Overview of Innovations in Geotechnical Engineering

This paper outlines some historical and current innovative concepts that underpin the developments in geotechnical engineering. The far reaching aim is to inspirationally encourage further innovation in that innovation need not necessarily be entirely new and unique ways of doing things. Accordingly, the lessons from the historical development, bio mimicry and emerging concepts are illustratively presented. The importance of creating added value to projects through innovation is endorsed. A number of examples based on the author’s research and experience, ranging widely across the themes of the conference are presented.. In many ways geotechnology has reached maturity over the last century, but some scenarios continue to remain as challenging engineering problems. In the recent times, geotechnical engineering finds benefit in being at the crossroads with the advancements in high-tech solutions and the expanding geo technology applications, and in multi disciplinary collaborations with nanotechnology, biotechnology and information technology. The goal of innovative geo engineering research must provide effective solutions in both short and long term, with knowledge and understanding to solve problems with more sustainable certaint

Some Built Environment Research Contributing to Sustainability

Engineering in all forms must address global challenges of sustainability including its dimensions such as poverty, urbanisation, and climate change. The built environment is the dynamic interface between human society as it interacts and influences the ecosystem.  An understanding of this inextricably linked interdependence underpins the sustainability issues relevant to Civil Engineering. Geotechnical engineering outstand the rest of the disciplines in being the most resource intensive and having an early stance in the construction process. Philosophies and definitions of sustainability, as appropriate to geotechnical engineering is punctuated with illustrations through such research studies that contribute to sustainable development. This paper is thus a technical narrative of such innovative geotechnical research focusing on the author’s research career to include the modeling and assessment of the performance of a rectangular hyperbolic paraboloid shell foundation to mimic the “duck’s foot” on very soft mud; innovative research on the development of rocker pipes to arrest the often unnoticed failure of utility services arising from differential settlement; industrial design and sustainable installation of thick compacted London clay surround to protect the Heathrow Express Rail link Tunnel from noxious gases entering the tunnel as it traversed through an old landfill site;  Urban Heat Island studies; Hemp in rammed earth construction,; Quality control and enhancement of geo synthetic clay liners; adoption of lightweight manufactured aggregates; used vegetable oil in asphalt pavements and soil stabilization and sustainable construction through use of enzymes and light geo composites on challenging soils are presented

The comparative in situ hygrothermal performance of Hemp and Stone Wool insulations in vapour open timber frame wall panels

An in situ experiment in a full scale timber frame test building was carried out to compare the hygrothermal performance of Hemp and Stone Wool insulations of identical thermal conductivity. Hemp and Stone Wool insulations were installed in timber frame wall panels without vapour barrier. The comparison was made in terms of heat transfer properties, likelihood of mould growth and condensation. Step changes in internal relative humidity were performed to explore the effect of high and normal internal moisture load on the wall panels. No significant difference between the average equivalent thermal transmittance (U-values) of the panels incorporating Hemp and Stone Wool insulations was observed. The average equivalent U-values of the panels were closer to the calculated U-values of the panels based on the manufacturers’ declared thermal conductivity of Hemp and Stone Wool insulations. It was observed that the placement of heat flux sensor along the depth of the insulation had significant influence on the measured equivalent U-value of the panels during high internal moisture load. The frequency and likelihood of condensation was higher in the interface of Stone Wool and Oriented Strand Board (OSB). In terms of the parametric assessment of mould germination potential, relative humidity, temperature and exposure conditions in the insulation-OSB interfaces were found to be favourable to germination of mould spore. However, when the insulations were dismantled, no mould was visually detected

Overview of the Sustainable Uses of Peat Soil in Malaysia with Some Relevant Geotechnical Assessments

