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By Stuart Coutts

"This paper presents an overview of the author’s experience related to the assessment of the base capacity of straight shafted and enlarged-base bored piles in sand. A design approach based on CPT qc is described which has been calibrated using a database of load tests. The importance of correct installation techniques with instrumentation are illustrated and a discussion is presented on the current use of high strain dynamic testing to validate compliance with design. An example of a recent project with high quality instrumented load test data illustrates the close match to the proposed best practice approach and also highlights the importance for consideration of the effects of stress relief for deep foundations installed in deep excavations.1 INTRODUCTIONContinuous Flight Auger (CFA) piles are the bored foundation pile of choice for sand deposits across Australia. The evolution of the determination of the base resistance of CFA piles has been shaped by available investigative techniques, calculation methods, and calibration of designs with laboratory and field testing. The Cone Penetration Test (CPT) has been widely used in Western Australia (WA) where the test has been commercially available via multiple contractors for more than 25 years. On the East coast, the adoption of CPT testing has been slower with a transition from traditional Standard Penetration Testing (SPT) still occurring. Dynamic pile load tests are often used to derive parameters. The influence of pile installation on performance is commonly misunderstood and is an important element on any discussion of pile capacity for CFA pile types. The interface between the base of the constructed pile and the in-situ soil has an influence on capacity such that a poorly constructed pile base will have limited (if any) contribution to pile performance within the normal working range, generally within a 10 mm movement. The research presented in this paper pertains to CFA piles (no drilling fluids) and enlarged base piles constructed using CFA techniques under drilling fluids such that clean pile/base interface is targeted. Developments in modern piling equipment and instrumentation allow the pressure and volume of delivered concrete/grout to piles to be accurately monitored at various stages of installation such that repeatable ‘best practice’ can be achieved. The changes in soil conditions that occur due to the disturbance of the install technique are also important.Although the results of this research are likely applicable to bored piles, the interface between the pile and in-situ soil (shaft and base) need to be considered for various installation techniques. The effects of stress relaxation (due to removal of soil above pile base and adjacent shaft), time to concreting, and the zone of disturbed soil around the pile shaft are paramount.2 INSTALLATION CONSIDERATIONS The pile mix (concrete/grout) and interface with the in-situ soil are also an important consideration. For example, coarse grained, poorly graded, dry, clean sand will be partially permeated by most pile mixes; such that the influenced soil will be enhanced and in instances the overall effective pile dimensions increased. Permeation of the disturbed zone of a pile or anchor shaft along with scale effects (Lehane 2009) can have significant effect on shaft capacity and shaft frictions significantly exceeding expected are not uncommon based on ‘theoretical’ dimensions. Advancements in mix technology and mix techniques also have a large influence on the pile/soil interface. The ability of the piling rig and augers to excavate a plumb and gauge hole can also have a large influence on the zone of soil disturbed adjacent the constructed pile with a resulting influence on capacity."

Jan 1, 1900

Roasting treatments were investigated to remove arsenic from a nickel concentrate. The main arsenic minerals and their proportions in the concentrate were niccolite (NiAs)-50%, gersdorffite (NiAsS)-40% and arsenopyrite (FeAsS)-10%. Thermal analysis showed that gersdorffite and niccolite began decomposing when heated above 640 and 830°C respectively. The maximum roasting temperature was limited by agglomeration of the concentrate above 900°C. A small vibrated bed reactor was used to investigate the effects of temperature and gas flowrate, the latter to sweep away evolved arsenic. At 900°C, 24% of the original arsenic remained in the concentrate. SEM examination of the calcine showed that the residual arsenic was associated with the calcium in the gangue minerals. Additions of sulphur (either as elemental sulphur or from pyrite) facilitated the decomposition of the arsenic-containing minerals, decreased reaction with calcium in the gangue and produced calcine containing 4-6% of the original arsenic. Treatment with chlorine during roasting was effective in reducing the arsenic content to similar levels. Generation of chlorine in the bed by sulphation of CaC12 also produced encouraging results. Arsenic, Nickel Concentrate, Roasting, Chlorine, Sulphur, Gersdorffite, Niccolite

