Soil mix technology for land remediation: Recent innovations

The past 15 years have seen increasing applications of soil mix technology in land remediation, mainly in stabilisation/solidification treatments and the construction of low-permeability cut-off walls and permeable reactive barriers; clear evidence of the versatility of the technology and its wide-ranging applications. This paper provides an overview of some of the recent innovations of soil mix technology in land remediation covering equipment developments and applications, including systems for rectangular panels and trenching systems, treatments, such as chemical oxidation, and additives, such as modified clays, zeolites and reactive magnesia. The paper also provides case studies for such innovations. The paper concludes with an overview of an on-going research and development project SMiRT (Soil Mix Remediation Technology) which will involve field trials on a contaminated site and will employ some of the innovations discussed in the paper. The range of significant advantages that soil mix technology now offers compared to other remediation techniques is likely to place this remediation method at the forefront of remedial options for future brownfield projects.

Synchronization in baroclinic systems

Synchronization of periodic and chaotic oscillations between two coupled rotating baroclinic fluid systems will be presented. The numerical part of the study involves a pair of coupled two-layer quasigeostrophic models, and the experimental part comprises two thermally coupled baroclinic fluid annuli, rotating one above the other on the same turntable. Phase synchronization and imperfect synchronization (phase slips) have been found in both model and experiments, and model simulations also exhibit chaos-destroying synchronization. © 2008 IOP Publishing Ltd.

3D FE Analyses of Buried Pipeline with Elbows Subjected to Lateral Loading

This study investigates the interaction between soil and pipeline in sand subjected to lateral ground displacements with emphasis on the peak force exerted to a bended elbow-pipe. A series of three-dimensional (3D) finite-element (FE) analyses were performed in both opening and closing modes of the elbow section for different initial pipe bending angles. To model the mechanical behavior of sands, two soil models were adopted: Mohr-Coulomb and Nor-Sand soil model. Investigations also included the effects of pipe embedment depth and soil density. Results show that the opening mode exhibits higher ultimate forces and greater localized deformations than the closing mode. Nondimensional charts that account for pipeline location, bending angle, and soil density are developed. Soil-spring pipeline analyses of an elbow-pipe were performed using modified F-δ soil-spring models based on the 3D FE results and were compared to the findings of conventional spring model analyses using the standard two-dimensional soil-spring model. Results show that the pipe strain does not change in the closing mode case. However, in the opening mode case, the pipe strain computed by the modified analysis is larger than that by the conventional analysis and the difference is more pronounced when the pipe stiffness is stiffer. © 2011 American Society of Civil Engineers.

Embodied Energy and Gas Emissions of Retaining Wall Structures

The embodied energy (EE) and gas emissions of four design alternatives for an embankment retaining wall system are analyzed for a hypothetical highway construction project. The airborne emissions considered are carbon dioxide (CO 2), methane (CH 4), nitrous oxide (N 2O), sulphur oxides (SO X), and nitrogen oxides (NO X). The process stages considered in this study are the initial materials production, transportation of construction machineries and materials, machinery operation during installation, and machinery depreciations. The objectives are (1) to determine whether there are statistically significant differences among the structural alternatives; (2) to understand the relative proportions of impacts for the process stages within each design; (3) to contextualize the impacts to other aspects in life by comparing the computed EE values to household energy consumption and car emission values; and (4) to examine the validity of the adopted EE as an environmental impact indicator through comparison with the amount of gas emissions. For the project considered in this study, the calculated results indicate that propped steel sheet pile wall and minipile wall systems have less embodied energy and gas emissions than cantilever steel tubular wall and secant concrete pile wall systems. The difference in CO 2 emission for the retaining wall of 100 m length between the most and least environmentally preferable wall design is equivalent to an average 2.0 L family car being driven for 6.2 million miles (or 62 cars with a mileage of 10,000 miles/year for 10 years). The impacts in construction are generally notable and careful consideration and optimization of designs will reduce such impacts. The use of recycled steel or steel pile as reinforcement bar is effective in reducing the environmental impact. The embodied energy value of a given design is correlated to the amount of gas emissions. © 2011 American Society of Civil Engineers.

Data fusion approaches and applications for construction engineering

Data fusion can be defined as the process of combining data or information for estimating the state of an entity. Data fusion is a multidisciplinary field that has several benefits, such as enhancing the confidence, improving reliability, and reducing ambiguity of measurements for estimating the state of entities in engineering systems. It can also enhance completeness of fused data that may be required for estimating the state of engineering systems. Data fusion has been applied to different fields, such as robotics, automation, and intelligent systems. This paper reviews some examples of recent applications of data fusion in civil engineering and presents some of the potential benefits of using data fusion in civil engineering.