scholarly journals Effect Of Unsaturated Soil Properties On The Intensity-Duration Threshold For Rainfall Triggered Landslides

Teknik Dergi ◽  
2019 ◽  
Author(s):  
Nabi Kartal Toker ◽  
Melih Birhan Kenanoğlu ◽  
Mohammad Ahmadi-adli ◽  
Nejan Huvaj
Author(s):  
Shaoyang Dong ◽  
Yuan Guo ◽  
Xiong (Bill) Yu

Hydraulic conductivity and soil-water retention are two critical soil properties describing the fluid flow in unsaturated soils. Existing experimental procedures tend to be time consuming and labor intensive. This paper describes a heuristic approach that combines a limited number of experimental measurements with a computational model with random finite element to significantly accelerate the process. A microstructure-based model is established to describe unsaturated soils with distribution of phases based on their respective volumetric contents. The model is converted into a finite element model, in which the intrinsic hydraulic properties of each phase (soil particle, water, and air) are applied based on the microscopic structures. The bulk hydraulic properties are then determined based on discharge rate using Darcy’s law. The intrinsic permeability of each phase of soil is first calibrated from soil measured under dry and saturated conditions, which is then used to predict the hydraulic conductivities at different extents of saturation. The results match the experimental data closely. Mualem’s equation is applied to fit the pore size parameter based on the hydraulic conductivity. From these, the soil-water characteristic curve is predicted from van Genuchten’s equation. The simulation results are compared with the experimental results from documented studies, and excellent agreements were observed. Overall, this study provides a new modeling-based approach to predict the hydraulic conductivity function and soil-water characteristic curve of unsaturated soils based on measurement at complete dry or completely saturated conditions. An efficient way to measure these critical unsaturated soil properties will be of benefit in introducing unsaturated soil mechanics into engineering practice.


Author(s):  
Brena Li En Tan ◽  
Alfrendo Satyanaga ◽  
Mărgărit-Mircea Nistor ◽  
Martin Wijaya ◽  
Harianto Rahardjo

1992 ◽  
Vol 29 (2) ◽  
pp. 195-207 ◽  
Author(s):  
D. Y. F. Ho ◽  
D. G. Fredlund ◽  
H. Rahardjo

The paper presents the volume change theory and the designation of associated soil properties that must be measured for an unsaturated soil. The equipment required for the measurement of each of the relevant volume relationships is described. Several testing procedures for obtaining the volume change indices during loading and unloading of an unsaturated soil are presented. Typical results from loading and unloading tests on compacted silt and compacted glacial till specimens are presented and analyzed. The analysis is given in order to illustrate the application of the volume change theory to practical problems. Key words : unsaturated soil, volume change indices, constitutive relations, coefficients of volume change, oedometer tests.


2003 ◽  
Vol 2003 (1) ◽  
pp. 1304-1327
Author(s):  
R. B. Valceschini ◽  
S. A. Morrow

2016 ◽  
Vol 200 ◽  
pp. 114-121 ◽  
Author(s):  
Anand J. Puppala ◽  
Aravind Pedarla ◽  
Laureano R. Hoyos ◽  
Claudia Zapata ◽  
Tejo V. Bheemasetti

2018 ◽  
Vol 162 ◽  
pp. 01014
Author(s):  
Abdul-Kareem Esmat Zainal ◽  
Shaimaa Hasan Fadhil

Soil-Water Characteristic Curve (SWCC) is an important relationship between matric suction and volumetric water content of soils especially when dealing with unsaturated soil problems, these problems may include seepage, bearing capacity, volume change, etc. where the matric or total suction may have a considerable effect on unsaturated soil properties. Obtaining an accurate SWCC for a soil could be cumbersome and sometimes it is time consuming and needs effort for some soils, either through laboratory tests or through field tests. Accurate prediction of this curve can give more precise expectations in design or analysis that include some unsaturated soil properties, which can save more effort and time. This work will concentrate on proposing a new approach for determining the SWCC using Artificial Neural Network (ANN) depending on some soil properties (air-entry point and residual degree of saturation) through computer software MatLab as a tool for ANN. The new approach is to plot the SWCC curve points instead of obtaining the parameters used in Brooks and Corey (BC) Model (1964), van Genuchten (VG) Model (1980), or Fredlund and Xing (FX) Model (1994). Results showed close agreement in determination of the SWCC by verification of the ANN results with an additional curve sample.


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