One of the consequences of the construction in the conditions of dense housing system is the development of underground part of buildings, which influences the surrounding buildings, changing the stress-strain state of soil masses and hydrogeological conditions of the construction site. The damming effect leads to local increase of hydrostatical pressure of ground waters on underground structures. The authors present a description of hydrogeological conditions of the construction site of underground construction and mathematical geofiltration model of the soil foundation. The results of numerical investigation of the change in the hydrogeological mode of the construction area in case of enveloping the foundation pit with the wall in the ground are considered. On the first stage the basic mathematical model was calibrated by variation of the values of geofiltration parameters of water-bearing sediments and water-resistant mass and the values of infiltration recharge. The validation criterion of the mathematical model was the good agreement of the modeled and real ground water levels obtained as a result of compilation of the existing geological and hydrogeological materials. The construction simulation was carried out in a multivariant formulation for the conditions of entirely impenetrable wall in the ground with the filtration coefficient 0.001 m/day.

Modern practice of analytical substantiation of the structures of buildings under design, and their foundations and beds presume investigations of the stress-strain state (SSS) of the total "building/foundation/soil-bed" system via computer programs implementing the finite-element method. In view of the complexity of correct combined analysis of the entire system, moreover, interaction between the building and soil bed is considered using coefficients of the bed's subgrade reaction, which can be calculated by simplified standard procedures. And, interaction between the soil bed and foundation is analyzed, disregarding the actual stiffness of the building itself.The above-enumerated analyses are performed using special computer programs for the solution of various problems, and are in no way related to one another.At the same time, the distribution of vertical displacements and coefficients of the bed's subgrade reaction along the lower surface of the foundation under actual conditions is extremely nonuniform, and will depend on the stiffness of the building, the character of the distribution of the load applied to the foundation, the geologic-engineering structure of the bed, the properties of the soils, and many other factors.Questions concerning determination of the diagram of the coefficient of subgrade reaction beneath the lower surface of a foundation are discussed in [1][2][3].Let us examine the influence exerted by one factor alone -the design of building (its stiffness and the character of the distribution of the load applied to the foundation) in an example of investigations of the interaction between a 40-story building (Fig. 1), the foundation of which is a monolithic reinforced-concrete slab 1.2 m thick with planform dimensions of 100 35 m, and an inhomogeneous soil bed (Fig. 2). The following SSS analyses were performed for this purpose:-the soil bed to which the uniformly distributed load due to the building is applied; -the foundation-slab/soil -bed" system; and, -the "building/foundation-slab/soil-bed" system. The analytical investigations were performed on the basis of the software package "Zemlya" [4] with allowance for the stepwise nature of the work (the natural SSS; the opening of the pit; the installation of the foundation slab; the erection of the building; and, the construction of an adjacent underground parking garage).A procedure is described for consideration of the construction of a building when analyzing the interaction between its foundation and soil bed by the finite-element method. Results of calculations, which illustrate the effect of the character of load transfer onto the foundation slab and the stiffness of a high-rise building on its settlement and the coefficient of subgrade reaction of the soil bed, are cited.

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Results of investigations of the earthquake resistance of structures are analyzed.The detailed design of the Boguchany HPP was developed in the 1990s when the seismicity of the region was evaluated at six points. The stress-strain state (SSS) of the basic structures had not been analyzed for a six-point seismic event in conformity with Construction Rule and Regulation II-59-74 "Riparian water-development works. Basic design positions," which was in force at that time.In 1999, the seismicity at the construction site of the Boguchany HPP was elevated, and is currently seven points with a repeatability of once every 5000 years (I norm = 7) according to the OSR-97-S map in Construction Rule and Regulation II-7-81* "Construction in seismic regions" [5].In 2000 -2002, the Center for Geodynamic Observations in the Power-Generation Industry (CGOPGI), Institute of the Earth's Crust, Siberian Division of the Russian Academy of Sciences (IEC SD RAS), and the Altai-Sayano Experimental and Seismological Party (EMSP) conducted seismological investigations in the area of the hydroproject's construction. As a result of the investigations, the level of the design intensity of earthquakes for the region of the Boguchany HPP was established at six points (I in = 6) based on the OSR-97-S map (i.e., with a design period of repeatability of the maximum design earthquake (MDE) of once in 5000 years), and up to five points based on the OSR-97-C map (with a design period of repeatability of the design earthquake (DE) of once in 1000 years) [7].According to the "Design rules for water-development works in seismic regions" [2], Construction Rule and Regulation II-7-81* "Construction in seismic regions" [5], and Construction Rule and Regulation 33-03 "Water-development works in seismic regions" [6], water-development works are not subject to analysis of seismic loads in a region with a six-point seismicity.In various organizations of the Krasnoyarsk Kray, doubts have been voiced concerning grounds for substantiation of the lowering of the level of the design seismicity, and, accordingly, the earthquake resistance of basic structures of the Boguchany HPP. To put these doubts to rest, the staff responsible for the construction charged the Institute Gidroproekt to conduct verification studies of the earthquake resistance of the concrete and rockfill dam (RFD), powerhouse, and service and production building (SPB) under an assigned seven-point seismicity (I in = 7). (Candidates of Technical Sciences A. V. Deineko and D. A. Krutov, and engineers L. D. Solov'eva and A. A. Yakushev participated in the studies).To utilize the design positions stated in Rules [2], and Construction Rules and Regulations [5] and [6], we conditionally worsened the seismic conditions at the construction site by a factor of two:-increased the initial seismicity from six to seven points (I in = 7) with a design period of once in 5,000 years; and, -lowered the class of the soils in the bed of the structures at the Boguchany HPP from Class I to Class I -II.The maximum peak ...

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