scholarly journals On measurement of underground water level and pore water pressure at the landslide with cohesive soil as the principal constituent

Landslides ◽  
1970 ◽  
Vol 7 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Hiroyuki NAKAMURA ◽  
Masashi KONDO ◽  
Kazuo SHIRAISHI
Keyword(s):  
Water Level ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Cohesive Soil ◽  
Underground Water ◽  
Underground Water Level

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 A Study on Pore Water Pressure Behavior of Fill Dam with Water Level Raising using Centrifugal Model Tests

2013 ◽  
Vol 55 (2) ◽  
pp. 87-95 ◽  
Author(s):  
Chung-Won Lee ◽  
Dong-Su Chang ◽  
Sung-Yong Park ◽  
Ki-Sung Kim ◽  
Yong-Seong Kim
Keyword(s):  
Water Level ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Model Tests ◽  
Pressure Behavior ◽  
Centrifugal Model

scholarly journals Evaluasi Tekanan Air Pori dan Rembesan Pada Bendungan Panohan

2019 ◽  
Vol 4 (2) ◽  
pp. 26
Author(s):  
Adib Lathiful Huda ◽  
Sri Prabandiyani Retno Wardani ◽  
Suharyanto Suharyanto
Keyword(s):  
Finite Element ◽  
Water Level ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
The Body ◽  
Reservoir Water ◽  
Planning Stage ◽  
Fem Method ◽  
Comparison Results

Salah satu penyebab kegagalan struktur bendungan adalah terjadinya rembesan yang dipicu oleh tingginya tekanan air pori yang terjadi pada tubuh bendungan. Pada Bendungan Panohan, kebocoran rembesan terjadi hingga memotong lereng hilir bendungan yang dapat mengganggu stabilitas tubuh bendungan. Tujuan dari penelitian ini adalah untuk mengevaluasi tekanan air pori dan rembesan di tubuh Bendungan Panohan menggunakan metode analisis instrumentasi piezometer dan v-notch yang kemudian dibandingkan dengan analisis metode elemen hingga (finite element method / FEM) menggunakan program perangkat lunak SEEP/W. Metode FEM menggunakan parameter desain material selama tahap perencanaan bendungan. Kedua analisis dilakukan pada section C - C Bendungan Panohan menggunakan beberapa variasi ketinggian muka air waduk. Hasil perbandingan menunjukkan bahwa nilai tekanan air pori dan rembesan pada metode FEM lebih besar dari hasil analisis dengan metode pembacaan instrumentasi pada kondisi muka air minimal dan normal. Kondisi sebaliknya terjadi pada kondisi ketinggian air banjir, yaitu nilai tekanan air pori dan rembesan dari pembacaan instrumentasi lebih besar dari hasil analisis metode FEM. Seiring dengan naiknya ketinggian muka air waduk, terjadi kenaikan nilai tekanan air pori dan rembesan dari kedua hasil analisis. Kondisi rembesan yang terjadi pada  Bendungan Panohan saat ini tidak aman pada kondisi muka air banjir, karena memiliki nilai debit rembesan 0,38 ltr/det melebihi dari yang disyaratkan yaitu sebesar 0,35 ltr/det.Kata kunci : bendungan panohan; tekanan air pori; rembesan; FEM ABSTRACTOne of the causes of the failure of a dam structure is the occurrence of seepage triggered by high pore water pressure that occurs in the body of the dam. In the Panohan Dam, seepage occurs on the downstream slope of the dam which can disturb the stability of the dam body. The purpose of this research is to evaluate the pore water pressure and seepage in the Panohan Dam body using the piezometer and v-notch instrumentation reading method which is then compared with the finite element (FEM) method using SEEP/W software program. FEM method uses material parameters during the dam planning stage. Both analyses were carried out on the C – C section of the Panohan Dam using several variations of reservoir water level. The comparison results show that pore water pressure in the FEM method is greater than the pore water pressure value based on the piezometer method at the minimum and normal water level conditions. The opposite condition occurs in maximum water level conditions. The seepage value of the v-notch reading is greater than the seepage value from the FEM method. Seepage that occurs in the Panohan Dam is currently unsafe under the maximal water level conditions.

scholarly journals STUDI GEOTEKNIK PENGARUH MUKA AIR TANAH TERHADAP KESTABILAN LERENG TAMBANG BATUBARA

2020 ◽  
Vol 1 (1) ◽  
pp. 475-488
Author(s):  
Jioni Santo Frans ◽  
Muhammad Hafizh Nurfalaq
Keyword(s):  
Rock Mass ◽  
Slope Stability ◽  
Ground Water ◽  
Water Level ◽  
Pore Water ◽  
Groundwater Level ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Slope Angle ◽  
Ground Water Level

