principal horizontal stresses in magnitude and direction.

Jan 1, 2010

By Roy A. Bell

A 200-foot diameter, 72-foot high petroleum storage tank was built in a hillside ravine where a portion of the site contained soft clay fill. Soil-cement piles, 40 inches in diameter and up to 38 feet long, were installed to support the tank shell and ringwall, and a portion of the tank floor by drilling into the stiff to hard underlying soils and weathered bedrock. The goal was to provide a strong enough foundation to resist the seismic tank shell loading and to minimize differential settlement of the tank shell to avoid out-of-round clearance problems between the shell and floating-roof. A cantilevered retaining wall up to 8 feet high was constructed around a portion of the tank perimeter by inserting steel H-beams into soil-cement piles. The cantilever soldier piles for the retaining wall were installed from a temporary earth embankment on the hillside directly over the top of the wall. The temporary embankment was then removed and the tank pad was cut to grade in front of the soldier piles. Some of the soil-cement piles for both the tank foundation and retaining wall could not be advanced to design depth because the drill/mixing tools could not penetrate to the required depth in the hard soils/bedrock. Smaller diameter borings (22 inches in diameter) were drilled through the centers of the short-of-design soil-cement piles to the design depth and then backfilled with concrete.

Jan 1, 1997

By Carl-John Grävare

This paper deals with some of the systems and equipment that are being developed and/or are in use in Scandinavia. The main subject is the development of loading tests on the piles using monitoring equipment. This paper also describes ground improvement using lime-cement columns, expander body piles and steel core piles.

Jan 1, 2000

By M. Kumaran, A. Vetriselvan, A. Purantharan

"This paper presents a case history of evaluating the stability of a distressed earth bund and rectification measures carried out. A 5.45 km long, 7m high earth bund for drinking water storage was constructed in Andhra Pradesh. During construction of the bund following were observed – (a) a longitudinal crack at the downstream side (b) Bund on the downstream side along the crack settled to a max of 700 mm and (c) downstream rock toe level area raised by heave up to 175 mm. Investigation of the events made important contributions to the fundamental understanding of the behaviour of large earthworks of this type. It was found that the variation in subsoil strata was not addressed during the execution.After careful evaluation, stone columns were recommended as a suitable ground improvement technique. Stone columns were used as a reinforcement to improve the shearing resistance of foundation and in turn ensure stability. By using and applying advanced geotechnical engineering analysis tools and modelling techniques, earth bund and its foundation was analysed and examined against failure by slope instability. Stone column design was carried out using in-house computer program GEOSTONECOL and stability of earth bund was analysed using TALREN software. Earth bund construction was completed after ground improvement and is performing satisfactorily.INTRODUCTIONIn order to supply water during summer season, Government of Andhra Pradesh decided to construct a 7m high and 5.45km long earth bund summer storage tank. It was one of the largest earth bund summer storage tanks in whole of South India at the time of its construction. During construction, the earth bund has undergone sudden distresses. Investigation of the series of events occurred during construction has made important contributions to the fundamental understanding of the behaviour of large earthworks of this type. This paper presents the reasons for earth bund failure, slope stability assessment of the distressed earth bund and recommendation of stone column as a suitable ground improvement remediation technique.DESCRIPTION OF STUDY SITEThe characteristics of the original construction are briefly described as follows. A shallow cut-off trench was excavated below existing ground level at the centreline of bund as shown in Fig. 1. Below the base of the trench a cut-off grout curtain was installed. Upstream and downstream shell earth filling was carried out using Clayey Sand ‘SC’ type soil. At some locations, bottom of cut-off trench has reached as deep as 12m from the existing ground level."

Jan 1, 2017

By Brian Maroney

In this paper an overview of the California Department of Transportation's (CALTRANS) bridge design criteria is presented. Special emphasis is focused upon seismic design and retrofit criteria. Topics include earthquake load definitions, foundation and structure type selection, structural earthquake analysis, and structure behavioral requirements.

