Unfavorable Soil Conditions For Soil Nailing

June 26, 2015

Last month, we covered some details about the most favorable soil conditions for the use of soil nailing. Today, we’re looking at unfavorable conditions in which we would not advise soil nails. At Thorcon Shotcrete and Shoring, our team of engineers reviews each project to ensure that the best method of shoring or slope stabilization is used based on the currents conditions. Located near Denver in Littleton, Colorado, we serve each of our clients here and in the surrounding region with custom solutions which ensure lasting and safe results.

In the past, we’ve reviewed how cost effective soil nailing can be as a slope stabilization solution, however if you are dealing with the following soil conditions, soil nailing is not ideal, so we would recommend an alternative strategy:

  • Water-infiltrated loess: While dry loess can provide suitable conditions for soil nailing, if water is a threat then the structure could collapse, which would not be an economic stabilization option.
  • Cohesionless soils: In soils which are poorly graded and particularly dry, it is difficult to make the appropriate cuts. Soils with some natural cohesion are preferable.
  • Organic soils: Because organic soils typically don’t exhibit much bond strength, longer nails must be used which can diminish the cost-efficiency of the project. Some organic soils can receive soil nailing and still save money, though, so our engineers will determine whether soil nailing is the best option in cases with organic soil.
  • High groundwater situations: When water threatens to interfere, it disrupts the stabilization of the soil and can cause the nail holes to collapse. Also, too much groundwater can hinder the initial application of the soil nails.
  • Weathered rock exhibiting karst or other weakness planes: Certain fractures and faults can be problematic to the stability of the soil nail holes and can also make the installation process difficult. Due to the ongoing change in karst areas, especially, soil nailing is not an economic option.

Other soil types can cause a problem as well, such as highly corrosive soils, which can threaten the longevity of the nails; fine-grained soils, which also exhibit little cohesion and bond strength; and soils which contain a lot of cobbles and boulders, which can cause problems in the initial drilling. While in many of these cases, soil nailing is possible, it often isn’t the best solution for your budget, time and satisfaction. At Thorcon Shotcrete and Shoring, we complete each job with the custom needs of the client in mind and with a focus on safety. Contact us today to get started.