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Guy Barnes
Arbitrator
Asked a question last year

Scouring of subgrade below/adjacent concrete driveway

During heavy downpour, the soil beneath the driveway keeps chipping away. Please can someone advise a cheaper solution to this?

Where am I?

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Scoring of subgrade : Scour highly reduces lateral soil support and Lateral soil support is very essential to bear maximum bending stress.

When the ultimate lateral pressure is lower then it was caused by decreased vertical effective stress and indirectly decreased the initial modulus of subgrade reaction.

How to reduce scour in subgrade :

Here I am discussing some points, through that we can easily reduce scour in the the the subgrade, they are as follows;

By the installation of geotextile carpet Using 3D geogrid By effective slope formation process By doing soil stabilization

I hope so your doubt is clear.

Ricardo Kuhn
Construction Foreman

Road shoulder, which is an important of the road, should be provided to protect the road from water ingression, and it also serves as lateral support for the road, parking area for disabled car is it is wide enough, and it prevents edge-drop of cars. Fig. 1 may be a cost-effective way to construct a road shoulder but it may not be the best way.

Figure 1
Figure 1
Figure 2
Figure 2

The soil under the driveway is being further compacted by the weight of vehicular passage and parking over and on its surface. Softened by the heavy downpours of rainwater permeating through the driveways surface which neither diverts the rainwater away from its accumulation on the surface or provides a sufficient, subsoil foundation to prevent compaction. Unfortunately there is no cheap, quick and permanent solution to preventing this softening and compaction erosion of the underlying, driveway surfaces soil without :-

  • Excavating the driveway back to a firm bedrock beneath the subsoil layer by removal of the topsoil. 
  • Investing the bedrock layer with graded, hardcore aggregate to fine stones on top of sufficient depth (to support a heavy vehicle) and use of a mechanical, rolling compactor to consolidate the permeable aggregate over a number of days to allow for any elastic recovery through accumulated rainwater permeation. 
  • Enabling a slight crest at the centre of the graded aggregate driveways surface to allow for rainwater run off to its edges with elevated, drainage gully channels to a rubble and coarse to fine aggregate soakaway beneath the subsoil, bedrock layer of aggregate to divert rainwater instead of its driveway accumulation. 
  • Fixing sufficient depth of shuttering timber against wooden stake pegs driven firmly into the foundation aggregate and bedrock around the entire circumference of the driveways rectilinear, surface area. 
  • To allow for an impermeable layer of either poured concrete aggregate mix or tarmacadam, cold roll coarse followed by fine aggregate mix with sufficient, heavy rolling by a mechanical roller in order to compact and consolidate each tarmacadam coarse followed by fine, aggregate mix layer.

The most common cause of driveway erosion is flowing water. If rain water from the downspouts of your house is directed to flow down the driveway, divert it. Water tends to flow along the sides of the driveway causing soil erosion. Still, you have water direct from rainfall. The best driveway erosion ctrl soln is to have a permeable paver driveway with necessary edging.

Scouring of subgrade: The soil which is in under the driveway is being further complicated by the weight of a killer passage and parking over and on its surface as well. Does soft ant bite the heavy downpours of rainwater which permits through the drive phase surface which neither diverts the rainwater away from its accumulation on the surface nor provide a sufficient subsoil Foundation to prevent the compaction process. But unfortunately, the reason no 3 as well as adequate and one of the permanent solution which prevents this type of software and compaction erosion of the underlying driveway surfaces soil without the following terms:

Excavation of the driveway back to the former Bedrock below the subsoil layer after removal of the topsoil. Investment of Bedrock layer with graded and hardcore aggregate to fine stones on the top of enough depth for supporting heavy The use of mechanical and rolling compactor used to consolidate the permeable aggregate which is present over a number of days to allow for inelastic recovery through accumulated rainwater permeation. enable a small crest that is present at the center of the graded aggregate the surface of a driveway to permit for rainwater runoff. Fixing sufficient depth of shuttering timber against wooden stake pegs driven firmly into the foundation aggregate and bedrock around the entire circumference of the driveways rectilinear, surface area. To allow for an impermeable layer which is either port concrete aggregate makes or cold roll course followed by a fine aggregate mix which is sufficient.

Thank you.

Scoring is defined as a process due to which the soil or rock particles around the abutments periphery or periphery of the pier of the highway bridges spanning are gets corroded and removed up to a certain depth which is called scour depth. Scoring can easily be observed. Scoring is not the term related to pavement and concrete. To avoid the removal of subgrade below the concrete for bituminous pavement is shoulders must be provided. Also, the embankment must be provided with proper slope and suitable method of stiffening and compacting should be adopted.

The most economical method of compacting is uses of bamboos and root fibres in the soil which makes it steep compact and highly tensile resistant.