Jan 1, 1993

By John P. Turner

The behavior of tieback retaining walls depends on many factors, including soil properties, groundwater conditions, construction sequence, spacing and stiffness of tiebacks and soldier piles, tieback loads, and others. The primary design considerations for tieback walls are 1) adequate stability and 2) limiting wall movements. Traditional design methods rely on apparent earth pressure diagrams and experience to predict the forces which must be supported by the tiebacks to provide adequate stability. The required soil properties depend upon whether the soil is sand, soft clay, or stiff clay. Design to limit wall movements is more difficult and the usual approach is to design the wall with an adequate factor of safety for stability and then evaluate wall movements during construction through the use of load tests on individual tiebacks and monitoring of wall movements by optical surveying, slope indicators, and extensometers. If excessive movements are likely to occur, it is often not known until construction is well underway. This approach is reflected in the fact that few tieback walls fail due to a lack of adequate stability, while most litigation involving tieback wall performance is related to excessive movements. Much progress has been made in recent years in methods for predicting the movement of all types of insitu retaining walls (Clough et al. 1989, Clough and O'Rourke 1990). These methods are based upon both experience and analytical methods. This paper reviews the methods currently available for evaluating both the stability and movements of tieback retaining walls. Case histories involving excavations constructed in the downtown Seattle area are used to evaluate the applicability of the available methods to Seattle conditions and to illustrate the importance of soil behavior in tieback wall performance.

Jan 1, 1990

By Alan J. Lutenegger

Some years ago, a method was developed to incorporate a grout column around square-shaft helical screw-piles and anchors to increase shaft buckling resistance under compression loading. An additional benefit of this grouted shaft is to increase the load capacity in both compression and tension, depending on the geometry of the lead helical section and the soil conditions. Because of the unique construction procedure, the contribution of the shaft to the total capacity has largely been unknown. The behavior of grouted shaft helical anchors in clay was investigated by performing full-scale axial uplift (tension) load tests on a series of anchors installed at the University of Massachusetts Geotechnical Test Site. In order to isolate the contribution of the grouted shaft to the total load capacity, anchors were installed with a wooden dowel connection between the lead helical section and extension sections on three of the four anchors so that only the shaft resistance would be measured during the load tests. The grouted shafts ranged in length from 10 to 30 ft (3 to 9 m). Initial tests were performed approximately 5½ months after installation. Nearly four years after the initial tests were performed, the tests were repeated to evaluate any significant change in capacity with time and/or repeat testing (preshearing). The soil conditions at the site are presented along with the load-displacement curves for both the initial and repeat teats and a discussion of the analysis of the results. Repeat load tests showed an increase in capacity from the initial testing, however the percent increase was not the same for all depths. The results demonstrate that considerable shaft resistance can be developed in clays from the grouted shafts as might be expected. Depending on the L/D ratio of the shaft and the contribution of the lead helical section, at working loads the shaft capacity can dominate the behavior.

Jan 1, 2011

By Benoit Virollet

Over the last 10 years the diameter of unbraced, unlined and unanchored circular shafts has grown dramatically in many parts of the world. This progress has taken place through improvements in: construction methods; concrete rheology; and design capabilities. Excavation equipment has become more precise in terms of operator control and ability to correct alignment of digging elements leading to better alignment tolerances. Also contributing to the increases in shaft diameters is the evolution of design models. A better understanding of soil structure interaction is being incorporated into the analyses in terms of radial soil stresses and imposed loads on the shaft. This paper provides an overview of the recent progress made in circular shaft construction, the primary design considerations, and some innovative uses of efficient arc elements to develop unsupported structures of other shapes. In addition, a summary of recent circular shafts constructed worldwide is provided.

