Whether artificially created karsts are dangerous to the cities?But first of all - what is a karst? It is geological process of formation of underground cavities (caves, grottoes, funnels) at the expense of chemical (leaching) and hydrological impact of underground waters on soft rocks (calcites, carbonates, dolomite, marl, plasters). However karsts as experience and objective reality of two last centuries confirms, can quite be a man-made, anthropogenous origin.
In the cities this intensive construction of subways, in provinces - underground mining: coal, nickel, chrome, manganese, diamonds and so forth. Now it is difficult to find the city with the population over one and a half million in which would not be such vital not only transport, but also as means of protection of the population on a case of potentially possible military operations, constructions. It is natural to ask a question: whether represents such construction for residents of the cities such type of transport and the corresponding underground architecture blockages, floodings, quicksands, explosions of gases, failures of soil how it quite often happens in mines?
If to consider that such objects are under construction with a large supply of durability of the best constructional materials and, probably, not for one century, then they on foreseeable prospect do not represent danger to the cities and their population. It is enough to tell that to the oldest in the world to the London subway hardly one and a half hundred years, but it, though with periodic emergencies, continues to function, extend, go deep. It is demanded by steadily progressing growth of the population.
However nothing does not stand still, everything flows in a temporary stream, changes, sooner or later being exposed to entropy. And if still relatively recently laying of adits, tunnels and developments was carried out in one horizon, then at present both in ore mining industry, and in a metrosystem began to have multilevel character, literally turning a layer of the subject breeds into a sponge, i.e. creating a man-made karst. Ask any geologist, the hydrologist or geophysics now: whether fundamental construction what is zhilishchno - an economic complex of the cities, on a karst is admissible? The answer will be unambiguous: though it is necessary, but dangerously and it is too unprofitable, however economic feasibility and an environment dictate the rules.
Somehow the mobile team of specialists of our institute which part also I was worked with the consulting purpose in the miner`s settlement what on area not one ten will be gained. I paid attention that one houses, apparently, quite suitable for accommodation, flaunted with empty eye-sockets of windows, others on perimeter were fitted by thick tapes - couplers. Took an interest at inhabitants what it would mean?
Everything began with the middle dashing 90 - x - with despair on faces explained questioned. Since as superfluous and in a mass order began to be closed and flood ground waters of mine. Their multilevel horizons settled down at a depth from 400 to 800 m not only beyond limits, but also under settlements. They did not represent danger to land constructions in the functioning state. The flash of breeds was not allowed by reliable fixture and the same infrastructure. On the ownerless and flooded objects process of entropy and a flash began already soon. It would seem, such huge rock mass will not allow to be reflected in integrity of objects of the day party negatively. Alas! Perhaps moreover and as.
And why similarity of it cannot happen to the subway especially as in the world there is no its such deep bedding anywhere, and laying of adits and tunnels is carried out nearly at the level of an occupation layer, without reaching radical breeds. Cases of failures, floodings, break of quicksands in world practice as much as necessary, and there are such emergencies in direct ratio to age of object. It would seem, tubings - these main bearing designs executed from the strongest brands constructional staly are capable to stand two - triple loading. Then as do not maintain, and collapse. In what the reason?
The main - in a hydrology and electrochemical corrosion processes which the strongest metal designs are not able to resist. It is known that all underground transport works at electrodraft of a direct current and high voltage. The part of this energy whatever was reliable isolation, the screen version, gets to the subject breeds. Interacting with the ground waters containing various salts they thereby form electrolytes.
Designers and metrostroyevets, however, with aplomb will object: everything is thought over, provided, constructed nearly on eternity. Precisely so also builders of the American twins of VTTs supposedly they thought as the Egyptian pyramids - are not subject to time. Deeply dear, their unshakable man-made children were mistaken were in actual fact scattered as houses of cards. Here the plane was the initiating factor, and chain reaction worked further.
And why not to assume that such initiating factor cannot happen to the subway, let us assume, as a result of tectonic motions of lithospheric plates or from electrochemical corrosion and fatigue of the bearing designs of tubings? Also will begin land constructions to accept a pose of the Tower of Pisa. Will not seem a little.
Underground transport is convenient, of course, and irreplaceable, but however we were attached to it, over time it is necessary to refuse it.