Settlement record of tower silos built on Champlain clays

1987 ◽  
Vol 24 (4) ◽  
pp. 490-498 ◽  
Author(s):  
J. P. Morin ◽  
R. Gervais
Keyword(s):  
Key Words ◽  
Case History ◽  
Laboratory Testing ◽  
Factor Of Safety ◽  
Shear Testing ◽  
Foundation Design ◽  
Design Recommendations ◽  
Original Group ◽  
Settlement Behaviour

Research has been carried out at Université de Sherbrooke since 1975 on the behaviour of agricultural tower silos built in the St. Lawrence Lowlands in the Province of Quebec. The structures considered are built over soft sensitive Champlain Sea clays. The current foundation designs usually rely heavily on qualitative estimations of the performance of previously built silos. Settlement surveys are now available for a 10 year period for 19 silos out of an original group of 28. Sampling and laboratory testing have been carried out at 11 of these locations, while Nilcon vane shear testing has been performed at each site. Settlement and stability calculations have been made. It is thus possible to compare the observed and predicted behaviours of each silo over a substantial period of time. Foundation design recommendations are proposed as a result of these observations. It is shown that the factor of safety against failure can be used as an indicator of settlement behaviour. Key words: case history, settlement, sensitive clays, tower silos.

Preloading thick compressible subsoils: a case history

1995 ◽  
Vol 32 (3) ◽  
pp. 465-480
Author(s):  
Charles F. Ripley
Keyword(s):  
Key Words ◽  
Case History ◽  
Construction Control ◽  
History Of ◽  
Settlement Analysis ◽  
Settlement Behaviour

A case history of preloading and surcharging a more than 300 ft (1 ft = 0.3048 m) thick compressible subsoil is presented, with data on the settlement analysis, the fill design, other measures used for control of settlements, and the 24 year postconstruction performance. The essential factors for successful application of preloading to thick compressible subsoils are discussed. Key words : preloading, settlement analysis, construction control, settlement behaviour.

scholarly journals Field verification of a new asphalt compactor, AMIR

1991 ◽  
Vol 18 (3) ◽  
pp. 465-471 ◽  
Author(s):  
Otto J. Svec ◽  
A. O. Abd El Halim
Keyword(s):  
Key Words ◽  
Laboratory Testing ◽  
Research Council ◽  
Joint Venture ◽  
National Research Council ◽  
Field Trials ◽  
Full Scale ◽  
Field Verification ◽  
Asphalt Mix

A prototype of a new asphalt compactor termed "asphalt multi-integrated roller (AMIR)" was built as a joint venture between the National Research Council of Canada (NRC) and a Canadian manufacturer, Lovat Tunnel Equipment, Inc. The purpose of this project was to prove this new compaction concept in a full-scale environment. This paper describes one of the field trials carried out on the campus of the NRC and reports the results quantifying the quality of the AMIR compaction. Key words: compactor, asphalt mix, field trials, laboratory testing.

Successful Single-Stage Cementing in a Weak Formation: A Case History in Spain

2014 ◽  
Author(s):  
A.. Bottiglieri ◽  
A.. Brandl ◽  
R.S.. S. Martin ◽  
R.. Nieto Prieto
Keyword(s):  
Engineering Design ◽  
Case History ◽  
Laboratory Testing ◽  
Single Stage ◽  
Formation Damage ◽  
Cement Slurry ◽  
Integrity Test ◽  
Open Hole ◽  
Zonal Isolation ◽  
Horizontal Wellbore