ABSTRAK Dalam keadaan normal, suatu massa batuan memiliki kesetimbangan gaya yang bekerja. Kesetimbangan gaya yang bekerja tersebut bisa terganggu akibat terjadinya perubahan kondisi massa batuan, baik secara alamiah (erosi, patah, peningkatan muka air tanah) maupun aktivitas manusia (pengupasan, pengangkutan, penggalian, penimbunan). Respon dari perubahan tersebut, massa batuan dapat mengalami ketidakstabilan sebagai usaha untuk mencapai kondisi kesetimbangan baru. Hal ini akan memicu gerakan massa batuan akibat lereng yang tidak stabil dan terjadinya longsor. Lereng yang tidak stabil akan berdampak terhadap faktor keselamatan, ekonomi, dan sosial. Air tanah memiliki permasalahan tersendiri dalam pengelolaan tambang. Tekanan air pori (pore water pressure) dari air tanah dapat menimbulkan gaya angkat (uplift force) dan menurunkan kekuatan suatu massa batuan penyusun lereng, yang mana akan mempengaruhi kestabilan suatu lereng. Karakteristik daerah penelitian yang memiliki muka air tanah relatif dekat dengan permukaan, menyebabkan lereng berada dalam kondisi hampir jenuh. Penelitian ini bertujuan untuk melakukan studi pengaruh muka air tanah terhadap kestabilan lereng tambang batubara di daerah penelitian. Metode penelitian yang digunakan meliputi pengumpulan data primer melalui observasi lapangan untuk mengumpulkan data-data teknis terkait dan pengumpulan data sekunder melalui studi literatur. Analisa kestabilan lereng dilakukan untuk mendapatkan rekomendasi dengan nilai Faktor Keamanan minimum 1,30. Hasil penelitian menunjukkan muka air tanah memiliki hubungan berbanding terbalik terhadap nilai Faktor Keamanan. Rekomendasi yang dihasilkan yaitu melakukan dewatering dengan menggunakan drain hole. Target penurunan muka air tanah pada dinding tambang daerah penelitian adalah RL+40 pada area sidewall dan RL+65 pada area highwall. Altenatif lain yang diajukan oleh penulis adalah dengan melandaikan sudut lereng keseluruhan (overall slope angle) pada dinding tambang di daerah penelitian. Dinding tambang daerah penelitian direkomendasikan untuk dilakukan pelandaian dengan sudut lereng keseluruhan berkisar 24°. Kata kunci: kestabilan lereng, muka air tanah, longsor, dewatering, sudut lereng keseluruhan  ABSTRACT Under normal circumstances, a rock mass has an equilibrium of working forces. The equilibrium of these working forces can be disrupted due to changes in rock mass conditions, both naturally (erosion, broken, increased ground water level) and human activities (stripping, loading, excavation, backfill). In response to these changes, rock mass can have instability issue as an effort to reach new equilibrium conditions. This  condition will trigger rock mass movements and slope failure due to unstable slopes. Unstable slopes will affect the safety, economic and social factors. Groundwater has its own problems in mining activities. Pore water pressure from ground water can cause uplift force and decrease the strength of a rock mass forming a slope, which will affect the slope stability. Characteristics of the study area which has groundwater level relatively close to surface, causes the slope to be in nearly saturated condition. This research aims to study the effect of groundwater level on the stability of coal mine slopes in the study area. The research method used includes collecting primary data through field observations to collect related technical data and secondary data collection through literature studies. Slope stability analysis is carried out to obtain recommendations with a minimum Safety Factor value of 1.30. The results showed the ground water level has an inverse relationship to the value of the Safety Factor. The recommendations are dewatering using drain holes. The target of groundwater level reduction in the mine wall of the study area is RL+40 in the sidewall area and RL+65 in the highwall area. Another alternative proposed by the author is by resloping the overall slope angle of the mine wall in the study area. The mining wall of the study area is recommended for alignment with an overall slope angle of around 24 °. Keywords: slope stability, ground water level, landslides, dewatering, overall slope angle

scholarly journals Model Test and Numerical Analysis on the Deformation and Stability of a Landslide Subjected to Reservoir Filling

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Xinli Hu ◽  
Chuncan He ◽  
Chang Zhou ◽  
Chu Xu ◽  
Han Zhang ◽  
...  
Keyword(s):  
Water Level ◽  
Physical Model ◽  
Pore Water ◽  
Model Test ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Physical Model Test ◽  
Landslide Stability ◽  
Landslide Deformation ◽  
Reservoir Filling

