An estimation method of pore water pressure using soil water index in heavy rain and its application to early warning of sediment-related disasters in hilly and mountainous areas

2021 ◽  
Vol 58 (1) ◽  
pp. 28-39
Author(s):  
Mitsuru YABE ◽  
Shoji UENO ◽  
Masashi TANIGAWA ◽  
Yasunori KATSUME
2019 ◽  
Vol 17 (03) ◽  
pp. 1850135 ◽  
Author(s):  
Hao Wu ◽  
Jian Wang ◽  
Chun Wang ◽  
Jian Hua Wang

A fully coupled soil–water-structure interaction algorithm was presented in the framework of smoothed particle hydrodynamics (SPH). In this algorithm, soil–water interaction was simulated based on the two-phase mixture theory. Each phase of the mixture occupies part of the macroscopic mixture and satisfies its own conservation equations of mass and momentum. The Drucker–Prager model with nonassociated plastic flow rule was used to describe the constitutive behavior of soil. The water was treated as Newtonian fluid. Interaction between soil and water was modeled by the pore water pressure and the viscous drag force. The structure was considered as rigid and the interaction with soil/water was modeled by the frictional sliding contact algorithm. With this algorithm, it is possible to investigate pore water pressure, the effective stress and deformation of the soil undergoing large deformation. Moreover, the effect of the temporal and spatial evolution of soil porosity was taken into consideration. This study first examined the proposed algorithm for a U-tube seepage problem and a two-dimensional consolidation problem. Afterwards, the continuous deep penetrating process of the spudcan, which involved large soil deformation and complex soil–water-structure interaction, was simulated under axisymmetric conditions. The comparison with previous research indicates the robustness and applicability of the proposed algorithm. Furthermore, the proposed approach could be a potentially efficient tool helping to reveal the mechanism of soil failure in geotechnical, costal and ocean engineering.


1998 ◽  
Vol 35 (6) ◽  
pp. 926-937 ◽  
Author(s):  
Tai T Wong ◽  
Delwyn G Fredlund ◽  
John Krahn

This paper first describes the numerical implementation of the coupled formulation for the theory of consolidation of unsaturated soils. The developed computer code is verified using the Mandel-Cryer problem and then is applied to the solution of coupled multidimensional consolidation problems. Using a parametric study, it is demonstrated that, in unsaturated soils, the Mandel-Cryer effect is suppressed and the consolidation process in unsaturated soils is affected significantly by the shape of the soil-water characteristic curve. Finally, the developed model is used to analyze the consolidation of an unsaturated-saturated soil column. Analysis results indicate that the classical "undrained" pore-water pressure response to an externally applied load only occurs in the saturated zone while the pore-water pressure response is subdued in the unsaturated zone. This paper also shows a method of deriving one of the two additional material parameters required for the analysis of unsaturated soils from laboratory test results.Key words: coupled consolidation, unsaturated soils, Mandel-Cryer effect, soil-water characteristic curve.


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.


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