Peat soil is an important ecosystem that provides a significant contribution to the global climate stability. In Malaysia, peat soils are considered as a soil with little economic benefit, apart from it being used for agricultural activity. The total world coverage of peat soil is about thirty million hectares with Canada and Russia having the largest distribution of peat (Zainorabiddin,2010). More than sixty percent of the world’s tropical peat lands are found in South-East Asia (Lette,2006). Most notable are the large peat land on the islands of Borneo (belonging to Indonesia, Malaysia and Brunei) and Sumatra (Indonesia). However, there are also significant occurrences in other parts of Indonesia, Malaysia, Vietnam, Thailand and the Philippines. The main contributory functions and benefits of peat soil are within the engineering disciplines of hydrology, agriculture, social-economics, biodiversity habitats and carbon sequestration. Peat was used in temperate climates (especially in Finland, Ireland, Sweden and UK) as a fuel to generate electricity and heat. Therefore peat can be considered as a renewable energy source but this will be very detrimental to the market of genuine renewables. The western coastal lowlands of Malaysia (such as Kukup) are mangroves that represent the initiation of peat soil formation. Such areas provide the natural habitat of mangrove forests. It also fixes more carbon from the atmosphere than is released and approximately one-quarter of the carbon stored in land plants and soils. On the other hand, peat is one of the problematic or challenging foundation soil of poor quality due to it’s very high water content, high compressibility and low shear strength. Peat consists of decomposed plant fragments and the unfavourable characteristics of peat soil deposits make them unsuitable for making sustainable infrastructure development for varied engineering projects. This paper therefore gives an overview of the pros and cons debate of sustainability aspects and in the light of the challenges it poses to infrastructure development in Malaysia

Moisture Desorption Studies on Polymer Hydrated and Vacuum Extruded Bentonite Clay Mat

Moisture desorption observations from two bentonite clay mats subjected to ten environmental zones with individually different combinations of laboratory-controlled constant temperatures (between 20 °C and 40 °C) and relative humidity (between 15% and 70%) are presented. These laboratory observations are compared with predictions from mathematical models, such as thin-layer drying equations and kinetic drying models proposed by Page, Wang and Singh, and Henderson and Pabis. The quality of fit of these models is assessed using standard error (SE) of estimate, relative percent of error, and coefficient of correlation. The Page model was found to better predict the drying kinetics of the bentonite clay mats for the simulated tropical climates. Critical study on the drying constant and moisture diffusion coefficient helps to assess the efficacy of a polymer to retain moisture and control desorption through water molecule bonding. This is further substantiated with the Guggenheim–Anderson–De Boer (GAB) desorption isotherm model which is presented

The Effects of Particle Morphology (Shape and Sizes) Characteristics on its Engineering Behaviour and Sustainable Engineering Performance of Sand

The mechanical behaviour of granular soil is interestingly dependent on the characteristics of the particles. The wide range of particle shapes and size distribution of sand, by virtue of its sedimentological process of formation plays a significant factor in the influence on its engineering behaviour reflected in terms of its packing density, permeability, shear strength and dilatancy. In this study, research on well graded sand (SW), poorly graded uniform sand (SPuKahang), gap graded sand (SPg) from Kahang Malaysia and also (SPuL.Buzzard) Leighton Buzzard sand from UK were tested in a direct shear box. The shapes were quantified using images from a digital microscope where its morphological features can lead via statistical methods to determined correlations between strength and its physical properties. The research effort focuses in obtaining its shear strength and roughness parameters and also its extreme packing (emin and emax). Results from published studies on related matter and also the study on permeability are presented. The findings would lead to a better way to classify the shape and size distribution for the assessment of the behaviour of sand in various engineering disciplines such a good foundation soil in geotechnical engineering, as an abrasive material in mechanical engineering, as a filler of concrete in civil engineering, as a filter in chemical engineering and occurs as oil sands in petroleum engineering

Development and field testing of Geocomposite Cellular Mats (GCM) to minimize the ground movements of highway embankments founded on peat ground

