scholarly journals Analiza numeryczna procesu odwodnienia budowlanego wykopu zlokalizowanego w pobliżu dużej rzeki

2018 ◽  
Vol 27 (2) ◽  
pp. 207-216
Author(s):  
Damian Kłobukowski ◽  
Tomasz Godlewski ◽  
Paweł Popielski
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Water Level ◽  
Groundwater Monitoring ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Levels ◽  
Vistula River ◽  
Subsequent Calculation ◽  
Virtual Analysis

The main aims of the paper are the analysis of a dewatering process and the preparation of a numerical model for a dewatering of an excavation located near a river with dynamically changing water level, while accounting for existing groundwater conditions. In the publication stages of the construction of the model and the calculations using ZSoil software utilising finite element method (FEM) are presented. The purpose of the calculations was to estimate the pore water pressure in the subsoil and the deformations at the bottom of the excavation in few subsequent calculation stages, while taking the variation of the Vistula river level into account. The results of the calculations were calibrated based on the groundwater monitoring results. The increasing water level of the river has been included in the calculations. The virtual analysis reproduces the existing piezometers, allowing to compare calculated results with the values measured at the site. Additionally, the model included variants characterizing the water levels in the Vistula river and the possibility of the dewatering well failure. Obtained results suggest that the location of the excavation, in reference to the river, is a major contributing factor, as the groundwater flow is dependent on the boundary conditions assumed for the river (inflow or drainage) based on its characteristics.

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 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 Fluctuation Effect of Reservoir Water Level on the Seepage of Earth-Fill Dam

2021 ◽  
Vol 9 (6) ◽  
pp. 11-19
Author(s):  
R. Asmaranto ◽  
D. Sisinggih ◽  
R.N.A Rastanto
Keyword(s):  
Water Level ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Levels ◽  
Water Infiltration ◽  
Seepage Discharge ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Critical Discharge ◽  
Earth Fill

Lots of dam failures are the result of uncontrolled seepage. The collapse of the Situ Gintung Dam in Tangerang, Banten-Indonesia in 2009 due to heavy rains caused the dam structure to collapse. This is due to increased pore water pressure in the landfill. To anticipate collapse due to uncontrolled seepage, it is necessary to monitor it based on the behavior of changes in rainfall and reservoir water levels. Seepage within the dam body is often monitored using instrumentation tools such as standpipe piezometer (standpipe piezometer) or electric piezometer. But often the piezometer cannot work properly because it is clogged, so it cannot monitor the condition of the seepage. Other instrumentations such as V-Notch are also used to measure seepage discharge. This study aims to determine the behavior of changes in the reservoir water level caused by changes in rainfall and its effect on body seepage of the earth-fill Type dam. By knowing the phenomenon of the behavior of the relationship between reservoir water infiltration and rainfall, it will obtain information on rainfall that endangers the dam which will affect the downstream. In this study, a case study of the Selorejo Dam was taken which has a large enough reservoir capacity of about 31 million m3 which is included in the Brantas River Basin. The results showed that 5 piezometers devices were damaged (SL 1, SL 2, SL 4, SL 6, and SL 7) where they could not read the phreatic water level properly, and 2 piezometers were less sensitive to reading fluctuations in reservoir water levels. namely SL 10 and SL 11 which showed R2 values of 29.78% and 39.4%, respectively. While the maximum seepage discharge is recorded at 1474 liters/minute, this is still below the critical discharge of 1630 liters/minute allowed for this dam, but this needs to be a concern, especially the discharge from toe drain from the left side seepage and C-area which is the leakage from the left support pedestal also contributes a larger discharge than other observation points.

scholarly journals Vacuum Preconsolidation Settlement Characteristics and Microstructural Evolution of Marine Dredger-Filled Silt

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Keping Chen ◽  
Xinkai Ren ◽  
Yong He ◽  
Muyuan Gan ◽  
Danwei Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Levels ◽  
Equivalent Diameter ◽  
Vacuum Preloading ◽  
Element Analysis ◽  
Scanning Electron

The method of vacuum preloading for foundation treatments is used in the construction of the Fangchenggang coastal area in Guangxi province, China. The thick marine dredger-filled silt has a considerable impact on the treatment effort. In this study, the mineral composition and grain size distribution of these silts were analyzed to investigate their consolidation settlement property and microstructures. The scanning electron microscope and finite element method were adopted. The results reveal that the dredger-filled silt in this area is composed mainly of sand with particle size mostly smaller than 0.075 mm. To replicate the construction process, the process of drainage by the vacuum preloading method was simulated by setting different water levels in the finite element analysis. The displacement and the dissipation of the pore water pressure obtained by simulations were reasonably consistent with the field monitoring data. In addition, the results obtained using the scanning electron microscope indicate that the equivalent diameter of the structural unit and that of the pore unit decrease with the silt depth. However, the value of the structural abundance approaches one, whereas the pore abundance is significantly different from one.

