Plastic, structural and csm diaphragms

Marflutt's technology is also particularly efficient for the formation of bulkheads and the construction of diaphragms. The vibroflotation and the use of special steel jackets properly shaped with male/female joint allow the realization of continuous walls with or without soil removal, with improvement of the mechanical characteristics of the soil around the panel. 

The absence of bentonite or polymeric sludge simplifies the organization of the site, speeds up production and determines economies in the production and management of sludge, all in an absolutely clean site. The limiting characteristics of the soil are those indicated in the section "Marflutt piles without soil removal" and "Marflutt piles with soil removal".

It is a soil consolidation technology that allows the formation of baffles between 50 and 120 cm wide and 220 or 280 cm long with a depth of up to 25 meters with guided operation and up to 60 meters with rope lowered operation. 

The operating principle is similar to soil mixing since the soil is treated and simultaneously mixed with a binary or tertiary mixture to form a sufficiently compact block with good mechanical properties.

The main difference is that the soil is literally cut and ground by the rotation of 2 cutters on horizontal axes and that the operation can eventually reach greater depths. 

The power of the equipment and the cutting effect of the soil allow to operate not only in soft soils, but also in more consistent soils. CSM currently represents the substitute technology to diaphragms, able to solve many of the problems generated by it. In fact, the peculiarities of cutter soil mixing are

• absence of vibrations induced on adjacent buildings and reduced noise of the work; the only fact that there is no casting of concrete for the formation of the septum greatly reduces the transit of truck mixers on site;
• the mixing of the soil in situ does not involve the problems of supporting the excavation walls and avoids the detensioning of the soil around the work;
• reduced drainage during the execution phase;
• there are no problems in case of resumption of work (resumption of casting); the bulkheads created are therefore continuous and without joints;
• greater flexibility in the management of geometries and possibility of execution of the partitions close to the buildings.

The CSM bulkhead is made structural by inserting reinforcements in steel beams in the partitions.

• Excavation protection diaphragms
• Excavation protection diaphragms with static functions for box culverts
• Diaphragms for the construction of sewage treatment plants
• Diaphragms for the construction of watertight tanks with static functions
• Diaphragms for the construction of channel walls etc.

They are reinforced concrete structures used both as temporary works to support excavations and as permanent works for the construction of deep foundations or to serve hydraulic works; they are composed of a succession of rectangular panels with a thickness varying from 40 to 150 cm, 250 or 300 cm long, made by means of a hydraulic bucket mounted on a kelly or on a free cable.

The execution of a panel implies the excavation with the substitution of the soil with bentonite or polymeric slurries that guarantee the support of the excavation walls; once the bottom of the excavation is reached, the metal reinforcement is inserted and then one or more conveyor tubes through which the concrete casting is carried out starting from the bottom of the excavation.

During the casting phase, the bentonite sludge is extracted with the help of pumps. A sludge preparation plant and a plant for the desanding of the bentonite sludge are required to serve the process. The bulkhead can be made impermeable by installing water-stop joints between the individual panels.

This technology, although relatively economical, has some limitations arising from:

• management and disposal of bentonite and excavation soil contaminated by it;
• need for space on site, considerable amount of equipment required, dirty and noisy site;
• possibility of damage to adjacent buildings;
• realization of the geometry based on individual modules or with disposable elements.

Therefore, this work can be recommended in open spaces and not in urban contexts.

Given the continuous demand for the execution of waterproof bulkheads, new types of plastic diaphragms have been realized, with a particular attention to the problems of pollution:

plastic diaphragm made with self-hardening mixtures, mainly used for waterproofing canals and waterways with static problems;

bentonite diaphragm "Marflutt" realized with granular dry bentonite with high impermeability for the protection of waste dumps, waterproofing of basins realized without removal of material;

thin diaphragm in self-hardening mixture, realized without removal of material.

These are usually used as bulkheads or containment tanks; their peculiarity is the reduced permeability coefficient that varies depending on the type of mixture used and can reach an order of magnitude of 10-10 m/s. 

The executive procedure can be the traditional one used for structural diaphragms, but much more used is the single-phase procedure in which the mixture is used in place of bentonite sludge.

The thickness of these bulkheads is thinner than structural diaphragms and hardly exceeds 80-100 cm. A valid alternative, if the soil allows it, is the technology of Marflutt diaphragms.

The natural field of application of these works are the reclamation and treatment of polluted sites; the insertion of a waterproof membrane inside the diaphragm is recurrent.o state realizzate nuove tipologie di diaframmi plastici, con un riguardo particolare ai problemi di inquinamento:

• plastic diaphragm made of self-hardening mixtures, mainly used for waterproofing canals and watercourses with static problems;
• bentonite diaphragm "Marflutt" made of dry granular bentonite with high impermeability for the protection of waste dumps, waterproofing of basins realized without removal of material;
• thin diaphragm made of a self-hardening mixture, produced without removal of material.

These are usually used as bulkheads or containment tanks; their peculiarity is the reduced permeability coefficient which varies according to the type of mixture used and can reach an order of magnitude of 10-10 m/s. 

The execution procedure can be the traditional one used for structural diaphragms, but much more used is the single-phase procedure in which the mixture is used instead of bentonite slurry.

The thickness of these bulkheads is thinner than that of structural diaphragms and rarely exceeds 80-100 cm. A viable alternative, where the soil permits, is Marflutt diaphragm technology.

The natural field of application for these works is the reclamation and treatment of polluted sites; the insertion of an impermeable membrane inside the diaphragm is common.