Phase 2 - Intrusive Investigation The findings of the desk study and site walkover, together with knowledge of the future land use, can be used to design and implement an appropriate intrusive ground investigation. Intrusive ground investigations typically comprise excavating trial pits and/or drilling boreholes so that soil types can be inspected, soil behaviour assessed and samples retrieved for geotechnical testing and/or chemical analysis. All our investigations are supervised by experienced geo-environmental consultants in order to maximise the data collected and record the ground conditions exposed by the exploratory holes. The range of investigation techniques that BRD offer include: | ||
| Inspection pits: Shallow hand dug holes to inspect near surface soils or existing foundations. | |
| Mechanically excavated trial pits: JCB type or 360º excavators used to excavate holes up to 4m deep |
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| Window/windowless sampling: Narrow diameter boreholes that can be undertaken in confined spaces. | |
| Cable percussive boreholes: The standard drilling method for deep (10s of metres) boreholes in soils and soft rocks. | |
| Hollow stem auger: An alternative technique for drilling boreholes. | |
| Rotary core boreholes: Method for drilling in hard rock. | |
| Dynamic probing: A method of measuring the penetration resistance of the soil. |
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| Geophysical techniques: A range of non-intrusive methods of mapping ground conditions and variations in strata. BRD has developed a successful working partnership with Zetica, an industry leader in this field, to meet this requirement. | |
| California Bearing Ratio (CBR) testing: An in-situ test undertaken to assist in the design of road construction. | |
| Laboratory analysis: Chemical and geotechnical testing of samples. | |
| Photo Ionisation Detector: Equipment used on site to measure volatile compounds. |
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| Groundwater monitoring: Measuring water levels and retrieving samples together with on site testing. | |
| Gas monitoring: Portable analyser used to measure hazardous ground gases such as methane and carbon dioxide. | |
| Soakage tests: A soil permeability test used to design soakaways for surface water disposal. | |
Data from the intrusive investigation enables the conceptual model of the ground conditions developed in Phase 1 to be revised. Geotechnical aspects of this model are used to make recommendations regarding foundation types and other construction considerations. The conceptual model is also used to identify and assess potential contamination risks. In addition to employing generic assessment criteria for comparison with contamination test results, BRD can develop site specific assessment criteria using software models to assess contamination risks to human health and the water environment. The information gathered from the investigation is collated in a comprehensive factual and interpretative report. Click here for case studies of Phase 2 Investigations | ||
