With a large number of projects in the UK requiring the construction of piling mats and requests forRoadCem stabilised soil design information, we have made a general table for the thickness of this typeof construction for different soil types.

Due to the fact that the type of vehicles during the “lifetime” of this construction is on all the sitespractically the same:

� pilling drilling machines and

� trucks, that are delivering the piles.

Based on the Bearing Capacity an estimation of the type of soil is made and a mix design is estimatedand the mechanical properties of the stabilization (1).

These mix designs are indicative, and might need to change if local circumstances are requiring this(large amounts of organic material in soil).

For the calculation of the bending moments, strains under the tires of the trucks (2) the multi-layerelastic methodology is used.

With the computer program BISAR the stresses and strains are determined.

For the calculations for the minimum thickness of the pilling drilling machines (3), the Hetenyi-method was used.

With this method the bending moment, and the shear strength can be accuratelydetermined under the specific continuous tracks of the pilling drilling machines.

Soil Piling Mats

1. Mix Designs and mechanical properties of the stabilized material.

2. Calculation of the stresses and strains for the heavy truck that are delivering the piles.

For the calculation we assumed a standard axle load of 100 kN, with 4 wheels per axle.

PROPERTIES DESIGN

Sub grade

Modulus ofsubgradereaction Soil type RoadCem Cement Stiffness

MinimumThickness Strain

Safetyfactor

[E : MPa]dyn [N/mm3] [kg/m3] [kg/m3] [Edyn: MPa] [cm] [mm/m]20 0,020 Clay 2,4 240 2500 30 202 1,1930 0,025 Clay 2,2 220 3000 25 214 1,0740 0,030 Clay 2,2 220 3500 25 179 1,1750 0,035 Clay 2 200 4000 25 146 1,3060 0,040 Sandy clay 1,8 180 4500 25 134 1,2770 0,045 Sandy clay 1,8 180 4500 25 130 1,3180 0,050 Sandy clay 1,8 180 4500 25 126 1,3590 0,055 Sand 1,6 160 5000 25 113 1,33

100 0,060 Sand 1,6 160 5000 25 110 1,36110 0,065 Sand 1,6 160 5000 20 146 1,03120 0,080 Sandy gravel 1,4 140 5500 20 133 1,05130 0,085 Sandy gravel 1,4 140 5500 20 130 1,08140 0,090 Sandy gravel 1,4 140 5500 20 127 1,10150 0,095 Sandy gravel 1,4 140 5500 20 125 1,12

Sub grade

Modulus ofsubgradereaction Soil type RoadCem Cement Stiffness

Breakingstrain

Flexuralstrength

Shearstrength

[E : MPa]dyn [N/mm3] [kg/m3] [kg/m3] [Edyn: MPa] [mm/m]20 0,020 Clay 2,4 240 2500 240 0,75 0,5030 0,025 Clay 2,2 220 3000 230 0,90 0,6040 0,030 Clay 2,2 220 3500 210 1,05 0,7050 0,035 Clay 2,0 200 4000 190 1,20 0,8060 0,040 Sandy clay 1,8 180 4500 170 1,35 0,9070 0,045 Sandy clay 1,8 180 4500 170 1,35 0,9080 0,050 Sandy clay 1,8 180 4500 170 1,35 0,9090 0,055 Sand 1,6 160 5000 150 1,50 1,00

100 0,060 Sand 1,6 160 5000 150 1,50 1,00110 0,065 Sand 1,6 160 5000 150 1,50 1,00120 0,080 Sandy gravel 1,4 140 5500 140 1,65 1,10130 0,085 Sandy gravel 1,4 140 5500 140 1,65 1,10140 0,090 Sandy gravel 1,4 140 5500 140 1,65 1,10150 0,095 Sandy gravel 1,4 140 5500 140 1,65 1,10

3. Calculation of the stresses and strains for the pilling drilling machine.

For the drilling machine the following assumptions are made:

