Measurement of earth pressures by means of the flat jack test

1953 ◽  
Author(s):  
P. Habib ◽  
R. Marchand ◽  
Severine Britt
Keyword(s):  
Earth Pressures

scholarly journals Geomechanical Behaviour of Uncemented Expanded Polystyrene (EPS) Beads–Clayey Soil Mixtures as Lightweight Fill

Geotechnics ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 38-58
Author(s):  
Pouyan Abbasimaedeh ◽  
Ali Ghanbari ◽  
Brendan C. O’Kelly ◽  
Mohsen Tavanafar ◽  
Kourosh Ghaffari Irdmoosa
Keyword(s):  
Clayey Soil ◽  
Expanded Polystyrene ◽  
Environmental Cost ◽  
Dry Density ◽  
Engineering Practice ◽  
Clayey Sand ◽  
Earth Pressures ◽  
Lightweight Fill ◽  
Soil Foundation ◽  
Geotechnical Testing

Lightweight fill can be advantageous in embankment construction for the purposes of reducing the (i) bearing pressures on the underlying soil foundation, (ii) destabilizing moments for constructed earthen slopes, and (iii) earth pressures acting behind retaining walls. This paper investigates the merits/limitations of particulate expanded polystyrene (EPS) beads mixed with clayey sand (CS) soil as lightweight fill, considering both geotechnical and environmental perspectives. The bench-scale geotechnical testing programme included standard Proctor (SP) compaction, California bearing ratio (CBR), direct shear (sheardox), oedometer and permeability testing performed on two different gradation CS soils amended with 0.5, 1.5 and 3.0 wt.% EPS, investigating two nominal bead sizes equivalent to poorly-graded medium and coarse sands. Compared to the unamended soils, the compacted dry density substantially decreased with increasing EPS beads content, from 2.09 t/m3 (0 wt.% EPS) to as low as 0.33 t/m3 for 3 wt.% (73 v.%) of larger-sized EPS beads. However, from analyses of the test results for the investigated 50 to 400 kPa applied stress range, even 0.5 wt.% (21 v.%) EPS beads caused a substantial mechanical failure, with a drastic decay of the CBR and compressibility parameters for the studied CS soils. Given the more detrimental environmental cost of leaving myriads of separate EPS beads mixed forever among the soil, it is concluded that the approach of adding particulate EPS beads to soils for producing uncemented lightened fill should not be employed in geotechnical engineering practice.

The Principle of Effective Stress Theory Research Based on Channel Rate

2013 ◽  
Vol 275-277 ◽  
pp. 336-342
Author(s):  
Xiao Feng Wu ◽  
Guang Fan Li ◽  
Wan Cheng He
Keyword(s):  
Effective Stress ◽  
Permeability Coefficient ◽  
Cohesive Soil ◽  
Stress Equation ◽  
Jump Problem ◽  
Stress Theory ◽  
Conventional Calculation ◽  
Earth Pressures ◽  
Stress Surface ◽  
Theory Research

Based on the debate of effective stress principle applicability on cohesive soil in recent years and the predecessor's research achievements, this paper puts forward the idea that the effective stress surface including hydrated film surrounding soil particles. And we obtained the extended soil effective stress equation by establishment of the model of channel rate.Combined with the physical significance of permeability coefficient and substantial experimental data, it can establish the fitting equation between permeability coefficient and new proposed physical parameter channel rate. A new calculation method to unify the separate calculation and combined calculation of water and earth pressures is proposed to carry out the transition between results of the two conventional calculation methods and provide a new idea for solving the jump problem between the two results.

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.

Discussion of “Stress-Dilatancy, Earth Pressures, and Slopes”

1964 ◽  
Vol 90 (1) ◽  
pp. 133-153
Author(s):  
Ronald F. Scott ◽  
George G. Meyerhof ◽  
K. H. Roscoe ◽  
A. N. Schofield ◽  
Pijushkanti Som ◽  
...  
Keyword(s):  
Earth Pressures

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

2008 ◽  
Vol 2045 (1) ◽  
pp. 68-76 ◽  
Author(s):  
Bethanie A. Parker ◽  
Rodney P. McAffee ◽  
Arun J. Valsangkar
Keyword(s):  
Pressure Distribution ◽  
Earth Pressure ◽  
Field Performance ◽  
Overburden Pressure ◽  
Vertical Pressure ◽  
Earth Pressures ◽  
Design Loads ◽  
Horizontal Pressure ◽  
Two Stages

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.

scholarly journals Thermo-hydro-mechanical coupling analysis of a thermo-active diaphragm wall

2018 ◽  
Vol 55 (5) ◽  
pp. 720-735 ◽  
Author(s):  
Yi Rui ◽  
Mei Yin
Keyword(s):  
New Technologies ◽  
Bending Moment ◽  
Diaphragm Wall ◽  
Elastic Model ◽  
Element Analysis ◽  
Thermally Induced ◽  
Mechanical Coupling ◽  
Reversal Effect ◽  
Earth Pressures ◽  
Geotechnical Aspect

Thermo-active diaphragm walls that combine load bearing ability with a ground source heat pump (GSHP) are considered to be one of the new technologies in geotechnical engineering. Despite the vast range of potential applications, current thermo-active diaphragm wall designs have very limited use from a geotechnical aspect. This paper investigates the wall–soil interaction behaviour of a thermo-active diaphragm wall by conducting a thermo-hydro-mechanical finite element analysis. The GSHP operates by circulating cold coolant into the thermo-active diaphragm wall during winter. Soil contraction and small changes in the earth pressures acting on the wall are observed. The strain reversal effect makes the soil stiffness increase when the wall moves in the unexcavated side direction, and hence gives different trends for long-term wall movements compared to the linear elastic model. The GSHP operation makes the wall move in a cyclic manner, and the seasonal variation is approximately 0.5–1 mm, caused by two factors: the thermal effects on the deformation of the diaphragm wall itself and the thermally induced volume change of the soil and pore water. In addition, it is found that the change in bending moment of the wall due to the seasonal GSHP cycle is caused mainly by the thermal differential across the wall during the winter, because the seasonal changes in earth pressures acting on the diaphragm wall are very limited.

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