Karst Engineering

It studies a complex of interconnected natural, chemical, physical and mechanical processes and phenomena caused by the dissolution and removal by natural waters of rock dissolution products with subsequent karst, corrosion and suffosion denudation of underground strata (the appearance of cavities, voids, structural disruption and change in properties) up to a dangerous sudden manifestations on the earth's surface in the form of karst dips, landing, subsidence and subsidence, against which engineering anti-karst protection of the foundations is required buildings using construction methods (planning, water-proofing and anti-filtering, geotechnical, structural, technological and operational), which do not allow and (or) reduce to a safe minimum the deformation of the soil foundations of buildings and structures, in which they maintain harmless reliability and general geostability.

Concept K is the study of the karst hazard of the territory, predicting the behavior of buildings, structures and other human objects on them and proactive engineering and construction anti-karst protection against any excess deformations of the bases that occurred as a result of activation of karst or karst-suffosion processes that cause abnormal behavior of foundation failures and ground structures. Failures appear externally on buildings, structures:

• cracks in the basement basement while maintaining the full operational state of the object;
  • local damage in the basement-basement zone (significant cracks, shifts, concrete spalling), in which continuity is violated without a significant reduction in bearing capacity and serviceability;
• subsidence of soil strata in the active zone of the base (by 5-10 cm), which translate the base and foundation of the building or the structure as a whole into a limited working condition while maintaining the general geostability of the object;
• dips of soil strata from under the base of the foundation with the collapse of the foundation and walls, falls inside the contour of the building or in the territory adjacent to the object, which leads to its emergency state due to the complete loss of the bearing capacity of the base and foundation in its local area.

Deformations of the foundations of buildings and structures of karst-suffusion originating from the fault of karst in Belarus account for 15% and occur according to the law of rare events ( Poisson's law ), that is, according to it, the date and place of karst occurrence are probabilistic. The karst territories also include those with a thickness of up to 80 m in the form of insoluble carbonate rocks ( limestone , dolomite , chalk , marble ), medium-soluble sulfate rocks ( gypsum , anhydrite) and semi-soluble halide rocks ( halite , carnallite ). Almost 31% of the territory of Belarus is affected by superficial karst occurrences. About 45% of the urban and at least 20% of the rural population live in areas of development of sulfate and simultaneous development of sulfate and carbonate karst.

The karst process develops in the presence of 3 prerequisites: soluble rock, dissolving ability of water and removal of dissolution products. The absence of at least one of any of these conditions puts the karst process in a passive state. The anthropogenic factor can activate or passivate the natural state of soluble rocks in the earth's crust.

Geotechnical surveys in the karst territories are carried out taking into account additional versus the usual technical requirements of the relevant regulatory documents. Survey materials should contain zoning of the territory according to the conditions, degree and nature of the development of karst, taking into account the manifestations of suffusion, displacement and collapse of rocks, as well as other processes involved in the formation of cavities, destroyed and unpaid zones in karst and cover deposits. Zoning consists in marking the territory into areas with equal probability of frequency of karst dips per 1 km² per year (category 1 6) and the average probable diameter (m) of karst dips (category A ... D). The technical survey report for the component stage of simple work should contain the information necessary and sufficient to justify the technical solutions (measures) and the development of building anti-karst structures. Traditionally, anti-karst structures are laid in the basement of the buildings (horizontal anti-karst continuous continuous reinforced concrete frames, tapes, slabs, etc., reinforced for a given probable diameter of failure). Slab foundations provide with technological channels.

Providing increased spatial rigidity of the skeleton of the building is given special importance (anchoring the external load-bearing walls, monolithic prefabricated ceilings, appropriate opening, interconnection of longitudinal and transverse elements of the skeleton, etc.). In justified cases, karst monitoring is envisaged to monitor the condition of the object and the adjacent territory according to a special program and for a specified period.

The main content of karstology was formed in 1947 at the Perm Conference.

In Bashkiria at the end of the 19th century, thorough research on karst was carried out by D. L. Ivanov in connection with the frequent karst failures along the just-built Samara-Zlatoust railway (20 in 4 years on a 38 km-long section - 1890-1894) under it regularly. The anti-karst service on this section of the railway is still functioning today.

