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Articles 12511 - 12540 of 21751

Full-Text Articles in Engineering

Estimation Of Maximum Advance In Kaka-Reza Water Conveyance Tunnel At 700 Meter Depth, D. Azizmohammadi, H. Abbasi Apr 2004

Estimation Of Maximum Advance In Kaka-Reza Water Conveyance Tunnel At 700 Meter Depth, D. Azizmohammadi, H. Abbasi

International Conference on Case Histories in Geotechnical Engineering

The purpose of this research is the determination of maximum rate of advance in one stage of blasting in middle zone of Kaka-Reza water conveyance tunnel. In this zone of tunnel with average 700 meters of overburden, based on geological and geo-mechanical conditions, the supporting system will install immediately after excavation. The methodology of this research is combined of direct strain evaluation technique (DSET), numerical modeling (FLAC 2D) and convergence analysis. The research is done in three stages. At the first stage, the allowable strain in surrounding rock mass of tunnel is calculated based on DSET. At the second stage, …

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Ground Subsidence Induced By Oil Drilling Process, E. A. J. George, L. Thomas, C. Oko Apr 2004

Ground Subsidence Induced By Oil Drilling Process, E. A. J. George, L. Thomas, C. Oko

International Conference on Case Histories in Geotechnical Engineering

The process for oil drilling through superficial deposits often results in ground movements. However, because of the rapid sequence of the operations, these movements are hardly noticed or monitored. Oil drilling is generally carried out over drilling slabs or platforms. Such a slab was constructed on a land location close to the Imo River in Niger delta of Nigeria. During the process of drilling over the slab, large depressions around the cellar pits were noticed. This development demanded the lowering of the rig and an investigation into the causes of the movements was initiated. The investigation confirmed the existence underneath …

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Site Development In Deep Karst Terrain, Thomas P. Hart, Giuliana Zelada-Tumialan Apr 2004

Site Development In Deep Karst Terrain, Thomas P. Hart, Giuliana Zelada-Tumialan

International Conference on Case Histories in Geotechnical Engineering

The development of a site for a power plant was complicated by the presence of pinnacled karst bedrock located beneath more than 24 meters (80 feet) of intermediate geo-materials (IGM). Shallow mat foundations had been planned in the conceptual design. Detailed subsurface investigations included an extensive supplemental drilling phase that identified a complex layer of pinnacled karst lying beneath a hard, nearly inelastic layer of residual IGM. In an effort to keep the site on shallow foundations, the design team attempted a preload approach to pretest the load-bearing capacity of the potentially karst prone site. Project schedule constraints required the …

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Forensic Analysis Of An Uncontrolled Fill, V. V. S. Rao, N. Santosh Rao Apr 2004

Forensic Analysis Of An Uncontrolled Fill, V. V. S. Rao, N. Santosh Rao

International Conference on Case Histories in Geotechnical Engineering

This paper outlines the forensic analysis done in relation to a filling done to raise the general ground level in an area where a large housing complex is under construction near New Delhi, India. After the structures had been completed, trenches were dug to lay sewage and other service lines and the soil at the bottom had been observed to be in a slushy condition. A meticulous and detailed forensic diagnosis and analysis indicated uncontrolled filling. Measures were evolved to contain the slushy zone and compact the upper layers so that the service lines as well as roads could be …

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Field Monitoring Of The Compressibility Of Municipal Solid Waste And Soft Alluvium, Erik O. Andersen, L. A. Balanko, Joyce M. Lem, Dave H. Davis Apr 2004

Field Monitoring Of The Compressibility Of Municipal Solid Waste And Soft Alluvium, Erik O. Andersen, L. A. Balanko, Joyce M. Lem, Dave H. Davis

