Various methods of analyzing the settlements and tilts of building foundations on a natural bed are currently being discussed, and are in practical use. Use of finite-element procedures is most promising for these analyses, and not to mention for analyses of interaction between structures and beds. Engineering approaches that make it possible, even if in approximate form, to account for experience gained from observations of the settlements of constructed buildings and different parameters, which may be difficult to consider in finite-element schemes, however, are recommended in modern regulatory documents [1-3, and others], and are most frequently employed in practical calculations.We are proposing an algorithm for practical computer utilization of a scheme that can be used for settlement calculation, and also a means of accounting for the shape and mutual arrangement of slabs in plan, nonuniformity of loading on the bed and its inhomogeneity, which can be assigned from data of geologicengineering surveys. The algorithm serves the same purposes as for the "KROSS" program for determination of the coefficient of subgrade reaction, which was developed under the guidance of Fedorovskii [4]. The scheme recommended in [1] for determination of the settlement at an individual point of the bed with allowance for the depth of embedment of the foundation is used; stress calculation by the method of "corner points" is optimized; assignment of an arbitrary nonuniform load distribution on the lower surfaces of the foundation slabs is possible; and, a procedure for consideration of actual geologic-engineering information, which makes it possible to avoid the subjective and ambiguous procedure of constructing sections, is employed [5]. This procedure utilizes formalization of the geologic-engineering information presented in [6].Foundation settlements and tilts, and also distribution diagrams of the stiffness coefficient of the bed along the lower surface of the slabs are calculated in the example of a specific building constructed in Moscow with a height of approximately 80 m and an adjacent underground parking garage. The surface of the section is inclined, and the foundation is placed in a pit ranging from 5.0 to 9.5 m deep. The foundation of the upper section is a slab with a thickness h p = 1.3 m, while the underground section, which is adjacent to the upper, is a slab with h p = 0.5 m.As in [4], a system of rectangular coordinates is introduced onto the site plan, and a computational domain is created in the form of a rectangle, which completely covers the system of foundation slabs with An algorithm is proposed for practical implementation of a scheme for analysis of the settlement of building foundations, which has been set forth in modern regulatory documents. Methods to account for a slab with a complex planform, nonuniform loading on the bed, and the actual heterogeneity of the soil bed, which can be assigned directly from survey data, are developed within the framework of this scheme.

The traditional approach to presentation of geologic-engineering information obtained during on-site surveys for a project under design consists in plotting of geologic sections showing assumed boundaries of isolated geologic-engineering elements (GEE), and tables containing computed values of physico-mechanical soil characteristics for each GEE. The indicated data are forwarded to designers in the form of a technical report on geologic-engineering conditions at the inspected site [1,2].In any case, further data preparation for geotechnical analyses, for example, construction of "cores" for zones of the mass that do not fall within the plotted sections, is assumed for such a "standard" content in the survey report. When modern computer programs are used, preparation of some sort should be algorithmized, i.e., sets of values for soil characteristics and other numerical parameters that apply to a point or zone of the soil mass for which the analysis is performed should be "automatically" evaluated on the basis of available information, and transferred to an effective block of the program.In this paper, we propose an algorithm for the preparation and computerized formalization of geologic-engineering data, which takes into account the actual processing of these data and diagramming of the soil mass, which can actually be used in performing geotechnical analyses and incorporated into regulatory documents [2,3]. The soil mass is modeled by a set of "homogeneous" geologic-engineering elements characterized by average and so-called "design" values of soil characteristics. Despite the limited nature of this model, it enables us to resolve the majority of problems that arise in practice relative to analysis of geotechnical systems on the basis of limiting states. As in the procedure previously proposed by the Scientific-Research Institute of Foundations and Underground Structures for evaluation of the "reliability" of geotechnical systems [4], therefore, we will proceed from the indicated scheme in the procedure developed in preparing initial data for computerized geotechnical analyses.A scheme and algorithm are proposed for formalization of information contained in reports on geologic-engineering surveys conducted for the design of buildings and structures. The data are presented in the form of a working base containing required descriptive information on design geological elements, which are written via a special coding, and digital data (hole parameters, roof elevations of geologic-engineering elements (GEE), values of the characteristics of corresponding soil varieties, and so forth). Relationships permitting calculation of the depth dependence of soil characteristics established in the base for any point in plan at the site with respect to the indicated data set are written out and programmed. "Automated" (without nonalgorithmized construction of geologic-engineering sections) calculation of these dependencies determines the adaptation of the proposed approach to computerized geotechnical analyses.Let us denote the e...