In the 2nd half of the 20th century, in 79 (1.75%) settlements of Bashkiria, within their residential areas or in the immediate vicinity of them, at least 200 new failures and other surface karst occurrences were reliably recorded (Kurmanayevo, Yaprykovo , Mikhailovka , Staronadezhdino , Talalaevka, Askino, Okhlebino, Karmaskaly, Aksakovo, Karlaman, etc.).

The most frequent failures in Ufa, Blagoveshchensk, Birsk caused by karst and karst suffusion processes. In most cases, construction anti-karst measures have been taken to strengthen the foundations and foundations, followed by restoration of ground structures (if necessary), which allows stabilizing deformations of the foundations. In case of dangerous undamped deformations, the foundation of the building is demolished (center of pensions on 9/1 Sorge St.; 40 GPTU on Nezhinskaya St.).

In 1963 and 1969 G. A. Maksimovich (Perm) published a monograph in 2 volumes, Fundamentals of Karst Studies, in which the geological and speleological interpretation of the karst phenomenon, which was the geological preamble of engineering karst studies, prevailed.

In Ufa in con. 60s 20 century there was an urgent need to address the engineering and construction aspects of karst in connection with the large volumes of housing construction at the site of demolished dilapidated buildings. For the first time in the USSR, a creative team of specialists from BashNIIstroy, ZapUralTISIV and Bashkirgrazhdanproekt developed a concept for the development of karst territories of the Republic of Belarus, which was the basis for Instruction BCH 2-86 and subsequently TSN 302-50-95. Studies of hydrology and the type of karst of Bashkiria are PhD theses (Martin V. I., 1975); calculation of pile foundations for karst failure (Ilyukhin V.A., 1988); prediction of karst hazard and zoning of karst territories (Travkin A. I., 1989); dangerous exogenous processes (Smirnov A.I., 1998); calculation of the foundations for karst failure (A. Ryzhov, 1999); control over the slab foundation or karst occurrences (A. Zhilin, 2000); study of the work of the pile foundation with karst failure (Davletyarov D.A., 2006). Problematic topics of failure of foundations and foundations and their elimination (Mulukov E. I., 1993); and calculation of pile-slab foundations during karst failure (Gotman N.Z., 2004) are the basis of doctoral dissertations. Of interest is the scientific work of Shammazov A.M. et al. “Calculation of gas pipelines in the karst zone” (Ufa, 1999).

The formation and filling of karst studies was facilitated by two all-union conferences. The first of them is for construction in karst territories ( Podolsk , 1983), and the second is for anti-karst protection of construction objects ( Kuibyshev , 1990). In 1992 ( Perm ), the International Symposium "Engineering Geology of Karst" was held, the works of which are 2 volumes of 10 sections (636s.) On various aspects of karstology.

In 2004, the International Symposium “Karst Studies of the 21st Century: Theoretical and Applied Significance” was held, the papers of which predominate only on engineering geology of karst.

In the 1st decade of this century, several Russian regulatory documents were issued that streamline the system of views on karstology. Since 2002, the discipline "Engineering and construction karstology" has been taught at the ASFU at the USTU for students of construction specialties. This is consistent with the opening general report at the International Symposium (Perm, 2004), which noted that "ensuring the safe development of karst territories depends on the competence of personnel ... Karst studies as an academic discipline is not included in the national educational standards of higher professional education in ... construction specialties."

• Karst

• Mulukov E.I. Karst process and construction development of the karst territories of the Republic of Bashkortostan // Bulletin of the Academy of Sciences of the Republic of Belarus. 1999. V. 4. Number 3.
• Smirnov A.I. Assessment of the impact of the karst process on the settlements of the Republic of Bashkortostan // Karstology - 21st century: theoretical and practical significance / Materials of the International Symposium. - Perm, Perm University 2004. - P.325 - 328.
• Mulukov E.I. On the construction karst introduction. // Transactions of Int. scientific and technical conf. - Ufa, BashNIIstroy. - 2006. - T.2. - S.92 - 97.
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