AN ESTIMATION METHOD OF PORE WATER PRESSURE USING FIELD MONITORING DATA AND TANK MODEL REGARDING SURFACE FAILURE

Abstract. Deep-seated landslides are an important and widespread natural hazard within alpine regions, and can have a massive impact on infrastructure. Pore water pressure plays an important role in determining the stability of hydro-triggered deep-seated landslides. We improve current methods of groundwater level prediction by introducing a means to account for time lags associated with groundwater supply caused by snow accumulation, snowmelt, and infiltration in deep-seated landslides. In this study, we demonstrate a simple method to improve the estimation of these time lags using a modified tank model to calculate groundwater levels. In a deep-seated landslide in Bavaria, Germany, our results predict daily changes in pore water pressure ranging from -1 to 1.6 kPa depending on daily rainfall and snowmelt. The inclusion of time lags improves the results of standard tank models by ~36% (linear correlation with measurement) after heavy rainfall and, respectively, by ~82% following snowmelt in a 1-2 day period. For the modified tank model, we introduced a representation of snow accumulation and snowmelt, based on a temperature index and an equivalent infiltration method, i.e. the melted snow water equivalent. This compares well to the in situ measurement for the same time interval which reflect changes of pore water pressure with 0-8% relative error in rainfall season (standard tank model: 2-16% relative error) and with 0-7% relative error in snowmelt season (standard tank model: 2-45% relative error). Here we demonstrate a modified tank model for deep-seated landslides that includes snow and infiltration effects and can effectively predict changes in pore water pressure in alpine environments.

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Monitoring of Inland Tide Embankment of Binzhou Port

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1065-1069.499 ◽

2014 ◽

Vol 1065-1069 ◽

pp. 499-502 ◽

Cited By ~ 1

Author(s):

Jian Shan Gao

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Soil Mass ◽

Monitoring Data ◽

Structure Stability ◽

Integrated Monitoring ◽

Initial Stage ◽

Hyperbolic Curve ◽

Settlement Monitoring

For the purpose of foundation and structure stability during the construction of tide embankment, three monitoring projects including embankment settlement monitoring, berm platform settlement monitoring and pore water pressure monitoring are installed. Integrated monitoring data shows that foundation appears oversize instantaneous settlement on account of high construction speed, short loading interval at initial stage. Following with the shaping of embankment, stable monitoring data range, slow change rate and high dissipation speed of pore water pressure come along. Based on actual embankment settlement data, consolidation degree of soil mass is high and foundation stability becomes strong by means of hyperbolic curve.

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Physical Tank Experiment Investigation on Rainfall Producing Groundwater Level in Homogeneous Material Slopes

Geofluids ◽

10.1155/2019/5368765 ◽

2019 ◽

Vol 2019 ◽

pp. 1-13

Author(s):

Chao Zhang ◽

Wei Shao ◽

Fucai Yue ◽

Pooya Saffari ◽

Wen Nie

Keyword(s):

Pore Water ◽

Surface Runoff ◽

Pore Water Pressure ◽

Water Pressure ◽

Critical Role ◽

Homogeneous Material ◽

Time Lags ◽

Tank Model ◽

Groundwater Levels ◽

Slope Structure

It has been recognized that pore water pressure (PWP) changes in response to precipitation play a critical role in rainfall-triggered landslides. Tank models as a kind of undetermined model are widely applied for estimating groundwater levels in slopes. Most of these applications treat the tank models as a theoretical model. Therefore, in this study, physical tank experiments are reported, indicating an evaluation of three typical conceptual tank models (i.e., simple tank model, surface runoff tank model, and lateral water flow supply tank model). To reduce the slope structure controlling affection, the study takes homogenous soil material as the simulation of the slope mass. The experimental results demonstrated how the groundwater tables producing pore water pressure were affected by infiltration time lags, surface runoff, and lateral flow.

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A modified tank model including snowmelt and infiltration time lags for deep-seated landslides in alpine environments (Aggenalm, Germany)

Natural Hazards and Earth System Science ◽

10.5194/nhess-17-1595-2017 ◽

2017 ◽

Vol 17 (9) ◽

pp. 1595-1610 ◽

Cited By ~ 6

Author(s):

Wen Nie ◽

Michael Krautblatter ◽

Kerry Leith ◽

Kurosch Thuro ◽

Judith Festl

Keyword(s):

