The aim of the paper was to document the use of 3D subsurface geological-geotechnical modelling to optimise the planning and development of subsurface structures in city areas. The proposed procedure was applied to the analysis of the subsoil of the City of Turin (Northern Italy). The results of more than 300 boreholes were analysed to develop a model of the geological setting up to a depth of 60 m from the surface. The cementation variability of the alluvial sediments was also spatially described and the influence of this aspect on the soil excavation resistance was highlighted. In order to face the need of archiving, correlating and analysing a large amount of data, a 3D GIS (Geographical Information System) was used to better manage the model and to achieve a useful methodological reference that would be available for the planning and construction of future underground works.
A portion of the geological model, related to the centre of the city of Turin (Italy), was chosen to set up a more detailed geotechnical model, based on laboratory tests and back-analysis procedures, as data input for some engineering applications.
Two case studies were performed concerning:
– analyses used to forecast the subsidence induced on the ground surface by the excavation of the metro line;
– the influence of the works of the metro line on the new Underground Railway Link (interference between two important underground works).
A comparison between the forecasts of the degree of cementation, supplied by the 3D model along a metro tunnel tract, and the excavation specific energy effectively absorbed by the head of the boring machine is reported to testify the reliability of the model of the subsoil of Turin centre. This comparison shows the good reliability of the model and its potential to choose of the optimal boring machines for the future development of the Underground Metro System in Turin. 相似文献
On May 20 th 2007, a brief but severe downpour rainstorm occurred in the coastal areas of Maoming and Yangjiang with rainfall of 115 mm per hour. Data from NCEP/NCAR reanalysis with 1°×1° resolution, Doppler weather radar, conventional surface observations, high-altitude radiosonde and wind profiler radar were used to analyze characteristics and contributions of synoptic scale and mesoscale systems during this torrential rainstorm. The results showed that:(1) the storm was caused by a quasi-linear mesoscale convective system(MCS) and the slow-movement of this system was the primary trigger of the torrential downpour;(2) water vapor was abundant, nearly saturated and in steady state throughout the atmosphere before the storm; intrusion of the weak dry and cold air in the middle level and a striking "dry above and wet below " structure had increased the atmospheric instability;(3) low-level southwesterly airflow from a low pressure(trough) at the Beibu Gulf provided abundant water vapor at the onset of the rainstorm; a deep dry layer was formed by dry and cold air behind the high-level trough, which facilitated latent heat release;upper-level divergence and low-level convergence circulations also provided vertical uplift for warm and moist air at the lower level;(4) Topography only played a minor role as the MCS developed and strengthened over relatively flat coastal terrain. Low level density flow induced by convection triggered new convective cell generation at the leading edge of the convective system, thereby playing a key role in the change of temperature gradient at lower layers, and resulting in strengthening atmospheric instability. 相似文献
There is extensive debate about the potential impact of the climate mechanism REDD+ on the welfare of forest-dwelling people. To provide emission reductions, REDD+ must slow the rate of deforestation and forest degradation: such a change will tend to result in local opportunity cost to farmers at the forest frontier. Social safeguard processes to mitigate negative impacts of REDD+ are being developed and can learn from existing safeguard procedures such as those implemented by the World Bank. Madagascar has a number of REDD+ pilot projects with World Bank support including the Corridor Ankeniheny-Zahamena (CAZ). Nearly two thousand households around the corridor have been identified as ‘project affected persons’ (PAPs) and given compensation. We compare households identified as project affected persons with those not identified. We found households with more socio-political power locally, those with greater food security, and those that are more accessible were more likely to be identified as eligible for compensation while many people likely to be negatively impacted by the REDD+ project did not receive compensation. We identify three issues which make it difficult for a social safeguard assessment to effectively target the households for compensation: (a) poor information on location of communities and challenging access means that information does not reach remote households; (b) reluctance of people dependant on shifting agriculture to reveal this due to government sanctions; and (c) reliance by safeguard assessors on non-representative local institutions. We suggest that in cases where the majority of households are likely to bear costs and identification of affected households is challenging, the optimal, and principled, strategy may be blanket compensation offered to all the households in affected communities; avoiding the dead weight costs of ineffective safeguard assessments. The Paris Agreement in December 2015 recognised REDD+ as a key policy instrument for climate change mitigation and explicitly recognised the need to respect human rights in all climate actions. However, safeguards will be prone to failure unless those entitled to compensation are aware of their rights and enabled to seek redress where safeguards fail. This research shows that existing safeguard commitments are not always being fulfilled and those implementing social safeguards in REDD+ should not continue with business as usual. 相似文献
Understanding species distributions and their community structure is increasingly important when taking an ecosystem‐based approach to conservation and management. However, knowledge of the distribution and community structure of species in mid‐range trophic levels (e.g. macroinvertebrates) is lacking in most marine ecosystems. Our study aimed to examine the spatial distribution and community‐level biogeographic patterns of common kelp forest–rocky reef macroinvertebrates in Southern California and to evaluate the effects of environmental gradients on these communities. Quantitative SCUBA surveys were used to estimate macroinvertebrate densities at 92 sites from 2008–2012. Non‐metric multidimensional scaling was used to evaluate spatial patterns of macroinvertebrate communities among Regions. We found that kelp forest–rocky reef macroinvertebrate communities are distinct among different island and mainland regions, and their community patterns exhibited a strong relationship with an environmental gradient (i.e. sea surface temperature) even after controlling for geographic distance between sites. High abundances of urchin species (Strongylocentrotus purpuratus and Strongylocentrotus franciscanus) were strong drivers of regional differences. Macroinvertebrate community patterns were driven by characteristic species that were typically more prevalent at warmer or colder sites. Our results provide the first quantitative analysis of macroinvertebrate community structure within the California kelp forest ecosystem. We also describe the distribution and abundance of 92 conspicuous kelp forest‐rocky reef macroinvertebrates among nine pre‐defined Regions. This study provides important preliminary information on these macroinvertebrate species that will be directly useful to inform management of invertebrate fisheries and spatial protection of marine resources. 相似文献