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.

scholarly journals Theoretical Equations for the Ratio of Undrained Shear Strength to Vertical Effective Stress for Normally Consolidated Saturated Cohesive Soils

2022 ◽  
Vol 28 (3) ◽  
pp. 241-252
Author(s):  
Sugeng Krisnanto
Keyword(s):  
Shear Strength ◽  
Pore Water ◽  
Effective Stress ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Undrained Shear Strength ◽  
Engineering Practice ◽  
Cohesive Soils ◽  
Vertical Effective Stress ◽  
Undrained Shear

Abstract Two theoretical equations are developed to calculate the ratio of undrained shear strength to the vertical effective stress (the ratio of (su/sv’)) for normally consolidated saturated cohesive soils. The effective stress approach is used as the basis in the development of the theoretical equations. The theoretical equations are developed by relating the total and the effective stress paths. The development of the excess pore-water pressure is quantified using Skempton A and B pore-water pressure parameters. The theoretical equations are developed for two initial stress conditions: (i) an initially hydrostatic condition and (ii) an initially Ko (non-hydrostatic) condition. The performance of the theoretical equations of this study is compared with field and laboratory measurement data obtained from the literature. The close results between the theoretical equations and the measurements show that the theoretical equations of this study can compute the ratio of (su/sv’) well. Using the theoretical equations, the values of the ratio of (su/sv’) commonly used in engineering practice can be explained from the soil mechanics framework. Keywords: Saturated cohesive soils, c/p ratio, normally consolidated soil, undrained shear strength, effective shear strength, theoretical equation. Abstrak Dua persamaan teoritis dikembangkan untuk menghitung rasio kuat geser tak teralirkan dengan tegangan efektif vertikal (rasio (su/sv’)) untuk tanah kohesif jenuh terkonsolidasi normal. Pendekatan tegangan efektif dijadikan dasar dalam pengembangan kedua persamaan teoretis ini. Persamaan teoretis tersebut dikembangkan menghubungkan lintasan tegangan total dan lintasan tegangan efektif. Kenaikan tekanan air pori ekses dikuantifikasi menggunakan parameter tekanan air pori A dan B dari Skempton. Persamaan teoretis dikembangkan untuk dua kondisi tegangan awal: (i) tegangan awal hidrostatik dan (ii) teganan awal Ko (non hidrostatik). Kinerja kedua persamaan teoretis tersebut dibandingkan terhadap data pengukuran lapangan dan pengujian laboratorium yang diperoleh dari literatur. Persamaan teoretis dari studi ini memiliki kinerja yang baik dalam memperhitungan rasio (su/sv’) yang ditunjukkan dengan dekatnya hasil perhitungan menggunakan persamaan teoretis dan hasil pengukuran lapangan maupun pengujan laboratorium. Dengan persamaan teoretis tersebut, nilai rasio (su/sv’) yang biasa digunakan dalam rekayasa praktis bisa dijelaskan secara mekanika tanah. Kata-kata Kunci: Tanah kohesif jenuh, rasio c/p, tanah terkonsolidasi normal, kuat geser tak teralirkan, kuat geser efektif, persamaan teoretis.  

scholarly journals Investigation on the Failure Mechanism of Rainfall-Induced Long-Runout Landslide at Upputhode, Kerala State of India

Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1212
Author(s):  
Rajkumar Andrewwinner ◽  
Sembulichampalayam Sennimalai Chandrasekaran
Keyword(s):  
Shear Strength ◽  
Failure Mechanism ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Pressure Ratio ◽  
Simulation Software ◽  
Engineering Properties ◽  
Antecedent Rainfall ◽  
Landslide Mass

The main objective of the study is to estimate the shear resistance mobilized on the slope surface under large deformation and to identify the failure mechanism of the landslide through the simulation model. The field investigations were carried out using Geophysical tests, and the laboratory tests were conducted to identify the engineering properties of the soil with weathering characteristics of the parent rock. The residual shear strength parameters from Torsional ring shear tests were used in LS-RAPID numerical simulation software to study the mechanism of the landslide. The critical pore water pressure ratio (ru = 0.32) required for the initiation of a landslide was obtained. The increase in pore water pressure reduces the soil matric suction and thereby results in the reduction of the shear strength of the soil. The progressive failure mechanism and the three landslide processes (initiation, run out and deposition) are investigated. The velocity of the moving landslide mass in the role of demolishing the building is studied and helps in finding suitable remedial measures for the nearby building. The empirical rainfall threshold based on the antecedent rainfall was developed and revealed that either a high daily rainfall intensity of 142 mm without any antecedent rainfall, or an antecedent rainfall of 151 mm for a cumulative period of 5 days with even continuous normal rainfall can initiate landslide.

Effectiveness of Capillary Barrier and Vegetative Slope Covers in Maintaining Soil Suction

2016 ◽  
pp. 51-69
Author(s):  
Harianto Rahardjo ◽  
S. Krisnanto ◽  
E.C. Leong
Keyword(s):  
Shear Strength ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Matric Suction ◽  
Numerical Analyses ◽  
Soil Suction ◽  
Vetiver Grass ◽  
Capillary Barrier ◽  
Maximum Rainfall

Capillary barrier and vegetative slope covers can be used to improve slope stability during rainfall by maintaining matric suction in the slope. A study was performed to investigate the effectiveness of capillary barrier system (CBS) and vegetative slope covers (Orange Jasmine and Vetiver grass) in maintaining soil suction. Performance of slopes with and without slope covers was investigated using field instrumentations and numerical analyses. Laboratory tests were performed to measure hydraulic and shear strength properties of the soil, the soils with Orange Jasmine and Vetiver grass root, and CBS materials. Numerical analyses were performed to investigate the variation of pore-water pressure profiles at a selected location and factor of safety during low, high, and maximum rainfall intensities. Pore-water pressures measured in the field were used to calibrate the numerical models. Laboratory test results showed that the presence of root increased the shear strength of soil. Numerical analyses and field monitoring results showed that the slope with covers can maintain negative pore-water pressure better than the original slope. Performance of Orange Jasmine, Vetiver grass, and CBS in maintaining matric suction in the slope is essentially similar during low, high, and maximum rainfall intensities.

Sign in / Sign up

Export Citation Format

Share Document