Consideration of soil-failure zones beneath foundation edges in analyzing a “bed-foundation-structure” system

An engineering method is developed for determination of the depth of failure zones beneath the edges of a foundation on the basis of the soil-strength parameters c and φ in analyzing a “bed-foundation-structure” system (BFSS). The formation of these zones must be considered in order to obtain reliable values of internal forces within the foundation, and its tilts. It is recommended to conduct additional research to determine c and φ at a depth to 1/4 the width of the foundation along its periphery. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 5–10, January–February, 2009.     

The residual shear strength of Neogene marly soils in the Granada and Guadix basins, southeastern Spain

The analysis of samples taken from the Neogene and Cretaceous marly series of the Granada and Guadix basins (south east Spain) shows an inverse correlation between the clay content and the residual friction angle. It has been verified that the carbonate fraction of the soil has a significant influence on the residual friction angle; there is a threshold of 25% carbonates, above which the value of φ′_r increases from 20 to 30°. It has been proved that the presence of smectitic clay as the dominant constituent produces a low value of residual shear strength, associated with high fragility in unconsolidated undrained tests. It has been proved that the degree of compaction of the soil and therefore the initial porosity, has a direct influence on the effective residual friction angle (φ′_r). Received: 2 February 1999 · Accepted: 31 March 1999     

Laboratory investigations of the pressure dependence of the frost heaving of soil

Structural and technical data are presented for a device used to determine the pressure dependence of the frost heaving of soil. It is demonstrated that the design of the device and the method employed to determine this dependence provide for the required accuracy of the computation of heaving parameters within the limits of standard requirements. Suggestions are given for calculating the pressure on a seasonally thawing bed in determining its bearing capacity. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 25–30, January–February, 2009.     

Experimental and theoretical research on the bearing capacity of ring-foundation beds

Results are presented for solution of the problem of the limiting pressure of a ring foundation on a soil bed. Formulas and tables are given for practical calculations. Experimental data are cited for determination of the limiting pressure of an annular plate on a sandy bed. It is demonstrated that theoretical limiting-load values obtained on the basis of the proposed procedure do not exceed experimental values. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 2–4, March–April, 2006.     

Stress-strain state of a frozen soil bed under a rigid plate

Results are presented for numerical analysis of the stress-strain state of a permanently frozen soil bed beneath a centrally loaded rigid plate by the finite-element method with allowance for elasto-plastic deformations and crack formation. Results of the analysis are compared with data derived from experimental investigations. An analysis of the stress-strain state of the soil is provided. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 2–6, January–February, 2006.     

Prediction of soil vibrations during pile driving from penetration data

A method of predicting soil vibrations during pile driving and determining safe distances to existing buildings using static-penetration data is discussed. Experimental data on determination of expected elastic failures of piles and elastic vibrations of the soil in the immediate vicinty of the pile using the slip factor are cited. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 7–9, January–February, 1995.     

Mathematical modeling of the thermal stabilization of soil masses by a superhigh-frequency field

A mathematical model and algorithm are developed for numerical solution of the problem of determining the thermal regimes generated in treating soil masses by a superhigh-frequency (SHF) field with variable thermophysical and electrophysical parameters as a function of temperature, moisture content, and pressure. The computational results are cited and compared with experimental data. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, Vol. 35, No. 1, pp. 8–11, January–February, 1998.     

Mathematical modeling of the installation of pile foundations in a dense urban setting

Principles are proposed for the construction of constitutive relationships for the solution of problems of geomechanics under large deformations. Examples are cited for the numerical modeling of the installation of pile foundations in accordance with various procedures for soil conditions found in Saint Petersburg. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, Nos. 4–5, pp. 13–18, July–October, 1998.     

Safe distance to foundations when compacting soil in the channels by hydraulic hammers

Results are presented for experimental studies conducted on models and full-scale foundations to evaluate the influence exerted by the operation of hydraulic hammers on foundation stability during the compaction of soil. Recommendations are given for safe distances to foundation walls when soil is compacted in the foundation channels with allowance for the impact energy of the hydraulic hammer. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 16–20, September–October, 1997.     

Algorithm and program for engineering analysis of foundation-slab settlement with allowance for nonuniform bed loading and heterogeneity of the mass

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. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 2–7, September–October, 2006.     

Effect of swelling soil on a moving retaining wall

A procedure is proposed for determining the effect of the displacement of a retaining wall on the stress-strain state of the mass swelling soil adjacent to it and the lateral pressure acting on it using the finite-element method. The results of calculations performed in accordance with the method in question and data derived from a field experiment are compared. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 14–17, September–October, 1995.     