Reservoir filling can affect the landslide stability and cause the landslide deformation within the reservoir area. In this paper, a physical model test and a series of numerical analyses were combined to investigate the landslide deformation and stability under reservoir filling. The surface deformation, deep displacement, and pore water pressure were recorded during the physical model test. In the model test, the increasing period of the pore water pressure inside the landslide is proposed to be a critical period for the landslide subjected to the reservoir filling. During this period, large landslide deformation occurred. The numerical analyses show that a greater factor of safety (FOS) appeared under a higher water level rising rate or a lower permeability coefficient during the water level rising stage when other variables are fixed, due to the domination of the reservoir buttressing effect which can increase the landslide resistance. During the reservoir maintaining stage, the reservoir water infiltrated into the landslide continuously to cause the matric suction dissipation and pore water pressure increase, which reduced the landslide shear strength and then decreased the landslide stability.

scholarly journals Behaviour of Cohesive Soil Subjected to Low-Frequency Cyclic Loading in Strain-Controlled Tests

2015 ◽  
Vol 36 (3) ◽  
pp. 21-35 ◽  
Author(s):  
Marta Kalinowska ◽  
Małgorzata Jastrzębska
Keyword(s):  
Cyclic Loading ◽  
Pore Water ◽  
Effective Stress ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Low Frequency ◽  
Cohesive Soil ◽  
Stress Deviator ◽  
Kaolinite Clay ◽  
Cyclic Shear

Abstract The subject of the paper comprises tests of cohesive soil subjected to low-frequency cyclic loading with constant strain amplitude. The main aim of the research is to define a failure criteria for cohesive soils subjected to this type of load. Tests of undrained cyclic shear were carried out in a triaxial apparatus on normally consolidated reworked soil samples made of kaolinite clay from Tułowice. Analysis of the results includes the influence of number of load cycles on the course of effective stress paths, development of excess pore water pressure and stress deviator value. Observed regularities may seem surprising. The effective stress path initially moves away from the boundary surface and only after a certain number of load-unload cycles change of its direction occurs and it starts to move consequently towards the surface. At the same time, it has been observed that pore water pressure value decreases at the beginning and after few hundred cycles increases again. It is a typical behaviour for overconsolidated soil, while test samples are normally consolidated. Additionally, a similar change in deviator stress value has been observed - at first it decreases and later, with subsequent cycles, re-increases.

scholarly journals STUDY ON VERIFICATION OF PORE WATER PRESSURE IN STATE OF RAISING UP WATER LEVEL USING FLUID AND SOIL WEAK COUPLING MODEL

2017 ◽  
Vol 73 (2) ◽  
pp. I_1111-I_1116
Author(s):  
Yuki OHKI ◽  
Mizuki KUSANO ◽  
Katsumi SEKI ◽  
Shinji TAENAKA ◽  
Shunsuke MORIYASU ◽  
...  
Keyword(s):  
Water Level ◽  
Pore Water ◽  
Weak Coupling ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Coupling Model

scholarly journals Long-term dynamic bearing capacity of shallow foundations on a contractive cohesive soil

2021 ◽  
Author(s):  
Daniel R. Panique Lazcano ◽  
Rubén Galindo Aires ◽  
Hernán Patiño Nieto
Keyword(s):  
Bearing Capacity ◽  
Pore Water ◽  
Cyclic Load ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Friction Angle ◽  
Cohesive Soil ◽  
Cyclic Softening ◽  
Pore Water Pressures

AbstractThe calculation of the long-term dynamic bearing capacity arises from the need to consider the generation of maximum pore-water pressure developed from a cyclic load. Under suitable conditions, a long-term equilibrium situation would be reached, when pore-water pressures stabilized. However, excess pore-water pressure generation can lead to cyclic softening. Consequently, it is necessary to define both the cohesion and the internal friction angle to calculate the dynamic bearing capacity of a foundation in the long term, being necessary to incorporate the influence of the self-weight of soil and therefore the width of the foundation. The present work is based on an analysis of the results of cyclic simple shear tests on soil samples from the port of El Prat in Barcelona. From these experimental data, a pore-water pressure generation formulation was obtained that was implemented in FLAC2D finite difference software. A methodology was developed for the calculation of the maximum cyclic load that a footing can resist before the occurrence of the cyclic softening. The type of soil studied is a contractive cohesive soil, which generates positive pore-water pressures. As a numerical result, design charts have been developed for long-term dynamic bearing capacity calculation and the charts were validated with the application of a real case study.

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

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.

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

1981 ◽  
Vol 27 (97) ◽  
pp. 503-505 ◽  
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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