Laboratory calibration of pressure transducer-tensiometer system for hydraulic studies

1994 ◽  
Vol 74 (3) ◽  
pp. 315-319 ◽  
Author(s):  
R. H. Azooz ◽  
M. A. Arshad
Keyword(s):  
Pore Water ◽  
Pressure Transducer ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Hydraulic Gradient ◽  
Gradient Distribution ◽  
Pressure Transducers ◽  
Soil Pore Water ◽  
Laboratory Calibration ◽  
Influence Of Temperature On

Pressure transducer-tensiometer (PTT) systems can be used to continuously monitor soil pore water pressure and the hydraulic gradient distribution in a field, and under laboratory conditions over relatively short time intervals. A reliable laboratory calibration of a PTT system can determine the effects of temperature fluctuations on output readings in the field. Laboratory calibrations of 20 PTTs were conducted under constant pressures of 0, − 25, − 50 and − 75 kPa and constant temperatures of 5, 15, 25 and 48 °C. Twenty Bourdon gauge tensiometers (BGTs) and pressure transducers (PTs) were also calibrated to check changes in the sensitivity and effectiveness of the PTT system, when the Bourdon gauge of the tensiometer is replaced by a PT. Readings of all the three systems revealed that pressure values gradually declined with an increase in temperature. With a temperature change from 5 to 48 °C, the pressure values at constant pressures of 0, − 25, − 50 and − 75 kPa decreased by 0, 3.7, 4.1 and 4.5 kPa for the BGT; 2.05, 2.16, 2.23 and 2.44 kPa for PT and 2.53, 2.87, 2.88 and 3.17 kPa for PTT. As the influence of temperature on the calibration curve of the PTT and PT systems was different, it is recommended that the complete PTT system should be calibrated in the laboratory to adjust the output readings to the anticipated temperature in the field. Key words: Tensiometer, tensiometer-pressure transducer, soil pore water pressure, hydraulic gradient

scholarly journals Analysis of Pore Water Pressure and Piping of Hydraulic Well

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 502
Author(s):  
Jinman Kim ◽  
Heuisoo Han ◽  
Yoonhwa Jin
Keyword(s):  
Numerical Analysis ◽  
Water Level ◽  
Pore Water ◽  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Hydraulic Gradient ◽  
Water Levels ◽  
Seepage Velocity ◽  
Seepage Analysis

This paper shows the results of a field appliance study of the hydraulic well method to prevent embankment piping, which is proposed by the Japanese Matsuyama River National Highway Office. The large-scale embankment experiment and seepage analysis were conducted to examine the hydraulic well. The experimental procedure is focused on the pore water pressure. The water levels of the hydraulic well were compared with pore water pressure data, which were used to look over the seepage variations. Two different types of large-scale experiments were conducted according to the installation points of hydraulic wells. The seepage velocity results by the experiment were almost similar to those of the analyses. Further, the pore water pressure oriented from the water level variations in the hydraulic well showed similar patterns between the experiment and numerical analysis; however, deeper from the surface, the larger pore water pressure of the numerical analysis was calculated compared to the experimental values. In addition, the piping effect according to the water level and location of the hydraulic well was quantitatively examined for an embankment having a piping guide part. As a result of applying the hydraulic well to the point where piping occurred, the hydraulic well with a 1.0 m water level reduced the seepage velocity by up to 86%. This is because the difference in the water level between the riverside and the protected side is reduced, and it resulted in reducing the seepage pressure. As a result of the theoretical and numerical hydraulic gradient analysis according to the change in the water level of the hydraulic well, the hydraulic gradient decreased linearly according to the water level of the hydraulic well. From the results according to the location of the hydraulic well, installation of it at the point where piping occurred was found to be the most effective. A hydraulic well is a good device for preventing the piping of an embankment if it is installed at the piping point and the proper water level of the hydraulic well is applied.

scholarly journals Effect of Seismic Loading on Variation of Pore Water Pressure During Pile Pull-Out Tests in Sandy Soils

2021 ◽  
Vol 27 (12) ◽  
pp. 1-12
Author(s):  
Haider N. Abdul Hussein ◽  
Qassun S. Mohammed Shafiqu ◽  
Zeyad S. M. Khaled
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Seismic Loading ◽  
Shaking Table ◽  
Dense Sand ◽  
Pressure Transducers ◽  
Pull Out ◽  
Pullout Tests ◽  
Pile Model

