采礦外文翻譯---受開采影響地表橫向剪切變形(文件)
【正文】 ter the extraction face has passed the survey site. The reversal in the sense of shearing has a potential to enhance the effects of shear deformations, and? The occurrences of permanent horizontal deformations.IMPLICATIONSFrom the 3D survey data collected from a number of collieries across all NSW Coalfields, the characteristics (. the magnitude, nature, distribution and timing of occurrences) of the conventionally defined subsidence parameters are pared with those of the following horizontal deformational parameters:(i) Mininginduced horizontal movements perpendicular to survey grid lines, and(ii) The corresponding Shear Index as discussed above.Implications from the findings of the current study so far are summarised as follows.1. Horizontal Shear Deformations – There is a need to recognise horizontal shear deformation as a significant mode of mininginduced deformations at the ground surface. Specific attention should be paid to surface features with inadequate shear resistance and to areas with deep cover depths (or relatively low “extraction widthtocover depth” ratios) where the conventionally defined horizontal strains predicted may suggest low risks.2. Assessment of Subsidence Impacts on Civil Structures – Further to Point (1) above, there is a need to recognise the limitations of subsidence models based on conventionally defined horizontal strains and AS 28701996 (Standards Australia, 1996) when predicting subsidence impacts on civil structures. Consequently, there is a need to identify areas where changes and improvements to these models are required.3. Civil Structures on Sloping Ground – Further to Point (1) above, specific attention should be paid to civil structures on the sloping ground. In this case, there is a potential for enhanced shear deformations due to the participation of downslope movements. In addition, the performance of any footings to resist or acmodate shear deformations in this environment needs to be investigated and understood.4. Capacity of Surface Features to Resist or Acmodate Shear Deformations – This is an area where knowledge has not been clearly established for subsidence engineering and management. The situation here, again, is different from many other engineering disciplines when shear deformations are concerned. There is a need to undertake necessary research into this area.5. Mininginduced Surface Wrinkles – Mininginduced surface wrinkles (Figure 3), or pression humps, are one of the significant factors for subsidence impacts on civil structures. Where these deformational features occurred in areas with low predicted horizontal strains according to conventional subsidence models, geological structures were often blamed for their occurrences resulting in unpredicted or higherthanpredicted impacts on civil structures. However, recently conducted field investigations have not been able to provide a clear link between geological structures and such surface wrinkles, while there is a continuing need for an improved understanding of these features to develop effective early warning and risk management system
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