Jan 1, 2006

By Craig T. Jones, Zachary Q. Maassen

"Jet grouting is a method of ground improvement that relies on the erosive capacity of high-speed jets to cut and mix the ground in place with a cementitious grout. A continuous return flow of cuttings, called jet grout backflow or spoils, is expelled to the surface during the grouting process. Data from projects completed in Toronto and Ottawa is presented where BOS Solutions’ services provided significant savings compared to the traditional spoils treatment utilizing vacuum trucks for spoils disposal. These traditional treatment methods are cumbersome and expensive by nature. BOS Solutions provided an alternative solution that is environmentally friendly and capable of handling full flow to process these jet grout spoils utilizing a tank system paired with centrifuges and flocculation additives to remove the ground soils and grout product from the spoils slurry. BOS’ process produced a clean water for reuse in the project while reducing the overall waste volume by producing a dry, stackable solid that could be hauled to a landfill. Benefits observed by using the BOS process were disposal waste volumes decreased over 30% and at least a 19% reduction on disposal costs.SCOPE OF WORKJet grouting is a method of ground improvement that relies on the erosive capacity of high-speed jets to cut and mix the ground in place with a cementitious grout. A continuous return flow of cuttings, called jet grout backflow or spoils, is expelled to the surface during the grouting process. The backflow, or spoils, is a mixture of grout, water and soils. Traditionally, the spoil would be collected in in-ground pits and allowed to solidify for a few days prior to hauling to a final disposal site. For the projects completed in Toronto and Ottawa, the jet grouting work was performed at street level, in high traffic congested areas, presenting the challenge of insufficient space for the contractors to process the jet grout spoils in the traditional way. At first, attempts were made of using vacuum trucks to collect and haul the wet spoils to an off-site location where the spoils would be allowed to solidify. However, this method proved cumbersome and expensive due to the high volumes of spoils generated daily and the high number of vacuum trucks required to support the jet grouting operations, respectively."

Jan 1, 2017

By K. Kawakami

In Japan, pile foundations have been used extensively for buildings, bridges and port facilities. A large number of steel pipe piles were first used in the 1960's and the amount of steel used in foundations increased by 1973 to one million tons. This report describes current practice in the actual use of large diameter and long steel pipe piles in Japan, related to their performance: including consideration of pile size, hammer types used for driving the results of field tests measuring stress occurring in the piles and the driving formulae currently being used in practice in Japan.

Jan 1, 2010

By J. Hartikainen

Kemi cardboard mill is founded on the alluvial bed of Kemi river at the north-eastern cost of Botnic Culf in Northern Finland. The alluvium consists of sandy and silty layers underlain by thick medium dense silty moraine layer. The first cardboard machine, having a belt width of 7,4 m, was constructed in 1972 on 7,5 to 9,5 m long wedge-shaped precast driven piles. Because of the excessive differential settlements and sometimes unexpected dynamic malfunctioning of the machine it was decided to strengthen the foundation before installing the partly new machine and increasing the running speed from 500 to 750 m/min. Piling was done under extremly strick limitations concerning space, vibrations, settlements, dust etc. Extra vertical support was made by using 23...25 long x-form steel piles driven by compressed air pile hammer down to rock. The piles were held together with old piles by a conctrete frame with diagonals, which made the total system - machine - foundation frame, piles and ground - ridgid enough to avoid resonance during dynamic loading.

Jan 1, 2010

By F. W. Liang

The geology of pearl River estuary belongs in strong weathered rock quaternary geological systen, so the conditions are complication. Since 80's we built the first deepwater wharf of Shenzhen chiwan port which has 3 berths of 10000 dwt, We have built 3 berths for vessels of 40000 dwt both in Shekou Port and Chiwan port. The berths for carriers of 10000 dwt in Yantian Port of Dapeng Bay are constructing now. In the five years, We built more than 20 deepwater berths of 5000 dwt to 40000 dwt. This paper will introduce how to solve the difficulties of the complex geological conditions and how to use the new fashion construction. We will reduce the period of engineering construction and get good quality and make a good beginning of rapid development of port construction in ShenZhen Special Economic Zone.

