scholarly journals Reservoir Landslide Physical Modelling under Ice-Snow Melting and Reservoir Water Combined Action

2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Tongqiang Xiong ◽  
Jianlin Li ◽  
Lehua Wang ◽  
Huafeng Deng ◽  
Xiaoliang Xu
Keyword(s):  
Failure Mode ◽  
Model Test ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Snow Melting ◽  
Reservoir Water ◽  
Infiltration Process ◽  
Deformation And Failure ◽  
Snow Water ◽  
Combined Action

Extreme ice-snow melting in winter affects the infiltration process of snow water on the slope surface significantly and plays an important role in the deformation stability of landslide. Variation in pore water pressure is regarded as an essential factor of landslide instability induced by snow water. In order to figure out the internal relationship between the infiltration process of snow water and the failure mode of deformation and instability of the accumulation landslide, the response law and deformation and failure mode of pore water pressure and soil pressure of landslide accumulation under different ice-snow melting conditions are deeply studied based on the indoor large-scale landslide model test. We have studied the physical model test under the combined action of reservoir water and ice-snow melting. It reveals the seepage erosion deformation and failure mechanism. It undoubtedly provides references of great importance for the geological hazard governance of bank slope in the Three Gorges Reservoir Area.

scholarly journals Mechanical Properties of Sandstone Roof and Surrounding-Rock Control of Mining Roadways Subject to Reservoir Water Disturbance

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Bin Ma ◽  
Zaiqiang Hu ◽  
Xingzhou Chen ◽  
Lili Chen ◽  
Wei Du
Keyword(s):  
Crack Initiation ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Surrounding Rock ◽  
Water Inflow ◽  
Reservoir Water ◽  
Deformation And Failure ◽  
Joint Dislocations ◽  
Rock Structure

Sandstone-roofed roadways are susceptible to deformation and failure caused by reservoir-water-induced disturbances, thereby compromising human safety. Using rock-mechanics testing techniques, numerical simulations, and engineering principles, this study investigates the strength, deformation, and pore-structure characteristics of sandstone roofs as well as means to support the surrounding rock structure. The results obtained in this study reveal that the residual strain is proportional to the pore-water pressure, which, in turn, causes a significant reduction in the elastic modulus during the unloading phase. Furthermore, an increase in the pore-water pressure causes the shear failure of specimens in compression. The delay between crack initiation and specimen-volume expansion decreases. Moreover, the specimen demonstrates increased deformation and failure responses to changes in the confining pressure, thereby resulting in accelerated conversion. Changes in water inflow can be correlated to crack initiation, propagation, and fracture. This water inflow gradually increases with an increase in the osmotic pressure. Correspondingly, the volumetric strain required for maximum water inflow undergoes a gradual decrease. The increased water inflow can be considered a precursor to specimen failure. In addition, fractures in the surrounding rock structures are mainly caused by joint dislocations. The increase in pore pressure promotes the development of dislocation fractures in the deep surrounding rocks. Subsequently, these fractures overlap with their open counterparts to form large fractures; this increases the roadway-roof subsidence and layer separation of the shallow surrounding rocks, thereby further increasing the fracture count. Lastly, the use of high-performance rock bolts, cable-bolt reinforcements, and W-shaped steel bands is expected to ensure the stability of rocks surrounding sandstone-roofed roadways subject to water-pressure disturbances.

scholarly journals Effect of Colluvial Soil Slope Fracture’s Anisotropy Characteristics on Rainwater Infiltration Process

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Ling Zeng ◽  
Jie Liu ◽  
Jun-hui Zhang ◽  
Han-bing Bian ◽  
Wei-hua Lu
Keyword(s):  
Pore Water ◽  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Positive Pressure ◽  
Saturated Zone ◽  
Infiltration Depth ◽  
Infiltration Process ◽  
Fracture Angle ◽  
Rainwater Infiltration

The SEEP/W module of finite element software GEO-slope is used to analyze the effects of fracture depth, permeability coefficient ratio, fracture angle, and fracture number on the rainwater infiltration process. Moreover, the effect of fracture seepage anisotropy on slope stability is discussed combining with unsaturated seepage theory. The results show that the pore water pressure in the fracture increases rapidly with the rainfall until it changes from negative pressure to positive pressure. The greater the fracture depth is, the greater the pore water pressure in the fracture is, and the greater the infiltration depth at the time of rainfall stopping is. When the permeability coefficient is greater than the rainfall intensity, the permeability coefficient ratio has a great influence on the infiltration process of rainwater. The smaller the fracture angle is, the greater the maximum pore water pressure is in the fracture depth range, and the greater the depth of the positive pore water pressure is. However, with the increase of fracture angle, the infiltration depth decreases, and the range of the surface saturation area of slope increases obviously. With the increase of fracture density, the saturated positive pressure region is connected to each other in the slope. The influence range and the degree of the rainwater on the seepage field are larger and larger. There is a power relation between the saturation area and the fracture number, and also the concentration distribution of long fractures directly forms the large-connected saturated zone and raises groundwater. The range of the saturated zone and variation law of the pore water pressure under fracture seepage are obtained, which provide a reference for the parameter partition assignment of slope stability analysis under fracture seepage.

