scholarly journals Long- and short-term pore water pressure variations in sandy river dike interpreted with 1- and 2-phase seepage flow analysis

2019 ◽  
Vol 7 (2) ◽  
pp. 648-653 ◽  
Author(s):  
Sho Nishiie ◽  
Satoshi Nishimura ◽  
Nobutaka Yamazoe
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Flow Analysis ◽  
Seepage Flow ◽  
Short Term ◽  
River Dike

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.

scholarly journals In situ equilibrium pore-water pressures derived from partial piezoprobe dissipation tests in marine sediments

2013 ◽  
Vol 50 (12) ◽  
pp. 1294-1305 ◽  
Author(s):  
Nabil Sultan ◽  
Sara Lafuerza
Keyword(s):  
Slope Stability ◽  
Pore Pressure ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Design Parameters ◽  
Short Term ◽  
Pore Water Pressures ◽  
Time Required

Excess pore-water pressure has a significant effect on submarine slope stability and sediment deformation, and therefore its in situ equilibrium measurement is crucial in carrying out accurate slope stability assessments and accurately deriving geotechnical design parameters. In situ equilibrium pore-water pressure is usually obtained from pore pressure decay during piezocone tests. However, submarine shelves and slopes are often characterized by the existence of low-permeability (fine-grained) sediments involving long dissipation tests that are an important issue for offshore operational costs. Consequently, short-term and (or) partial dissipation tests are usually performed and in situ equilibrium pore-water pressures are predicted from partial measurements. Using a modified cavity expansion approach, this paper aims to predict for four different sites the in situ equilibrium pore-water pressures. Comparisons between predicted and observed in situ equilibrium pore-water pressures allowed the development of a guide to evaluate the minimum time required to perform short-term dissipation tests for a given marine sediment. The main finding of this Note is that the second derivative of the pore pressure, u, versus the logarithm of time, t, ∂2u/∂ln(t)2 must be positive to calculate accurately the in situ equilibrium pore-water pressures from partial measurements.

Hydrological response of hillslope soils above a debris-slide headscarp

1999 ◽  
Vol 36 (6) ◽  
pp. 1111-1122 ◽  
Author(s):  
R J Fannin ◽  
J Jaakkola
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Surface ◽  
Seepage Flow ◽  
Hydrological Response ◽  
Linear Distribution ◽  
Soil Matrix ◽  
Maximum Rainfall ◽  
Debris Slide

The Jamieson Creek debris slide initiated in thin soils over a competent bedrock surface, on a planar section of hillslope, during a heavy rainstorm in November 1990. An array of automated piezometers and tensiometers was placed along a 22 m wide section of the headscarp in 1997 to monitor the temporal variation of pore-water pressures. Interpretation of the data addresses the hydrologic response to the storms in October and November 1997. The piezometers, which were designed for installation by driving, reveal very localized responses in what otherwise appears to be a uniform soil matrix. Peak positive pressures occur at the time of maximum rainfall intensity. The tensiometers indicate the hydrological response at the ground surface appears uncoupled from that at the bedrock interface. Implications of the extreme spatial variability in pore-water pressure are evaluated for conceptual models of hillslope hydrology. The assumption of parallel seepage flow is widely adopted in translational slope stability analyses, imposing a linear distribution of pore-water pressure with depth. None of the reported field data are consistent with such a linear distribution with depth or a uniform response across the slope.

scholarly journals SEEPAGE FLOW IN A BREAKER ZONE

2011 ◽  
Vol 1 (32) ◽  
pp. 54
Author(s):  
Taro Kakinuma ◽  
Shizuka Ohishi ◽  
Kazuo Nakamura
Keyword(s):  
Pore Water ◽  
Incident Wave ◽  
Time Variation ◽  
Wave Breaking ◽  
Laboratory Experiments ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Maximum Velocity ◽  
Seepage Flow ◽  
Wave Period

Seepage velocities in several breaker zones were measured with dye for visualization. Pressure gauges were also installed to obtain pore water pressure. Three cases of different incident-wave periods were treated in laboratory experiments. The time-averaged pore water pressure was higher near the shoreline, resulting in the seepage flow, the maximum velocity of which was larger as the incident-wave period was longer, generally moving from onshore to offshore. The penetrated water flowed out from the permeable seabed at a bar top or on the rather offshore side of the bar top if a bar was developed remarkably. The pore water pressure in the breaker zone showed time variation depending on the wave phases including wave breaking and bore propagation. There was a phase when the pore water pressure was locally low below the bar.

scholarly journals VERIFICATION OF SEEPAGE FLOW CALCULATION BASED ON FLUID-GROUND WEAK COUPLING ANALYSIS MODEL

2018 ◽  
pp. 68
Author(s):  
Riku Okajima ◽  
Yuki Ohki ◽  
Shinji Taenaka ◽  
Shunsuke Moriyasu ◽  
Takeji Deji ◽  
...  
Keyword(s):  
Weak Coupling ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Flow Analysis ◽  
Seepage Flow ◽  
Coupling Method ◽  
Resistance Force ◽  
Analysis Model ◽  
Fluid Analysis ◽  
Fluid Resistance

In order to evaluate destruction of coastal structure caused by tsunami, it is essential to establish coupling method of fluid and ground. Arikawa et. Al.(2009) developed the model using weak coupling method of fluid analysis and ground analysis (named as CADMAS-STR). It is performed by mutual communication between pressure on fluid side and displacement on structure side. Based on boundary pressure from the fluid side, the ground side calculates seepage flow analysis using Biot's equation. On the other hand, the fluid side converts the ground region to porosity and calculates the resistance force to calculate seepage on the fluid side. In this study, based on Yoshioka's research, we applied Dupuit-Forchheimer's rule in CADMAS-STR's fluid resistance calculation, and verify its validity by comparing it with physical experiment. Furthermore, we compared pore water pressure

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.

The temperature and pore water pressure in soil subjected to dynamic load

2018 ◽  
Vol 35 (2) ◽  
pp. 111
Author(s):  
Kun ZHANG ◽  
Ze ZHANG ◽  
Xiangyang SHI ◽  
Sihai LI ◽  
Donghui XIAO
Keyword(s):  
Pore Water ◽  
Dynamic Load ◽  
Pore Water Pressure ◽  
Water Pressure
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