Jan 1, 1991

By A. R. Katti

The stone columns are widely used in the improving the bearing capacity of weak soils mostly for supporting flexible foundation systems. The load carrying capacity of a stone column is complex in nature. The load capacity is derived from the lateral stresses acting on the stone column due to load transmitted from the flexible structure due to deformation to soil mass and which in turn transmits lateral pressure in s3 direction. The load capacity is also function of the f value of the stone column, cohesion of the surrounding soil, K0 and Gb2 of surround­ing soil including passive resistance developed to lateral deformation of the stone column. The assessment of axial and radial deformation is much more complex. Recently Katti et.al. have developed a method based on a granular heap approach and computed with equivalent fe. which combines the effect of s3a and equivalent volume concept to estimate radial and axial strains. In this paper an attempt is made to put forward guidelines for design of stone column accounting for both stability with respect to shear and also with respect to settlement. The estimate of settlement are based on the internal properties of stone column and surrounding soil. It is considered thus the settlements computed are more realistic.

Jan 1, 1996

By D. E. Sherwood

Recent developments in high torque hydraulic rotary rigs has lead to the construction of secant bored pile walls by rotary drilling methods in circumstances where earlier methods were difficult and in some cases impossible. The evolution of secant bored pile wall construction is described including classical, rotary drilled and continuous flight auger construction methods. The paper then details the restraints which have been created in recent inner city redevelopment, many of which were not relevant in the early days of the technique. Typical examples of walls are presented to show the adapatability and advantages of the secant bored pile wall method. A number of in-situ retaining wall construction techniques are then compared in detail with regard to relative cost, technical quality and practicality.

Jan 1, 1989

By Michael W. Neill, O&apos

The engineering profession generally does not accept vibro-driven piles as bearing piles unless their capacities can be verified by restriking with an impact hammer, which significantly reduces the economic benefits of vibratory driving. In part, the concern for capacity development in piles driven by vibration arises out of observations that vibro-driven piles do not develop capacities equivalent to those driven by impact (e. g., Mosher, 1987). Nonetheless, if capacities are predictable, vibratory installation may be more cost effective than installation by impact, due to savings in time of installation, even if capacities are lower than those of impact-driven piles. Throughout the past few decades, a number of attempts have been made to develop capacity prediction methods for vibro-driven piles, mostly along the same lines as methods for impact-driven piles. That is, (1) totally empirical formulae, (2) power balance / power transfer formulae, and (3) "time domain-nonlinear" (TDN) computational procedures such as the wave equation. Some of the formulae have been based partly on field experience, but the majority have been developed from simple theoretical models with parameters evaluated from laboratory studies. Neither these formulae nor the TDN solutions have been systematically checked (or modified) by recording appropriate field data over a variety of site

Jan 1, 1989

By Paul J. Axtell

This case history describes the foundation design and construction for the New Mississippi River Bridge, presently under construction in St. Louis, Missouri. The 1,500 ft (457.2 m) main span of the cable-stayed bridge is supported by two delta tower pylons in the river, with anchor piers on each bank. The final foundation design was completed as a part of an Alternate Technical Concept (ATC) proposal by the winning construction team, and utilized drilled shafts up to 11.5-ft (3.5-m) diameter that were socketed into very hard limestone. As part of the ATC foundation design, a full-scale, bi-directional static load test was performed to verify the design and allow use of higher resistance values. This paper presents the results of the site exploration, construction of the load test shaft, details of the load testing, and a comparison of the test results with various design parameters.

