tooyoung
Civil/Environmental
- Dec 30, 2010
- 1
Hi,
I am trying to determine a suitable strata for foundation of an office block from a borehole sample, but am struggling to understand the effect of groundwater. The soils present consist of gravel, then soft silt, firm clay (from 6-9m), then stiff silt and then medium sandstone. I am thinking the foundation will be located in firm clay via piles but dont understand the effects of water change in the silt layer below.
I can see the water table is at 2m below the surface, however when the stiff silt is encountered the depth to water recorded is nil, however then a day later rises to 8.8 metres below ground level in the clay. just below the installation of piezometer in this silt strata (at 11.4m) rapid seepage occurs and rises to 9.2m below ground in the clay. then a few days later the piezometer records water at 8.4 meters. I really dont understood whats happening in the soil.
I think artesian water conditions are present in the silt and disturbance of borehole caused water level to rise to 8.8m in the clay. but dont understand what then caused the rapid seepage to 9.2. then why the water level in the piezometer is at 8.4m a few days later????
I am trying to determine a suitable strata for foundation of an office block from a borehole sample, but am struggling to understand the effect of groundwater. The soils present consist of gravel, then soft silt, firm clay (from 6-9m), then stiff silt and then medium sandstone. I am thinking the foundation will be located in firm clay via piles but dont understand the effects of water change in the silt layer below.
I can see the water table is at 2m below the surface, however when the stiff silt is encountered the depth to water recorded is nil, however then a day later rises to 8.8 metres below ground level in the clay. just below the installation of piezometer in this silt strata (at 11.4m) rapid seepage occurs and rises to 9.2m below ground in the clay. then a few days later the piezometer records water at 8.4 meters. I really dont understood whats happening in the soil.
I think artesian water conditions are present in the silt and disturbance of borehole caused water level to rise to 8.8m in the clay. but dont understand what then caused the rapid seepage to 9.2. then why the water level in the piezometer is at 8.4m a few days later????