This can be performed when ground conditions are "soft" or incompetent. Polyurethane grouts of an expansive type are particularly suitable for this purpose since they are injected in liquid form (allowing for excellent penetration) and during reaction are expansive, which simultaneously creates compaction and consolidation. This increases in-situ strength enormously and generally, also provides a waterproof barrier.
As older industrial sites are decommissioned, the underlying infrastructure must be free from contaminants and hazardous substances prior to reassignment of the land for other uses. Often void or redundant pipes and transmission lines for processing plants need to be sealed prior to removal or evacuation. Our materials are often viewed as ideal for this purpose, because they have excellent chemical resistance and NSF 61 approval for use in potable water, around groundwater and streams and rivers.
Permeation grouting is the injection of a grout into granular fissured or fractured ground in order to improve load bearing capacity. Sub-Technical's range of Polyurethane grouts and advanced injection processes have clear advantages over traditional cements and sodium silicates. They are stronger, up to 10,000 P.S.I., compressive they can be flexible or rigid, their migration can be precisely controlled, and many have environmental approvals. (U.L./N.S.F.)
Rail Tunnel Rehabilitation
For rail tunnels, whether for void filling, water control or ground consolidation and control, a range of materials are available to address these problems. Coupled with non-invasive methodology means that solutions can be applied quickly and economically.
A common means of retention and support, Sub-Technical has the equipment and workforce to effectively place these anchors. Where doubtful conditions exist engineers may wish to consider polyurethane grouts as the anchoring medium due to its versatility and mechanical properties. Sub-Technical is also involved in remedial measures to seal and reconstitute failed anchors to and beyond original test criteria.
Over the last decade Sub-Technical has performed projects in active tunnel construction, we have worked with many of the J.V.'s and their associated engineering consultants. Our work has covered many of the common ailments such as ground and water control grouting, but has extended to include liner stabilization, preventing "overbreak" problems and gas control. Our range of materials coupled many processes adapted from our vast experience in the mining industry means that we provide innovative time saving processes to get driveages back in business quickly and effectively.
Void Filling is performed for a variety of reasons - sometimes structural and often also related to water control and even ventilation. Sub-Technical has developed techniques and materials that directly address these issues. Polyurethanes with reaction times in seconds allow extremely rapid deployment. Due to their speed of set-up they can eliminate, or greatly reduce the need for formwork. Consequently, these systems compete with other conventional cementitous systems very favorably.
Straight, Curved, Block-built, Earthen and Coffer dams all have problems with leaking and the associated deterioration of foundations, monoliths etc. Sub-Technical has years of experience with all types of dams. Our forte is offering permanent solutions through the engineered-back application of polyurethane grouts.
Hydro Electric Units
Although, of course, usually directly related to their attendant dams, many of these units exist and they are often of "turn of the century" construction. This means that anyone involved in their maintenance and waterproofing has to understand this and apply the appropriate solutions. Sub-Technical's technicians have practiced this specialized knowledge in polyurethane grouting for well over a decade to help keep these units up and running.
With over a decade of direct experience with this geologic feature we have the ability to secure the conditions from leaking and eliminating the possibility of "blow out" from extruding clays. Pits and quarries can suffer huge pumping costs as a result of not addressing these problems. The extent of the effects of "Karst" are truly global; and the issues pertinent to it are numerous, including subsidence, sink holes, damage to utilities, property and general infrastructure. It effects many aspects of ground, hydrology and can be extremely destructive.
Power & Telecommunication Vaults
Many industries use a number of types of sub-surface vaults to house equipment. These vaults and the various cables, conduit and pipes that enter them often allow groundwater to penetrate. The only repair option in many cases is excavation which is costly, time consuming, and in many cases impossible due to the surrounding environment. Sub-Technical can easily supply a range of external and internal options which are minimally invasive and wholly effective.
Road Tunnel Rehabilitation
For road tunnels, whether for void filling, water control or ground consolidation and control, a range of materials are available to address these problems. Coupled with non-invasive methodology means that solutions can be applied quickly and economically.
Where concrete liners deteriorated through ground pressures or water intrusion and freeze thaw cycle. Polyurethane grount injection can control water and consolidate poor ground conditions providing effective long term relief. Additionally, prior to sinking, when shafts are projected to pass through water laden strata they can be "pre-grouted" to stop the water BEFORE it becomes a problem.
Whether to halt deteriorating sheet piling at a dock, or to reinforce river and stream banks, polyurethane grouts are ideally suited to the task at hand. Their expansive nature combined with chemical resistance (including brine) and the National Sanitation Foundation Standard 61 approvals make them the choice of Structural and Environmental Engineers for work adjacent to bodies of water.
This technique of placing cement foundations and cut-off walls by excavation/slurry placement and displacement with cement has proven extremely effective. However, when problems with the integrity of the wall occur during construction, issues with cracking or "soft" zones and groundwater can be easily addressed by polyurethane grout injection. Polyurethanes can seal and bond the structure, returning the effected area to service to or beyond the original specification.