Question

Referring to below borehole log. Referring specifically to information provided on the borehole log- Would this borehole lend itself to standard methods of construction for a large wastewater treatment plant? What geotechnical aspects might you need to consider during design and construction phases?

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Figure 2 Borehole log Holst Soil Engineering Limited Borehole No BOREHOLE LOG Location. Davyhulse Sewage Worke. ST 79 NE - 287 Sheet 1 of 2 5253 964.95 Ground Level 20.23 A.0.D. Contract No . 3256 Client North West Water Authority Method of Boring Shell and A Diameter of Borehole 0.250 79255 763 Chanage Ground Level 20.23 A. Date 3.12.25-6.12.15 Description of Strata MADE ROUND Medium dense ash, enders and brieks 1.00 MADEGROUND Soft to rin, dark grey. clayey silt and 13 33.0 33.0 1870 1775 18 0 o 207.0 107.0 1245 1215 Very loose, grey fine sandy SILT Sabik under Very loose, fine to medium grey alty SAND (Moving Slightly) Dense, brown coarse SAND and sau to coarse GRAVEL and COBBLES 9.59 O Type of Samole Remarks Observations of Ground Water en Dundturbed Saw . Ang of Fiction Water struk 1.609 3.12.35 Casine 1.609 bed Sample me Mure Cart Standing level 1.0 A W Sample YB Density Ieration Test NSPTV Apparere Cohesion

Answer 1

* with available bore log details, it shows clay is present upto 5m depth from Ground level and N values of less than 50 upto depth of 8.8m.

*from the details available amount of waste water to be treated or stored is not availble, taking the soil condition into consideration , with release or discharge of water into treatment plant or from the treatement plant , its not sutiable to have its foundation upto 9m depth from level.

* if its necessary to provide foundation at even lower depth like 0-5m from ground level we need consider in improving the soil properties like providing pile foundation to hard strata or upto 13m as N value is more than 50 and with presence of garavel its suitable to construct the large treatement plant.