International Conference on Case Histories in Geotechnical Engineering

The paper presents the results of a settlement-monitoring program for a preloaded roadway embankment over a closed landfill underlain by three compressible units: municipal solid waste, alluvial peat, and organic silt. To monitor the progression of embankment settlement and assess the effectiveness of the preload treatment, a field instrumentation system was installed within the embankment footprint. The field instrumentation system, consisting of settlement plates, and vertical extensometer and vibrating wire piezometer stations, was monitored prior to construction, during construction, and for approximately 18 months thereafter. The extensometer and piezometer stations provided information on the individual response characteristics of the compressible …

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Lessons Learned From The Macon County Slurry Wall, Jeffrey C. Evans, John M. Trast, Randy L. Frank Apr 2004

Lessons Learned From The Macon County Slurry Wall, Jeffrey C. Evans, John M. Trast, Randy L. Frank

International Conference on Case Histories in Geotechnical Engineering

A soil-bentonite slurry trench cutoff wall was installed as part of landfill improvements at the Macon County Landfill located in Decatur, Illinois. In order for a soil-bentonite barrier to be continuous and defect-free, a homogeneous, well-graded backfill needs to displace the slurry used to maintain trench stability. Historically, specifications required that the backfill have a unit weight of 15 pounds per cubic foot (pcf) higher than the unit weight of the in-trench slurry and the slurry have a maximum density of 85 pcf. More recently, specifications have also required that the sand content of the slurry, not exceed 10 to …

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Site Characterization, Design, And Construction For Closure Of Four Hazardous Waste Landfills At A Superfund Site, Anirban De, R. Jeffrey Dunn, Neven Matasovic Apr 2004

Site Characterization, Design, And Construction For Closure Of Four Hazardous Waste Landfills At A Superfund Site, Anirban De, R. Jeffrey Dunn, Neven Matasovic

International Conference on Case Histories in Geotechnical Engineering

Various elements related to extensive geotechnical and seismic site characterization, design, and construction for the closure of four hazardous waste landfills and their interstitial areas at a major federal Superfund site are discussed. A major challenge was the geotechnical characterization of bulk and containerized hazardous waste for the purpose of stability analyses. Design constraints included a highly seismic environment and a large design precipitation event. Design was completed in two separate phases, such that the closure design of three of the landfills was performed during and after the construction of the first. This allowed for lessons learned from the construction …

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Quality Investigations On Ground Improvement In Highway Engineering Practice, Minglei Shi, Zhenshun Hong, Fei Jin, Li Shao, Heng Zhu, Renmin Li Apr 2004

Quality Investigations On Ground Improvement In Highway Engineering Practice, Minglei Shi, Zhenshun Hong, Fei Jin, Li Shao, Heng Zhu, Renmin Li

International Conference on Case Histories in Geotechnical Engineering

The constructions of highway often pass through naturally-deposited liquefiable grounds. Anti-earthquake design is essential for highway engineering practice in east China. Gravel column and dynamic compaction are often adopted for the improvements of such problematical grounds. The stability and settlement of the treated grounds depend much on the construction quality. How to investigate the quality of ground improvement is an important issue in highway engineering practice. In this study, the method of Spectral-Analysis-of-Surface-Waves (SASW) is applied to evaluate the construction quality on ground improvements by vibration gravel piles and dynamic compaction technique. The case studies show that the SASW method …

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Injection Of A Microfine Cement Grout For The Tunneling Of Meteor, C. Dano, H. Vergnaux Apr 2004

Injection Of A Microfine Cement Grout For The Tunneling Of Meteor, C. Dano, H. Vergnaux

International Conference on Case Histories in Geotechnical Engineering

The fourteenth line of the Paris metro (France), called Météor, is currently extended towards Saint-Lazare railway station in a very busy and historic district of Paris. The Transport Company (RATP), as a contracting authority, is then confronted with a complex environment. The constraints have determined works planning and construction methods. In particular, the alluvial deposits were reinforced by injection of microfine cement grout whose fluidity allows to accurately permeate fine soils. It was preferred to more traditional and potentially polluting grouts. After a description of the geotechnical conditions of the site, the different steps of underground constructions are briefly showed. …