Abstract Cementing in wellbores with low fracture gradients can be challenging due to the risk of formation breakdowns when exceeding maximum allowable equivalent circulation densities (ECDs). Consequences include severe losses and formation damage, and insufficient placement of the cement slurry that necessitates time-consuming and costly remedial cementing to ensure zonal isolation. In recent cementing operations in Spain, the formation integrity test (FIT) of the open hole section indicated that the formation would have been broken down and losses occurred based on calculated equivalent circulating densities (ECDs) if the cement slurry had been pumped in a single-stage to achieve the operator's top-of-cement goal. As a solution to this problem, cementing was performed in stages, using specialty tools. However, during these operations, the stage tool did not work properly, wasting rig time and resulting in unsuccessful cement placement. To overcome this issue, the operator decided to cement the section in a single stage, preceded by a novel aqueous spacer system that aids in strengthening weak formations and controlling circulation losses. Before the operation, laboratory testing was conducted to ensure the spacer system's performance in weak, porous formations and better understand its mechanism. This paper will outline the laboratory testing, modeling and engineering design that preceded this successful single stage cementing job in a horizontal wellbore, with a final ECD calculated to be 0.12 g/cm3 (1.00 lb/gal) higher than the FIT-estimated figure.

Movement and stability analysis of the Beaver Creek landslide, Saskatchewan, Canada

1985 ◽  
Vol 22 (3) ◽  
pp. 277-285 ◽  
Author(s):  
R. T. Yoshida ◽  
J. Krahn
Keyword(s):  
Stability Analysis ◽  
Key Words ◽  
Residual Strength ◽  
Case History ◽  
Single Unit ◽  
Slip Surface ◽  
Friction Angle ◽  
Slide Mass ◽  
History Of ◽  
Residual Values

This paper presents a case history of a multiblock landslide where the blocks move at varying rates along a common horizontal slip surface which follows the contact between stratified drift and underlying till. Movement measurements indicate that the blocks towards the toe move at a higher rate than blocks towards the scarp. Stability analyses show that the entire slide mass can be analyzed as a single unit as opposed to considering each block separately. This finding is compared with the analysis of other multiblock slides. The friction angle mobilized along the horizontal slip surface falls within the range of residual values measured in the laboratory. Key words: landslides, stability, analysis, translational slides, residual strength.

Design Recommendations for Controlling the Jam-Clearing Hazard on Recycling Industry Balers

2005 ◽  
Author(s):  
T. Mick ◽  
K. Means ◽  
J. Etherton ◽  
J. Powers ◽  
E. A. McKenzie
Keyword(s):  
United States ◽  
Laboratory Testing ◽  
Occupational Safety ◽  
The United States ◽  
Operating Conditions ◽  
Occupational Safety And Health ◽  
Hydraulic Pressure ◽  
Design Recommendations ◽  
Recycling Industry ◽  
Safety And Health

Between 1986 and 2002, there were 43 fatalities in the United States to operators of recycling industry balers. Of these fatalities, 29 involved horizontal balers that were baling paper and cardboard (Taylor, 2002). Balers often become jammed while the baling process is occurring, and the only way to remove the jam is manually. This requires an employee to place a limb of their body into the jamming area and remove the material that is causing the jam. While lockout and tagout procedures reduce the risk of hazardous energy being released, they can still be easily bypassed, ignored, or forgotten. Recent efforts to reduce machine-related injury and death involve the development of a control system for these machines that automatically detects hazardous operating conditions and responds accordingly. The system is being developed at the National Institute for Occupational Safety and Health (NIOSH). This system, JamAlert, automatically terminates the power to the machine when a jam is detected. JamAlert detects a jam by observing both the strain that is experienced by the shear bar of the baler and the hydraulic pressure at which the ram is operating. The strain that is experienced by the baler shear bar when a jam is initiated was calculated in this study through laboratory testing and finite element modeling. Design recommendations are presented on how best to tune the JamAlert’s operating program to most effectively control the jam-clearing hazard.

Structural analysis of pipeline stresses created by line lowering

1987 ◽  
Vol 14 (6) ◽  
pp. 719-727 ◽  
Author(s):  
Sid Czinkota
Keyword(s):  
High Pressure ◽  
Structural Analysis ◽  
Natural Gas ◽  
Stress Analysis ◽  
Key Words ◽  
Case History ◽  
Axial Stress ◽  
Axial Strain ◽  
Critical Factor ◽  
The Other

To increase the depth of soil which covers a buried steel pipeline, the line can be lowered without cutting and welding. The degree of curvature in the new profile is the critical factor for controlling the resultant strains. Presented are two methods of calculating the required profile for a line containing high-pressure natural gas. One of the two is selected as being more efficient than the other and is compared with other known methods. Finally, a case history using the new method is presented. Key words: pipelines, gas pipelines, structural analysis, stress analysis, axial stress, axial strain, deflection, curvature, profiles.

