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

Author(s):  
Riku Okajima ◽  
Yuki Ohki ◽  
Shinji Taenaka ◽  
Shunsuke Moriyasu ◽  
Takeji Deji ◽  
...  

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

2012 ◽  
Vol 157-158 ◽  
pp. 865-869
Author(s):  
Ji Ming Zhu ◽  
Wen Quan Zhang ◽  
Hai Ling Yu ◽  
Xiang Lan Liu

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.


2021 ◽  
Vol 337 ◽  
pp. 03017
Author(s):  
Tahyara Fontoura ◽  
Roberto Coutinho ◽  
Bruno Morais

Due to the increase in the number of mass movements on hillslopes during the rainy season in the city of Recife, the importance of analyzing and understanding the unsaturated behavior of the soil is verified. Therefore, this paper covers the stability analysis of an unsaturated soil belonging to the Barreiras Formation located at an important hillslope of Recife. This area has been affected by landslides in 2000, and about 100 families were left homeless after losing their homes. The slope is approximately 56 m high and 414 m long (lined up with Chagas Ferreira Avenue). The results of physical characterization and parameters from shear resistance of soil obtained in laboratory tests are presented. The modeling work was divided in two parts: (1) transient unsaturated seepage analysis; (2) stability analyses. To achieve this, computational solutions were implemented applying the SLOPE / W and SEEP / W programs, which analyzes the stability and flow of the slope. For analyzes, a rainfall of July / 2019 and pontual leaks was considered in the values of of 0.5, 1.0 and 1.5 m3/day. It was possible to observe that, as the intensity of the leaks increased, the pore water pressure values increased considerably at the deepest levels. The water table was also compatible with the increase in the intensity of water infiltration. In the slope stability analyzes conducted was observed that the increase in moisture content and the decrease in suction during intense precipitation periods combined with leak infiltration reflect in the decrease in the safety factor to values around 1.


1999 ◽  
Vol 36 (6) ◽  
pp. 1111-1122 ◽  
Author(s):  
R J Fannin ◽  
J Jaakkola

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.


2011 ◽  
Vol 1 (32) ◽  
pp. 54
Author(s):  
Taro Kakinuma ◽  
Shizuka Ohishi ◽  
Kazuo Nakamura

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.


2017 ◽  
Vol 73 (2) ◽  
pp. I_1111-I_1116
Author(s):  
Yuki OHKI ◽  
Mizuki KUSANO ◽  
Katsumi SEKI ◽  
Shinji TAENAKA ◽  
Shunsuke MORIYASU ◽  
...  

Author(s):  
Trần Thanh Nhàn

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.


1981 ◽  
Vol 27 (97) ◽  
pp. 503-505 ◽  
Author(s):  
Ian J. Smalley

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.


2018 ◽  
Vol 35 (2) ◽  
pp. 111
Author(s):  
Kun ZHANG ◽  
Ze ZHANG ◽  
Xiangyang SHI ◽  
Sihai LI ◽  
Donghui XIAO

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