Observed And Calculated Behaviour Of A Geotextile Reinforced Embankment On A Soft Compressible Soil

An instrumented test embankment was constructed to failure on a soft compressible organic clayey silt deposit at Sackville, New Brunwick, Canada in Sept./Oct., 1989. This embankment consisted of an unreinforccd section and a section reinforced with a relatively high strength polyester woven geotextile. The instrumentation, field performance and analyses of these embankment are examined in this thesis.;The observed responses of pore pressure, settlement, heave and lateral displacements in the foundation soil and the strain in the geotextile are correlated and failure of each embankment is discussed. An account of the development and propagation of cracks in relation to the construction and the interpretation of failure for each embankment is also discussed. The excess pore pressure response and soil deformations showed some evidence of the susceptibility of the soil to progressive failure. The actual failure was of a plastic (or visco-plastic) type and no classical-type of abrupt failure was encountered during the construction of either of these embankments.;A numerical model is developed to perform fully coupled large strain elasto-plastic consolidation analysis with Modified cam-clay material behaviour using 15-noded cubic strain triangular elements. The viscous/creep effects and the potential strain softening behaviour of the soil are not considered in this numerical model. The test embankment was back analyzed using information obtained from the field investigation together with engineering properties of the soils and geotextile obtained from laboratory tests. The results of finite element analysis using this model are shown to be in reasonable agreement with the observed performance. The deformations at large depth and the large settlements and heaves observed in the field at high embankment thicknesses could not be predicted satisfactorily using this model.;Finite element analyses are used to study the sensitivity of embankment behaviour to variations in the foundation soil and embankment fill properties. The influence of the variation of over consolidation ratio (OCR), the coefficient of earth pressure at rest (K{dollar}\sb{lcub}\rm o{rcub}{dollar}), angle of internal friction, Poisson\u27s ratio and the permeability of the foundation soil as well as the effective friction angle of the embankment fill are examined. This sensitivity study indicated that the effective friction angle ({dollar}\phi\sp\prime{dollar}), K{dollar}\sb{lcub}\rm o{rcub}{dollar} and OCR of the foundation soil are all important parameters and therefore should be measured or estimated carefully. Furthermore, uncertainties regarding the Poisson\u27s ratio did not affect the results of the analysis significantly but the uncertainties regarding permeabilities of the foundation soil or effective friction angle may have a significant influence on the behaviour of such reinforced embankments on soft soil.;Both small strain and large strain undrained finite element models are also used to back analyze the reinforced embankment. The effect of changing the undrained shear strength profile on the behaviour of this embankment is examined. The failure of the reinforced embankment could be predicted accurately by a small strain undrained finite element analysis using the mean shear strength profile (between the field vane and the CAU triaxial and constant volume direct simple shear tests in the lab)

Integrating Pricing And Distribution Decisions In Multiple Markets

This paper deals with the simultaneous optimization of prices and shipment quantities in a supply network when the supplier has the market power to set prices, thereby influencing demand directly.  We focus on the distribution stage of the supply chain where the firm’s products are shipped from several  locations (plants, warehouses) to various independent markets, and address the following questions: (i) what is the best price at each market?, and (ii) what is the best distribution plan given these prices?   The combined problem can be modeled as a nonlinear optimization problem.  For its solution, we propose an iterative linear programming approach that utilizes shadow price information from a series of successive transportation problems.  To evaluate the heuristic’s effectiveness, we compare it with a “brute-force” enumeration using a grid-search.  The grid-search is implemented on a spreadsheet with a programming loop to facilitate repeated invocation of the transportation problem solver routine

A Production Planning Model For Reconfigurable Lines

A key indicator of the efficiency of a production line is cyclic idle time.  Manufacturers use heuristic line balancing techniques to determine the allocation of elemental tasks to workers so as to minimize labor costs.  The productive, i.e. non-idle, portion of each cycle then reflects the efficiency of the line.  Line balancing techniques determine the allocation of tasks based on a pre-specified throughput.  When demand changes however, the line may have to be reconfigured to reflect the new desired flow rate, resulting possibly in a lower efficiency and a higher per-unit labor cost.  This raises an interesting question: should one use a flow rate that corresponds to the higher efficiency, handling any mismatch with demand through the use of inventory or backordering, or should the aim be to match flow rate precisely with demand rate even though the resulting efficiency might be lower?  This paper proposes an answer to this question by embedding line balance and efficiency into the framework of a well-known production planning model.  A heuristic method for solving the extended model is developed, and its application demonstrated using numerical examples.

