Slope Stabilization

Slope instability refers to the collapse of a portion of a natural or man-made slope. For natural slopes, a slope failure or landslide may be caused by natural phenomena such as weathering, seismic events, rainfall, erosion, freezing, and thawing. However, for man-made slopes, a slope failure or slope instability may be caused by man-made activities such as mining, road construction, excavation, and building foundations.

For man-made excavations, it is quite common to have the specified excavation dimensional limits exceeded due to practicality issues and/or poor workmanship. In most cases, the deviation from design limits is not correctly recorded, and no reconciliation is ever conducted, which leads to slope instability.

In a large number of cases, major slope failures have been attributed to large-scale geological features such as shear zones, major faults, and contact zones that are running parallel to or in an unfavorable orientation to the excavated slope.

Slope stabilization and lateral ground support refers to the construction of structural elements used for the mitigation of potential slope instability. Slope stabilization systems are also used for shoring steeply excavated building foundations. Slope instability ranges from small failures to substantial failures that cause serious damage to critical public and private infrastructure. Slope failures may also lead to disruptions of critical economic systems, such as the closure of a mine or critical road access. There is a wide range of slope stabilization and lateral ground support systems currently available on the market. These include soil nails, rock anchors, shotcrete, and micropiles. The selection of the most efficient slope stabilization system is based on the results of the slope stability analyses and the desired factor of safety or as specified by the project design engineer. 

In most countries in the world, the basic requirement before any major ground excavation activities is to conduct a detailed geotechnical investigation. This is done to establish the basic properties of the sub-surface rock mass or soil conditions. A geotechnical investigation usually includes digging test pits and drilling boreholes to obtain representative samples of soil or rock for further laboratory testing. Laboratory test results are used as parameters in the software for slope stability analysis. The results of the slope stability analyses are used for the design of excavation limits such as maximum depth, slope angle, berm width, etc.

Hoff Geotechnik offers turn-key solutions for slope stabilization and lateral ground support for mining and civil engineering projects. Our range of solutions for slope stabilization and lateral ground support can be summarised as follows:

• Soil nailing 

• Rock anchors

• Micro piling 

• Wire-mesh 

• Shortcrete

Hoff Geotechnik is a specialist contractor for slope stabilisation and lateral ground support for areas with limited access by conventional means such as scaffolding and high access cranes. In conventional slope stabilization projects, ground anchors are drilled from a natural ground platform. With Hoff Geotechnik, ground anchors are drilled from a suspended platform, up to 500m below ground surface. Our drill depth ranges from 1-50m, and the borehole diameter ranges from 21-115mm.  

Why US

Our methods for slope stabilization methods are suitable for conditions where conventional methods are limited. This includes difficult topography such as steep cliffs, high walls and confined excavations such as hydro power plants, mine box-cuts, and/or access portals. Hoff Geotechnik is not limited by topography, height, access space, etc. 

Think about lateral support in a mine box cut or underground access portal? This particular type of project sometimes occurs within very limited time constraint. For this type of project, the rate of excavation is very important. Often, the rate of excavation is dictated by the method of slope stabilization and lateral ground support. Conventional slope stabilization and lateral ground support methods will dictate the excavation rate to go in 2,5m benches. However, it should be noted that where ground conditions permit the sink rate can go at a rate of 10-30m benches. Also, it should be noted that the box-cuts and the mine access portals are associated with limited and highly confined spaces. Limited access slope stabilization and lateral ground support allows for ground support to be installed simultaneously with the rest of the activities that must take place within the confined and limited space available in a box-cut. 

Get in touch with us to find out how we can assist you.