Installation, accessories and compaction requirements

 

Installation, accessories and compaction requirements

Installation and accessories

It is both simple and fast to install small and large drywells using BIO-BLOK® elements. The hole is excavated and the bottom is levelled.

Geotextile (fibre cloth) is then laid and the elements are put in place. The inflow and outflow to the drywell is established, after which the drywell is covered and wrapped around the sides and top with fibre cloth. We recommend that the fibre cloth be perforated in the bottom of the drywell. This is very easily done through the vertical net tube.

When the drywell (incl. fibre cloth) is installed, it is covered by approximately 10cm clean sand so that the fibre cloth is protected against sharp stones and similar. In areas subject to heavy loads or poor soil, we recommend that the construction be reinforced with a plastic reinforcement net such as EXPO-1211 Std. Lay this net on top of the sand layer specified. This ensures that the fibre cloth will remain intact and that a more uniform and evenly distributed load is achieved. See schematic diagrams under the section Configuration of drywells by clicking on the following link. » Read more


Drywell being installed

All BIO-BLOK® elements must be assembled using stainless steel staples. EXPO-NET will be happy to hire out staple guns on request for assembling individual elements and can supply stainless steel staples.


Staple gun and staples



Elements fixed together

If the drywell is built up in several layers, a stacking pipe should be used to hold the layers in place. Depending on the soil load, BIO-BLOK® drywells can be built up in several layers. See more information under the section on Product data by clicking on the following link. » Read more


BIO-BLOK® stacking pipe

BIO-BLOK® stacking pipes are rounded in the ends in a conical shape, making the fitting of the overlying elements fast and simple. The conical ends of the stacking pipes “catch” the ends of the top element when the element is inserted.


Installation of stacking pipes


The use of stacking pipes in drywells with elements in several layers makes the elements function as a whole, locked unit, which contributes to an easy installation process when installing the drywells.


The drywell is locked with stacking pipes


All horizontal joins between the elements must be locked together with stainless steel staples. In this way, a strong and flexible construction is achieved that will be able to withstand the different loads of surrounding layers of soil, without the net tube construction of the elements breaking.


BIO-BLOK® fitted with stacking pipes

Compaction

Soil compaction in connection with installing BIO-BLOK® elements
Generally speaking, the excavated soil could be reused as surrounding and backfilling material, since both friction and cohesive soil can be used. Cohesive soil will usually lead to larger settlements than friction soil. The stone content in the surrounding and filling material may lead to point deformations. If the excavated material fulfils the following requirements and those laid down for compaction, the material can be used for refilling. We recommend that tight supervision be carried out during this installation phase.


Compaction of natural soil
Natural soil must be integrated/compacted according to the following average requirements laid down for at least three tests, and no individual values must be less than 3% below the average requirement.

    Control Method
    Isotope method Sand refilling
a)  Natural soil level below natural soil fill 92% S. P. 94% S. P.
b)  Natural soil level below sand fill 95% S. P. 97% S. P.
c) Natural soil level below bottom protection gravel 96% S. P. 98% S. P.
d) Natural soil filling in ground 92% S. P. 94% S. P.
e) Natural soil filling in road embankment –
depth > 2m
92% S. P. 94% S. P.
f) Natural soil filling in road embankment –
depth ≤ 2m
92% S. P. 94% S. P.
Reference value set by Standard Proctor (S.P.) tests carried out in laboratories.

Compaction of sand fill
Sand fill must be integrated/compacted to the following average requirements laid down for at least three tests. No individual values must be less than 3% below the average requirement.


  Control Method
Isotope method Sand refilling
a)  Sand fill in installation trench/installation
excavation in ground
93% S. P. 95% S. P.
b)  Sand fill in installation trench/installation
excavation in surface areas –
light traffic (cycle path/pavement, etc.)
95% S. P. 97% S. P.
c) Sand fill in installation trench/installation
excavation in surface areas –
Heavy traffic (roads)
98% S. P. 100% S. P.
d) Sand fill in surface areas –
light traffic (pavements, cycle paths, etc.)
95% S. P. 97% S. P.
e) Sand fill in surface areas –
heavy traffic (roads)
98% S. P. 100% S. P.
f) Sand fill for sand cushion foundation
(supporting walls)
98% S. P. 100% S. P.
g) Sand fill in building areas –
light flooring (residential development)
96% S .P. 98% S. P.
h) Sand fill in building areas –
heavy flooring (industrial development)
98% S. P. 100% S. P.
i) Sand fill outside building areas 93% S. P. 95% S. P.
Reference value set by Standard Proctor (S.P.) tests carried out in laboratories.

Compaction of bottom protection gravel
Bottom protection gravel must be integrated/compacted to the following average requirements laid down for at least three tests. No individual values must be less than 3% below the average requirement.


  Control Method
Isotope method Sand refilling
a)  Bottom protection gravel in surface areas –
light pressure (pavements, cycle paths etc.)
95% S. P. 97% S. P.
b)  Bottom protection gravel in surface areas –
heavy traffic (roads)
95% S. P. 97% S. P.
Reference value set by Standard Proctor (S.P.) tests carried out in laboratories.


Compaction of stable gravel
Stable gravel must be integrated/compacted to the following average requirements laid down for at least three tests. No individual values must be less than 2% below the average requirement.

  Control Method
Isotope method Sand refilling
a)  Stable gravel on roads in construction sites 93% M. P. 96% M. P.
b)  Stable gravel under surfaces –
light pressure (pavements, cycle paths, etc.)
92% M. P. 95% M. P.
c) Stable gravel under surfaces –
heavy pressure (pavements/cycle paths, etc.)
94% M. P. 97% M.P.

Reference value set by Modified Protocol (M.P.) or American Standard Test Methods (ASTM) for Vibration stamping carried out in laboratories.

Reinforced excavation

EXPO-NET has prepared an example of how to reinforce an excavation.

To see the example, click on the icon below.

Klik her
(only in Danish)



Source for text regarding compaction:
The Danish Road Directorate standards