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Use Of Cemented Rock Fill For Enhanced Pillar Recovery In Area 1 Of The Doe Run Company, Kenneth J. Zur, Derek Apel Apr 2004

Use Of Cemented Rock Fill For Enhanced Pillar Recovery In Area 1 Of The Doe Run Company, Kenneth J. Zur, Derek Apel

International Conference on Case Histories in Geotechnical Engineering

Area 1 of Doe Run Company’s Buick North Mine was selected for placement of cemented rockfill (CRF) to “trap” or encapsulate select pillars. This method of “trapping” pillars takes advantage of the passive confinement effect of CRF to increase the post-peak load bearing ability of trapped pillars so that other ore bearing pillars can be extracted while still maintaining local and global mine stability. A total of 73 pillars in this area were extracted from October 1998 thru January 2002. Thirteen of 73 pillars were totally trapped by CRF (i.e., the pillars were totally encased in CRF). Eight of the …

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Load Transfer Of Cement-Soil Column By Full Scale Load Test In Soft Clay, Jiwei Duan, Issa Oweis Apr 2004

Load Transfer Of Cement-Soil Column By Full Scale Load Test In Soft Clay, Jiwei Duan, Issa Oweis

International Conference on Case Histories in Geotechnical Engineering

The deep mixing method (DMM), by which, soil and cement are blended together in situ to form soil-cement columns, is used throughout the world. In this paper, load transfer behavior of cement-soil columns was performed by full-scale load tests in situ. By developing Chin’s method (Chin, 1970), a method is presented to estimate the pile ultimate capacity based on the load to settlement curve of pile static load test. The measured results showed that the strain near the pile tip was small. The major deformation of the pile is in the range of 0 to the effective length, beyond which …

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The Densification Of Loose Sand Using Compaction Piles, Kátia Vanessa Bicalho, Reno Reine Castello, Renata D’Andréa Apr 2004

The Densification Of Loose Sand Using Compaction Piles, Kátia Vanessa Bicalho, Reno Reine Castello, Renata D’Andréa

International Conference on Case Histories in Geotechnical Engineering

Two case histories of densification of loose sandy soils using compaction piles are analyzed. The sandy soils were improved to support heavily loaded structures using shallow foundations. The technique used was deep compaction through compaction piles driven with Franki -type equipment, and shallow compaction by vibratory plate. Results of the compaction processes are presented and discussed to provide guidance for future projects. The analysis includes distance from the compaction pile, initial relative density, time delay for results verification after compaction, and depth. The results of densification demonstrate the method is efficient.

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Excavation Shoring Failure Threatens A Historic Church: Exploration Of Causes And Remedial Measures, Salah Sadek, Philippe Fayyad, Walid Choucair Apr 2004

Excavation Shoring Failure Threatens A Historic Church: Exploration Of Causes And Remedial Measures, Salah Sadek, Philippe Fayyad, Walid Choucair

International Conference on Case Histories in Geotechnical Engineering

The city of Beirut is home to a very large number of historic monuments. Given the recent development boom following the years of civil strife, modern projects have begun to encroach on the spaces afforded older monuments. Recently, excavation works adjacent to the Lady of Annunciation Church resulted in severe cracking and deformations within the walls and floors of the stone and brick structure. The shoring provisions which were executed within the excavated lot consisted of contiguous bored piles with pre-stressed anchors. The failure occurred when the excavation works had progressed to a level of about 12m below original grade. …

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Design Of Subsurface Geodrain For Automated Industrial Unit – Case Study, D. L. Shah, C. R. Shah, H. M. Patel Apr 2004

Design Of Subsurface Geodrain For Automated Industrial Unit – Case Study, D. L. Shah, C. R. Shah, H. M. Patel