A general limit equilibrium model for three-dimensional slope stability analysis

1993 ◽  
Vol 30 (6) ◽  
pp. 905-919 ◽  
Author(s):  
L. Lam ◽  
D.G. Fredlund
Keyword(s):  
Stability Analysis ◽  
Case History ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Three Dimensional ◽  
Open Pit ◽  
Open Pit Mining ◽  
Two Dimensional ◽  
General Limit

A generalized model for three-dimensional analysis, using the method of columns, is presented. The model is an extension of the two-dimensional general limit equilibrium formulation. Intercolumn force functions of arbitrary shape can be specified to simulate various directions for the intercolumn resultant forces. A unique feature of the model involves the use of a geostatistical procedure (i.e., the Kriging technique) in modelling the geometry of the slope, the stratigraphy, the potential slip surface, and the pore-water pressure conditions. The technique simplifies the data-input procedure and expedites the column discretization and the factor of safety computations. The shape of the intercolumn force functions was investigated for several slope geometries using a three-dimensional finite element stress analysis. The significance of the intercolumn force functions in three-dimensional stability analyses was also studied. The model was utilized to study a case history involving an open-pit mining failure. The results indicate that the model is able to provide a more realistic simulation of the case history than was possible using a conventional two-dimensional model. Key words : stability analysis, general limit equilibrium, three-dimensional, method of columns, factor of safety.

Charts for the design and evaluation of simple earth slopes using total and partial factors of safety: a review of several available methods

1987 ◽  
Vol 24 (2) ◽  
pp. 216-231 ◽  
Author(s):  
L. D. Baikie
Keyword(s):  
Key Words ◽  
Factor Of Safety ◽  
Safety Factors ◽  
Traditional Practice ◽  
Stability Chart ◽  
Earth Slopes ◽  
Partial Safety Factors

A review of several available stability chart solutions for simple earth slopes was undertaken to assess their suitability for use with partial safety factors. The [Formula: see text] charts and Casagrande resistance envelopes were found to be particularly suited to the use of such factors and for comparing this approach with the traditional practice of using total safety factors. Casagrande resistance envelopes and factor of safety charts are presented for a range in slope inclinations. Key words: earth slopes, stability charts, total safety factors, partial safety factors, Casagrande resistance envelopes.

Embankment failures at Vernon, British Columbia

1995 ◽  
Vol 32 (2) ◽  
pp. 271-284 ◽  
Author(s):  
C.B. Crawford ◽  
R.J. Fannin ◽  
C.B. Kern
Keyword(s):  
Case History ◽  
Field Observation ◽  
Factor Of Safety ◽  
Strain Softening ◽  
Progressive Failure ◽  
Back Analysis ◽  
Site Investigation ◽  
Silty Clay ◽  
Pore Pressures ◽  
Similar Materials

A section of Highway 97, west of Vernon, B.C., is located over a soft-to-firm, compressible, silty clay subsoil. In addition to an extensive site investigation, the performance of two test embankments was observed for 2 years before construction was begun on the highway grade between them. When the highway fill reached a maximum thickness of about 10 m a failure occurred. The design was then changed to include berms on either side, but a second failure occurred when the grade was rebuilt. An undrained back-analysis of the first failure shows the influence of various variables on the factor of safety and illustrates the difficulty of choosing appropriate strength values for design when the site has a strong crust overlying a weaker layer and there is potential for progressive failure. Observations of settlements, pore pressures, and lateral movements in the subsoil describe the performance of the embankment during construction and reveal the importance of strain softening as a factor in the failures. Comparisons with a variety of similar failures in Canada, Scandinavia, and southeast Asia provide some guidance for future construction over similar materials. Key words : case history, embankment failure, field observation, pore pressures, stability, strength, undrained analysis.

Sign in / Sign up

Export Citation Format

Share Document