A simple method to account for non-uniform initial excess pore water pressures in settlement computations

2014 ◽  
Vol 9 (1) ◽  
pp. 89-100
Author(s):  
Julie Lovisa ◽  
Nagaratnam Sivakugan
Keyword(s):  
Pore Water ◽  
Simple Method ◽  
Pore Water Pressures ◽  
Excess Pore

A new approach to the stability analysis of thawing slopes

1980 ◽  
Vol 17 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Luis E. Vallejo
Keyword(s):  
Stability Analysis ◽  
Water Content ◽  
Pore Water ◽  
Active Layer ◽  
Necessary Conditions ◽  
Mass Movements ◽  
New Approach ◽  
Pore Water Pressures ◽  
The Stability ◽  
Excess Pore

A new approach to the stability analysis of thawing slopes at shallow depths, taking into consideration their structure (this being a mixture of hard crumbs of soil and a fluid matrix), is presented. The new approach explains shallow mass movements such as skin flows and tongues of bimodal flows, which usually take place on very low slope inclinations independently of excess pore water pressures or increased water content in the active layer, which are necessary conditions in the methods available to date to explain these movements.

scholarly journals Experiment Study of Lateral Unloading Stress Path and Excess Pore Water Pressure on Creep Behavior of Soft Soil

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Huang ◽  
Kejun Wen ◽  
Dongsheng Li ◽  
Xiaojia Deng ◽  
Lin Li ◽  
...  
Keyword(s):  
Pore Water ◽  
Creep Behavior ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Stress Path ◽  
Deviatoric Stress ◽  
Excess Pore Water Pressure ◽  
Pore Water Pressures ◽  
Excess Pore

The unloading creep behavior of soft soil under lateral unloading stress path and excess pore water pressure is the core problem of time-dependent analysis of surrounding rock deformation under excavation of soft soil. The soft soil in Shenzhen, China, was selected in this study. The triaxial unloading creep tests of soft soil under different initial excess pore water pressures (0, 20, 40, and 60 kPa) were conducted with the K0 consolidation and lateral unloading stress paths. The results show that the unloading creep of soft soil was divided into three stages: attenuation creep, constant velocity creep, and accelerated creep. The duration of creep failure is approximately 5 to 30 mins. The unloading creep behavior of soft soil is significantly affected by the deviatoric stress and time. The nonlinearity of unloading creep of soft soil is gradually enhanced with the increase of the deviatoric stress and time. The initial excess pore water pressure has an obvious weakening effect on the unloading creep of soft soil. Under the same deviatoric stress, the unloading creep of soft soil is more significant with the increase of initial excess pore water pressure. Under undrained conditions, the excess pore water pressure generally decreases during the lateral unloading process and drops sharply at the moment of unloading creep damage. The pore water pressure coefficients during the unloading process were 0.73–1.16, 0.26–1.08, and 0.35–0.96, respectively, corresponding to the initial excess pore water pressures of 20, 40, and 60 kPa.

Cyclic loading of an Ottawa area Champlain Sea clay

1977 ◽  
Vol 14 (1) ◽  
pp. 52-63 ◽  
Author(s):  
R. J. Mitchell ◽  
R. Douglas King
Keyword(s):  
Shear Strength ◽  
Cyclic Loading ◽  
Pore Water ◽  
Soil Structure ◽  
Shear Failure ◽  
Large Deformations ◽  
Cemented Soil ◽  
Pore Water Pressures ◽  
Excess Pore ◽  
Static Shear

Undrained cyclic loading of triaxial samples of a sensitive Champlain Sea clay at deviatoric stress levels in excess of 50% of the static shear strength is shown to produce large deformations and eventual shear failure. Continued deformation of the clay under repeated loadings is believed to result from a progressive destruction of the cemented soil structure. Effective stress failures result from an increase in the excess pore water pressures within the sample.

Effect of drainage and sequential filling on the behavior of backfill in mine stopes

2014 ◽  
Vol 51 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Nawfal El Mkadmi ◽  
Michel Aubertin ◽  
Li Li
Keyword(s):  
Pore Water ◽  
Numerical Study ◽  
Water Drainage ◽  
Filling Rate ◽  
Mining Operations ◽  
Overburden Pressure ◽  
Filling Sequence ◽  
Pore Water Pressures ◽  
Backfilled Stopes ◽  
Excess Pore

Underground backfilling offers significant economic and environmental advantages to mining operations. There is however a limited knowledge and understanding of how the backfill behaves within mine stopes, which creates some concern regarding the risk of accidents with potentially serious consequences. It is thus important to investigate further the response of backfill to ensure safe working conditions and optimize the filling sequence. This paper presents key results from a numerical study aimed at analyzing the hydrogeotechnical response of backfill in a narrow vertical stope. The simulations illustrate how stresses are influenced by stope geometry, water drainage, and filling rate. Three main cases are presented here to illustrate these effects; namely, (i) simulation of dry (or drained) backfill, (ii) a rapidly filled stope with progressive drainage and consolidation, and (iii) sequential backfill placement with different filling rates. The third case includes a simulation with evolving properties due to the binder added to the backfill. The results from the numerical analyses show that arching effects develop within narrow backfilled stopes because of the stiffness contrast between the rock and the fill material. This can produce a significant reduction of the stresses (horizontal and vertical) in comparison with the overburden pressure. The simulation results also show the development of excess pore-water pressures after the placement of the saturated backfill within the stope. Drainage tends to reduce these pressures and increase the frictional stresses along the rock walls. The sequentially filled stope simulations show that a rapid filling rate produces much higher total stresses and excess pore-water pressures, compared to slower rates. The simulation of the cemented backfill, with evolving properties, indicates that the progressive changes can have a significant effect on the total and effective stresses in the stope. A discussion follows on the implications of these results.

Key Factors for the Dynamic-Static Drainage Consolidation Method

2011 ◽  
Vol 105-107 ◽  
pp. 827-831 ◽  
Author(s):  
Li Juan Zhang ◽  
Zhang Ming Li ◽  
K. Tim Law
Keyword(s):  
Field Experiment ◽  
Pore Water ◽  
Storage Site ◽  
Key Factors ◽  
Pore Water Pressures ◽  
Compaction Energy ◽  
Number Of Passes ◽  
Petroleum Storage ◽  
As Effects ◽  
Excess Pore

This paper discusses the key factors of the dynamic-static drainage consolidation method as it applies to a petroleum storage site that features very soft mud of strength as low as 8.5 kPa. A field experiment was conducted to study the key factors on the success of this method such as effects of the number of tampings and the number of passes. The excess pore water pressures, settlements, field vane strengths were measured. Analysis of the results of measurements at the site leads to the conclusions that this method gives excellent results for strengthening the very soft mud. In addition, for a given total compaction energy, better result is obtained by increasing the number of passes with corresponding decrease in the number of tamping in each pass and limiting the compaction energy at a point for each pass to less than 1000kN.m.

Sign in / Sign up

Export Citation Format

Share Document