Field Performance and Analysis of 3-m-Diameter Induced Trench Culvert under a 19.4-m Soil Cover

An induced trench installation was instrumented to monitor earth pressures and settlements during construction. Some of the unique features of this case study are as follows: (a) both contact and earth pressure cells were used; (b) part of the culvert is under a new embankment and part was installed in a wide trench within an existing embankment; (c) a large stockpile was temporarily placed over the induced trench; and (d) the compressible material was placed in two stages. The maximum vertical pressure measured in the field at the crown of the culvert was 0.24 times the overburden pressure. The maximum horizontal pressure measured on the side of the culvert at the springline was 0.45 times the overburden pressure. The column of soil directly above the compressible zone settled approximately 40% more than did the adjacent fill. The field results at the crown and springline compared reasonably with those observed with numerical modeling. However, the overall pressure distribution on the pipe was expected to be nonuniform, the average vertical pressure calculated by using numerical analysis on top of the culvert over its full width was 0.61 times the overburden pressure, and the average horizontal pressure calculated on the side of the culvert over its full height was 0.44 times the overburden pressure. When the full pressure distribution on the pipe is considered, the recommended design loads from the Marston–Spangler theory slightly underpredict the maximum loads, and the vertical loads control the design.

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Field performance, centrifuge testing, and numerical modelling of an induced trench installation

Canadian Geotechnical Journal ◽

10.1139/t07-086 ◽

2008 ◽

Vol 45 (1) ◽

pp. 85-101 ◽

Cited By ~ 38

Author(s):

Rodney P. McAffee ◽

Arun J. Valsangkar

Keyword(s):

Numerical Modelling ◽

Pressure Distribution ◽

Earth Pressure ◽

Field Performance ◽

Overburden Pressure ◽

Centrifuge Testing ◽

Geotechnical Centrifuge ◽

Earth Pressures ◽

Prototype Structure ◽

Box Culvert

The field performance of an induced trench installation is compared to the results of centrifuge testing and numerical modelling. The measured vertical pressure at the crown of the pipe in the field ranged from 0.24 to 0.36 times the overburden pressure. The horizontal earth pressures measured in the field at the springline level determined a coefficient of lateral earth pressure between 0.39 and 0.49. The culvert was monitored over a period of 2 years following completion of embankment construction indicating no measurable changes in earth pressures and deformations. A model box culvert simulating the prototype height of soil cover, the pipe width, and the thickness of the compressible layer was tested using a geotechnical centrifuge. The prototype structure was also evaluated using numerical modelling to predict full earth pressure distribution and deformations. A comparison of field data, centrifuge testing, and numerical modelling shows that the Marston–Spangler theory used in designing induced trench culverts is conservative. The theory however, does not address or predict the nonuniform pressures on the top, sides, or bottom of the pipe, and therefore numerical analysis should be used to estimate the complete pressure distribution.

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The Implementation of Biological Phosphorus and Nitrogen Removal with the Bio-Denipho Process on a 265,000 PE Treatment Plant

Water Science & Technology ◽

10.2166/wst.1992.0491 ◽

1992 ◽

Vol 25 (4-5) ◽

pp. 161-168 ◽

Cited By ~ 16

Author(s):

J. Einfeldt

Keyword(s):

Nitrogen Removal ◽

Treatment Plant ◽

First Year ◽

In Series ◽

Design Loads ◽

Last Stage ◽

Two Stages ◽

The City ◽

Biological Phosphorus

A process, called Bio-Denipho, for combined biological phosphorus and nitrogen removal in a combination of an anaerobic tank and two oxidation ditches is described. In this process the anaerobic tank consisting of three sections working in series is followed by two oxidation ditches. These too are working in series, but with both inlet to and outlet from the tanks changing in a cycle. The Bio-Denipho process is described specifically for the process itself and as a case study for the implementation of the process on a 265,000 pe wastewater treatment plant for the city of Aalborg in Denmark. The plant was designed and erected in two stages and the last stage was inaugurated October 31,1989. Lay-out and functions for the plant is described and design loads, plan lay-out and tank volumes are given in this paper together with performance data for the first year in operation.

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Earth pressures exerted on an induced trench cast-in-place double-cell rectangular box culvert

Canadian Geotechnical Journal ◽

10.1139/t2012-093 ◽

2012 ◽

Vol 49 (11) ◽

pp. 1267-1284 ◽

Cited By ~ 22

Author(s):

Olajide Samuel Oshati ◽

Arun J. Valsangkar ◽

Allison B. Schriver

Keyword(s):

