ABSTRACTThe ground is one of the most highly variable of all engineering materials. As a result, geotechnical designs depend upon a site investigation to estimate the ability of the ground to perform acceptably. For example, when a shallow foundation is being proportioned to avoid a bearing capacity failure under a certain applied load, the frictional and cohesive properties of the ground under the foundation must first be estimated through a site investigation. Questions which arise are: How does the quality and intensity of the site investigation affect the design? Is more investigation cost effective? If the site is sampled at one location and the foundation placed at a different location, how does this mismatch affect the target design and the reliability of the final foundation? By modelling the ground as a spatially variable material, questions such as the above can be investigated through Monte Carlo simulation and sometimes theoretical probabilistic models. Using such tools, this paper looks specifically at how the intensity (frequency and spatial distribution) of a site sampling plan, and how the samples are used, affects the understanding of the ground properties under a foundation. Interestingly, it is found that removing the sample mean outperforms removing the best linear unbiased estimate (BLUE) when the actual field correlation length is small but the BLUE correlation length is assumed equal to the field size. Recommendations are made regarding number of samples and the type of trend to best characterise the field.Abbreviations: BLUE: best linear unbiased estimate; MCS: Monte Carlo simulation; LAS: local average subdivision 相似文献
AbstractJohn Wood, the 19th-century urban cartographer, surveyed almost 150 towns spread widely across Great Britain. His detailed large-scale plans are an astounding achievement. In light of this, two questions are posed: did he have a strategy that guided the places which he surveyed; and how did he pay for his work, given that so few copies of his plans appear to have been produced for sale – or at least to have survived. 相似文献
Climate change mitigation is a wicked problem that cuts horizontally across sectors and vertically across levels of government. To address it effectively, governments around the world, in particular in the EU, have developed several generations of multi-sectoral national mitigation strategies (NMS) since the early 1990s. Although NMS became the main effort to systematically coordinate mitigation policies, few works have studied them comparatively so far. The present article fills this gap by analysing how the EU-15 group of countries operationalized climate protection through NMS. First, we introduce the three roles policy strategies usually aim to fulfil: besides being policy documents they also represent governance processes (supposed to coordinate sectoral implementation), and capacity-building efforts. Empirically, we then explore the rationale, origins and prevalence of NMS. Subsequently, we characterize them as policy documents (with regards to their contents and structures) and as governance processes that address capacity building only implicitly. Based on existing assessments we finally review some performance indications of NMS. We find that in particular second- and third-generation NMS aimed to take their governance function seriously but resembled ‘lacklustre bookkeeping' of emissions, targets and mitigation options. Instead of approximating NMS towards their obviously overcharging governance function, we suggest to recalibrate them towards their communication and capacity-building function in a way that goes beyond bookkeeping.
Policy relevance
The present article shows that NMS fail to effectively govern climate change mitigation across a broad range of sectoral policy domains. Since most European countries have adopted not one but up to three generations of NMS since the 1990s, this finding is highly relevant for them – and for all others aiming to adopt similarly broad strategies. Instead of piling one strategy on top of another irrespective of their implementation, and instead of abolishing mitigation strategies altogether, we recommend recalibrating them towards what they can realistically accomplish: effective communication and capacity building so that NMS can advance from lacklustre bookkeeping to actively promoting a government-wide climate change mitigation vision. The article can help governments to realise that renewing integrated strategies such as NMS without overhauling them comes close to flogging a dead horse. 相似文献