Estimation of total settlement of embankments by field measurements

1996 ◽  
Vol 33 (5) ◽  
pp. 834-841 ◽  
Author(s):  
Elmer L Matyas ◽  
Leo Rothenburg
Keyword(s):  
Laboratory Tests ◽  
Factor Versus ◽  
Field Measurements ◽  
Coefficient Of Consolidation ◽  
Consolidation Settlement ◽  
Compressibility Coefficient ◽  
Total Settlement ◽  
Degree Of Consolidation ◽  
Secondary Compressibility ◽  
Hyperbolic Method

In the absence of compressibility data from laboratory tests, the total primary consolidation settlement of a structure founded on clay can be estimated from settlement measurements taken over a period of time. In this note, the hyperbolic and Asaoka methods are applied to a case history where an embankment fill was placed on a clay exhibiting secondary compression. It is shown that significant inaccuracies in time–settlement predictions can result if an appropriate time factor versus degree of consolidation relationship is not taken into account. Key words: primary and secondary compressibility, coefficient of consolidation, field measurements, hyperbolic method, Asaoka method.

scholarly journals Settlement analysis of the Gloucester test fill

1976 ◽  
Vol 13 (4) ◽  
pp. 339-354 ◽  
Author(s):  
K. Y. Lo ◽  
M. Bozozuk ◽  
K. T. Law
Keyword(s):  
Experimental Program ◽  
Canadian Forces ◽  
Test Results ◽  
Time Rate ◽  
Coefficient Of Consolidation ◽  
Total Settlement ◽  
Induced Stresses ◽  
Secondary Compressibility ◽  
Settlement Analysis ◽  
Test Embankment

This paper reports the observation and analysis of the rate and magnitude of settlement under the test embankment at Canadian Forces Station Gloucester. The embankment has been in existence for 7 years and, because of extensive instrumentation, a sufficiently complete record has emerged. An advanced finite element method has been used for the computation of the induced stresses in the foundation soil.Both block samples and 5 in. (12.7 cm) diameter Osterberg samples were recovered at various depths from the site. An experimental program, including the use of the 6 in. (15.2 cm) Rowe cell, has been carried out and an analysis of the test results based on the Gibson and Lo theory. The test results have also been used in the estimation of the field performance.From the present study it is found that: the coefficient of consolidation and the primary and secondary compressibility can be adequately determined from samples of size 4.5 in. (11.3 cm) diameter by 2 in. (5.1 cm) high or larger; the secondary compression contributes significantly to the total settlement for the soil considered; and the Gibson and Lo theory predicts fairly accurately both the time rate and magnitude of settlement in the field.

Flow Fields Inside Stocked Fish Cages and the Near Environment

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Lars C. Gansel ◽  
Siri Rackebrandt ◽  
Frode Oppedal ◽  
Thomas A. McClimans
Keyword(s):  
Atlantic Salmon ◽  
Water Flow ◽  
Laboratory Tests ◽  
Numerical Models ◽  
Field Measurements ◽  
Flow Patterns ◽  
Fish Swimming ◽  
Swimming Depth ◽  
Starting Point ◽  
Fish Cages

This study explores the average flow field inside and around stocked Atlantic salmon (Salmo salar L.) fish cages. Laboratory tests and field measurements were conducted to study flow patterns around and through fish cages and the effect of fish on the water flow. Currents were measured around an empty and a stocked fish cage in a fjord to verify the results obtained from laboratory tests without fish and to study the effects of fish swimming in the cage. Fluorescein, a nontoxic, fluorescent dye, was released inside a stocked fish cage for visualization of three-dimensional flow patterns inside the cage. Atlantic salmon tend to form a torus shaped school and swim in a circular path, following the net during the daytime. Current measurements around an empty and a stocked fish cage show a strong influence of fish swimming in this circular pattern: while most of the oncoming water mass passes through the empty cage, significantly more water is pushed around the stocked fish cage. Dye experiments show that surface water inside stocked fish cages converges toward the center, where it sinks and spreads out of the cage at the depth of maximum biomass. In order to achieve a circular motion, fish must accelerate toward the center of the cage. This inward-directed force must be balanced by an outward force that pushes the water out of the cage, resulting in a low pressure area in the center of the rotational motion of the fish. Thus, water is pulled from above and below the fish swimming depth. Laboratory tests with empty cages agree well with field measurements around empty fish cages, and give a good starting point for further laboratory tests including the effect of fish-induced currents inside the cage to document the details of the flow patterns inside and adjacent to stocked fish cages. The results of such experiments can be used as benchmarks for numerical models to simulate the water flow in and around net pens, and model the oxygen supply and the spreading of wastes in the near wake of stocked fish farms.