Jan 1, 2011

By K. Englehardt

J BERESFORD introduced the subject of the paper which is the use of polymeric slurries to support the sides of diaphragm wall and bored pile excavations during construction. In the opinion of the authors the use of a suitable polymeric fluid offers financial and technical advantages compared with traditional bentonite based slurries. Under quiescent conditions a support slurry must have the following properties. - sufficient viscosity to support the sides of the excavation, to prevent infiltration into soils and to hold loose soil particles in suspension. - when agitated it should thin quickly to assist pumping transfer and cleaning and allow free passage of the grab or drill. - viscosity should be low enough during concreting to facilitate placement but high enough to prevent contamination of the concrete.

Jan 1, 1991

By D. A. Greenwood

Dr David Greenwood opened the first technical session of the conference by highlighting the diverse nature of the papers in this session but drawing attention to the common theme that each solved a particular problem. PAPER 1.1 Tony Elliott introduced his paper on deep mix-in-place soil/cement stabilisation by stressing its simplicity. The engineering solution adopted at Elland was detailed in his paper and had formed the key to success of the project. The process itself is not widely used or known in the UK, although it has the potential to achieve significant benefits, subject to proper engineering control being exercised. It was explained that although the concept was not new, development of the technique for soil modification was relatively recent. The alternatives to mechanical mixing are injection, which is very dependent on soil type, site geometry, etc, and jet grouting; both processes are soil-responsive, and not easily monitored or programmed, difficulties which can largely be overcome by mixing. To achieve this at depths to say 30m requires high-powered, high torque machines and has resulted in significant equipment development.

Jan 1, 1991

By A. R. Dover

The Richmond-San Rafael Bridge is a 6.92 kilometer (4.3 mile) long major toll bridge span that crosses the northern San Francisco Bay in a highly seismically active region. Tutor-Saliba / Koch / Tidewater JV was contracted by Caltrans to conduct a comprehensive seismic retrofit. The JV provided geotechnical planning and quality control services as described herein, under normal oversight by Caltrans. Part of the robust foundation retrofit design included the installation of 26 new, large diameter piles, including eleven 3.81 m (12.5 ft) diameter, cast-in-drilled-hole (CIDH) marine piles that were drilled 9.15 m (30 ft) into the bedrock beneath the Bay, where the water depth ranged up to about 21.3 m (70 ft). These reinforced concrete-filled composite piles have a steel shell permanent casing from the bridge substructure pile cap through the water column and 30.5 to 39.6 meters (100 ft to 130 ft) of marine sediments to the top of rock. This paper discusses construction, inspection (ranging from the QA employed in the planning of the CIDH pile installation methods and equipment to the actual construction inspection required for the routine installation of the shafts), problems that were encountered during construction, and the solutions that were developed and implemented. Inspection, particularly with the usual difficulties in the marine environment, coupled with the difficult and complex bedrock conditions was particularly challenging, and ranged from non-destructive testing to "in-water, inshell" diver inspection. Similarly, the complexities of dealing with both the steel casing "riser" and the associated drilled shaft (rock socket) portion of these composite foundation elements created some unusual issues. The paper also presents important lessons learned from the project.

Jan 1, 2008

By Robert B. Bittner

The Sutong Bridge across the lower Yangtze River in China will have, when completed, the longest span (1,088 m) and the highest towers (306 m) of any cable stayed span in the world. The foundations for this record setting span will also be record setting. They are located in water depths exceeding 30 m with maximum flows exceeding 3 m/sec. The soil at the site of the main pylons consists of layers of silty sands and silty clays extending to bed rock at 270 m below river elevation. This paper describes the innovative methods used by the team of foundation designers and constructors to support this record setting bridge at this very challenging site. This paper covers three specific topics related to the foundations of the Sutong Bridge: ? Design and construction of the 131 drilled shafts (2.8/2.5 m diameter and 114/117 m long) under each of the two main pylons, including the post-grouting of all drilled shaft tips. ? Design and construction of the scour protection for the two main pylons. ? Construction methods used to construct the waterline pile caps (113.8 m by 48.1 m by 13.3 m deep) under each pylon.

Jan 1, 2007