Experimental observations of the stress regime in unsaturated compacted clay when laterally confined

Construction processes often involve reformation of the landscape, which will inevitably encompass compaction of artificially placed soils. A common application of fill materials is their use as backfill in many engineering applications, for example behind a retaining wall. The post-construction behaviour of clay fills is complex with respect to stresses and deformation when the fills become saturated over time. Heavily compacted fills swells significantly more than the lightly compacted fills. This will produce enhanced lateral stresses if the fill is laterally restrained. The work presented in this paper examines how the stress regime in unsaturated clay fills changes with wetting under laterally restrained conditions. Specimens of compacted kaolin, with different initial conditions, were wetted to various values of suction under zero lateral strain at constant net overburden pressure which allowed the concept of K _{0 (the ratio between the net horizontal stress and the net vertical stress) to be examined. Tests were also carried out to examine the traditional concept of the earth pressure coefficient ‘at rest' under loading and unloading and its likely effects on the stress–strain properties. The results have shown that the stress regime (i.e. the lateral stress) changes significantly during wetting under laterally restrained conditions. The magnitude of the change is affected by the initial condition of the soil. The results have also indicated that the earth pressure coefficient ‘at rest' during loading (under the normally consolidated condition) is unaffected by suction and such loading conditions inevitably lead to the development of anisotropic stress–strain properties}

Population-based study reveals new risk-stratification biomarker panel for Barrett's esophagus

BACKGROUND & AIMS: The risk of progression of Barrett's esophagus (BE) to esophageal adenocarcinoma (EAC) is low and difficult to calculate. Accurate tools to determine risk are needed to optimize surveillance and intervention. We assessed the ability of candidate biomarkers to predict which cases of BE will progress to EAC or high-grade dysplasia and identified those that can be measured in formalin-fixed tissues. METHODS: We analyzed data from a nested case-control study performed using the population-based Northern Ireland BE Register (1993-2005). Cases who progressed to EAC (n = 89) or high-grade dysplasia =6 months after diagnosis with BE were matched to controls (nonprogressors, n = 291), for age, sex, and year of BE diagnosis. Established biomarkers (abnormal DNA content, p53, and cyclin A expression) and new biomarkers (levels of sialyl Lewis(a), Lewis(x), and Aspergillus oryzae lectin [AOL] and binding of wheat germ agglutinin) were assessed in paraffin-embedded tissue samples from patients with a first diagnosis of BE. Conditional logistic regression analysis was applied to assess odds of progression for patients with dysplastic and nondysplastic BE, based on biomarker status. RESULTS: Low-grade dysplasia and all biomarkers tested, other than Lewis(x), were associated with risk of EAC or high-grade dysplasia. In backward selection, a panel comprising low-grade dysplasia, abnormal DNA ploidy, and AOL most accurately identified progressors and nonprogressors. The adjusted odds ratio for progression of patients with BE with low-grade dysplasia was 3.74 (95% confidence interval, 2.43-5.79) for each additional biomarker and the risk increased by 2.99 for each additional factor (95% confidence interval, 1.72-5.20) in patients without dysplasia. CONCLUSIONS: Low-grade dysplasia, abnormal DNA ploidy, and AOL can be used to identify patients with BE most likely to develop EAC or high-grade dysplasia.

Material Management in Confined Site Construction

The objective of this paper is to identify various managerial issues encountered and resulting strategies adopted, with regards management of materials on confined construction site. This is achieved through classifying the various managerial burdens encountered with the numerous strategies adopted, for the successful management of such confined environments within the realm of materials management.


Through conducting an extensive literature review and detailed interviews, a comprehensive insight into the materials management concerns within a confined construction site environment is envisaged and portrayed. The following are the leading issues highlighted; (1)Lack of adequate storage space, (2)Work place becoming over-crowded, (3)Lack of adequate room for the effective handling of materials and (4)Difficult to transport materials around site. The leading managerial strategies to the management of materials on confined construction sites may be listed in order of importance, as follows; (1)Pre-fabrication and pre-assembly, (2)Providing adequate storage, (3)Space scheduling, (4)Just-In-Time delivery techniques, and (5)Effective design site layout.

Based on the research conducted, it can be concluded, that through effective management of the issues identified along with implementing the various strategies highlighted; successful materials management within a confined construction site environment is attainable.


Innovative Aspect of Paper: An empirical study of three different construction sites in three different countries (Ireland, England and USA) investigating the managerial issues and strategies relating to implementation of materials management in confined construction sites.