scholarly journals Research on Horizontal Coefficient of Consolidation of Vietnam’s Soft Soil

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Nu Nguyen Thi ◽  
Bui Truong Son ◽  
Do Minh Ngoc
Keyword(s):  
Experimental Study ◽  
Laboratory Tests ◽  
Soft Soil ◽  
Coefficient Of Consolidation ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Constant Rate ◽  
Different Types ◽  
Cell Test ◽  
Dissipation Test

The horizontal coefficient of consolidation is the most important parameter for designing the improvement of soil soft by prefabricated vertical drains (PVDs) combined with surcharge and vacuum preloading. This paper presents the experimental study on the horizontal coefficient of consolidation (ch) of some soft soils distributed in Vietnam. The ch value was determined by the laboratory test and CPTu dissipation test. The laboratory tests included the Rowe consolidation cell test and constant rate of strain consolidation with radial drainage test. Two types of consolidation laboratory tests were performed. The experimental results indicated that the ch value is always larger than the vertical coefficient of consolidation of soil (cv). The ratio of ch/cv depends on the consolidated pressure, type of soil, and the anisotropy of soil. The ratio of ch/cv is different in different types of soft soil in Vietnam. In the normally consolidated state, the ch/cv ratio ranges from 1.35 to 10.59. It was necessary to choose the ch value at the consolidated stress level for calculating the PVD spacing.

Solution charts for the consolidation of double soil layers

2005 ◽  
Vol 42 (3) ◽  
pp. 949-956 ◽  
Author(s):  
Guofu Zhu ◽  
Jian-Hua Yin
Keyword(s):  
Solution Procedure ◽  
Technical Note ◽  
Average Degree ◽  
Soil Layers ◽  
Consolidation Settlement ◽  
Degree Of Consolidation ◽  
Independent Parameters

This technical note presents solution charts for determining the average degree of consolidation of double soil layers for both one-way and two-way drainage. The influence of two newly introduced independent parameters on the average degree of consolidation is examined. The solution procedure is described clearly. When the compressibility, permeability, and thickness of the material making up each layer are given, the charts can be used to obtain the average degree of consolidation of the double soil layers for consolidation settlement calculations.Key words: consolidation, double soil layers, solution charts, drainage, settlement, soil.

Probabilistic Analysis of One-Dimensional Consolidation with Monte Carlo Simulations

2011 ◽  
Vol 55-57 ◽  
pp. 907-912
Author(s):  
Xiao Yong Li ◽  
Liao Qi Hu
Keyword(s):  
Probabilistic Analysis ◽  
Clay Soil ◽  
Probabilistic Method ◽  
Distribution Model ◽  
Considerable Influence ◽  
Coefficient Of Consolidation ◽  
One Dimensional ◽  
Degree Of Consolidation ◽  
Distribution Type ◽  
Substantial Degree

Themeasured coefficient of consolidation can have a substantial degreeof variation even in a uniform clay layer. This paper examines the variability of one-dimensional consolidationsolutions through a probabilistic analysis. The spatial probabilistic characteristics for the coefficient of vertical consolidation are studied. The influence of a spatially random coefficient of consolidation on one-dimensional consolidation has been studied using the probabilistic method. In the probabilistic analysis, the adequacy of distribution model for coefficient of consolidation is tested using experimental data. A sensitivity analysis of the degree of consolidation to uncertain parameters is presented for clay soil. It is the analysis result that probability distribution type of vertical consolidation has a considerable influence on degree of consolidation. Theresults are discussed in terms of confidence level.

Back-calculation of consolidation parameters from field measurements at a reclamation site

2001 ◽  
Vol 38 (4) ◽  
pp. 755-769 ◽  
Author(s):  
Lai Fa Cao ◽  
Ming-Fang Chang ◽  
Cee Ing Teh ◽  
Yung Mook Na
Keyword(s):  
Pore Pressure ◽  
Land Reclamation ◽  
Ground Improvement ◽  
Field Measurements ◽  
Coefficient Of Consolidation ◽  
Vertical Drains ◽  
Undisturbed Samples ◽  
Back Calculation ◽  
Reclamation Project ◽  
Consolidation Parameters

A pilot test was carried out at a land reclamation project site to study the effect of vertical drains on the rate of consolidation of a marine clay deposit in Singapore. Theoretical and numerical analyses were conducted to interpret the field measurements of pore pressure and settlement, and consolidation parameters were back-calculated. The back-calculated preconsolidation pressure is similar to that obtained from the laboratory consolidation test on undisturbed samples, but the field-deduced compression index is generally larger than that measured in the laboratory. The coefficient of consolidation back-calculated from the settlement measurement is larger than that from the pore-pressure measurement. The coefficient of consolidation for horizontal flow obtained from the Rowe cell test, which is comparable to that back-calculated from the field settlement measurement, is recommended for the preliminary design of vertical drains without the need of considering the smear effect.Key words: clays, consolidation, ground improvement, numerical modelling and analysis, permeability, vertical drains.

