Strength and deformation characteristics of clay subjected to pore water pressure increment

2021 ◽  
pp. 721-726
Author(s):  
T. Umezaki ◽  
M. Suzuki ◽  
T. Yamamoto
2020 ◽  
Vol 24 (2) ◽  
pp. 183-190
Author(s):  
Bin Liu ◽  
Xiugen Jiang

The widespread distribution of soft rock and soft soil in hydrological wetland environment is a common geotechnical engineering problem encountered in coastal engineering construction. To solve this problem, a study method for consolidation and deformation characteristics of soft rock and soft soil foundation in hydrological wetland environment is proposed. Taking K9+280-K11+120 section along Fu-Nehe section of National Highway 111 as the research object, the consolidation and deformation characteristics and loading conditions of soft soil foundation under embankment filling load, treatment methods of soft rock foundation, stratum conditions, temperature changes and time effects are analyzed. The results show that although the wetland soft rock and soil layer is not thick, the settlement of soft rock and soil accounts for more than 80% of the total settlement. Negative temperature has a certain influence on the consolidation settlement of soft rock foundation, which is mainly manifested in the difference between the settlement process of the central separation zone and the roadbed soft soil foundation; the pore water pressure of soft rock foundation dissipates to varying degrees. According to the monitoring results of settlement and pore water pressure, bagged sand wells are more suitable for soft rock foundation engineering treatment in hydrological wetland. The research results can provide a reference for the study, calculation and design of consolidation and deformation of soft rock foundation in hydrological wetland.


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

2016 ◽  
Vol 24 (7) ◽  
pp. 1821-1833 ◽  
Author(s):  
Nuraddeen Muhammad Babangida ◽  
Muhammad Raza Ul Mustafa ◽  
Khamaruzaman Wan Yusuf ◽  
Mohamed Hasnain Isa

Author(s):  
B. M. Minchew ◽  
C. R. Meyer

Glacier surges are quasi-periodic episodes of rapid ice flow that arise from increases in slip rate at the ice–bed interface. The mechanisms that trigger and sustain surges are not well understood. Here, we develop a new model of incipient surge motion for glaciers underlain by sediments to explore how surges may arise from slip instabilities within a thin layer of saturated, deforming subglacial till. Our model represents the evolution of internal friction, porosity and pore water pressure within the till as functions of the rate and history of shear deformation, and couples the till mechanics to a simple ice-flow model. Changes in pore water pressure govern incipient surge motion, with less permeable till facilitating surging because dilation-driven reductions in pore water pressure slow the rate at which till tends towards a new steady state, thereby allowing time for the glacier to thin dynamically. The reduction of overburden (and thus effective) pressure at the bed caused by dynamic thinning of the glacier sustains surge acceleration in our model. The need for changes in both the hydromechanical properties of the till and the thickness of the glacier creates restrictive conditions for surge motion that are consistent with the rarity of surge-type glaciers and their geographical clustering.


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