Jan 1, 2005

By F. L. Sizer

SOME old-time views which have recently come into my possession have inspired me to record that part of the early history of Leadville, Color- ado, with which I am familiar, the years 1878 to 1882, in the hope that others will add to what is here mentioned. My first appearance in Leadville was in June, 1878, immediately after graduation from the University of Michigan, and I found a congenial and lively crowd of young men, already there. The old log hotel, at the corner of Pine and State streets, housed some distinguished guests in the summer and fall of 1878. It was my good fortune there to make the acquaintance of James B. Grant, afterwards Governor of Colorado, in July of that year, when we were both glad of the accommodation afforded by cots in the second floor loft of the hostelry presided over by Herman Hibschle. Grant was then building his smelter and our associates were Eddy and James, August R. Meyer, and Berdell and Witherell. The Grand Hotel-Harris and Walsh, pro- prietors-was the first-class hotel of the place; but in a very few months there were many competitors.

Jan 1, 1924

By Milton Gomez, Nico Sutmoller

Low-density cellular concrete (LDCC) was first introduced to the market in the early 1900s and since then has made continuous technological advances. There are two primary types of LDCC: permeable and non-permeable. Both types of cellular concrete offer advantages in different types of geotechnical engineering applications. Because of its unique characteristics of low density, high compressive strength, and high fluidity during placement, LDCC offers an effective solution for a wide variety of engineering applications, and in many cases provides a more cost-effective, labor saving alternative to traditional fill materials. This paper will review the history, characteristics, and technological advances of LDCC, highlighting multiple real-world case studies that showcase the high-performance capabilities of both permeable and non-permeable LDCC.

Dec 1, 2022

By Francesco Chiappalone, Tanner Murt, Lance Waddell, Cristina Oñate Salazar

The 3RPORT project is a 5-mile-long, 16-foot-internal-diameter tunnel excavated in hard rock by Slurry TBM in Fort Wayne, Indiana. Two-component grouting can be separated into two core areas of operation: batching and underground operations. This paper addresses the challenges faced and solutions implemented in these fundamental areas. The effects of external factors and their impacts on mix design and batching of grout will be explored. Underground, challenges of monitoring parameters and ensuring a proper mix between the two-components will be discussed, focusing on the adopted technical solutions and considerations to be taken in the design stage of tailskin grout ports.

Jun 13, 2021

By Matthew Preedy, Anthony Pooley, Mike Wongkaew, Dirk Bakker, Raghu Bhargava

Sound Transit’s ST3 program will add 62 miles of light rail to the Puget Sound area, including connections to the neighborhoods of West Seattle currently anticipated by 2031 and Ballard by 2036. These connections include considerations for both elevated and tunnel alternatives, as well as a new downtown tunnel for which different configurations are being considered with potentially very different construction logistics and risk profiles. This paper describes the latest developments in the ongoing evaluation process that will inform the consideration of different tunnel and station construction methods, technical and operational challenges and contracting methodologies, including construction of deep stations in dense urban environments.

Jun 13, 2021

By CK Tsang, Jack Muir, Dharman Gersch, Joshua Barry

Correct face pressure is critical to safe operation of a closed face TBM. If inadequate face pressure is applied, this will lead to excessive ground movement, and may result in collapse of the tunnel face. Face pressure calculations are performed manually every few meters along the tunnel alignment. With the application of a 3D ground model, ground profile information can be extracted for automatic computation. This will significantly improve the efficiency and accuracy and is adaptable to changes in design parameters. This paper will discuss the development of automatic computation techniques in extracting information from a 3D ground model.

Jun 13, 2021

By Evan Brinkerhoff, Steve Chorley

The largest hard rock TBM ever to bore in the USA, an 11.6 m diameter Robbins Main Beam TBM, recently underwent a planned in-tunnel diameter change to a more compact 9.9 meters. The first-of-itskind conversion process for the Main Beam TBM was undertaken 2.8 km into the bore and was not done inside a shaft or pre-excavated portal. This paper will detail the unique dual-diameter machine designed for the Mill Creek Drainage Relief Tunnel in Dallas, Texas, USA, machine performance, and successful size conversion process that took place in early 2021—a process that utilized the four C’s of construction to enormous benefit: Communication, Cooperation, Collaboration and Coordination.

