June 2007 - construction

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Thursday 28th June

 

 

The top tier retaining wall is now approx 2m high - another 1.5m to go

 

 

 

 

Concrete foundations have been started for the lower of the two retaining walls

 

 

Pre-mixed concrete is delivered to the site

 

Concrete is poured from the mixer into the bucket of a 21tonne excavator. 

The mixer doesn't have caterpillar tracks so is unable to take the concrete directly to the trench.

 

 

The geo-grid is set within the foundations

 

 

The level of the newly poured concrete is checked with points at each end of the wall and adjusted as necessary

 

Dark clouds gather ominously - the start of the wet weather to come!

 

Tuesday 26th June

 

 

 

 

Thursday 21st June

 

The retaining wall at the east end is now approx 1m high - with a further 2.5m to go

 

As well as the plastic dowels, shingle is also used to fill the vertical gaps within the purpose-built blocks

to increase the wall's rigidity, whilst still allowing it to flex within specified limits. 

The dowels within each course of blocks also hold in place a plastic geo-grid which can be

seen laying across the top of the soil.  This helps to bind the soil and wall together.

 

The first two courses have been laid in the middle of the wall, the west end has yet to be started

 

 

 

 

 

Looking east, with the first course of blocks in the middle section of

the wall and bare concrete foundations at the western end

 

Preparatory work continues on the middle tier, concrete foundations will be poured next week

 

 

 

 

Tuesday 19th June

 

Retaining wall of the top tier

 

In order that the wall can flex to accommodate moisture changes within

 the soil it is retaining, the blocks are held in place by vertical dowels - no mortar is used. 

The blocks are purpose-built to be used in retaining walls such as this.

 

Layers of soil, clean limestone, shingle and porous teram (the black plastic sheeting

sold in garden centres) are placed behind the retaining wall and then compressed.

 

 

Once the first course of blocks has been laid the next length of trench is prepared

 

 

The first two courses of blocks have been laid at the eastern end

Friday 15th June

Concrete foundations have been poured for the eastern end and

north edge of the retaining wall.  A plastic geo-grid is set

within the concrete to be laid across the soil behind the wall