International Conference on Case Histories in Geotechnical Engineering

This paper describes the pre-construction modeling for design and post-construction evaluation of subsurface drainage systems for an industrial plant. Rajshree Polyfil Ltd has a polyester filament manufacturing plant spread over 50 hectare area in Bharuch district of Gujarat State, India. The plant is fully automatic and robotics operated. The cable duct for control system was laid below formation level. The seepage water was observed in the cable trench and nearby vicinity. This seriously affects the functioning of computer controlled production system. Preliminary investigation revealed that the ground water level was around 1.0m depth below formation level, which was more than …

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Effect Of Curing Time And Moisture Content On Swelling Potential Of Bottom Ash-Bentonite Mixtures, Sanjeev Kumar, Nick Burrus Apr 2004

Effect Of Curing Time And Moisture Content On Swelling Potential Of Bottom Ash-Bentonite Mixtures, Sanjeev Kumar, Nick Burrus

International Conference on Case Histories in Geotechnical Engineering

Over the last decade, there has been increased attention aimed toward the use of coal combustion products in geotechnical applications. Several studies have been completed to determine the properties of bottom ash from burning of pulverized coal, amended with admixtures such as bentonite, clay, and lime. Because of significant volume change characteristics of bentonite, soils or similar granular materials amended with it should be evaluated for their swelling behavior. A study recently conducted on bottom ash has shown that strength and stiffness characteristics of bottom ash amended with bentonite change significantly with the curing of the mixture. Therefore, this study …

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The Construction Of The A650 Bingley Relief Road Adjacent To An Unstable Tied Sheet Pile Retaining Structure, Jim Johnson, David Gwede, Andrew Smith, Ian Webber, Mike Murphy Apr 2004

The Construction Of The A650 Bingley Relief Road Adjacent To An Unstable Tied Sheet Pile Retaining Structure, Jim Johnson, David Gwede, Andrew Smith, Ian Webber, Mike Murphy

International Conference on Case Histories in Geotechnical Engineering

The proposed A650 Bingley Relief Road in West Yorkshire, UK, required the construction of a new dual carriageway to relieve traffic congestion in the town of Bingley. Part of the scheme involved constructing the road adjacent to an existing tied sheet pile wall, the “Canal Tied Wall” that had a history of movement. In this area the road passes over a kettlehole with peat and soft silts between 10 m and 14 m deep. The Canal Tied Wall forms the boundary between the realigned canal and the proposed new trunk road. It consists of two sets of steel sheet piles …

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A Model Based On Mechanics To Predict Settlements In Bioreactor Landfills, C. H. Hettiarachchi, J. N. Meegoda, J. P. Hettiaratchi Apr 2004

A Model Based On Mechanics To Predict Settlements In Bioreactor Landfills, C. H. Hettiarachchi, J. N. Meegoda, J. P. Hettiaratchi

International Conference on Case Histories in Geotechnical Engineering

Prediction of waste settlement behavior during the construction phase of a landfill is vital to effective functioning of leachate recirculation systems and gas collection pipe network, yet prediction of waste settlement is complex and difficult to perform. Few models, are currently available which can be used to calculate landfill settlement of the entire waste thickness after closure without accounting for variation in density and other parameters with depth. By starting after closure, these models do not account for settlements during construction. The use of entire depth does not allow for the calculation of strains at different depths. When landfills are …

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Seismic Foundation Retrofit Of West Stands Of Michie Stadium, Prapa Haran, N. Vaikunthan, Steven Brokken Apr 2004

Seismic Foundation Retrofit Of West Stands Of Michie Stadium, Prapa Haran, N. Vaikunthan, Steven Brokken

International Conference on Case Histories in Geotechnical Engineering

The Michie Stadium is located at the U.S. Military Academy at West Point, New York. The West Stands of the stadium, consisting of upper and lower tier seating and other facilities, are supported on columns which are founded on shallow footings resting mainly on shallow bedrock. A structural seismic assessment of the West Stands indicated that uplift of the foundations would occur during a seismic event thereby causing significant distress to the superstructure. In order to prevent the uplift of the foundations and to provide base fixity, it was proposed to install rock anchors through the foundation. A supplementary subsurface …

