Construction pits within urban areas, involve a major construction risk due to potential endangering the stability of surrounding objects/structures, as well due to existence of significant diversities of municipality infrastructure.
The pit, itself, cannot be constructed simply – by excavation only; it must become stable in advance to excavation, i.e.: underground must be threatened before excavation.
Protection of construction pit secures stability of vertical walls by preventing displacements of underground strata, which could cause serious damages on surrounding buildings and infrastructure.
In cases where excavations are very deep, groundwater and leachate water may have a very negative impact to the stability of the pit and subsequent construction works; therefore, protection must provide also a water- tightness of the walls. Otherwise, incoming water should be pumped constantly out of the pit (with uncertain effects) and as a consequence of additional works, the costs of coming construction works shall be considerably increased.
Design of construction pit, hence, the type of protection, depends on few different but correlated parameters, such as, but not limited to:
- architectural & structural design of future structure;
- depth of future construction pit, i.e.: the deepness of excavation;
- geological/geotechnical/hydrological properties of the ground formations of the foundation;
- geometry and depth/lay-out of surrounding foundations, municipal infrastructures etc.
Among several, the vertical elements of the protection structure could be piles/micropiles; driven steel profiles and sheet piles (Larsen); jet-grouting columns and reinforced- concrete diaphragms.
The elements, accommodating horizontal forces, are different types of self-drilling anchors, geotechnical anchors and bracing steel structures.
Excavation lining is prepared of geotextile, grids and shotcrete.
KARST has completed a large number of protections of construction pits; individually or in the partnership with other contractors. Goes without saying that such complex and demanding works could not be executed without highly skilled and experienced manpower at any level of the works (operators, mechanics, foremen, technicians, engineers, logistic personnel and management)
As well, none of such goals could be performed without “state of art” equipment and appropriate “know how” for carrying out the works on micropiles and piles, all types of self-drilling anchors, anchors and geotechnical anchors.
In short; in this field of geotechnical works we are specialized to carry out following products: