scholarly journals Evidence of creep in steep natural slopes of Champlain Sea clay

1977 ◽  
Vol 14 (4) ◽  
pp. 620-627 ◽  
Author(s):  
W. J. Eden
Keyword(s):  
Groundwater Table ◽  
Bridge Superstructure ◽  
The Stability ◽  
Clay Slopes ◽  
Natural Slopes

Three types of evidence of deep seated creep of steep natural slopes are considered: surface manifestations such as fissures and depressions; inclinometer measurements on three slopes in the Ottawa area; and movements of a bridge superstructure spanning a steep sided ravine.Results of measurements show that the movements are not continuous but occur in response to seasonal high levels of the groundwater table. The implications of the movements are discussed in relation to the stability of clay slopes.

scholarly journals Effect of Strength Anisotropy on the Stability of Natural Slopes

2021 ◽  
Vol 710 (1) ◽  
pp. 012025
Author(s):  
Magnus T Aamodt ◽  
Gustav Grimstad ◽  
Steinar Nordal
Keyword(s):  
Strength Anisotropy ◽  
The Stability ◽  
Natural Slopes

Analysis of the Stability of Some Norwegian Natural Clay Slopes

Géotechnique ◽  
1957 ◽  
Vol 7 (1) ◽  
pp. 1-16 ◽  
Author(s):  
L. Bjerrum ◽  
B. Kjaernsli
Keyword(s):  
Natural Clay ◽  
The Stability ◽  
Clay Slopes

Interpretation of the limits in shear strength in binary granular mixtures

2001 ◽  
Vol 38 (5) ◽  
pp. 1097-1104 ◽  
Author(s):  
Luis E Vallejo
Keyword(s):  
Shear Strength ◽  
Laboratory Tests ◽  
Relative Concentration ◽  
Frictional Resistance ◽  
Glass Beads ◽  
Rock Fragments ◽  
Structural Support ◽  
Granular Mixtures ◽  
The Stability ◽  
Natural Slopes

Many natural slopes and rockfill structures are made of a mixture of rock fragments and sand-size particles. To analyze the stability of such natural slopes and rockfills, a knowledge of how rock–sand mixtures develop their shear strength is needed. Laboratory tests conducted on mixtures of glass beads of two different sizes (5 and 0.4 mm) have indicated that their shear strength depends upon the relative concentration by weight of the large and small beads in the mixtures. If the concentration by weight of the large beads is greater than 70%, the shear strength of the mixtures is controlled by the frictional resistance of the large beads. If the concentration of the large beads is less than 40%, the shear strength of the mixtures is controlled by the frictional resistance of the small beads. If the concentration of the large beads is between 40 and 70%, the shear strength of the mixture is partially controlled by the frictional resistance provided by the large beads in the mixtures. These limits are very similar to those reported for rock–sand mixtures. To date, no explanation has been put forward to account for why these limits exist. This study presents an explanation for their existence. The explanation is based on the porosity developed by the mixtures and the type of structural support provided by the coarse and fine grains.Key words: shear strength, granular mixtures, porosity, fabric, compaction.

The Stability of Natural Slopes: Discussion

1945 ◽  
Vol 105 (5/6) ◽  
pp. 192
Author(s):  
Leonard Brooks ◽  
S. E. Hollingworth ◽  
W. D. Evans ◽  
Reginald Bee ◽  
H. L. Richardson ◽  
...  
Keyword(s):  
The Stability ◽  
Natural Slopes

scholarly journals Earthflows at the Beattie Mine Quebec, Canada

1964 ◽  
Vol 1 (2) ◽  
pp. 104-114 ◽  
Author(s):  
W J Eden
Keyword(s):  
Soil Conditions ◽  
Remedial Measures ◽  
Sequence Of Events ◽  
The Stability ◽  
Clay Slopes ◽  
Varved Clay

In June 1943 an earthflow involving more than one million cubic yards of varved clay occurred at the Beattie Mine. Subsequent remedial measures resulted in further large landslides. This paper describes the soil conditions, the sequence of events, and attempts to assess the stability of the clay slopes. It was found that the undrained analysis led to an unsafe assessment but that Terzaghi's rule for critical heights of slope gave a better indication of stability.

scholarly journals Theoretical Analysis and Experimental Study of Subgrade Moisture Variation and Underground Antidrainage Technique under Groundwater Fluctuations

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Liu Jie ◽  
Hailin Yao ◽  
Pan Chen ◽  
Zheng Lu ◽  
Xingwen Luo
Keyword(s):  
Groundwater Table ◽  
Richards Equation ◽  
Natural Factor ◽  
Capillary Action ◽  
Moisture Variation ◽  
Study Results ◽  
Water Tables ◽  
Groundwater Fluctuations ◽  
The Stability ◽  
Drainage Effect

Groundwater is a main natural factor impacting the subgrade structure, and it plays a significant role in the stability of the subgrade. In this paper, the analytical solution of the subgrade moisture variations considering groundwater fluctuations is derived based on Richards’ equation. Laboratory subgrade model is built, and three working cases are performed in the model to study the capillary action of groundwater at different water tables. Two types of antidrainage materials are employed in the subgrade model, and their anti-drainage effects are discussed. Moreover, numerical calculation is conducted on the basis of subgrade model, and the calculate results are compared with the experimental measurements. The study results are shown. The agreement between the numerical and the experimental results is good. Capillary action is obvious when the groundwater table is rising. As the groundwater table is falling, the moisture decreases in the position of the subgrade near the water table and has no variations in the subgrade where far above the table. The anti-drainage effect of the sand cushion is associated with its thickness and material properties. New waterproofing and drainage material can prevent groundwater entering the subgrade effectively, and its anti-drainage effect is good.

A Regional Study of Landsliding Near Ottawa

1971 ◽  
Vol 8 (2) ◽  
pp. 315-335 ◽  
Author(s):  
D. A. Sangrey ◽  
M. J. Paul
Keyword(s):  
Soil Characteristics ◽  
Aerial Photographs ◽  
Test Results ◽  
Regional Study ◽  
Field Situation ◽  
Flow Slides ◽  
The Stability ◽  
Clay Layers ◽  
Strength Relationship ◽  
Natural Slopes

The stability of natural slopes near Ottawa has been examined from a regional approach. With the aid of aerial photographs, the density and distribution of past landslides have been ascertained, and the development of more recent slides has been traced. This information, combined with details of the present day topography, groundwater conditions, and soil characteristics, leads to a conclusion that factors influencing slope stability vary markedly throughout the region, and certain areas are much more prone to sliding than others.The strength of soils in the region is discussed, including the development of a logical shear strength relationship which incorporates the effects both of cementation strength and fissuring. The influence of sample size on the extrapolation of laboratory triaxial test results to the field situation is introduced. Details of the method of landslide analysis used are given.Considerable evidence is presented to support the presence of separate marine and freshwater clay layers in the Ottawa area, and to suggest that flow slides are confined to the upper freshwater deposit. These two clay soils are most graphically distinguished by differences in fissure spacing and pore water chemistry.

scholarly journals Long-term Variation in the Stability of the Meromictic Lake Nordbytjernet Caused by Groundwater Fluctuations

1999 ◽  
Vol 30 (1) ◽  
pp. 21-38 ◽  
Author(s):  
Dag Hongve
Keyword(s):  
Stream Water ◽  
Solute Concentration ◽  
Groundwater Table ◽  
Depth Gradient ◽  
Deep Waters ◽  
Iron Sulphides ◽  
Major Variation ◽  
High Concentrations ◽  
Temporary Rise ◽  
The Stability

A zone with permanent anoxic conditions prevailed in the deep waters of Nordbytjernet before 1978 due to a significant depth gradient in dissolved substances. High concentrations of manganese and bicarbonate in the deep waters were most important for the lake's stability. The electrolyte concentrations in the mixed layer increased between 1978 and 1991, wiping out the depth gradient. A subsequent study showed a major variation in the solute concentration in the most important surface tributary that depends on fluctuations in the elevation of the groundwater table. A rising groundwater table seems to enhance oxidation of iron sulphides and dissolution of carbonates. Increasing solute concentrations in the mixed zone contributes to a weakening of the density gradient and reduced stability. Mineralised stream water may also intrude into the anoxic zone when the lake is not thermally stratified and cause precipitation of iron and manganese. Thus, a temporary rise of the groundwater table seems to be the reason why the lake changed from meromixis to holomixis. Lately the stream water concentrations have decreased and the lake has returned to meromixis. This periodic shift may be normal for this kind of lake.

scholarly journals Influence of Both Soil Properties and Geometric Parameters on Failure Mechanisms and Stability of Two-Layer Undrained Slopes

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Shuangfeng Guo ◽  
Ning Li ◽  
Wenpeng Liu ◽  
Zongyuan Ma ◽  
Naifei Liu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Failure Mechanism ◽  
Failure Mechanisms ◽  
Slope Angle ◽  
Strength Parameter ◽  
Strength Ratio ◽  
Stability Number ◽  
Parametric Studies ◽  
The Stability ◽  
Clay Slopes

The stability of the two-layer undrained clay slopes should be given considerable attention since they are commonly observed in nature and in manmade structures, and they traditionally have low stability. Therefore, with the elastoplastic finite element method, this paper thoroughly explores the influence of the soil strength parameter cu, slope angle β, and slope depth ratio DH on the slope stability and failure mechanisms by the wide-ranging parametric changes. The aims of this study are also to find the critical strength ratio (cu2/cu1)crit and the maximum values of the stability number Nc that were observed in the parametric studies. Numerical results are displayed in the form of charts to give Nc and (cu2/cu1)crit as a function of cu, β, and DH. Moreover, influences of DH and β on Nc and failure mechanisms are examined in this study. The results of numerical analysis demonstrate that cu2/cu1 significantly affects both the critical failure mechanism and the stability of the two-layer undrained slope. Improved knowledge of the location of the critical failure mechanism allows for accurately estimating the stability of the two-layer undrained slopes for future strengthening measurements to preserve stability.

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