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Effectiveness Of Dynamic Compaction On Liquefied Foundation In Highway Practice, Minglei Shi, Songyu Liu, Yisheng Zhu, Guangyin Du, Peng Ji, Lei Fang Apr 2004

Effectiveness Of Dynamic Compaction On Liquefied Foundation In Highway Practice, Minglei Shi, Songyu Liu, Yisheng Zhu, Guangyin Du, Peng Ji, Lei Fang

International Conference on Case Histories in Geotechnical Engineering

In this paper, the in-situ dynamic compaction tests with different values of single-drop-compaction energy are performed on a liquefiable ground encountered in highway engineering practice. Excess pore pressure, total surface settlement and lateral deformation under dynamic compaction impact are measured and analyzed at different conditions, such as single drop-compaction-energy, drop numbers, depth of soil layer etc. The standard penetration test (SPT) is used for investigating the compaction effectiveness. The investigation results indicate dynamic compaction technique is an effective way for improving liquefiable ground in highway engineering practice. Relatively small single-drop-compaction energy and relatively more drop numbers should be adopted for …

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Seismic Pavement Evaluation In Development Of Seasonal Variation Models Of Pavement Properties, Nenad Gucunski, Rambod Hadidi, Ali Maher, Nick Vitillo Apr 2004

Seismic Pavement Evaluation In Development Of Seasonal Variation Models Of Pavement Properties, Nenad Gucunski, Rambod Hadidi, Ali Maher, Nick Vitillo

International Conference on Case Histories in Geotechnical Engineering

The AASHTO seasonal and temperature adjustment models do not take into consideration state specific conditions. New Jersey Department of Transportation initiated a study with an objective to calibrate the AASHTO models, or to develop new ones that will take into consideration New Jersey specific conditions. To achieve the objective, twenty-four pavement sections were instrumented and nondestructive testing (NDT) program is being conducted for a period of two years. The main task of the instrumentation is to monitor environmental parameters: air and pavement temperature, moisture, frost/thaw depth and rainfall. Seismic Pavement Analyzer (SPA) and Falling Weight Deflectometer (FWD) are used to …

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Empirical, Analytical Methods For Surface Settlement Prediction Due To Tbm-Tunnelling In Dutch Soft Soil, H. Netzel Apr 2004

Empirical, Analytical Methods For Surface Settlement Prediction Due To Tbm-Tunnelling In Dutch Soft Soil, H. Netzel

International Conference on Case Histories in Geotechnical Engineering

TBM-tunnelling in soft soil causes a 3D-ground deformation field, developing in longitudinal direction (parallel to the axis of the tunnel) and transverse direction (perpendicular to the axis of the tunnels). Empirical based methods are used for the prediction of the distribution of ground movements in both directions. Consequently the differential settlements are used to predict the damage risks of adjacent buildings due to TBM-tunnelling in the design stage. The Gaussian-curve is commonly applied for the prediction of green field ground movements transverse to the tunnel axis. Different authors derived methods for determining the characteristic inputparameter i, being the point of …

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Axial-Compressive Capacities Of A New Type Of Tapered Steel Pipe Pile At The John F. Kennedy International Airport, John S. Horvath, Thomas Trochalides, Andrew Burns, Stanley Merjan Apr 2004

Axial-Compressive Capacities Of A New Type Of Tapered Steel Pipe Pile At The John F. Kennedy International Airport, John S. Horvath, Thomas Trochalides, Andrew Burns, Stanley Merjan

