Articles

Geotechnical design and testing for 40+ Over-Head Lines and 5 Substations for Fictner, the CE of the project.

Borehole drilling for each OHL and substation was carried out, bearing capacity design and recommendations for each case to determine the ultimate safe load and if stabilisation was required.

Quality control of works for substations during construction through soil testing of foundations and appropriate materials, giving the go ahead if acceptable and recommendations of where to improve if not meeting requirements.

Geoconsult was tasked with all the quality control of all concrete, from the early stages of aggregate testing, mix designs as well as a having a concrete technician batching on site for all concrete pours at every substation to ensure that the concrete was to Fictner’s specifications. Concrete cube casting and crushing was also carried out by Geoconsult.

Sole consultants for Katahira and Engineers International from Japan to conduct a geotechnical survey across the length of road spanning from Mchinji Roundabout in Lilongwe to Chidzanja Junction. This included 56 road side CBRs, Benkelman beam analysis, geotechnical borehole drilling by Lilongwe bridge to determine design bearing capacity.

Traffic surveys were also conducted to map and plan the flow of traffic to allow the adequate design of the new road. Six different surveys including Axle Load Surveys were conducted over the space of 3 weeks.

Carried out geotechnical investigations for 60Ha site, including ground water mapping and foundation recommendations based on bearing capacities.

On ground support for the client, providing topographical surveys, deed submissions and land planning permits at government level. Participated in EPC meetings to provide local knowledge of local laws and procedures.

Assisted the contractor on the best possible solutions for mass scale pumpable concrete with extended setting times. Various types of locally available aggregates were tested for suitability for each mix.

Concrete additives were tested and recommended, with the client proceeding to order 200,000 litres of admixture after our report was submitted.

Geotechnical, hydrological and topographical/drone surveys were carried out for both sites, totalling 300Ha, to compile a comprehensive report for OPIC investors. Report include seismic activity, 15m boreholes across the sites with compressive tests carried out on bedrock, triaxial testing allowable bearing capacity for various foundations.

Over 200km of new and existing pipe line was to be replaced or installed across the capital city of Lilongwe. Testing was carried out every 1km to establish subsoil conditions. Drilling was conducted for all reservoirs and pumping stations to establish the potential site’s ultimate bearing capacity and any recommendations for improvements.

Full geotechnical testing and design for proposed powerplant in Chipata. This included 16 boreholes to analyse subsoil conditions and bearing capacity across the site, 30+ trial pits to test percolation, water seepage and insitu soil strength.

Full hydrological flood assessment to include modelled flood lines for 2, 5, 10, 25, 50 and 100 year floods. Drainage recommendations as well as road elevations for access roads were given.

In excess of 40 boreholes were drilled across the site to determine bearing capacities across the area to identify potential weak layers and provide suggestions for cut levels. 30m of rock coring was conducted to identify rock type and strengths.

Full range of geotechnical testing was required due to poor soil conditions at the site. Investigations into the decomposed rock were required to find competent bearing strata for the multi-story buildings.

Quality control and consulting of all material layers though the cut and fill process.

Engineer had concerns the subsoil did not achieve the required bearing capacity for a ground plus 3 building.

o Conducted analysis into the layer of decomposed rock beneath the foundation level. After processing the test results it was concluded that a 600mm laterite gravel bed would mitigate the effects of the decomposed rock

o Conducted a plate load test every 1m to ensure the bearing capacity was above the requirement in each 1m layer.

Installed an onsite laboratory to identify suitable borrow pits for all layers of road construction. Supervised and tests all compaction and material requirements throughout the earthworks. Testing for all surfacing, chippings, and slurry layer, including the slurry mix design.