Pore Water ◽

Relative Error ◽

Snow Water Equivalent ◽

Pore Water Pressure ◽

Water Pressure ◽

Snow Accumulation ◽

Time Lags ◽

Tank Model ◽

Groundwater Supply ◽

Alpine Environments

Abstract. Deep-seated landslides are an important and widespread natural hazard within alpine regions and can have significant impacts on infrastructure. Pore water pressure plays an important role in determining the stability of hydrologically triggered deep-seated landslides. Based on a simple tank model structure, we improve groundwater level prediction by introducing time lags associated with groundwater supply caused by snow accumulation, snowmelt and infiltration in deep-seated landslides. In this study, we demonstrate an equivalent infiltration calculation to improve the estimation of time lags using a modified tank model to calculate regional groundwater levels. Applied to the deep-seated Aggenalm landslide in the German Alps at 1000–1200 m a. s. l. , our results predict daily changes in pore water pressure ranging from −1 to 1.6 kPa, depending on daily rainfall and snowmelt, which are compared to piezometric measurements in boreholes. The inclusion of time lags improves the results of standard tank models by ∼ 36 % (linear correlation with measurement) after heavy rainfall and by ∼ 82 % following snowmelt in a 1–2-day period. For the modified tank model, we introduced a representation of snow accumulation and snowmelt based on a temperature index and an equivalent infiltration method, i.e. the melted snow-water equivalent. The modified tank model compares well to borehole-derived water pressures. Changes of pore water pressure can be modelled with 0–8 % relative error in rainfall season (standard tank model: 2–16 % relative error) and with 0–7 % relative error in snowmelt season (standard tank model: 2–45 % relative error). Here we demonstrate a modified tank model for deep-seated landslides which includes snow accumulation, snowmelt and infiltration effects and can effectively predict changes in pore water pressure in alpine environments.

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Analysis of instability conditions and failure mode of a special type of translational landslide using a long-period monitoring data: a case study of the Wobaoshi landslide (Bazhong city, China)

10.5194/nhess-2019-133 ◽

2019 ◽

Author(s):

Yimin Liu ◽

Chenghu Wang ◽

Guiyun Gao ◽

Pu Wang ◽

Zhengyang Hou ◽

...

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Monitoring Data ◽

Theoretical Research ◽

Deformation And Failure ◽

Long Period ◽

Translational Landslide ◽

Multi Stage ◽

Parameter Monitoring

Abstract. A translational landslide comprising nearly horizontal sand and mud interbed was widely developed in the Ba river basin of the Qinba–Longnan mountain area. Scholars have conducted theoretical research on this rainfall-induced landslide; however, owing to the lack of landslide monitoring engineering and data, demonstrating and validating the theoretical research wasdifficult. This study considered a translational landslide with an unusual morphology: the Wobaoshi landslide, which is located in Bazhong city, China. First, the formation conditions of this landslide were ascertained through field exploration, and the deformation and failure characteristics of the plate-shaped sliding body were analyzed. Then, long-period monitoring engineering was conducted to obtain multi-parameter monitoring data, such as crack width, rainfall intensity, and pore-water pressure. Finally, through the mechanical model analysis of the multi-stage sliding bodies, the calculating formula of the maximum height of the multi-stage plate girders, hcr, was derived，and the long-period monitoring data were used to verify its accuracy. Combined with numerical simulation and calculations, the deformation and failure modes of the plate-shaped sliding bodies were analyzed and explored. In this paper, the multi-parameter monitoring data proved that the stability of the sliding body is affected greatly by the rainfall intensity and pore-water pressure and the pore-water pressure in the crack is positive for the beginning of the plate-shaped sliding bodies, and an optimization monitoring method for this type of landslide was proposed. Therefore, this paper has theoretical and practical significance for the intensive study of translational landslides in this area.

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TIME TO THE END OF PRIMARY CONSOLIDATION (EOP) OF SOFT CLAYEY SOILS: CONCERNING THE EFFECT OF ATTERBERG’S LIMIT AND CYCLIC LOADING HISTORY

HUE UNIVERSITY JOURNAL OF SCIENCE TECHNIQUES AND TECHNOLOGY ◽

10.26459/hueuni-jtt.v128i2b.5424 ◽

2019 ◽

Vol 128 (2B) ◽

pp. 29-41

Author(s):

Trần Thanh Nhàn

Keyword(s):

Cyclic Loading ◽

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Clayey Soils ◽

Loading History ◽

Cyclic Shear ◽

Wide Range ◽

Primary Consolidation ◽

Time Required

In order to observe the end of primary consolidation (EOP) of cohesive soils with and without subjecting to cyclic loading, reconstituted specimens of clayey soils at various Atterberg’s limits were used for oedometer test at different loading increments and undrained cyclic shear test followed by drainage with various cyclic shear directions and a wide range of shear strain amplitudes. The pore water pressure and settlement of the soils were measured with time and the time to EOP was then determined by different methods. It is shown from observed results that the time to EOP determined by 3-t method agrees well with the time required for full dissipation of the pore water pressure and being considerably larger than those determined by Log Time method. These observations were then further evaluated in connection with effects of the Atterberg’s limit and the cyclic loading history.

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Conjectures, Hypotheses, and Theories of Drumlin Formation (In memory of Stanislaw Baranowski)

Journal of Glaciology ◽

10.3189/s0022143000011552 ◽

1981 ◽

Vol 27 (97) ◽

pp. 503-505 ◽

Cited By ~ 1

Author(s):

Ian J. Smalley

Keyword(s):

Shear Strength ◽

Pore Water ◽

Stress Level ◽

Critical Stress ◽

Pore Water Pressure ◽

Water Pressure ◽

Glacial Till ◽

Forming Process ◽

Stress Levels

AbstractRecent investigations have shown that various factors may affect the shear strength of glacial till and that these factors may be involved in the drumlin-forming process. The presence of frozen till in the deforming zone, variation in pore-water pressure in the till, and the occurrence of random patches of dense stony-till texture have been considered. The occurrence of dense stony till may relate to the dilatancy hypothesis and can be considered a likely drumlin-forming factor within the region of critical stress levels. The up-glacier stress level now appears to be the more important, and to provide a sharper division between drumlin-forming and non-drumlin-forming conditions.

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