Consolidation modelling of soils under the test embankment at Chek Lap Kok International Airport in Hong Kong using a simplified finite element method

2001 ◽  
Vol 38 (2) ◽  
pp. 349-363 ◽  
Author(s):  
Guofu Zhu ◽  
Jian-Hua Yin ◽  
James Graham
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Hong Kong ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
International Airport ◽  
Geological Conditions ◽  
Test Embankment ◽  
Element Method

This paper models consolidation of the foundation soils under a test embankment at the new Chek Lap Kok International Airport in Hong Kong. The modelling used a simplified finite element method and material parameters derived from results in the original site investigation report. Various features that need to be considered in applying the simplified method are illustrated through this case study. Good predictions of settlement results are obtained. Relatively large discrepancies in pore-water pressure predictions suggest that the nonlinear nature of hydraulic conductivity needs to be taken into account when large compressions are likely to occur. Geological conditions are shown to be a key factor in successful modelling of consolidation behaviour.Key words: consolidation, pore-water pressure, case modelling, finite element method, vertical drains, settlement.

Application of Support Vector Machine for Prediction of Slope Stability Coefficient Considering the Influence of Rainfall and Water Level

2016 ◽  
Vol 851 ◽  
pp. 840-845
Author(s):  
Gui Lan Tao ◽  
Zi Shun Yao ◽  
Bin Zheng Tan ◽  
Cong Cong Gao ◽  
Yi Wen Yao
Keyword(s):  
Finite Element ◽  
Slope Stability ◽  
Water Level ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Element Model ◽  
Support Vector ◽  
High Slope ◽  
Stability Coefficient ◽  
The Finite Element Model

Slope stability estimation is a complex engineering problem involving many factors. A hybrid model based on the combination of finite element software GEO-STUDIO and support vector machine (SVM) is proposed to address the problem. The study took a high slope of Jingjiang reach of Yangtze River as the research object. Several important parameters, including values of geometric and geotechnical properties of slope as well as rainfall and water level data were used to establish the finite element model for the high slope. Besides, the validity of the model was estimate using the measured data of pore water pressure. The slope stability coefficients were calculated in GEO-STUDIO environment. And the data were used as the input samples to train and test SVM model. Results show that the agreement achieved in pore water pressure between measurement and analysis using the finite element model can be considered very reasonable. And the slope stability coefficient results by SVM coincided well with that of finite element analysis. It suggests that the proposed model has the potential to be a useful tool for the prediction of slope stability coefficient considering the influence of rainfall and water level.

Interaction between water pressure in the basal drainage system and discharge from an Alpine glacier before and during a rainfall-induced subglacial hydrological event

1997 ◽  
Vol 24 ◽  
pp. 288-292 ◽  
Author(s):  
Andrew P. Barrett ◽  
David N. Collins
Keyword(s):  
Water Level ◽  
Water Pressure ◽  
Drainage System ◽  
Water Levels ◽  
Drainage Network ◽  
Alpine Glacier ◽  
Hydraulic Conditions ◽  
Borehole Water ◽  
Progressive Growth ◽  
Resultant Increase

Combined measurements of meltwater discharge from the portal and of water level in a borehole drilled to the bed of Findelengletscher, Switzerland, were obtained during the later part of the 1993 ablation season. A severe storm, lasting from 22 through 24 September, produced at least 130 mm of precipitation over the glacier, largely as rain. The combined hydrological records indicate periods during which the basal drainage system became constricted and water storage in the glacier increased, as well as phases of channel growth. During the storm, water pressure generally increased as water backed up in the drainage network. Abrupt, temporary falls in borehole water level were accompanied by pulses in portal discharge. On 24 September, whilst borehole water level continued to rise, water started to escape under pressure with a resultant increase in discharge. As the drainage network expanded, a large amount of debris was flushed from a wide area of the bed. Progressive growth in channel capacity as discharge increased enabled stored water to drain and borehole water level to fall rapidly. Possible relationships between observed borehole water levels and water pressures in subglacial channels are influenced by hydraulic conditions at the base of the hole, distance between the hole and a channel, and the nature of the substrate.

Research on Simulation of Land Subsidence Characteristics under the Groundwater Level Fluctuation

2013 ◽  
Vol 368-370 ◽  
pp. 1697-1700
Author(s):  
Long Zhang ◽  
Xue Wen Lei ◽  
Qing Shang Meng
Keyword(s):  
Finite Element ◽  
Land Subsidence ◽  
Groundwater Level ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Clay ◽  
Level Fluctuation ◽  
Finite Element Software ◽  
Coastal Cities ◽  
Groundwater Level Fluctuation

Based on the characteristics of frequent land subsidence events caused by groundwater level fluctuation in coastal cities in China and studying on the quaternary sedimentary soft clay in Shanghai, the effects of groundwater level fluctuation on the deformation of soft clay is simulated by Geo-Studio finite element software. It has summarized the law of deformation, effective stress with the change of groundwater level fluctuation, especially the process of dissipation of pore water pressure with the groundwater level fluctuation. The low can be sued as a reference for similar engineering and land subsidence prevention.

On XFEM Applications to Crack Surface under External Force

2012 ◽  
Vol 152-154 ◽  
pp. 210-215
Author(s):  
Tian Tang Yu ◽  
Lu Yang Shi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Intensity ◽  
Extended Finite Element Method ◽  
Crack Surface ◽  
Water Pressure ◽  
Intensity Factors ◽  
Extended Finite Element ◽  
Modeling Growth ◽  
Element Method

The extended finite element method is applied to modeling growth of arbitrary crack with crack surface tractions. Firstly, the extended finite element method is investigated for the stress intensity factor solution of surface traction problems. Secondly, for different water pressure acting on the crack surfaces and different crack length, the variation of the stress intensity factors is investigated. Finally, the process of hydraulic fracturing is simulated with the method. Numerical simulations illustrate that the method can effectively model the fracture problems with surface tractions.

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