International Conference on Case Histories in Geotechnical Engineering

Tapered driven piles have been the deep foundation of choice at the well-known John F. Kennedy International Airport (JFKIA) in New York City ever since construction of and at the airport began in the late 1940s. For many decades naturally tapered timber piles were used primarily but various brands of closed-end steel pipe piles have become preferred in recent years as design engineers have sought ever-increasing allowable axial-compressive loads per pile. Toward the end of the 20th century, construction of new passenger terminals and a light-rail system called AirTrain at JFKIA pushed existing steel-piling alternatives to their performance limit in …

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Ground Improvement By Optimized Preload Program, Henrik Kristiansen, Todd Martin Apr 2004

Ground Improvement By Optimized Preload Program, Henrik Kristiansen, Todd Martin

International Conference on Case Histories in Geotechnical Engineering

Preloading of sites underlain by compressible soils is a well-established site development procedure to reduce post-construction settlements of structures supported on shallow foundations. Considerable reduction in the preload duration can often be achieved by installation of vertical drains. It is desirable to extend vertical drains down through the compressible soils impacted by the preload and terminate the drains within relatively incompressible soils. If this cannot be achieved, then the potential exists for unacceptable post-construction differential settlements due to greater settlement below the center of the building than along its edges. If no relatively incompressible soils exist below the compressible soils …

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Ground Improvement By Stone Columns And Surcharge At A Tank Site, Kul Bhushan, Ashok Dhingra, Curt Scheyhing, Endi Zhai Apr 2004

Ground Improvement By Stone Columns And Surcharge At A Tank Site, Kul Bhushan, Ashok Dhingra, Curt Scheyhing, Endi Zhai

International Conference on Case Histories in Geotechnical Engineering

The ground improvement performed at the site of two 190-ft (57.9 m) diameter, 40-ft (12.2 m) high, 8 million-gallon (30,300 m3), circular steel water storage tanks consisted of installation of stone columns to mitigate liquefaction and lateral spreading potential and a surcharge program to reduce post-construction settlements. Settlement during the surcharge program ranged between 9 and 15 in. (225 and 375 mm) and post-construction settlement during the hydrotest was about 1.2 inches (305 mm).

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The Geotechnical Hazard Induced By 8.1 Earthquake In West Pass Of Kunlun Mountatin In China In 2001, Lanmin Wang, Zhongxia Yuan, Xu Liu, Yongming Chen, Weifeng Wang Apr 2004

The Geotechnical Hazard Induced By 8.1 Earthquake In West Pass Of Kunlun Mountatin In China In 2001, Lanmin Wang, Zhongxia Yuan, Xu Liu, Yongming Chen, Weifeng Wang

International Conference on Case Histories in Geotechnical Engineering

On November 14, 2001, a great earthquake with a magnitude of Ms=8.1 occurred in the Qinhai-Tibet Plateau, China, which is called as the west pass of Kunlun mountain Ms8.1 earthquake. This earthquake is the largest and the first one with a magnitude greater than 8.0 in mainland China in the recent 50 years. It caused a large-scale deformation zone with a length of 426 km in frozen soil deposit in the plateau with a height of 4000-5500 meters above sea level. Some geotechnical hazards induced in the meizoseismal area, such as compression and tension failure of soil deposit, shaking landslides …

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Estimate The Magnitude And Nature Of Distress The Various Structures Have Undergone Due To Recent Bhuj Earthquake, A. R. Katti Apr 2004

Estimate The Magnitude And Nature Of Distress The Various Structures Have Undergone Due To Recent Bhuj Earthquake, A. R. Katti

International Conference on Case Histories in Geotechnical Engineering

On January 26, 2001 one of the most destructive earthquakes ever to strike India occurred in Gujarat. More than 13,000 lives were lost in this earthquake. Several civil engineering sections have undergone moderate to severe distress. In this paper two cases of one port at Adani and a salt factory which has undergone severe distress has been covered.