Earth Pressure ◽

Test Results ◽

Overburden Pressure ◽

Centrifuge Testing ◽

Geotechnical Centrifuge ◽

Drag Forces ◽

Field Instrumentation ◽

Earth Pressures ◽

Box Culvert ◽

Base Contact

Earth pressure data from the field instrumentation of a cast-in-place reinforced rectangular box culvert are presented in this paper. The instrumented culvert is a 2.60 m by 3.60 m double-cell reinforced cast-in-place rectangular box buried under 25.10 m of fill constructed using the induced trench installation (ITI) method. The average earth pressure measured across the roof was 0.42 times the overburden pressure, and an average of 0.52 times the overburden pressure was measured at mid-height of the culvert on the sidewalls. Base contact pressure under the rectangular box culvert was also measured, providing field-based data demonstrating increased base pressure resulting from downward drag forces developed along the sidewalls of the box culvert. An average increase of 25% from the measured vertical earth pressures on the roof plus the culvert dead load (DL) pressure was calculated at the culvert base. A model culvert was also tested in a geotechnical centrifuge to obtain data on earth pressures at the top, sides, and base of the culvert. The data from the centrifuge testing were compared with the prototype structure, and the centrifuge test results agreed closely with the measured field prototype pressures, in spite of the fact that full similitude was not attempted in centrifuge testing.

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Evaluation of Earth Pressures Against Rigid Retaining Structures with RTT Mode

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.168-170.200 ◽

2010 ◽

Vol 168-170 ◽

pp. 200-205

Author(s):

Fei Song ◽

Jian Min Zhang ◽

Lu Yu Zhang

Keyword(s):

Pressure Distribution ◽

Formation Mechanism ◽

Retaining Wall ◽

Experimental Studies ◽

Earth Pressure ◽

Retaining Walls ◽

Wall Displacement ◽

The Earth ◽

Earth Pressures ◽

Mode A

The evaluation of earth pressure is of vital importance for the design of various retaining walls and infrastructures. Experimental studies show that earth pressures are closely related to the mode and amount of wall displacement. In this paper, based on the reveal of the formation mechanism of earth pressures against rigid retaining wall with RTT mode, a new method is proposed to calculate the earth pressure distribution in such conditions. Finally, the effectiveness of the method is confirmed by the experimental results.

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Analysis and Performance of a Braced Cut in Sand with Large Deformations

Canadian Geotechnical Journal ◽

10.1139/t72-041 ◽

1972 ◽

Vol 9 (4) ◽

pp. 384-406 ◽

Cited By ~ 2

Author(s):

J. D. Scott ◽

N. E. Wilson ◽

Gunther E. Bauer

Keyword(s):

Experimental Data ◽

Pressure Distribution ◽

Earth Pressure ◽

Water Levels ◽

Active Earth Pressure ◽

Actual Distribution ◽

Dense Sand ◽

The North ◽

The Earth ◽

Earth Pressures

The paper is divided into two parts. The first part deals with the systematic program of measurements undertaken on an open braced cut in dense sand at the Greenway Pollution Control Centre in London, Ontario. In the second part, the experimental data are analyzed and a new solution is presented based on Dubrova's analysis, which related qualitatively and quantitatively the active earth pressure distribution to the mode of deformation of a retaining structure.The roughly L-shaped excavation measured 68 × 42 ft (20.7 × 12.8 m) for the longest leg, the other leg was 30 × 23 ft (9.1 × 7.0 m). The temporary bracing system consisted of interlocking steel sheet piles (Larssen IIIN), and wales and struts from wide-flanged steel sections. The maximum depth of the cut was 50 ft (15.2 m) below ground elevation of 722 ft (220.1 m). The soil consisted of fine uniform dense sand having a relative density varying from medium to very dense. The natural water level was approximately 20 ft (6.1 m) below the ground surface prior to construction.The instrumentation program was carried out during the 6-month construction period (January–June 1964) and consisted of measuring: (1) The strut loads with a mechanical strain indicator (Whitmore gauge) over 8 in. (20.3 cm) gauge lengths, (2) The deformation of the north wall in a horizontal and a vertical plane, (3) The water levels and water pressures from borehole and standpipe observations, and (4) The active and passive earth pressures over the cut with 'Geonor vibrating-wire pressure transducers mounted flush on two adjacent sheet piles of the north wall.Field and laboratory tests supplied the necessary soil data.Comprehensive measurements of this kind in deep cuts in sand, prior to this London investigation, had only been made in Berlin, Munich, and New York. But at London, for the first time the actual distribution of earth pressures in sand were measured on a full-scale braced wall.The analysis of the experimental data showed that the earth pressure distribution can be approximated by the extended Dubrova’s solution. The agreement between the total active earth pressure obtained from the pressure cells and the corresponding Coulomb values varied from excellent (upper bound) to good (lower bound).An experimental relationship between the horizontal soil strain and the variation of K-values over the depth of the cut was established.The different theories for predicting Ko-values do not seem to apply to over consolidated dense sand deposits. The experimental Ko-values, rather, agree with other published experimental values for similar soils.The strut load readings were somewhat erratic, not necessarily corresponding to the excavation progress. The total strut loads were lower than the corresponding forces from the earth pressure cells or the corresponding Coulomb values.

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