scholarly journals Strengthening the Rigidity of Landslide Materials Measured by Seismic Interferometry

2021 ◽  
Vol 13 (14) ◽  
pp. 2834
Author(s):  
Keng-Hao Kang ◽  
Wei-An Chao ◽  
Che-Ming Yang ◽  
Ming-Chien Chung ◽  
Yu-Ting Kuo ◽  
...  
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Recovery Process ◽  
Mechanistic Explanation ◽  
Seepage Water ◽  
Vertical Force ◽  
Water Tank ◽  
Rainy Period ◽  
Intense Precipitation ◽  
Stress Dependent

Landslides have caused extensive infrastructure damage and caused human fatalities for centuries. Intense precipitation and large earthquakes are considered to be two major landslide triggers, particularly in the case of catastrophic landslides. The most widely accepted mechanistic explanation for landslides is the effective-stress dependent shear strength reduction due to increases in pore water pressure. The Chashan landslide site, selected for the present study, has been intensively studied from geological, geophysical, geodetic, geotechnical, hydrological, and seismological perspectives. Our seismic monitoring of daily relative velocity changes (dv/v) indicated that landslide material decreases coincided with the first half of the rainy period and increased during the latter half of the rainy period. The geodetic surveys before and after the rainy period identified vertical subsidence without horizontal movement. The results from the multidisciplinary investigation enabled us to draw a conceptual model of the landslide recovery process induced by water loading. Where all sliding materials were stable (safety factor > 1.0), unconsolidated landslide colluvium and impermeable sliding surfaces trapped the seepage water to form a water tank, provided that compact forces were acting on the materials below the sliding boundary. The vertical force of compaction facilitates an increase in the cohesion and strength of landslide materials, thereby increasing the landslide materials’ stability. We demonstrated that the recovery process periodically occurs only under the combined conditions of prolonged and intense precipitation and the related stability conditions.

scholarly journals Numerical Analysis to Assess the Vertical Drainage Within Flexible Pavement.

2018 ◽  
Vol 7 (4.20) ◽  
pp. 95
Author(s):  
Aqeel Al-Adili ◽  
Rasha H. Abdul-Amir ◽  
Osamah Hassan Chfat
Keyword(s):  
Cross Section ◽  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Flux ◽  
Flexible Pavement ◽  
Laboratory Model ◽  
Typical Structure ◽  
Rainy Period ◽  
Vertical Drainage

In this research the work methodology include the software program SEEP/W routine of the GEOSLOPE 2012; which was used to simulate and analyze the vertical drainage of the pavement cross section using steady-state and transient analysis. A laboratory model consisting of typical structure layers of flexible pavement was considered in this research with a 2% slope with the influence of three different rain intensities (30mm/min, 60mm/min and 90mm/min); in which each one has a duration differs from the other. The results indicated that the value of the pore-water pressure in the surface layer resulting from 90 mm/min rainfall intensity is 83.65% greater than the pressure generated by the 60mm/min intensity of rain and 91.076% greater than the pressure produced from 30mm/min intensity. The average of accumulation water produced by the 30mm/min rainfall intensity in the pavement structure is 44.73 % greater than the average of accumulation of water from the 60mm/min intensity and 77.85% higher than the 90mm/min intensity of rain. The water flux through the pavement cross section during the rainy period of 30 mm/min was 8.42% higher than the water flux of 60 mm/min and 49.82% of the water flux of 90 mm/min intensity of rain.  

scholarly journals Seepage Force on a Buried Submarine Pipeline Induced by a Solitary Wave

2020 ◽  
Vol 8 (5) ◽  
pp. 324
Author(s):  
Meng-Yu Lin ◽  
Li-Jie Wang
Keyword(s):  
Solitary Wave ◽  
Young’S Modulus ◽  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Young's Modulus ◽  
Water Pressure ◽  
Vertical Force ◽  
Submarine Pipeline ◽  
Seepage Force ◽  
Poroelastic Seabed

In this study, a finite element method was used to establish a two-dimensional numerical model to solve the problem of the Biot equation describing the poroelastic seabed, and to analyze the seepage force on a buried submarine pipeline under the propagation of a solitary wave. The model provides a solution to the displacement of the poroelastic seabed and the variation of the pore-water pressure. By means of numerical simulation, the effects of Young’s modulus and permeability coefficient of the soil on the pore-water pressure and seepage force are discussed. In the simulation of solitary waves passing through fully buried submarine pipelines, numerical results indicate that the smaller the permeability coefficient in dense sandy bed the greater the vertical force acting on the pipeline, and the smaller the permeability coefficient in loose sand bed the smaller the vertical force acting on the pipeline. In general, when the permeability coefficient is large, the smaller the Young’s modulus the more obvious the influence of the vertical force on the pipeline, and when the permeability coefficient is small, the larger the Young’s modulus the more obvious the influence of the vertical force on the pipeline.

