Field monitoring and analysis of twin 3660 mm inside diameter induced trench culverts installed under 21.7 m of fill

2011 ◽  
Vol 48 (5) ◽  
pp. 781-794 ◽  
Author(s):  
Benjamin L. McGuigan ◽  
Arun J. Valsangkar
Keyword(s):  
Numerical Modelling ◽  
Large Diameter ◽  
Field Monitoring ◽  
Inside Diameter ◽  
Field Instrumentation ◽  
Earth Pressures ◽  
Low Pressures

Although several induced trench field instrumentations have been reported in the literature, none have been for twin culverts. This paper describes a field instrumentation of twin 3660 mm inside diameter concrete culverts installed in an induced trench under 21.7 m of fill. Earth pressures were measured at the crown, shoulder, springline, haunch, and invert locations. Average earth pressures measured at the crown and springline were 0.67 and 0.32 times the overburden, respectively. Due to the large culvert size, proper compaction in the haunch regions was not achieved and the bedding was lightly compacted for constructability reasons. These factors resulted in high earth pressures at the inverts (greater than approximately 1400 kPa) and low pressures at the haunches (32–165 kPa). Numerical modelling was used to determine a vertical earth load of 0.87 times the soil prism load. The twin induced trench condition resulted in vertical earth loads 6% higher and 30% lower than the single induced trench and twin positive projecting conditions, respectively. The induced trench method therefore appears to be a viable installation option for large-diameter twin culverts, provided that issues related to bedding and constructability are addressed.

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

2012 ◽  
Vol 49 (11) ◽  
pp. 1267-1284 ◽  
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.

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

2008 ◽  
Vol 45 (1) ◽  
pp. 85-101 ◽  
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.

scholarly journals Field and Numerical Modelling Investigations on the Stability of Underground Strata during Longwall Workings

2021 ◽  
Author(s):  
G Budi ◽  
Kolikipogu Nageswara Rao ◽  
Punit Mohanty
Keyword(s):  
Numerical Modelling ◽  
Longwall Mining ◽  
High Capacity ◽  
Field Monitoring ◽  
Longwall Face ◽  
Mining Method ◽  
Company Limited ◽  
Extensive Field ◽  
Powered Support ◽  
The Stability

Abstract Understanding the behaviour of underground workings is essential for the success of any mining method. The longwall mining method is one of the predominant underground methods to extract coal. Since 1978, in India, 22 underground coal mines of different collieries have been implemented the mechanized longwall method. SCCL is one of that colliery has mixed working experiences with longwall method in their mines. The longwall faces in GDK-10A, JK-5, and VK-7 of SCCL had produced good results, but the faces in GDK-7, GDK-9, GDK-11A, and PVK-5 had suffered due to the geological disturbances and unavailability of real-time information about the strata behaviour. By addressing the previous experiences of longwall workings, Singareni Collieries Company Limited (SCCL) has implemented a high capacity (1 × 1152T) powered support system in Adriyala Longwall Project (ALP) at a depth of 375m. In this study, extensive field monitoring with different strata monitoring instruments was conducted in ALP to analyze the gate roads convergence, stress variation on longwall and chain pillars at different stages of extraction (i.e., 8m, 25m, 35m, and 45m) and the pressure variation on the powered support systems. It was observed from the results that the convergence in the gate roads was increasing with the advance of the longwall face and the area of exposure. The pressure of the legs on the dip side was less than the pressure of the legs on the rise side, which implies a stable roof condition over the longwall face. To better understand the behaviour of ALP workings, a numerical modelling study with FLAC 7.0 has been conducted with actual physio-mechanical properties. The computed numerical modelling results have been remarkably well in consistent with the field monitoring results. The stability of chain pillars has been estimated at every stage of extraction by the Factor of Safety (FoS) criterion and it was found that the pillars could be ensured stability in longwall workings.

Numerical modelling of coupled seepage-deformation subjected to rainfall infiltration in unsaturated slope

2020 ◽  
Vol 17 (6) ◽  
pp. 867-875
Author(s):  
Edgar Jr Joe ◽  
Nazri Ali ◽  
Siti Norafida Jusoh
Keyword(s):  
Numerical Modelling ◽  
Design Methodology ◽  
Factor Of Safety ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Field Monitoring ◽  
Rainfall Infiltration ◽  
Deformation Analysis ◽  
Content Type ◽  
Fully Coupled

Purpose This study aims to propose another alternative numerical modelling tool, i.e. ABAQUS, to simulate a fully coupled seepage-deformation analysis in unsaturated slope subjected to rainfall infiltration. Design/methodology/approach The effect of rainfall infiltration on the response of pore water pressure and factor of safety has been analysed and discussed. The results of this study have also been validated based on the results of field monitoring and previous numerical modelling. Findings The results from ABAQUS show a better agreement with those from field monitoring compared to other numerical modelling tools. Originality/value The procedures adopted in this study can be adopted and used as a guide to model similar slope problems in ABAQUS.

Measurement of soil arching above a large diameter flexible culvert

1976 ◽  
Vol 13 (1) ◽  
pp. 58-71 ◽  
Author(s):  
Guy Lefebvre ◽  
Maurice Laliberté ◽  
Liguori M. Lefebvre ◽  
Jean Lafleur ◽  
C. L. Fisher
Keyword(s):  
Large Diameter ◽  
Adjacent Area ◽  
Soil Arching ◽  
Arching Effect ◽  
Earth Pressures ◽  
Arch Shape

The paper reports on the measurement of an arching effect over a large diameter flexible culvert. An arch shape culvert, 51 ft (15.5m) in span, was erected and covered by a 44 ft (13.4m) high embankment. An extensive instrumentation program was laid out in order to check the mobilization of an arching effect during construction by measuring displacements, earth pressures, and stresses in the steel. The instrumentation data indicated that a large portion of the load due to the weight of the soil above the structure was transferred to the adjacent area.

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