SOILS STABILIZATION

Settlement is often attributable to inadequate fill material such as frozen fill or improper base compaction. Other causes contributing to a weak base soils condition also include: drying out of the ground surface layers (desiccation); reduction in water table level; wash-out caused by leaking water pipes, sewers and drains; excavations adjacent to buildings; inadequate foundation design; vibrations caused by heavy road traffic or adjacent construction sites; and base soils with different geological strata.

Whatever the cause for subsidence in the building floor slab or foundation, the base soils will require densification to enhance their load-bearing capacity to bear the loading of the building structure.

POLY-MOR uses a form of “chemical compaction grouting” where a special high density, hydro-insensitive expanding polymer resin is used to fill, densify and stabilize low density, compressible soils to depths of 30 feet and beyond. The POLY-MOR resins are delivered and placed at the appropriate depths in the required soils strata via drilled or driven injection probes . As the POLY-MOR resin is injected, it expands and provides a compaction or lift force of up to 50 tons per square meter thereby filling, compressing and compacting adjacent soils and significantly increasing the load bearing capacity of the base soils resting under a structure. Our soils densification process is also excellent for conglomerating and binding non-cohesive soils.

There are limitations to this process. The parameters of this treatment technique make it suited to a large range of cohesive soils including a wide range of clays up to 44% plasticity index. We are unable to treat clays, silts or other fine soils with large volumetric changes where thrust from the clay exceeds the dead load of the building or foundation weight or where the soils are so heavily compacted that our resins cannot permeate same. Also, in very weak alluvial soils such as peat, hog fuel, saturated silts and other weak sediments direct injection into same will densify the weak soils but an inordinate amount of expanding resin would be required and thus make the process uneconomical. Further, and in all cases, injection at depth is done blindly and there is no telling exactly where the expanding resin is traveling to. Before and After Standard Penetration Tests (SPT) are the only way to determine if the base soils have been densified sufficiently to accomplish the desired load bearing requirements.

POLY-MOR strongly advises that a third party engineering firm be involved to undertake and provide the appropriate soils testing and analysis of the “Before” and “After” SPT’s. In most cases Poly-Mor would recommend that a field test firstly be undertaken prior to any large scale treatment being undertaken

Standard Penetration Test (Before & After)

POLY-MOR Canada Inc. has developed a method of densifying weak and very weak soils. Soils such as peat, hog fuel, super-saturated silts, etc, where SPT blow counts are from weight of hammer to 3 — 5 are typically very difficult to densify to prevent surface settlement. The amount of expanding resin that would be required to densify these weak soils would be so large that the process would prove uneconomical.

The Patent Pending modus operandi (MO) that POLY-MOR Canada Inc. would employ would be to firstly analyze the geo-technical data to determine the depth of the strata to be treated. The analysis would provide direction as to the depth of the weak soils strata that has to be treated and at what depth this strata is located. An appropriately sized and shaped containment bag would be manufactured and placed at depth in the weak soils strata to be treated. The containment bag would then be injected with a predetermined amount of expanding resin. The expansion of the resin within the containment bag will then compact and compress the weak soils thereby densifying and stabilizing same. The grid pattern typically would be staggered and separation at 3′ or 6′ depending upon the soils strength being treated. A field test may be required to determine the most effective grid pattern.

Applications

This technology is applicable in the industrial, commercial, residential, public works and institutional markets where soils stabilization is required. Some examples of soils stabilization uses include:

  • Under foundations that are experiencing settlement due to desiccation or a weak strata of base soils at depth.
  • To stabilize poorly compacted base materials under rigid and flexible road pavements and other slab-on-grade structures.
  • Densify soils under the base of manholes and catch basins prevent further settlement as well as rehabilitating the soils around these structures.
  • Under and around failing piles,including vertical stabilization members carrying above grade pipes and other structures.
  • Gravel-lock as a form of armoring to prevent erosion.
  • Slough-erosion protection where excavation in tight places is required.
  • Agglomeration of blast rock to prevent movement or washout of fines through the blast rock.
  • Well-head stabilization in perma-frost ladened soils to stabilize and insulate the soils to minimize the melting of the perma-frost and re-establish a firm base at the well head site.

Key Benefits

POLY-MOR material is guaranteed for a period of 10 years against any significant deterioration.

POLY-MOR material is light weight thereby adding little additional overburden weight to an already distressed sub-grade.

POLY-MOR material is highly insulative and therefore desirable to be used in where perma frost and ice lensing is a consideration.

The POLY-MOR resins are environmentally friendly and no leaching takes place.

The closed cell nature of the POLY-MOR resins is impermeable to water and other liquids and is not affected by freeze-thaw cycling.

We are able to “fix dirt”!!! If you are challenged by a poorly compacted sub- grade, or a weak base soils strata at depth, or require agglomeration of base soils such as blast rock, etc., POLY-MOR technology will resolve your challenge! Do you have such a challenge?