A5030130872- Soil and Unsaturated Flow
- Landslides and related hazards
- Geotechnical Engineering and Soil Mechanics
- Dam Engineering and Safety
- Groundwater flow and contamination studies
- Geotechnical Engineering and Soil Stabilization
- Geotechnical Engineering and Analysis
- Soil Moisture and Remote Sensing
- Tree Root and Stability Studies
- Geotechnical and construction materials studies
- Geotechnical Engineering and Underground Structures
- Landfill Environmental Impact Studies
- Grouting, Rheology, and Soil Mechanics
- Geotechnical and Geomechanical Engineering
- Climate change and permafrost
- Soil erosion and sediment transport
- Seedling growth and survival studies
- Advanced Fiber Optic Sensors
- Soil, Finite Element Methods
- Forest ecology and management
- Soil Mechanics and Vehicle Dynamics
- Plant Water Relations and Carbon Dynamics
- Soil Geostatistics and Mapping
- Geophysical and Geoelectrical Methods
- Hydraulic Fracturing and Reservoir Analysis
Nanyang Technological University
2016-2025
National Parks Board
2019
Housing and Development Board
2010-2018
Water Research Institute
2017
Universitat Politècnica de Catalunya
2012
Parsons Brinckerhoff
2011
China Academy of Building Research
2011
Amec Foster Wheeler (United States)
2009-2010
Universiti Teknologi Petronas
2007
Thuyloi University
2006
Practical applications of unsaturated soil mechanics still lag behind the state-of-the-art knowledge. The main stumbling block is time-consuming processes involved in measurement parameters required for constitutive models. Recent research has shown that soil-water characteristic curves a can be used establishment number parameters. In many it become obvious satisfactory equation describing curve will simplify determination Over years equations have been suggested. Most these limited success...
Rainfall-induced slope failure is a common geotechnical problem in the tropics where residual soils are abundant. Although significance of rainwater infiltration causing landslides widely recognized, there have been different conclusions as to relative roles antecedent rainfall landslides. The importance soil properties, intensity, initial water table location and geometry inducing instability homogenous under was investigated through series parametric studies. Soil properties intensity were...
The effectiveness of using vegetation to reinforce slopes is influenced by the soil and characteristics. Hence, this study pioneers construction an extensive database random forest machine learning ordinary kriging methods, focusing on influence plant roots saturated unsaturated properties residual soils. Soil organic content, which includes contributions from both organisms roots, functions as a key factor in estimating hydraulic mechanical roots. This innovative approach content estimate...
Multistage direct shear tests have been performed on saturated and unsaturated specimens of a compacted glacial till. A conventional apparatus was modified in order to use the axis-translation technique for soils. The soil can be subjected wide range matric suctions. testing procedure some typical results are presented. Nonlinearity failure envelope with respect suction observed. Suggestions made as how best handle nonlinearity from practical engineering standpoint. Key words: strength,...
This paper examines the three categories of permeability functions for unsaturated soils, including empirical, macroscopic, and statistical models. The theoretical backgrounds performance each category are examined against various experimental data. also shows that it is possible to degenerate models macroscopic then empirical A new equation function suggested. model demonstrates good can be readily applied. In some cases further improved with introduction a correction factor.
Shallow landslides in natural residual soils slopes are common all over the world. The slip surfaces associated with these often situated above groundwater table. Therefore, it is important to quantify contribution of negative pore-water pressure shear strength soil. shear-strength characteristics soil from Jurong Formation Singapore were assessed using multistage, consolidated drained triaxial tests. These tests involved shearing under either a constant net confining and varying matric...
Rainfall-induced landslides are a common problem in residual soil slopes of the tropics. It is widely known that rainfall-induced slope failures mainly caused by infiltration rainwater; however, response to not fully understood. The difficulties lie quantification flux boundary condition across surface with respect and its effect on pore-water pressure conditions slope. Therefore, it important understand different rainfall resulting changes pressures water contents. A Singapore was...
A slope stability study involving shallow slip surfaces should include the effect of negative pore-water pressures in a slope. field instrumentation program was carried out to monitor pressure (i.e., situ matric suction) residual soil Singapore. Variations suction and profiles under (1) canvas-convered grassed surface, (2) (3) bare ground response rainfalls were investigated. Changes due changes climatic conditions decrease rapidly with depth. The change found be most significant least...
Abstract The filter paper method is used as an indirect means of measuring soil suctions. advantages the include its simplicity, low cost, and ability to measure a wide range has also been in field However, simplicity led inadequate understanding and, therefore, improper usage. Recent findings have highlighted need for more precautions use suction measurements. This presents literature review factors affecting accuracy identifies gaps current knowledge method. An experimental study was...
Drying and wetting soil-water characteristic curves (SWCCs) for five sandy soils are investigated using a Tempe pressure cell capillary rise open tube. The test data fitted to two SWCC equations least-squares algorithm. obtained fitting parameters some hysteretic behaviour discussed correlated with grain-size distribution parameters. A concept of total hysteresis is proposed quantify the SWCC. measured one soil also compared estimated from its distribution. was at high dry density soils....
The total suction of a soil consists two components: matric and osmotic suction. There are different techniques for measuring the total, is related to water vapour pressure in air space soil, can be measured by devices capable relative humidity. A range available measure In this paper, device using chilled-mirror dew-point technique with selectable temperature environment was used humidity sample. Two residual soils Singapore were evaluation measurement. compacted at various contents three...
Rainfall-induced slope failure occurs in many parts of the world, especially tropics. Many rainfall-induced failures have been attributed to antecedent rainfalls. Although it has identified as a cause failure, pattern or distribution rainfall not received adequate attention. In this study, parametric studies were performed by using three typical patterns, analysis available data for Singapore and two different soil types represent high- low-conductivity residual soils Singapore. Antecedent...
Shear strength of unsaturated soil is an important engineering property in various geotechnical designs. In response to varying climatic conditions, behaves differently under the drying and wetting processes due hysteresis. Many research works were conducted numerous equations proposed for shear strength, however, most them limited process. this study, categorized according nature equation, i.e., fitting prediction type equations. The purpose study propose wetting. Twelve published selected...
Abstract The use of bender element to measure shear wave velocity is popular due its simplicity. However, there are still some uncertainties in the interpretation test. In this paper, elements determination velocities dry, unsaturated, and saturated soil specimens examined with respect characteristics elements, waveform, magnitude, frequency applied voltage transmitter method travel time determination. test can be improved if two performance criteria adopted: (1) a signal-to-noise ratio at...
Rainfall, hydrological condition, and geological formation of slope are important contributing factors to failures. Parametric studies were carried out study the effect groundwater table position, rainfall intensities, soil properties in affecting stability. Three different positions corresponding wettest, typical, driest periods Singapore four intensities (9, 22, 36, 80 mm/h) used numerical analyses. Typical two main residual soils from Bukit Timah Granite sedimentary Jurong Formation...