Challenging grounds are often met in planning, design and construction of highway embankments which as a consequence succumb to undesirably excessive ground movements. Such ground conditions can range from unforeseen cavernous grounds to soft compressible organic soils of variable depths. Often alternate route planning is not feasible, and if necessary alternative construction procedures are not adopted, the net result will be unwanted roads user discomforts such as bumpy roads or even fatal road collapse. Highway constructions norms to circumvent such occurrences are to replace with alternative transported foundation soil/ground improvement or use an appropriate form of geo mats. Hence, this paper presents an alternative and innovative lightweight fill material: Geocomposite Cellular Mat (GCM) used to minimize the ground movements of highway embankments over peat ground. The conceptual development of a stiff mat structure but with a weight lighter than the embankment fill soil is described. The material used for the stiff mat is environmentally friendly in utilizing recycled plastic and its structure, enabling the free movement of water to dissipate any excessive porewater pressures. The performance of theGCMwas appraised under field trial conditions on a test site in Parit Nipah, Johor, Malaysia. The site comprised of a vast expanse of hemic peat and environmental conditions at the test site were fully monitored. The geotechnical properties of the peat at Parit Nipah were typically high organic matter content (~85%), high moisture content (>600%) and very low undrained shear strength (<15 kPa). Details of the set up and layout of the trial embankments tested are fully described, and the techniques adopted to get a comprehensive narrative of the settlement characteristics using innovative measurement techniques are also described. The performance of the GCM incorporated embankment was compared with that of a similar embankment that was formed of conventional backfill (sand fill). The findings show that the field ground movement observations confirmed that themaximum settlementswere reduced by up to 84% with the GCMfills.Moreover, the differential settlements were reduced by up to 70%

Hygrothermal performance of wood-hemp insulation in timber frame wall panels with and without a vapour barrier

An in situ experiment on a full-scale timber frame test building was carried out to study the hygrothermal performance of wood-hemp composite insulation in timber frame wall panels with and without a vapour barrier. The heat transfer properties and the likelihood of mould growth and condensation in the panels were compared. Step changes in the internal relative humidity were performed to explore the effects of high, normal and low internal moisture loads on the wall panels. No significant difference in the average equivalent thermal transmittance (U-values) between the panels with and without a vapour barrier was observed. The average equivalent U-values of the panels were close to the U-values calculated from the manufacturers’ declared thermal conductivity values of the insulation. The likelihood of condensation was higher at the interface of the wood-hemp insulation and the oriented strand board (OSB) in the panel without a vapour barrier. In terms of the parametric assessment of the mould germination potential, the relative humidity, the temperature and the exposure conditions in the insulation-OSB interfaces of the panel without a vapour barrier were found to be more favourable to the germination of mould spores. Nonetheless, when the insulations were dismantled, no mould was visually detected

The comparative in situ hygrothermal performance of Hemp and Stone Wool insulations in vapour open timber frame wall panels

An in situ experiment in a full scale timber frame test building was carried out to compare the hygrothermal performance of Hemp and Stone Wool insulations of identical thermal conductivity. Hemp and Stone Wool insulations were installed in timber frame wall panels without vapour barrier. The comparison was made in terms of heat transfer properties, likelihood of mould growth and condensation. Step changes in internal relative humidity were performed to explore the effect of high and normal internal moisture load on the wall panels. No significant difference between the average equivalent thermal transmittance (U-values) of the panels incorporating Hemp and Stone Wool insulations was observed. The average equivalent U-values of the panels were closer to the calculated U-values of the panels based on the manufacturers’ declared thermal conductivity of Hemp and Stone Wool insulations. It was observed that the placement of heat flux sensor along the depth of the insulation had significant influence on the measured equivalent U-value of the panels during high internal moisture load. The frequency and likelihood of condensation was higher in the interface of Stone Wool and Oriented Strand Board (OSB). In terms of the parametric assessment of mould germination potential, relative humidity, temperature and exposure conditions in the insulation-OSB interfaces were found to be favourable to germination of mould spore. However, when the insulations were dismantled, no mould was visually detected

Hygric properties of hemp bio-insulations with differing compositions

The paper presents the results of a laboratory investigation on the hygric properties of five hemp insulation materials commercially available in the UK. The hemp fibre content varies between 30-95% in the total fibre content of the insulation materials examined. The adsorption-desorption isotherm, moisture buffer value, vapour diffusion resistance factor and water absorption coefficient were determined for the insulation materials investigated. The results showed that the hygric properties of the hemp insulation materials could vary widely depending on the constituents and fibrous structure. The considerable differences noted in the hygric properties of the insulation materials examined could potentially influence their hygrothermal performance as part of a building thermal envelope