Numerical Analysis of Grouting and Blocking of Deep Large Section Shaft at Working Face

2012 ◽  
Vol 157-158 ◽  
pp. 865-869
Author(s):  
Ji Ming Zhu ◽  
Wen Quan Zhang ◽  
Hai Ling Yu ◽  
Xiang Lan Liu
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Channel ◽  
Seepage Flow ◽  
Water Inflow ◽  
Seepage Water ◽  
Large Section ◽  
Working Face ◽  
Water Block

To estimate the effect of deep large section Shaft Face Grouting for water block, the mathematical model is obtained according to the seepage theory. The numerical model for calculation is established by the program ABAQUS. The laws of change of pore water pressure, the effect area of dewatering, the velocity of seepage, water inflow of shaft working face before and after grouting is obtained by numerical simulation. It is shown that the grouting can effectively plug water channel of cracked surrounding rock, and prevent the pore water pressure lowering range to be larger. The working face seepage flow velocity was significantly reduced. The water inflow is decreased significantly. The safety of the shaft construction and the stability structure of shaft lining and upper strata are ensured by grouting. The numbers of grout stop and grouting construction can be largely reduced. The economic benefit is obvious. The scientific reference is provided for deep large section Shaft Face Grouting for water block.

Characteristics of nonlinear response of deep saturated soil deposits

1997 ◽  
Vol 87 (2) ◽  
pp. 342-355 ◽  
Author(s):  
Shean-Der Ni ◽  
Raj V. Siddharthan ◽  
John G. Anderson
Keyword(s):  
Resonant Frequency ◽  
Soil Properties ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Saturated Soil ◽  
Soil Conditions ◽  
Base Excitation ◽  
Soil Deposits ◽  
Stress Dependent

Abstract Recent EPRI seismic design guidelines call for dynamic soil properties (shear modulus ratio and damping) and liquefaction strength curves to be characterized as a function of the effective vertical stress (or depth). A modified version of the DESRA2 constitutive model for saturated soil has been applied to study the nonlinear seismic response including liquefaction of medium dense soil deposits of various thicknesses. The results of the stress-dependent soil properties model show lower deamplification and higher first-mode (resonant) frequency than that of the stress-independent soil properties model. By using the stress-dependent model with impulse base excitation, the nonlinear behavior of various soil deposits has been investigated under a variety of conditions. The results show that (1) the saturated soil deposit has a smaller surface amplitude and significantly lower resonant frequency than the unsaturated soil deposit of the same thickness; (2) for the saturated soil conditions, the larger the base excitation, the lower the surface amplification and the resonant frequency; (3) the deep soil deposits show lower surface amplification and resonant frequency compared to the response of shallow deposits; (4) when shallow and deep deposits are compared, the shallow deposits develop much higher residual pore-water pressure; and (5) the amplification and residual pore-water-pressure response of deposits deeper than 100 m or so are very similar. The application of the method has also been illustrated using a strong synthetic base excitation applied to the base at a site near Reno. The results in general are consistent with those computed using the impulse loading. The study reveals that the response predicted from the conventionally used stress-independent soil properties model is unconservative for deep deposit.

Groundwater Seepage Rule Simulation of Horse River Based on MIDAS/GTS

2012 ◽  
Vol 170-173 ◽  
pp. 3715-3719
Author(s):  
Bo Liu ◽  
Yong Tao Gao ◽  
Ai Bing Jin ◽  
Fu Gen Deng ◽  
Min Zhe Zhang
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Dynamic Change ◽  
Element Model ◽  
Seepage Water ◽  
Reinforcement Scheme ◽  
Groundwater Seepage ◽  
Water Head ◽  
Total Head ◽  
Seepage Law

In order to understand more clearly the law of groundwater seepage, recharge, excretion and dynamic change of groundwater level in the Horse River of Xishimen Iron Mine, it makes full use of MIDAS/GTS to build seepage model of settlement zone in Horse River, and by the analysis of changes of total head and the pore water pressure of the model ,we can study Horse River seepage law in the influence of mining , and track and survey the actual project. The results show that, the finite element model with the actual engineering seepage water head, pore pressure are compared, so as to provide the basis for the selection of Horse River seepage reinforcement scheme.