Experimental model was done for pile model of L / D = 25 installed into a laminar shear box contains different saturation soil densities (loose and dense sand) to evaluate the variation of pore water pressure before and after apply seismic loading. Two pore water pressure transducers placed at position near the middle and bottom of pile model to evaluate the pore water pressure during pullout tests. Seismic loading applied by uniaxial shaking table device, while the pullout tests were conducted through pullout device. The results of changing pore water pressure showed that the variation of pore water pressure near the bottom of pile is more than variation near the middle of pile in all tests. The variation of pore water pressure after apply seismic loading is more than the variation before apply seismic loading near the middle of pile and near the bottom of pile and in loose and dense sand. Variation of pore water pressure after apply seismic loading and uplift force is less than the variation after apply seismic loading in loose sand at middle and bottom of pile.

scholarly journals In situ measurements of till deformation and water pressure

2006 ◽  
Vol 52 (177) ◽  
pp. 175-182 ◽  
Author(s):  
Martin Truffer ◽  
William D. Harrison
Keyword(s):  
Pore Water ◽  
Pressure Transducer ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Spatial Homogeneity ◽  
Early Season ◽  
Surface Motion ◽  
Speed Up ◽  
Tilt Sensor

AbstractA newly developed hammer was used to insert two autonomous probes 0.8 m and 2.1 m into clast-rich subglacial till under Black Rapids Glacier, Alaska, USA. Both probes were instrumented with a dual-axis tilt sensor and a pore-water pressure transducer. The data are compared to a 75 day record of surface velocities. Till deformation at depth was found to be highly seasonal: it is significant during an early-season speed-up event, but during long periods thereafter measured till deformation rates are negligible. Both tilt records show rotation around the probe axis, which indicates a change in tilt direction of about 30°. The tilt records are very similar, suggesting spatial homogeneity on the scale of the probe separation (4 m horizontal and 3.3 m vertical). There is evidence that during much of the year sliding of ice over till or deformation of a thin till layer (<20 cm) accounts for at least two-thirds of total basal motion. Basal motion accounts for 50–70% of the total surface motion. The inferred amount of ice–till sliding is larger than that found at the same location in a previous study, when surface velocities were about 10% lower. We suggest that variations in ice–till coupling account for the observed variations in mean annual speed.

scholarly journals Intensive Measurements of Soil Pore Water Pressure for Analyzing Heterogeneous Hydrological Processes on a Hillslope

2010 ◽  
Vol 3 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Naoya MASAOKA ◽  
Yosuke YAMAKAWA ◽  
Ken'ichirou KOSUGI ◽  
Takahisa MIZUYAMA ◽  
Daizo TSUTSUMI
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Hydrological Processes ◽  
Soil Pore Water

scholarly journals Artificial Neural Network Modeling for Spatial and Temporal Variations of Pore-Water Pressure Responses to Rainfall

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
M. R. Mustafa ◽  
R. B. Rezaur ◽  
H. Rahardjo ◽  
M. H. Isa ◽  
A. Arif
Keyword(s):  
Neural Network ◽  
Time Series ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Ann Model ◽  
Soil Pore Water ◽  
Pore Water Pressures

Knowledge of spatial and temporal variations of soil pore-water pressure in a slope is vital in hydrogeological and hillslope related processes (i.e., slope failure, slope stability analysis, etc.). Measurements of soil pore-water pressure data are challenging, expensive, time consuming, and difficult task. This paper evaluates the applicability of artificial neural network (ANN) technique for modeling soil pore-water pressure variations at multiple soil depths from the knowledge of rainfall patterns. A multilayer perceptron neural network model was constructed using Levenberg-Marquardt training algorithm for prediction of soil pore-water pressure variations. Time series records of rainfall and pore-water pressures at soil depth of 0.5 m were used to develop the ANN model. To investigate applicability of the model for prediction of spatial and temporal variations of pore-water pressure, the model was tested for the time series data of pore-water pressure at multiple soil depths (i.e., 0.5 m, 1.1 m, 1.7 m, 2.3 m, and 2.9 m). The performance of the ANN model was evaluated by root mean square error, mean absolute error, coefficient of correlation, and coefficient of efficiency. The results revealed that the ANN performed satisfactorily implying that the model can be used to examine the spatial and temporal behavior of time series of pore-water pressures with respect to multiple soil depths from knowledge of rainfall patterns and pore-water pressure with some antecedent conditions.

Evaluation of MLP-ANN Training Algorithms for Modeling Soil Pore-Water Pressure Responses to Rainfall

2013 ◽  
Vol 18 (1) ◽  
pp. 50-57 ◽  
Author(s):  
M. R. Mustafa ◽  
R. B. Rezaur ◽  
S. Saiedi ◽  
H. Rahardjo ◽  
M. H. Isa
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Training Algorithms ◽  
Soil Pore Water
Sign in / Sign up

Export Citation Format

Share Document