土木工程專業(yè)外文翻譯---土方工程的地基勘察與施工-建筑結(jié)構(gòu)-wenkub
2023-05-19 14:18:46 本頁(yè)面
【正文】 ion and strength. The selection process should aim to maximise the use of locally available soils and with careful evaluation it is possible to use or incorporate ‘poor or marginal soils’ within fill areas and embankments. Fill material needs to be placed at a moisture content such that it is neither too wet to be stable and trafficable or too dry to be properly pacted. High moisture content / low strength boulder clay soils can be suitable for use as fill in low height embankments (. 2 to ) but not suitable for trafficking by earthwork plant without using a geotextile separator and granular fill capping layer. Hence, it is vital that the earthworks contractor fully understands the handling properties of the soils, as for many projects this is effectively governed by the trafficability of earthmoving equipment. 2. TRADITIONAL GROUND INVESTIGATION METHODS For road projects, a principal aim of the ground investigation is to classify the suitability of the soils in accordance with Table from Series 600 of the NRA Specification for Road Works (SRW), March 2020. The majority of current ground investigations for road works includes a bination of the following to give the required geotechnical data: ? Trial pits ? Cable percussion boreholes ? Dynamic probing ? Rotary core drilling ? Insitu testing (SPT, variable head permeability tests, geophysical etc.) ? Laboratory testing The importance of ‘phasing’ the fieldwork operations cannot be overstressed, particularly when assessing soil suitability from deep cut areas. Cable percussion boreholes are normally sunk to a desired depth or ‘refusal’ with disturbed and undisturbed samples recovered at intervals or change of strata. In many instances, cable percussion boring is unable to perate through very stiff, hard boulder clay soils due to cobble, boulder obstructions. Sample disturbance in boreholes should be prevented and loss of fines is mon, invariably this leads to inaccurate classification. Trial pits are considered more appropriate for recovering appropriate size samples and for observing the proportion of clasts to matrix and sizes of cobbles, boulders. Detailed and accurate field descriptions are therefore vital for cut areas and trial pits provide an opportunity to examine the soils on a larger scale than boreholes. Trial pits also provide an insight on trench stability and to observe water ingress and its effects. A suitably experienced geotechnical engineer or engineering geologist should supervise the trial pitting works and recovery of sample
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