Study on tsunami-resistance of a reinforced soil wall based on water tank experiment

2020 ◽  
Author(s):  
Kentaro Kuribayashi ◽  
Tadashi Hara ◽  
Hemanta Hazarika ◽  
Shinichiro Tsuji ◽  
Shuichi Kuroda
Keyword(s):  
Water Level ◽  
Water Flow ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Tohoku Earthquake ◽  
Wave Force ◽  
Reinforced Soil ◽  
Water Tank ◽  
Reinforced Soil Wall ◽  
Backfill Soil

Abstract Background：The 2011 off the pacific coast of Tohoku earthquake (Mw=9.0) caused great damage of geotechnical structures in the vicinity of the eastern coasts. In contrast, many of reinforced soil walls constructed along the coast were less damaged by the tsunami. In this study, a model test using water tank is conducted to evaluate the behavior of a reinforced soil wall under strong water flow and water pressure like tsunami as an experimental prototype. The scale of model is 1/40, the height of wall is 25cm and the water level is 20cm, supposing that a tsunami hit the wall whose height is 10m in a full-scale without overflowing. Water flow hit the wall keeping its velocity and level. When the water penetrates into the backfill soil until ground water level is same as the level of water flow, the water was stopped and drained out of the tank.In this study, 2 test cases were conducted. One is a sound wall, and the other is a wall with some opening of the front panels which simulates the gap of the wall due to residual settlement after an earthquake.Results：The sound wall has no deformation during and after the tsunami action. In the wall with some opening, around 30 minutes after the start of the tsunami action, the wall panel showed gradual deviations such as slippage. In all cases, the pore water pressure in the backfill soil rises with seepage of the water, but the soil was not completely saturated.Conclusions：It was found that a reinforced soil wall does not have large deformation unless there are some opening of the front panels and the backfill soil flow out of the wall. This result shows that reinforced soil wall does not collapse by seepage to the backfill soil or wave force of tsunami, but collapses by backfill soil flowing out from wall surface. Our results support that a reinforced soil wall has high tsunami-resistance. Given this information, it is necessary to prevent the wall from making some opening and prevent the backfill soil from flowing out.

Research on the Deformation of Tunnel with the Influence of Seepage Water after Excavation

2014 ◽  
Vol 577 ◽  
pp. 1131-1134 ◽  
Author(s):  
Jian Jun Li ◽  
Fu Jiao Tang
Keyword(s):  
Numerical Simulation ◽  
Pore Pressure ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Surface ◽  
Simulation Software ◽  
Seepage Water ◽  
Software Modeling ◽  
Geological Exploration ◽  
Tunnel Excavation

This paper discusses a tunnel whose entrance region is the main engineering background. Based on tunnel geological exploration report, we make the model. By establishing model and using numerical simulation software SIGMA/W and COMSOL to simulate the distortion in seepage condition, we find as tunnel excavation goes on, the pore water pressure of tunnel changes and it leads to infiltration of water in the tunnel, and the deformation of soil increases. The ground surface may sink if the evacuation goes on without taking actions, which is not safe for the buildings around. In case of this situation, the pore pressure of the tunnel around should be controlled from decreasing too fast. The result from our model is just like the result by monitoring measurement. The result shows the feasibility of software modeling in the prediction of tunnel seepage situation.

scholarly journals Seismic Performance Evaluation of Agricultural Reservoir Embankment through Shaking Table Tests

2021 ◽  
Vol 21 (3) ◽  
pp. 151-161
Author(s):  
Younghak Lee ◽  
Junghyun Ryu ◽  
Bora Yoon ◽  
Joon Heo ◽  
Dalwon Lee
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Pressure Ratio ◽  
Horizontal Displacement ◽  
National Standards ◽  
Shaking Table ◽  
Seepage Water ◽  
Shaking Table Tests ◽  
Experimental Conditions

In this study, shaking table tests were performed to compare and analyze the acceleration response, displacement behavior, and pore-water pressure behavior of reservoirs with parapets installed to prevent overtopping of deteriorative homogeneous reservoirs. During the shaking table tests, the experimental conditions were divided into four cases considering the range and magnitude of seismic acceleration according to national standards. The vibration-type waveform (Gongen) and shock-type waveform (Minogawa) were applied as input waveforms. The acceleration amplification ratios of both vibration- and shock-wave types were the largest in the dam crest, and the amplification ratio decreased as the design earthquake acceleration increased. In addition, the horizontal displacement was maximum on the upstream slope, owing to the influence of seepage water, and the vertical displacement was maximum on the dam crest, owing to the self-weight effect of the parapet structure. A comparison of the waveform results indicates that the vibration-type waveform may exhibit a more significant effect on the embankment zone displacement than the shock-type waveform. However, when the safety standards for the horizontal displacement, settlement ratio, and excess pore-water pressure ratio were applied, the embankment was stable within the allowable range in both the shock-type and vibration-type waveforms. Therefore, the parapet structure is expected to influence the overflow resistance and stability of embankments positively.

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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