Dec 1, 2022

By Elisa Comis, Jeffrey Peterson, Yama Ebrahimi

Construction of the Northeast Boundary Tunnel (NEBT), the last leg of the Anacostia River Tunnel System on DC Water’s Clean Rivers Project, started in September 2018 and was completed in April 2021. The 26-foot-bore earth pressure balance (EPB) tunnel boring machine (TBM) mined 26,737 feet at elevations between 80 to 160 feet belowground. Approximately 55% of the tunnel was cut through lower predominantly coarse-grained facies identified as the Cretaceous Patuxent Formation (undifferentiated) (PTX), and the remainder was cut through upper predominantly overconsolidated fine-grained plastic material facies identified as the Cretaceous Patapsco/Arundel Formation (P/A). Mixed face conditions were encountered in the transition from the P/A to the PTX and vice versa. This paper reviews the performance of the TBM that mined the NEBT through several unique challenges, including 8,000 feet of tunneling under the heavily developed Rhode Island Avenue corridor, major sensitive structures, cast iron water distribution mains, and other sensitive utilities.

Dec 1, 2022

By Sherwin F. Kelly

THE geophysical scene shifts and alters, the emphasis changes, and new possibilities loom, but the tendency is always towards widening the field and deepening the analytical penetration. Seismic methods have had their heyday, the torsion balance is being displaced by the gravimeter, electrical methods are showing deeper penetration, soil analysis is the newest tool, and gamma-ray logging appears on the horizon. One of the striking features of re- cent geophysical work in the oil fields has been the marked decrease in the number of seismic crews employed. Although the percentage of company crews is believed to have increased appreciably. the sum total has fallen sharply, as shown by the figures for the Gulf Coast area. About two years ago probably over 100 seismic parties were operating there, whereas now there are only about 35. This decrease may be partly due to the low prices of petroleum with a consequent reluctance to spend money to increase crude-oil re- serves but more probably to the fact that reflection and refraction shooting have been carried on so extensively that they have been applied to a large pro- portion of the areas in which they may reasonably be expected to succeed. Some of the earlier enthusiasm, particularly over reflection prospecting, may have erred on the side of over- optimism; some of the present curtailment may be due to over pessimism; but in the opinion of various observers seismic work at the present rate seems to be at it- optimum. It nevertheless remains pre-eminent as a technique for detailing structures in areas where good reflections can be obtained and is the only method that will give accurate depth to definite beds. Results may be poor in certain areas but many regions still remain wherein it can be applied, so that plenty of structural mapping remains to be done by the reflection seismic method.

Jan 1, 1940

By Ravi Sahu, Ankit Jha, Sudarshan Rajagopal, Purushotham Tukkaraja

Geologic structures are one of the crucial parameters in blast design. Structural geology and rock properties influence drilling patterns, blast layout, and initiation systems. A comprehensive understanding of structural characteristics is essential to achieve the desired blasting objectives. This paper aims to identify geologic features in a bench using images obtained from the drone.

Feb 1, 2020

By André de Albuquerque Vicente

Foram estudadas três corridas comerciais de ferro fundido nodular. Para produção das corridas, partiu-se do mesmo metal base e utilizou-se a mesma liga nodularizante. Cada uma das corridas foi feita com inoculantes diferentes. Os percentuais em peso de inoculante e liga nodularizante foram, respectivamente, 1,0% e 1,3%. Estudou-se a nucleação e o crescimento dos nódulos de grafita. Várias técnicas complementares de análise microestrutural foram utilizadas, tais como microscopia óptica, microscopia eletrônica de varredura (MEV) e espectroscopia de raios-X por dispersão de energia (EDS). Observou-se a sequência de crescimento dos nódulos de grafita, evidenciando-se a formação de silicatos complexos ricos em alumínio, cálcio e bário ao redor dos núcleos, gerando uma interface favorável à solidificação heterogênea de grafita a partir destas partículas de tamanho superior ao raio crítico.

Aug 17, 2017

By Waddah Akili

This paper describes the steps taken in planning, developing, and executing a case study/ case history course in geotechnical/ foundation engineering at an international university. The paper sheds light on: how a “workable” format for the course was arrived at; the organization of the course; and the results of evaluating the effectiveness of this approach versus traditional lecturing. Problems and challenges that could arise when offering the course for the first time are also addressed. Embedded in this experience and its related protocols are: the emphases on engineering design and the practice, teamwork and leadership development, organizational management, and oral and written communication skills. The paper concludes by confirming that discussions, through an open forum, are judged to be superior to traditional lectures in improving critical thinking, cultivating desirable personal attributes, and acquiring problem-solving skills.

