Breakout of submerged structures buried to a shallow depth

1978 ◽  
Vol 15 (2) ◽  
pp. 146-154 ◽  
Author(s):  
Peter M. Byrne ◽  
W. D. Liam Finn
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Ocean Floor ◽  
Shallow Depth ◽  
Testing Program ◽  
Uplift Pressure ◽  
Undrained Conditions

The results from a testing program designed to simulate the problem of lifting an object embedded in the ocean floor are presented and examined herein. The breakout force, defined as the force in excess of the submerged weight required to dislodge the object, was found to depend on the shear strength of the soil or sediment. The maximum breakout force occurs for undrained conditions and can be estimated from bearing capacity equations.The uplift pressure is transferred to the sediments by a reduction in pore-water pressure. If the reduction in pressure is limited by infiltration of water, or any other process, then a reduction in the breakout pressure will result.The reduction in breakout pressure that occurs when time for infiltration is allowed can be estimated from available solution curves from theory of consolidation.

Shear strength of a compacted residual soil from consolidated drained and constant water content triaxial tests

2004 ◽  
Vol 41 (3) ◽  
pp. 421-436 ◽  
Author(s):  
Harianto Rahardjo ◽  
Ong Boo Heng ◽  
Leong Eng Choon
Keyword(s):  
Shear Strength ◽  
Water Content ◽  
Pore Water ◽  
Volume Change ◽  
Triaxial Test ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Triaxial Tests ◽  
Residual Soil ◽  
Undrained Conditions

Rainfall-induced landslides in unsaturated residual soils can occur slowly under drained conditions or rapidly under undrained conditions. Consolidated drained (CD) and constant water content (CW) tests have been performed to simulate the stress paths followed by soil elements in a slope that fails under drained and undrained conditions. The study was carried out to investigate the shear strength characteristics of soils associated with rainfall-induced slope failures. The soil tested was residual soil from the Jurong sedimentary formation and was reconstituted using static compaction. The test results indicate that the shear strength of the compacted specimens obtained from the CW tests agrees well with the shear strength obtained from the CD tests for the specimens with initial matric suctions less than their air-entry values. The shear strength results from the CD and CW triaxial tests start to differ when the matric suction exceeds the air-entry value of the soil. The CD and CW triaxial tests also indicate that the compacted specimens behave as a normally consolidated soil at matric suctions below the air-entry value of the soil and as an overconsolidated soil at matric suctions above the air-entry value of the soil. Results of the CW triaxial tests show that the relationship between the response of pore-water pressure and the total volume change of the specimen is more complicated than that found in the saturated undrained triaxial tests. In other words, the change in pore-water pressure during shearing is not directly related to the overall volume change of the specimen.Key words: unsaturated soil, compacted soil, residual soil, consolidated drained triaxial test, constant water content triaxial test.

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.

scholarly journals 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.

EXPERIMENT STUDY ON DYNAMIC STRENGTH OF LOESS UNDER REPEATED LOAD

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5825-5830 ◽  
Author(s):  
ZHENGHUA XIAO ◽  
BO HAN ◽  
HONGJIAN LIAO ◽  
AKENJIANG TUOHUTI
Keyword(s):  
Shear Strength ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Axial Strain ◽  
Water Pressure ◽  
Dynamic Strength ◽  
Triaxial Tests ◽  
Dynamic Shear ◽  
Anisotropic Consolidation ◽  
Dynamic Shear Strength

A series of dynamic triaxial tests are performed on normal anisotropic consolidation and over anisotropic consolidation specimens of loess. Based on the test results, the variable regularity of dynamic shear stress, axial strain and pore water pressure of loess under dynamic loading are measured and analyzed. The influences of the dynamic shear strength and pore water pressure at different over consolidation ratio are analyzed. The relationship between dynamic shear strength and over consolidation ratio of loess is obtained. The evaluating standard of dynamic shear strength of loess is discussed. Meanwhile, how to determine the effective dynamic shear strength index of normal anisotropic consolidated loess is also discussed in this paper. Several obtained conclusions can be referenced for studying the dynamic shear strength of loess foundation.

scholarly journals Evaluation of direct shear strength of compacted bentonite having pore-water pressure

2020 ◽  
Vol 195 ◽  
pp. 02028
Author(s):  
Tomoyoshi Nishimura ◽  
Masaaki Fukaya
Keyword(s):  
Shear Strength ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Simulation Models ◽  
Radioactive Waste Disposal ◽  
Direct Shear ◽  
Compacted Bentonite ◽  
Barrier Formation ◽  
Behaviour Simulation

Safety of great deep repository design has been investigated for high-level radioactive waste disposal system in several countries such as Belgium, Canada, China, France, Germany, Japan, Sweden and Switzerland. The repository of the disposal is in most cases based on the concept of a multi-barrier system using the host rock barrier formation and a man-made barrier formation. The man-made barrier consists of high expansive bentonite. Thermal-hydro-mechanical behaviour simulation models were developed, including some parameters described by experimental works. The complex phenomena due to the transition into saturation and chemical reactions at the bentonite barrier system have been explained. This study focused on direct shear strength for compacted bentonite related to some factors induced by uncertainty problems such as hydration effect and pore-water pressure. Measured shear strength properties of compacted bentonite had been determined at high suction values. Also, it is clear that there is some influence of direct shear speed on direct shear strength both under unsaturated-saturated conditions. A modified direct shear apparatus was used in this study to observe changes in shear strength with increments of pore-water pressures.

Time Effect of the Pile Bearing Capacity in Dredger Fill

2013 ◽  
Vol 639-640 ◽  
pp. 630-638
Author(s):  
Hua Yang Lei ◽  
Qian Qian Lv
Keyword(s):  
Numerical Simulation ◽  
Bearing Capacity ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Ultimate Bearing Capacity ◽  
Time Effect ◽  
Second Phase ◽  
Excess Pore Water Pressure ◽  
Excess Pore

The dissipating of pore water pressure caused by pile sinking is one of the main factors resulting in time effect of ultimate bearing capacity of pile.The pore water pressure is monitored at each observing point during pile sinking and after that. With the pore pressure plan embedded in advance, by means of spot test in the process of pile sinking, under this geological conditions of the pile foundation by referring to the second phase project of the free port logistics processing zone in Dongjiang, Tianjin.The change law of the distribution and dissipation of excess pore water pressure with time, depth, radial distance and permeability coefficient of soil was also discussed. It’s found that the excess pore water pressure attenuates approximately linearly with the increase of the distance from the pile heart and the scope influenced is around 10d. As the numerical simulation accord with the test results effectively, promote the results then get the change rule of pile bearing capacity with time.The formula of pile bearing capacity about time effect in dredge fill was deduced for engineering reference.The effect of soil internal friction angle on the ultimate bearing capacity of pile was discussed. Numerical simulation shows that the ultimate bearing capacity of pipe pile increases over time and keeps stable after 20d.The ultimate limit bearing capacity is 1473kN with increase of 12.3%, the time when it reaches the stable state is in accord with the excess pore water pressure dissipation monitored at each observing point. The larger the internal frictional angle of soil becomes, the more the ultimate bearing capacity is. The angle exceeding 20°,the bearing capacity would not increase as internal frictional angle of soil increases.

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