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Estimation Of Site Effects In The Israel Seacoast Area By Ambient Noise Records For Microzonation, Y. Zaslavsky, A. Shapira, M. Gorstein, M. Kalmanovich Apr 2004

Estimation Of Site Effects In The Israel Seacoast Area By Ambient Noise Records For Microzonation, Y. Zaslavsky, A. Shapira, M. Gorstein, M. Kalmanovich

International Conference on Case Histories in Geotechnical Engineering

Owing to the proximity to seismically active faults as well as the population density in the band of Israel Seacoast between the towns of Ashqelon and Haifa, this region may be considered a high seismic risk zone. For quantitative assessment of seismic response in terms of horizontal-to-vertical (H/V) spectral ratios the ambient noise survey was carried out at 190 sites. Results derived from H/V analysis indicate site amplifications ranging from 1 to 8 within the frequency band 1.0-6.0 Hz. The soil profiles at the investigated sites were very different. Some sites have simple profiles in the uppermost surface layer and …

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Source Process Of Normal Earthquakes: The 3 February 2002, M6.3 Afyon, Turkey And The 7 September 1999, M5.9 Athens, Greece Earthquakes, Zafeiria Roumelioti, Christoforos Benetatos, Anastasia Kiratzi, Nikos Theodoulidis, Mustafa Aktar, Hayrullah Karabulut, Gonca Orgulu Apr 2004

Source Process Of Normal Earthquakes: The 3 February 2002, M6.3 Afyon, Turkey And The 7 September 1999, M5.9 Athens, Greece Earthquakes, Zafeiria Roumelioti, Christoforos Benetatos, Anastasia Kiratzi, Nikos Theodoulidis, Mustafa Aktar, Hayrullah Karabulut, Gonca Orgulu

International Conference on Case Histories in Geotechnical Engineering

The source process of two normal-fault earthquakes, the 3 February 2002, M6.3 Afyon, Turkey and the 7 September 1999, M5.9 Athens, Greece earthquakes are studied using regional, teleseismic and strong motion data. Detailed information derived from teleseismic waveform modeling and source time functions inversions are combined and used to forward model recorded strong ground motion. Both events presented evidence for emergence of strong directivity effects during their rupture, which greatly affected the distribution of strong ground motion. These results are indicative of the contribution of the source factor to the distribution of earthquake damage and consequently of its importance in …

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Stone Column Ground Improvement Against Liquefaction For The Preveza-Aktio Immersed Tunnel, Christos Vrettos, Stavros Savidis Apr 2004

Stone Column Ground Improvement Against Liquefaction For The Preveza-Aktio Immersed Tunnel, Christos Vrettos, Stavros Savidis

International Conference on Case Histories in Geotechnical Engineering

The construction of the road fixed-link crossing between Preveza and Aktio on the north-western coast of Greece has recently been completed. The project consists of an immersed single-tube tunnel under the strait and two cut-and-cover tunnels at the ends of the immersed part. The immersed section is constructed of eight precast rectangular concrete elements placed on the sea bottom at a depth of 25 m. The site is characterized by high seismicity. Foundation soil consists of Holocene marine sediments comprising irregular layers of sands, silts and clays that extend to great depth in the central part of the strait. Along …

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Nonlinear Site Response Analysis In The New Madrid Seismic Zone, Wei Zheng, Ronaldo Luna Apr 2004

Nonlinear Site Response Analysis In The New Madrid Seismic Zone, Wei Zheng, Ronaldo Luna

International Conference on Case Histories in Geotechnical Engineering

Deep alluvial soil deposit of the Mississippi Embayment overlies the New Madrid Seismic Zone. A new nonlinear site response analysis model has been developed for wave propagation in deep soil deposits. The shape of the backbone curve of the model is described by the empirical unified formulas. Extended Masing criteria are used to represent hysteretic loading and unloading of soils. The new model takes into account the influence of the effective confining pressure on the shear modulus degradation and the viscous damping development in soil. The model is implemented into a two-dimensional finite element code in the time domain and …

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