NATURAL HAZARD MITIGATION
We offer our clients maximum support (providing drawings, dispatching specialists for consultations, providing turnkey project estimates, etc.) in the design of engineering structures to protect areas from the following hazardous geological processes:
- Snow avalanches
- Mountain mudflows
- Landslides
- Rockfalls
- Rock falls in the broad sense.
LANDSLIDE PROTECTION
Landslides are defined as the movement (sliding, viscoplastic flow) of rock masses on a slope, occurring without loss of contact between the displacing mass and the underlying stationary rock mass, often leading to catastrophic consequences.
During surveys on landslide-prone slopes, it is necessary to determine the types and subtypes of slope processes based on the mechanism of rock displacement, the conditions under which they occur, and the nature of their manifestation. It is also necessary to identify the relationship between landslide deformations and the terrain, geological structure, groundwater exposure, geological and engineering-geological processes (erosion, abrasion, weathering, flooding, drainage, etc.), as well as the results of economic activity (slope undercutting, slope loading, changes in groundwater levels, destruction of woody vegetation, dynamic loads, etc.).
The stage of engineering surveys in landslide-prone areas is fundamental for subsequent stages of development of design and working documentation for landslide prevention measures, since the calculation of any loading or retaining devices and structures is impossible without taking into account the parameters of the physical and geological model of the landslide massif.
ROCKFALL PROTECTION
Rockfalls (rock slides and taluses) are defined as the collapse (tipping, falling, or rolling) of rock masses on a slope (in the form of large and small boulders – rock slides; crushed rock and debris – scree) as a result of their separation from the bedrock.
During engineering surveys in areas prone to rock slides and talus processes, our specialists consider the following specific factors within the developed work program:
-The association of slope processes with specific geological formations, tectonic structures, and geomorphological elements;
-The influence of hydrogeological, hydrological, and meteorological conditions on the occurrence of slope processes;
-The influence of slope topography, steepness, and aspect on the occurrence of talus and rockfalls;
-The role of economic activity in activating slope processes;
-The presence of other types of modern exogenous geological processes (weathering, erosion, abrasion, etc.) and the degree of their influence on slope stability and, in particular, on the occurrence and development of various types of landslides and rockfalls.
Slope hazard assessments are determined by calculations that determine:
-rock masses subject to rockfall;
-paths traversed by rockfalls;
-estimated rock displacement velocity during rockfalls;
-energy released during rockfalls.
Landslide hazard assessments and calculations should be based on mathematical models that take into account the spatial nature of phenomena. These calculations are based on engineering-geological maps that reflect the spatial distribution of blocks detached from slopes, with actual and potential surfaces and zones of weakness. Topographic data is used to calculate the volumes of rocks that may be moving, the areas over which they will be displaced, their deposition sites, their paths and trajectories, and the speed and destructive forces of movement.
Currently, existing measures to counter rockfalls and slides are divided into:
-Catching structures: rockfall barriers or curtains;
-Cross-cutting structures: concrete galleries;
-Retaining structures: 2D-GEO landslide protection system.
PROTECTION FROM DEBRIS FLOW
Under the debrisflow (mudflow) we understand suddenly encountered short time destructive mountain flows of mud and rocks (flow rate up to 10 m / s), full of detrital material (up to 50 - 70% of total) formed in mountain river beds and temporary water streams during heavy rains or intensive melting of snow and ice, as well as a result of breakout of dams, natural and artificial dikes in valleys, with stocks of loose debris.
To design an individual debris flow barrier for your area we will need as minimum the following parameters of debris flows:
• Speed of movement;
• Density;
• Impact force of the flow;
• Volume concentration of solids in the mudflow mass;
• The nature of the movement;
• Hydraulic flow radius;
• Lag time of stream to a given cross-section of valley.
PROTECTION FROM SNOW AVALANCHES
The safety of people and the economic efficiency of mountain facilities largely depend on the correct determination of avalanche initiation zones and the assessment of their dynamic characteristics, such as volume, velocity, throwing range, impact force, and avalanche flow height. However, landscape indicators of avalanche activity do not always define the boundaries of potential avalanches or allow for the assessment of their dynamic characteristics.
Therefore, collecting reliable data on the avalanche catchment area, average avalanche front height, snowpack density and depth, avalanche path length, slope angle, etc. is particularly important for calculating avalanche characteristics when designing avalanche control structures. This task should be accomplished by trained specialists during the comprehensive engineering survey phase.
Based on the analysis of the collected data, the probable dynamic characteristics of rare avalanches are assessed using computational methods. Based on the results of calculations and modeling, a set of measures for protecting the area from snow avalanches is selected, taking into account actual conditions, and design and working documentation is prepared.
Snow barriers are designed based on accumulated experience.