By Douglas Glenn Stalheim

Production of structural steel with a minimum yield strength of 700 Mpa produced as hot rolled coil has become increasingly popular due to cost considerations when compared to quench and temper equivalent product. This grade when produced as hot rolled coil requires the use of microalloy precipitation strengthening mechanisms. This is typically a combination of niobium and titanium microalloys. While the metallurgical concept of structural steel precipitation strengthening mechanisms has been well researched and published, actual implementation into the production process can be very challenging. In addition to achieving a minimum yield strength of 700 Mpa, in many applications additional mechanical property attributes of formability as measured by hole expansion testing along with low temperature toughness properties are now required. Achieving a balance of all the mechanical properties in a stable and repeatable performance in production using microalloy precipitation strengthening mechanisms further increases the challenges. This paper will discuss the metallurgical/process strategies required to successfully produce 700 Mpa minimum yield strength hot rolled structural steel coil. In addition, the role and goals of both niobium and titanium in this product design will be presented.

Oct 30, 2017

By M. Z. Emad, S. Raza, K. Jalil, M. A. Raza, M. U. Khan, S. A. Saki

Dimension stone mining is Increasing because of growing demand from the building and construction industries. Diamond wire saw cutting is a popular dimension stone mining technique around the world. Estimation of the production cost for this method is critical for these operations. n this research a production cost model was developed for the mining of granite using a diamond wire saw. Cost and production data were collected from a granitic dolerite operation in Pakistan for a 4.5-year period, and analysed to identify the cost components. Fuel (34%), labour (15%), consumables (40%), and maintenance (5%) were found to be the four major cost components in this operation. A regression-based dimension stone production cost model incorporating statistically significant variables was developed. The data presented a strong correlation of production cost with fuel, labour, and consumables costs. Finally, a production cost model based on the consumption cost of diamond wire is presented. The model was verified using actual production cost data, which indicated 95% (R2 = 0.95) variance in the data between the predicted and actual production cost values. The model may help field engineers in computing their dimension stone operational cost during the cutting phase.

Nov 6, 2023

By D. J. Buchanan

British Coal's mining research programme is directed towards the strategic objectives of reducing production costs, improving product quality and resolving health, safety and environmental issues. The strategy for R&D is described and selected parts of the programme are reviewed. Two major initiatives are directed towards reducing production costs: geotechnics and automation. Integrated exploration techniques are used to delineate geological structures as an aid to mine planning. Rockbolting is being rapidly introduced and the in situ stress field has been found to be of significant influence. Automation is the subject of a major programme. A strategy for coal quality has been devised. The health, safety and environmental programme concentrates on the traditional hazards together with surface environmental problems.

Jan 12, 1992

By Yazen Khasawneh, Osvaldo P. M. Vitali, Mohammad Nassim

Wind turbines are subjected to complex form of cyclic loadings with variable amplitudes and frequencies. The cyclic loading and the accumulation of plastic strains with the number of cycles will result in degradation of the foundation soil stiffness. The foundation stiffness degradation will result in a shift (reduction) of the fundamental frequency of the wind turbine. Although this issue is recognized in the guidelines for wind turbines foundation design, no specific provisions are provided in the guidelines to consider the long-term stiffness degradation. In this paper, a practical procedure to consider the long-term cyclic loading effects on the stiffness of wind turbine foundations in cohesive soil is proposed. The procedure is based on 3D FEM modeling and reliable empirical methods to estimate the stiffness degradation due to the cyclic loading. Using the proposed procedure, the long-term performance of the P&H tensionless pier foundation with and without a reinforcing collar at the top of the pier is assessed. The numerical results demonstrated that the long-term performance of the P&H tensionless pier foundation with a reinforcing collar at the top of the pier is outstanding with negligible long-term degradation of the foundation stiffness.

