Diaphragm and bored pile retaining walls are often used for the construction of basements, metro ... more Diaphragm and bored pile retaining walls are often used for the construction of basements, metro station boxes and cut-and-cover tunnels in urban areas. While diaphragm and secant pile walls are generally intended (and assumed in analysis) to be effectively impermeable, contiguous piles may allow through-the-wall seepage even when preventative measures have been undertaken. Provided the flow rates can be tolerated or dealt with, through-the-wall seepage should result in a reduction in pore water pressures behind the retaining wall compared with an impermeable construction, giving the potential for reductions in the depth of embedment and wall thickness, and hence cost. However, this potential is rarely realised owing to the difficulty in quantifying with sufficient confidence the hydraulic regime associated with a leaky retaining wall. This paper reports the results of laboratory investigations and numerical analyses carried out to assess the effect of the inter-pile gaps on the por...
Geotechnical engineering guidelines mandate the use of the most onerous hydraulic criteria for th... more Geotechnical engineering guidelines mandate the use of the most onerous hydraulic criteria for the design of earth retaining structures below the water table. Consequently, favourable local conditions, including the geometry of the structure, are not usually exploited. This means that retaining walls in particular are typically designed to resist hydrostatic pressures below the water table. Investigations have shown however that pore water pressures, axial stresses and bending moments reduce when groundwater seepage is allowed through the segmented linings of shallow tunnels. Contiguous pile retaining walls, by their nature, are also permeable. Allowing for groundwater seepage through the gaps in a retaining wall formed from contiguous piles could result in the pore water pressures on the active side of the wall being less than behind conventional impermeable retaining walls such as diaphragm walls. Numerical simulations, laboratory flow tank experiments and long-term field monitori...
Diaphragm and bored pile retaining walls are often used for the construction of basements, metro ... more Diaphragm and bored pile retaining walls are often used for the construction of basements, metro station boxes and cut-and-cover tunnels in urban areas. While diaphragm and secant pile walls are generally intended (and assumed in analysis) to be effectively impermeable, contiguous piles may allow through-the-wall seepage even when preventative measures have been undertaken. Provided the flow rates can be tolerated or dealt with, through-the-wall seepage should result in a reduction in pore water pressures behind the retaining wall compared with an impermeable construction, giving the potential for reductions in the depth of embedment and wall thickness, and hence cost. However, this potential is rarely realised owing to the difficulty in quantifying with sufficient confidence the hydraulic regime associated with a leaky retaining wall. This paper reports the results of laboratory investigations and numerical analyses carried out to assess the effect of the inter-pile gaps on the por...
Geotechnical engineering guidelines mandate the use of the most onerous hydraulic criteria for th... more Geotechnical engineering guidelines mandate the use of the most onerous hydraulic criteria for the design of earth retaining structures below the water table. Consequently, favourable local conditions, including the geometry of the structure, are not usually exploited. This means that retaining walls in particular are typically designed to resist hydrostatic pressures below the water table. Investigations have shown however that pore water pressures, axial stresses and bending moments reduce when groundwater seepage is allowed through the segmented linings of shallow tunnels. Contiguous pile retaining walls, by their nature, are also permeable. Allowing for groundwater seepage through the gaps in a retaining wall formed from contiguous piles could result in the pore water pressures on the active side of the wall being less than behind conventional impermeable retaining walls such as diaphragm walls. Numerical simulations, laboratory flow tank experiments and long-term field monitori...
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Papers by clive wiggan