• Controlled Modulus Columns (CMC)    CMC ( Controlled Modulus Columns - patents pending worldwide ) uses a revolutionary patented in-house designed type of auger to build cement columns by displacement of the surrounding soil.    The result is a high capacity cement column with virtually no spoil that can be used in close vicinity to sensitive structures.    The differences with classical piles are twofold :    - Ability to control the compression modulus of the cement grout leading to a stress-sharing concept between soil and columns allowing considerable savings in the columns required depth ( see design concept ).    - Due to the revolutionary shape of the auger, columns are built by displacement of the surrounding soil without spoil.    It means that soil is laterally displaced leading to an improvement of the surrounding soil itself.    Furthermore, after grouting, the auger is driven down again inside the cement-grout inside the column allowing to compact this grout and push laterally surrounding soil in the same concept as the stone columns process.    Therefore, considerable torque is required to install CMC due to the necessary energy for lateral displacement of the surrounding soil and compaction of the cement grout.    In addition to that, at the contrary of stone columns, there is no limitation of the internal stress due to lack of confinement.    It means that there is no risk that the columns bulks when loaded due to poor confinement ability of the surrounding soils.    For example, thanks to their internal strength, it is possible to install the CMC columns in peat with very low lateral confining pressure.    CMC columns dimensioning concept has been patented worldwide and has proven revolutionary in the field of application of the CMC technology.    The ability to control the compression modulus of the grout allows to maintain a reasonable ratio between the moduli of the soil itself and the column.    This ratio is preliminarily designed given the soil and project characteristics.    In the classical piles approach, the soil modulus is negligible to the concrete modulus.    As a result, it is admitted that the load is fully transmitted to the piles with no change in stresses inside the soil : the soil is a passive spectator.    Therefore, it is necessary to transmit the total load to hard uncompressible layers by anchoring the piles inside bedrock.    The deeper the bedrock, the longer the piles, the more expensive the solution.    Menard Soltraitement has introduced a new concept of dimensioning applicable for CMC technology straight from its years of experience of soil improvement.    With the CMC method, the complex soil-column is acting on an equal strain concept.    It means the load applied on the top of the ground is shared between the columns and the soil itself according to the ratio of moduli previously defined.    Thanks to this approach, it is no more necessary to anchor the columns down to bedrock, dramatically reducing the column length compared to piles.    Furthermore, there is no need of expensive pile caps and repartition beams to transmit the full load to the piles. Buildings can be constructed on shallow spread footings and slab on grades directly on the improved soil surface provided a granular material mat is installed between CMC head and the foundation to allow stress repartition and arching effect. As a result, CMC method is by far less expensive than classical pile method.    The technique requires a high torque and a high vertical thrust in order to both displace laterally the soil without spoil and to compact the workable grout.    The patented auger rotates in the same direction during penetration and removal ensuring the soil above the auger remains compacted by the reverse direction flights located at the top of the auger.    During the formation of the CMC column, the rate of auger extraction is controlled with respect to the cement grout flow rate.    Quality control devices continuously control the supply quantity giving records of the column diameter versus depth.