scholarly journals Post-Evaluation of Slope-Cutting on Loess Slopes Under Long-Term Rainfall Based on Model Test

2021 ◽  
Author(s):  
Guodong Liu ◽  
Shiqiang Xu ◽  
Zhijun Zhou ◽  
Tao Li
Keyword(s):  
Model Test ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Pressure Sensors ◽  
In Situ Stress ◽  
Shaanxi Province ◽  
Wetting Front ◽  
Loess Slope ◽  
Post Evaluation ◽  
Steady Stage

Abstract Failures of treated slope occurring in China are at a consistently increasing rate, leaving the huge number of treated loess slopes calling for post-evaluation, however, no mature technique is in place. Depended on an loess slope in Shaanxi province treated by slope-cutting, indoor geotechnical and model tests were conducted, revealing the rainwater infiltration characteristics and pressure varying characteristics inside the slope, the results of which were then adopted to perform the post-evaluation of the treated slope. The results showed that the rainwater scouring effect on the loess slope surface attenuates gradually, and enters a steady stage after the first year of rainfall. The rainwater preferentially penetrates the platforms with gradually attenuating rates, however the wetting front can not be deemed as the boundary between the saturated and unsaturated areas, as the most parts of the model slope were indicated unsaturated by the pore water pressure sensors. Caused by the in-situ stress release, the soil pressures don’t increase but decrease sharply at the start of the rainfall. The displacements mainly occurs in the first two years of rainfall, following by steady periods. The model test results and investigation results were then used to conduct the post-evaluation of the prototype slope, which formed a post-evaluation frame relevant to other slope post-evaluations.

scholarly journals Interpretasi Instrumentasi Piezometer Dalam Rangka Pemantauan Keamanan Bendungan Kedung Ombo

2021 ◽  
Vol 7 (2) ◽  
pp. 131-145
Author(s):  
Gerald Guntur Pandapotan Siregar ◽  
Fajar aldoko Kurniawan
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Level Fluctuations ◽  
Embankment Dam ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Embankment Dams ◽  
The World ◽  
Earthfill Dams

The embankment dam is the most widely built dam in the world, especially in Indonesia. However, embankment dams are also prone to collapse. Dam failures due to the piping process through the dam body account for 30.5% of the total dam collapses worldwide. Therefore, it is necessary to periodically monitor and evaluate the condition of pore water pressure and seepage in a dam which is usually carried out using installed instrumentation. Very little has been done on instrumentation interpretation of earthfill dams in Indonesia, which is a very worrying condition. It is possible that old or even new dams have shown behavior that leads to a decrease in safety. This condition can be monitored by instrumentation in the dam if interpreted properly. Kedung Ombo Dam as an old embankment dam but has a fairly complete instrumentation can be evaluated for safety related to pore water pressure and phreatic line (seepage line). Pore water pressure evaluation is carried out by collecting piezometer readings and reservoir water level fluctuations over a period of several years. The results of the research on the interpretation of piezometer readings indicate that the overall safety of the Kedung Ombo dam is still good in terms of pore water pressure conditions. However, there are some anomalous conditions that should be investigated further

scholarly journals Influence of Layer Transition Zone on Rainfall-Induced Instability of Multilayered Slope

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 4) ◽  
Author(s):  
Zhi Dou ◽  
Yimin Liu ◽  
Xueyi Zhang ◽  
Yashan Wang ◽  
Zhou Chen ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Transition Zone ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Layer Transition ◽  
Infiltration Process ◽  
Local Factor ◽  
The Stability ◽  
Different Thickness

Abstract Although numerous studies have been paid much attention to rainfall-induced instability of multilayered slopes, the interface between layers is generally considered to be “zero thickness”, and the layer transition zone between layers is neglected. In this study, the influence of the layer transition zone on the rainfall-induced instability of multilayered slope was investigated. A model was developed to simulate the rainfall infiltration process, the distribution of pore water pressure, and the stability of multilayered slope by coupling the unsaturated seepage model and the slope stability analysis method. Based on the analysis of the multilayered slopes with the different thickness ratios of the layer transition zone, a method for determining the critical thickness of the layer transition zone was proposed. The results showed that the layer transition zone had a significant influence on the stability of multilayered slope. It was found that the presence of the layer transition zone in the multilayered slope reduced the hydraulic conductivity of the slope and increased the rate of formation of transient saturated zone, which contributed to excess pore water pressure at the toe of the slope. The analysis of the local factor of safety (LFS) showed that when the thickness ratios of the layer transition zone were between 2.5% and 5%, the corresponding hydraulic conductivity of the slope decreased by 1%-2.5% and the maximum failure area of the slope during the rainfall was 25% of the slope. Our study highlighted the importance of the layer transition zone for the rainfall-induced instability of the multilayered slope.

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.

Sign in / Sign up

Export Citation Format

Share Document