Evaluation of the quality of compacting water-saturated sands by sounding

Various methods of sounding were investigated for evaluating the quality of compacting water-saturated fine and medium sands. A comparative analysis of the data obtained with the data of direct soil sampling was carried out. The given recommendations can be used when preparing the new edition of the building codes for engineering surveys for construction. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 17–20, July–August, 1994     

Analyses of the seismic responses of soil layers with deep deposits

Several typical problems in the seismic response analysis of soil layers with deep deposits have been studied according to the seismic response analysis of the soil layer in the Shanghai region. The problems include the effect of the inclination of the bedrock under the soil layer on the seismic responses of the soil layer, the rationality of the artificial horizontal bedrock boundary in the soil layer, and the effect of the wave velocity of the bedrock and dynamic characteristics of the soil media on the seismic responses of the soil layer. Some results are obtained by numerical analysis. In the seismic response analysis, the effect of angle of inclination of the rock surface under the soil layer can be neglected if the angle is not more than two degrees. A significant error will be introduced in the calculation when the artificial horizontal rock surface is assumed in the soil layer according to the shear velocity of the soil media. The elasticity of the solid rock has little influence on the seismic response of the deep soil layer. The field investigation on the soil dynamic property should be paid more attention to. Translated from Journal of Tongji University (Natural Science), 2006, 34(4): 423–427 [译自: 同济大学学报(自然科学版)]     

Effect of local loads on the character of soil pressure on productive structures

Conclusions An approximate analytical solution has been obtained for the law of soil pressure distribution in a PS in the presence of a local load on the surface. The solution is characterized by the following conditions: 1. The effect of the local load leads to formation of four zones in the plane of the PS. Different rules are applied for calculating stresses in each of these zones. 2. In the presence of local loads, horizontal pressure on the PS should be determined only from the combined effect of the load, soil weight, and soil cohesion since the principle of superimposition is not applicable under these conditions. 3. Unlike existing methods of calculations using the Coulomb's theory, the solution provides for a common method of calculation for all locations and sizes of the loading area. Here, error due to the use of the proposed approximate dependences does not exceed 2–3% in comparison with computer calculated numerical solutions. 4. Comparison of the methods of calculation used in design practice showed that Klein's method [3] yields reliable results for wide loading areas of b>2 while the method in SN-RF 54.1–85 [6] yields almost reliable results for narrow loading areas of b<1. For wide loading areas the latter method underestimates the pressure. For narrow loading areas, the methods in [3] for a concentrated and distributed load are at variance with one another and yield differing results while the method in SNiP 2.09.03–85 [7] is unreliable in all cases and yields underestimated results. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 24–27, July–August, 1991.     

Describing dynamic stress variation in soils on the basis of measurement data on the intensity of infrared radiation

The procedure employed for, and results obtained from experimental investigations conducted to substantiate the effectiveness of measurements of the power of infrared (IR) radiation are set forth for the diagnostics of changes in the stress state of soils over time. The construction of a bench on which a soil specimen is subjected to a variable load so that the total principal stresses in the specimen vary periodically over time is described. It is demonstrated that the relationship obtained, which is reestablished on the basis of IR-measurement data, is found to be virtually identical to the corresponding relationship defined in accordance with data derived from calibration measurements using a load-cell strain gage. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 2–7, November–December, 1999.     

Analysis of shallow double-slot foundations

An analysis is developed on the basis of interaction between double-slot foundations and the soil bed for broader use of data on foundation structures in construction practice. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 11–14, January–February, 2006.     

Experimental studies of the deformation of soil beds reinforced with rod elements

A procedure for and results of experimental investigation of the effect of the reinforcement of a soil bed by rigid rod structures on its deformation properties are cited. A conclusion is drawn concerning the strengthening of a soil where the ratio of the area of reinforcing elements to the loaded surface is 1:80 and higher. It is demonstrated that the reinforcement of soil is associated primarily with the constraint of plastic deformations and does not affect the properties of the soil mass being deformed. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 14–16, March–April, 1998.     

Determination of the modulus of soil deformation from results of tests with stamps along the horizontal

Conclusions The obtained formulas for calculating the modulus of soil deformation by accounting for the discontinuity of the base and the effect of the free surface were found on checking to be quite reliable. This points to the practical utility of these formulas for determining the deformability of soil bases with stamps along the horizontal. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 25–27, March–April, 1990.     

Finite-element analysis of tapered piles under combined vertical and horizontal loadings

A universal method of analyzing tapered piles under the combined action of a horizontal, vertical, and moment loading is developed using the finite-element method and with consideration of their bending stiffness. It is derived on the basis of experimental data that the coefficient of subgrade reaction varies as a function of the horizontal displacement of the pile and the depth of the layer under consideration. Procedures are proposed for determination of the coefficient of subgrade reaction on the basis of data from static probing and for consideration of the non-linearity of the deformation of the soil bed and pile material, which makes it possible to calculate the “load-displacement” curve. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 6–12, January–February, 2000.