Type of drilling machine: Woltman THW 4017Weight 40 tonTracks 900 x 4850mm

PROPERTIES DESIGN

Subgrade

Modulus ofsubgradereaction Soil type RoadCem Cement Stiffness Thickness Flexural strength. shear

[Edyn:MPa] [N/mm3] [kg/m3] [kg/m3]

[Edyn:MPa] [cm]

Stress[MPa]

safetyfactor

Stress[MPa]

safetyfactor

20 0,020 Clay 2,4 240 2500 55 0,69 1,09 0,10 5,0030 0,025 Clay 2,2 220 3000 45 0,92 0,98 0,12 5,0040 0,030 Clay 2,2 220 3500 35 0,99 1,06 0,15 4,6750 0,035 Clay 2,0 200 4000 30 1,19 1,01 0,18 4,4460 0,040 Sandy clay 1,8 180 4500 30 1,18 1,14 0,18 5,0070 0,045 Sandy clay 1,8 180 4500 25 1,31 1,03 0,21 4,2980 0,050 Sandy clay 1,8 180 4500 25 1,25 1,08 0,21 4,2990 0,055 Sand 1,6 160 5000 20 1,48 1,01 0,27 3,70

100 0,060 Sand 1,6 160 5000 20 1,42 1,06 0,27 3,70110 0,065 Sand 1,6 160 5000 20 1,37 1,09 0,27 3,70120 0,080 Sandy gravel 1,4 140 5500 15 1,52 1,09 0,36 3,06130 0,085 Sandy gravel 1,4 140 5500 15 1,47 1,12 0,36 3,06140 0,090 Sandy gravel 1,4 140 5500 15 1,43 1,15 0,36 3,06150 0,095 Sandy gravel 1,4 140 5500 15 1,39 1,19 0,36 3,06

Whilst PowerCem only started our business in the UK quite recently we have been able to learn from the many PowerCemapplications carried out abroad over the last ten years.

RoadCem soil stabilisation technology enables any materials including organic top soils to be effectively stabilised to buildstrong, safe piling mats for both driven and auger piles.

With this proven time and cost saving technology now available in the UK. Why is stone and crushed concrete still beingtrucked to new sites for piling mat construction?

Have you had any of the following problems with a stone piling mat?

o Planning and local issues with the trucking of large amounts of materials to and from your site.

o Miscalculations with quantities of cut and fill.

o Levels issues as the weak sub soils compact under the heavy stone mat.

o Mats that need to be far larger than the piling area to allow for the problems of shear.

o Dangers of moving top heavy rigs onto and off the unbound stone mat, at commencementand end of operations.

o Dangers of moving top heavy rigs around the unbound stone mat.

o Unpredictability and delays when setting up the rig for each pile on the unbound stone mat.

o Deflection of the piles due to hard and soft areas/pieces of stone.

o Heavy rains causing the stone fines to migrate lower in the mat, allowing the larger stoneson the top to move.

o Frost getting into trapped water in the mat.

o Piles snagging in the supporting geogrid/mat.

o Problems removing the stone and pierced geogrid/mat from between the piles is timeconsuming and labour intensive.

o All used stone and geogrid removed after piling must be trucked off site, as waste

o These materials used are now classed as contaminated and must be landfilled or recycled(cleaned). Both costly options.

It has been shown that most piling mats can be constructed from materials already in-situ on your site.RoadCem can be used to produce predictable, safe mats, with visco static properties which absorb dynamic impactpreventing cracking and breakaway during piling, enabling quick rig set setup and deflection free piling.RoadCem mats are shear resistant, allowing smaller mats to be used, they are also impermeable to water, oil and acidsenabling planned collection of run off of spills or heavy rain.They are also frost resistant and can be constructed and used in all weathers.Finally when the piling is complete they can be left in place as blinding for foundation components. Or milled back to soilfor reuse elsewhere on the site.

Certified stabilised soil piling mat designs can be prepared by our colleagues Rodgers Leask consulting engineers of Derby.