Radial consolidation with vertical drains and general time-dependent loading

2009 ◽  
Vol 46 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Enrico Conte ◽  
Antonello Troncone
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Time Dependent ◽  
Case Histories ◽  
Vertical Drains ◽  
Excess Pore Water Pressure ◽  
Theoretical Methods ◽  
Consolidation Settlement ◽  
Degree Of Consolidation ◽  
General Time

A simple-to-use analytical solution for radial consolidation with vertical drains under equal strain conditions is presented in this paper. This solution accounts for the effects of soil smear, drain hydraulic resistance, and general time-dependent loading. A number of comparisons with other theoretical methods are shown to assess the accuracy of the proposed solution, both in terms of excess pore-water pressure and degree of consolidation settlement. Moreover, two case histories documented in the literature are analysed to evaluate the main parameters affecting radial consolidation in the presence of vertical drains.

Quantification of sewer leakage by a continuous tracer method

2011 ◽  
Vol 64 (1) ◽  
pp. 132-138 ◽  
Author(s):  
V. Prigiobbe ◽  
M. Giulianelli
Keyword(s):  
Urban Areas ◽  
Structural Damage ◽  
Laboratory Tests ◽  
Low Cost ◽  
Field Measurements ◽  
Tracer Method ◽  
Catchment Scale ◽  
Chemical Tracers ◽  
Challenging Tasks ◽  
Dry Weather Flow

Water authorities interested in the evaluation of the structural state of a sewer must quantify leakage to plan strategic intervention. However, the quantification of the exfiltration and the localisation of structural damage are challenging tasks that usually require expensive and time-consuming inspections. Herein, we report one of the first applications of the QUEST-C method to quantify the exfiltration in a continuously operating sewer by dosing two chemical tracers, sodium bromide (NaBr) and lithium chloride (LiCl). The method was applied at the catchment scale in a 14-year-old sewer in Rome, Italy. Preliminary laboratory tests, field measurements, and numerical simulations showed that reliable results require the QUEST-C method to be applied to sewers without lateral inflows, during periods of quasi-steady flow, and that the travel time of the NaBr tracer is minimised. Three sewer reaches were tested and the estimated exfiltration, as a fraction of the dry weather flow (DWF), increased from 0.128 in the agricultural area to 0.208 in the urban area. Although our estimates are at the lower end of the range given in the literature (0.01–0.56 DWF), the exfiltration was not negligible, and interventions should focus on the sewers in urban areas. This illustrates the capability of the QUEST-C method to guide strategic intervention at low cost and without an interruption of sewer operation. However, careful interpretation of the results is recommended for sewers with many lateral inflows, where leakage may be overestimated.

Solution charts for the consolidation of circular footings embedded in a finite stratum

2009 ◽  
Vol 46 (6) ◽  
pp. 708-718 ◽  
Author(s):  
Wen-Wei Zhang ◽  
Guofu Zhu ◽  
Ren Wang ◽  
Qingshan Meng
Keyword(s):  
Finite Element Method ◽  
Time Factors ◽  
Maximum Error ◽  
Technical Note ◽  
The Finite Element Method ◽  
Present Solution ◽  
Consolidation Settlement ◽  
Soil Skeleton ◽  
Degree Of Consolidation ◽  
Biot’S Consolidation

This technical note used the finite element method to investigate the consolidation behaviour of circular footings embedded in a finite stratum based on Biot’s consolidation theory. The influence of three factors on the degree of consolidation settlement was examined: (1) the ratio of the buried depth to the thickness of the stratum, (2) the ratio of the footing radius to the thickness of the stratum, and (3) the Poisson’s ratio of the soil skeleton. Based on the results of analysis, new normalized time factors are suggested. It is shown that the degree of consolidation exhibits very good normalized behaviour using the time factors. The authors also present solution charts for determining the degree of consolidation settlement of circular footings embedded in a finite stratum. These charts can provide engineers with a quick answer to the design issues. The maximum error caused by using the solution charts is within 3%.

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