In modern documents [1][2][3][4] regulating bed design of for high-rise buildings, engineering procedures, which employ "layer-by-layer summation" are recommended for calculation of the settlements of foundations on natural beds. Ultimately, this approach is theoretically less substantiated than use of the threedimensional elastoplastic approach based on the finite-element method (FEM). When the FEM is used, however, familiar difficulties arise, starting from selection of the soil model and its assurance by reliable parameter values, and ending with selection of the computational domain, to say nothing of the difficulties that arise in replacing the three-dimensional by a more accessible two-dimensional approach, i.e., the effectiveness of the numerical prediction of settlements will depend on the number of difficult-to-determine factors. The "engineering" approach, which is based largely on observational experience gained with the settlements of constructed buildings, however, will make it possible to account, even though approximately, for various factors and parameters that are difficult to account for in finite-element schemes.Among other things, the algorithm for computerized implementation of an engineering approach to settlement prediction, which has been developed by the Scientific-Research Institute of Foundations and Underground Structures [5,6], includes an accounting of the shape and mutual arrangement of an arbitrary number of slabs, and the irregularities and time dependence of loads in plan, as well as the actual inhomogeneity of the bed, which can be assigned on the basis of data derived from geologic-engineering surveys. In this paper, we present a further development of the engineering procedure proposed in [5, 6] for calculation of bed-deformation parameters. Basic attention is focused on calculation of bed settlements and the tilts of individual foundations, as well as values of the coefficient of stiffness of the bed, which are required for finite-element calculations of building designs within the framework of familiar software packages ("Lira," "SKAD," etc.). Two "extreme" schematizations of the interaction between a foundation slab and bed, which make it possible to determine the settlements without solving the problem of the deformations of the slab and superstructure, are isolated:A procedure for calculation of bed settlement beneath a slab foundation, which was previously formulated in conformity with schematic representations of regulatory documents and which takes into account the shape of the foundation, the load distribution, and inhomogeneity of the bed is presented. For simulation of the load on the bed of a high-rise building, a diagram of its deformation beneath the lower surface of a "rigid plate" is proposed. A successive-approximation procedure based on use of equilibrium equations of the slab is developed for calculation of the settlement. Determination of the settlements and tilts of the foundation of a specific high-rise building are discussed as an example.

According to [1,2], no analysis of bed deformation need be performed for buildings erected on rock. However, in accordance with accepted normative documents on the design of high-rise buildings and those under development, analysis of bed settlement should be carried out even if rock lies under the bottom of the slab. In addition, for high-rise buildings under elevated load levels on the bed, such an analysis is necessary, in part, for a more reliable determination of the bed foundation modulus curve and, consequently, for a more accurate calculation of the forces arising in the foundation slab and aboveground structures.An engineering procedure is being developed at the Gersevanov Research Institute to analyze bed deformations under foundations on a natural bed, constructed in accordance with schematizations proposed and adopted in normative documents [1, 2, 4, and others]. Without using finite-element programs, the procedure [5, 6] allows, during determination of settlement, effective consideration of the shape of slabs in plan view, the pressure distribution under their bottom side and the depth of their placement, as well as information on the geological aspects of the bed and soil properties, which is incorporated into the analysis in the form in which it appears in geological engineering survey reports.Earlier, within the scope of [5, 6, and others], two extreme schematizations of the interaction between the foundation and bed were used, allowing bed settlement to be estimated without analyzing deformations of the building structure and the slab, and the foundation modulus curve, which is requiredThe development of a Gersevanov Institute procedure is given for analyzing bed settlement under a slab foundation, with consideration of the foundation shape, uneven load, and bed nonuniformity. In the proposed procedure alternative, which has been adapted for the analysis of foundation slabs on a nonuniform rock bed, the load distribution under the slab bottom is taken from the results of a finite-element analysis of a building structure on a base assumed to be absolutely inelastic. Implementation of the analytical procedure is shown using the example of calculating the settlement and deformation of a high-rise building slab, for which a "weakened" area was identified in the bed during surveys. Stochastic simulation of additional "columns" of geological engineering boreholes is carried out to estimate the impact of insufficiently complete information on the properties of the rock mass. The impact of bed nonuniformity on the results of analyzing settlement, slab tilt, and forces within the slab are analyzed.

С применением модификации метода «типовых кривых», разработанного для прогноза осадок поверхности над подземными выработками, и с учетом результатов гидрогеологических фильтрационных расчетов проведено комплексное оценивание масштабов карстопроявлений и осадок основания гидротехнического сооружения. Карстовые полости полагаются образующимися вследствие процессов фильтрации воды в растворимой породе, подстилающей грунтовую толщу, на которую опирается фундамент сооружения. С учетом указанных условий предложена состоящая из дугэллипса модель формы сечения полости.Размеры полостей и вызываемые имиосадки поверхности основания оцениваются для различных участков основания с учетом распределения значений скорости фильтрации в породе и данных о переменной мощности защитного слоя глин. Прогнозируемые значения осадок предлагается использовать для обоснования необходимости противокарстовых мероприятий и для районирования их параметров.