Sep 8, 2021

By Tai Luu, Michael McNicholas, James C. McIntyre

The Jersey City Municipal Utilities Authority (JCMUA), discovered that an existing sewer pipe had collapsed under the New Jersey Transit Conrail Railroad between Pine Street and Ash Street in Jersey City New Jersey. Immediate action was taken to abandon the pipe in place and install a new sanitary sewer. The borings showed 10-20 ft (3.04 m.- 6.09 m) of competent fill overlaying approximately 8 ft. (2.44 m.) of compressible peat and organics. Groundwater was at 8 ft (2.44 m) below ground level. The poor condition of the soils at subgrade could not withstand the extreme weight of the jacking machine or the thrust force required to push the casing from the launching pit to receiving pit. The support of excavation (SOE) would therefore not only need to retain the soil to allow the jacking equipment to reach subgrade at 14 ft (4.27m) below working grade, but also the back wall of the SOE would need to be sufficiently robust to function as the reaction block for jacking operations. The alignment and allowable tolerance for the jacked casing was minimal, therefore the performance of the SOE was extremely critical to the success of jacking operations. This paper will discuss in detail the design concepts that were developed and implemented by the team to overcome these obstacles. HISTORY The discovery of a collapsed section of an existing sanitary sewer led the Jersey City Municipal Utilities Authority to act on an emergency contract. The project design team was tasked with developing an abandonment plan for the broken pipe and installation of the new pipe through challenging geology. The new 180 ft.(54.96 m) long, 54-in. (1.37 m) . diameter sewer pipe was designed to be contained within a 72-in. (1.83 m) protective steel casing. The installation of the new sewer pipe would require a detailed understanding of the geology. The geotechnical subcontractor assembled a subsurface investigation report on November 2nd, 2017. It was quickly realized that the only way to replace the pipe was with a jacked pipe system since the large grade change and the Conrail Right of Way created no other alternative. Delaying or closing the railway was absolutely not an option as that particular railway served as the main heavy-haul route to and from Jersey City. It became apparent that a major obstacle to pipe jacking was the challenging geology present across and beneath the proposed sanitary sewer. The following challenges faced the design team prior to the installation of the replacement pipe:

Jan 1, 2019

By M. Salimov, J. Sattarvand

The conventional visualisation method of remote equipment is through the installation of one or more cameras on the machine, and sending a live feed to the operator’s flat display. However, the performance of the teleoperation can be enhanced using better visualisation through virtual reality (VR). This paper presents the process of the design and manufacturing of a robotic platform that will be used in the next phase of the project for a VR-assisted teleoperated excavator. The robot consists of a loading boom and arm arrangement installed on the undercarriage of a CAT300-9D. All hydraulic cylinders are replaced with electric actuators, and crawling motors are substituted by electric motors. The pieces of the boom and the arm, as well as the bucket were designed in Autodesk Inventor, and manufactured from aluminium sheets using a desktop and CNC machine. Parts are joined by pins and welding as needed. An Arduino-based control system is developed for the robot, and motor controllers are used to convert the power commands from the microcontroller to the high-amperage actuators. The control system is capable of communicating with a wireless Play Station controller to operate remotely. The manufactured robotic excavator is planned to be utilised in multiple autonomy research projects.

Sep 1, 2021

By Thomas Jancic

Two of the open-pit, copper-molybdenum mining operations of Duval Corporation are located in the foothills of the Sierrita Mountains approximately 30 miles southwest of Tucson, Arizona. In March 1959, mining from a moderate sized porphyry deposit known as the "Esperanza orebody" was begun at a rate of 10,000 tons of ore per day. Some five years later, a sizeable group of mineral claims west of Esperanza became available to Duval. Earlier exploration and development drilling in this area by others indicated an orebody of greater size but lower tenor than that of Esperanza. A drilling program conducted by Duval not only verified the results of the prior drilling but in addition, revealed a continuation of the mineralization to the south and east. Thus was developed the Sierrita orebody. Open pit design delineated 414 million tons of ore containing an average copper content of 0.35 percent and a molybdenum content of 0.036 percent. In April 1966, the office of Emergency Planning authorized General Services Administration to undertake a program under the Defense Production Act to en¬courage additional domestic production of copper in the interest of national defense. Duval's Sierrita Project was brought to GSA's attention in May 1966 on November 28, 1967, an agreement providing for the development of the Sierrita Property was consummated with GSA. In March 1970, the first copper-molybdenum concentrates were produced in the 72,000 tons-per-day concentrator. Pre-production stripping exceeded the scheduled 105 million tons despite the comparatively short lead time available to equip the mine, build the mine plant facilities, and staff the technical, supervisory, and labor forces. Shortly before the first concentrates were produced, plans were being formulated for a program to increase processing capacity by approximately 15 percent, which entailed increasing overall mining capacity by approximately 50,000 tons per day. This program is scheduled for completion early in 1971.

Jan 1, 1971