Pore-pressure response beneath a ring foundation on clay

1979 ◽  
Vol 16 (3) ◽  
pp. 551-566 ◽  
Author(s):  
K. Y. Lo ◽  
D. E. Becker
Keyword(s):  
Pore Pressure ◽  
Load Transfer ◽  
Earth Pressure ◽  
Pressure Response ◽  
Excess Pore Pressure ◽  
Coefficient Of Consolidation ◽  
Continuous Sampling ◽  
Total Settlement ◽  
Rate Of Dissipation ◽  
Pore Pressure Response

A 9 m diameter and 22 m high concrete silo with a ring footing was instrumented and its performance monitored. The instrumentation included 12 pressure cells, 7 piezometers, 9 settlement cells, and 12 settlement pins. Continuous sampling and vane testing, together with field determination of permeability and coefficient of earth pressure at rest, were also carried out.The subsoil conditions at the site consist of a 3 m crust overlying an 18 m thick soft to firm, slightly overconsolidated clay stratum, which is underlain by bedrock.This paper presents the results of field observation in general, with particular emphasis on the pore-pressure response. It was found that, in spite of the relatively low factor of safety against bearing capacity failure and the considerable load transfer, the maximum measured excess pore pressure amounts to only 40% of the measured applied stress at the silage–soil interface. Important dissipation of pore pressure during loading occurred. The postfilling rate of dissipation of pore pressure was also rapid, due to the high field value of the coefficient of consolidation. Consistently, the total settlement observed up to date was also small.An analysis of the results is carried out for the interpretation of the favourable performance. The implication to the design of similar foundations is also discussed.

scholarly journals Contribution of Pumping Action of Wave-Induced Pore-Pressure Response to Development of Fluid Mud Layer

2019 ◽  
Vol 7 (9) ◽  
pp. 317 ◽  
Author(s):  
Yang ◽  
Zhu ◽  
Liu ◽  
Sun ◽  
Ling ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Fine Particles ◽  
Pore Water Pressure ◽  
Theoretical Calculations ◽  
Water Pressure ◽  
Pressure Response ◽  
Excess Pore Pressure ◽  
Pore Pressure Response ◽  
Wave Induced ◽  
Excess Pore

To investigate the vertical migration response of fine sediments, the pore pressure response of the silty seabed under the action of waves was tested. Under the action of waves, there is an obvious pumping phenomenon in the sludge accumulated by pore pressure. The excess pore water pressure caused by the waves in the seabed is unevenly distributed with respect to depth and there is an extreme value of up to 1.19 kPa. The pressure affects the liquefaction properties of the sludge. According to instantaneous-liquefaction judgment, the liquefaction of surface soil occurs, but the soil is not completely liquefied. Using theoretical calculations, the vertical source supply of floating mud development was analyzed. The pumping effect of the wave-induced excess pore pressure manifests in two aspects, as follows: (1) The centralized migration of splitting channels, which is visible to the naked eye, and (2) the general migration of fine particles between particle gaps at the mesoscopic level, which accounts for up to 22.2% of the migration of fine particles.

Prediction of impending failure of embankments on soft ground

2003 ◽  
Vol 40 (1) ◽  
pp. 209-220 ◽  
Author(s):  
Gavan Hunter ◽  
Robin Fell
Keyword(s):  
Pore Pressure ◽  
Factor Of Safety ◽  
Ground Deformation ◽  
Lateral Displacement ◽  
Deformation Behaviour ◽  
Vertical Displacement ◽  
Pressure Response ◽  
Excess Pore Pressure ◽  
Soft Ground ◽  
Pore Pressure Response

The deformation behaviour and excess pore pressure response of 13 well-monitored embankments on soft ground that were constructed to failure have been analyzed. The analysis shows that by monitoring lateral displacement at the toe of the embankment and vertical displacement at the toe and about 5 m beyond the toe, the onset of impending failure of embankments on soft ground can be detected while the slope is at about 70–90% of the failure height. This equates to an actual factor of safety of around 1.25. Monitoring of borehole inclinometers at the toe of the embankment, cracking of the embankment, and the pore pressure response and deformation during pauses in construction can provide useful additional data for detection of an impending failure.Key words: embankment on soft ground, deformation, pore pressure, failure, factor of safety.

Interpreting pore-water pressure changes induced by water table fluctuations and mechanical loading due to soil moisture changes

2012 ◽  
Vol 49 (3) ◽  
pp. 357-366 ◽  
Author(s):  
Collins Ifeanyichukwu Anochikwa ◽  
Garth van der Kamp ◽  
S. Lee Barbour
Keyword(s):  
Soil Moisture ◽  
Pore Pressure ◽  
Mechanical Loading ◽  
Water Table ◽  
Pressure Response ◽  
Stress Strain ◽  
Near Surface ◽  
Water Table Fluctuations ◽  
Pore Pressure Response ◽  
Pressure Changes

Pore pressures within saturated subsurface formations respond to stress changes due to loading as well as to changes in pore pressure at the boundaries of the formation. The pore-pressure dynamics within a thick aquitard in response to water table fluctuations and mechanical loading due to soil moisture changes have been simulated using a coupled stress–strain and groundwater flow finite element formulation. This modelling approach isolates the component of pore-pressure response of soil moisture loading from that caused by water table fluctuations, by using a method of superposition. In this manner, the contributions to pore-pressure fluctuations that occur as a result of surface moisture loading (e.g., precipitation, evapotranspiration) can be isolated from the pore-pressure record. The required elastic stress–strain properties of the aquitard were obtained from the measured pore-pressure response to barometric pressure changes. Subsequently, the numerical simulations could be calibrated to the measured response by adjusting only the hydraulic conductivity. This paper highlights the significance of moisture loading effects in pore-pressure observations and describes an efficient technique for obtaining in situ stress–strain and hydraulic properties of near-surface aquitards.

Pore pressure response of seabed in standing waves and its mechanism

2014 ◽  
Vol 91 ◽  
pp. 213-219 ◽  
Author(s):  
Hu Wang ◽  
Hong-jun Liu ◽  
Min-sheng Zhang
Keyword(s):  
Pore Pressure ◽  
Standing Waves ◽  
Pressure Response ◽  
Pore Pressure Response
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