Attitudes of medical students, clinicians and sports scientists towards exercise counseling

We compared the amount of exercise undertaken by medical students, clinicians, and sport scientists with the National Australian Physical Activity (NAPA) Guidelines. A second aim was to compare attitudes to exercise counseling as preventive medicine between university- and clinic-based professionals. The research setting was a university medical school and a sports science sports medicine centre. A 20-item questionnaire was completed by 216 individuals (131 medical students, 43 clinicians and 37 sports scientists). Self-reported physical activity habits, exercise counseling practices and attitudes towards preventive medicine were assessed. The physical activity undertaken by most respondents (70%) met NAPA Guidelines. General practitioners had significantly lower compliance rates with NAPA Guidelines than other professionals. More than half of clinicians and medical students (54%) were less active now compared with levels of activity undertaken prior to graduate training. Most physicians (68%) reported they sometimes discuss physical activity with patients. In contrast, the majority of non-medically qualified respondents (60%) said they never discuss physical activity with their doctor. Most respondents (70%) had positive attitudes to exercise counseling. Sports scientists and respondents who were highly active in childhood had more positive attitudes to exercise counseling than others. Health professionals in this study were more active than the general population; however healthy exercise habits tend to deteriorate after the commencement of medical training. Despite the important role of doctors in health promotion, the degree of exercise counseling to patients is low

Civil Engineering Materials

Civil Engineering Materials prepares you for today’s engineering challenges, providing a broad overview of the materials you will use in your studies and career. You are not only introduced to traditional materials, such as concrete, steel, timber, and soils, but you also explore important non-traditional materials, such as synthetics and industrial-by products. The authors use a wealth of practical examples and straight-forward explanations to ensure you gain a full understanding of the characteristics and behavior of various materials, how they interact, and how to best utilize and combine traditional and non-traditional materials. While emphasizing the effective use of civil engineering materials, the authors carefully consider sustainability to give you a broader context of how materials are current used in contemporary applications

On equivalent granular void ratio and steady state behaviour of loose sand with fines

Void ratio has traditionally, been used as a state variable for predicting the liquefaction behaviour of soils under the Critical State Soil Mechanics framework. Recent publications show that void ratio may not be a good parameter for characterizing sand with fines. An alternative state variable referred to as equivalent granular void ratio has been proposed to resolve this problem. To calculate this alternative state variable, a bparameter is needed. This b-parameter represents the fraction of fines that actively participate in the force structure of the solid skeleton. However, predicting the “b” value is problematic. Most, if not all, of the b-values reported were determined by casespecific back-analysis, that is, the b-value was selected so that a single correlation between equivalent granular void ratio and the measured steady state strength (or cyclic resistance) could be achieved. This paper examines the factors affecting the “b” value based on published work on binary packing. This leads to a simple semi-empirical equation for predicting the value of “b” based on fines size and fines content. Published data appears to be in support of the proposed equation. A series of experiments were conducted on a specially designed sand-fines type in order to provide additional validation of the proposed equation and to reinforce the use of equivalent granular void ratio in a more generalized context

Proceedings of the 17th African Regional Conference on Soil Mechanics and Geotechnical Engineering

The mechanism involved in ground improvements with vacuum assisted prefabricated verticaldrains (PVDs) for road embankments is essentially 3-dimensional (3-D) but could reasonably well approximatedas axisymmetric. In this context, axisymmetric unit cell modelling generally provides a very good representationfor Finite Element (FE) modelling. However, it carries significant limitations in terms of the scopeof the analysis. Hence, to get an understanding of the overall deformational behaviour of the foundation soilbeing improved, a full scale Plane Strain (PS) FE model would be necessary. In this paper, conversion of axisymmetricunit cell to an equivalent PS model is carried in the context of a vacuum consolidation project.Foundation soft soil is modelled using an elastic-viscoplastic (EVP) model which accounts for the time dependentbehaviour of soft clay. Results of this PS conversion is compared with the axisymmetric FE solution. Stabilityof the embankment is also analysed using maximum lateral displacements