Diaphragm wall-soil-cap interaction in rectangular-closed- diaphragm-wall bridge foundations

Rectangular-closed-diaphragm-wall foundation is a new type of bridge foundation. Diaphragm wall-soil-cap interaction was studied using a model test. It was observed that the distribution of soil resistance under the cap is not homogeneous. The soil resistance in the corner under the cap is larger than that in the border; and that in the center is the smallest. The distribution of soil resistance under the cap will be more uniform, if the sectional area of soil core is enlarged within a certain range. Due to the existence of cap, there is a “weakening effect” in inner shaft resistance of the upper wall segments, and there is “enhancement effect” in the lower wall segments and in toe resistance. The load shearing percentage of soil resistance under the cap is 10%-20%. It is unreasonable to ignore the effects of the cap and the soil resistance under the cap in bearing capacity calculations.     

矩形闭合墙桥梁基础墙-土-承台相互作用研究

矩形闭合地下连续墙基础是一种新型的桥梁基础。通过室内模型试验,对闭合墙基础墙-土-承台相互作用进行系统的研究。试验研究表明:闭合墙基础承台土反力分布的总体特征是承台下土芯的角点处最大,边缘处次之,中心区最小。在一定范围内,承台下土芯截面积越大,承台土反力分布越趋于均匀化。承台对上部墙段的内摩阻力存在"削弱效应",而对下部墙段的内摩阻力则有一定的"增强效应",承台对墙端阻力也有一定的"增强效应"。承台土反力的荷载分担比约为10%～20%,若在闭合墙的竖向承载力计算方法中,不考虑承台的作用,忽略承台土反力,是不合理的。模型试验和分析结果为矩形闭合地下连续墙基础的设计计算提供了重要依据。     

Combined method of compaction of collapsible soils

The writer proposes a combined method of compaction of collapsible soils. He presents results of investigations carried out to study compacted zones of pads punched (tamped-out) by rammers 10 and 20 tons in mass, as well as a comparative analysis of the pads over against compacted zones obtained by means of plane rammers. The analysis results are illustrated by the “arch effect” on the stress conditions of the soaked soil mass. NIIOSP Institute. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 19–21, January–February, 1994.     

A design method for seepage barriers with allowance for the initial filtration gradient

A method is presented for calculation of the basic parameters of an anti-seepage “wall” with allowance for the initial filtration gradient of the filler material. The case of plane-radial seepage through a contour “wall” of the perfect and imperfect type, which is constructed by various modifications of the “wall-in-the-ground” method and using kinematic jet energy, is discussed. Computational analytical relationships and working equations for a number of special cases are derived in general form for the schemes under consideration. A software package, which makes it possible to make a rational projection of structural parameters of the “wall” and determine the position of the depression curve ahead of the “wall,” is developed. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, Nos. 4–5, pp. 37–42, July–October, 1998.     

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.     

Negatives in symmetric input–output tables: the impossible quest for the Holy Grail

In the Supply-Use (or Make-Use) input–output models, “product-technology” (PT) or “fixed-industry-sales-structure” (FISS) assumptions are more widely adopted (SNA, Eurostat) for deriving symmetric input–output tables (SIOT) than “industry-technology” or “fixed-product-sales-structure” assumptions, but generate negatives in the SIOT. A SIOT deduced from the Supply-Use model is considered as satisfactory as soon as it contains no more negatives; scholars have focused on the negatives in the SIOT and on how to remove them. However, as a SIOT may include no negatives even if there are some negatives in the inverse Supply matrix, we have completely reversed the reasoning. A counter-example demonstrates that computing the inverse Supply matrix, as imposed by PT or FISS assumptions, is mathematically a nonsense operation even when the symmetric input–output tables do not include any negative; this result is new. Hence, deriving a SIOT under PT or FISS assumption must be rejected. Three applications are provided: Austria 2000 and 2005 and USA 2007.     

矩形闭合地下连续墙基础负摩阻力模型试验研究

矩形闭合地下连续墙基础(简称闭合墙基础)是一种新型的桥梁基础。通过单片墙与矩形闭合墙的对比性浸水模型试验,对闭合墙基础负摩阻力的作用机理以及浸水后闭合墙基础的竖向承载性状进行了研究。试验研究结果表明:单片墙与闭合墙基础的中性点深度比在0.34～0.64之间,与现场试验实测结果十分接近,且闭合墙基础的中性点位置比单片墙的低。负摩阻力分布曲线大致呈抛物线型,与桩基现场浸水试验结果相似。由于闭合墙基础良好的整体性和防渗特性,当墙周土层浸水发生湿陷变形,土芯不会受到水的影响,因此在负摩阻力作用下,内摩阻力与承台土反力能够得以发挥。闭合墙基础所有竖向荷载均由外侧正摩阻力、内摩阻力以及端阻力和承台土反力四者共同分担,能够有效地阻止墙身附加沉降的继续发展。在相同的湿陷性黄土地层且浸水条件相同的情况下,闭合墙浸水后的附加沉降小于单片墙,表现出良好的抗沉降特性,在一定程度上能减小负摩阻力对桥梁工程的危害。     

Upper bounds of the bearing capacity of strip foundations

An alternate scheme, which is illustrated by examples, is proposed for determination of the upper (“kinematic”) bound of the bearing capacity of the “foundation/soil-bed” system. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 2–6, November–December, 1997.     

The impact of immigration on interregional migrations: an input–output analysis with an application for Spain

Developed countries in general, Spain in particular, have experienced a dramatic rise in the reception of foreign workers in the last decade. Among all the economic and social effects originated by the arrivals of immigrants, the literature has paid some attention to the potential effect that this immigration can produce on the internal migration patterns (the so-called “displacement effect”). This paper proposes the use of a multi-region input–output model of migrations for measuring how the reception of immigrants in one region displaces population among all the regions included in the model. From some basic assumptions, the input–output methodology proposed describes how the arrival of one immigrant in one region i, by the dissemination of internal population from i, generates indirect effects on other region j. To illustrate the methodology proposed in the paper, an empirical application for Spain is also included.     

Active and passive pressures with seismically induced changes in the direction of surface-friction forces

Conditions favorable to the development, and characteristic features of the accounting of the “reverse” direction of surface-friction forces at the contact between a retaining wall and soil medium with determination of the latter's lateral pressure are indicated. Basic computational relationships are presented for steep and inclined walls, and also the results of the mathematical modeling of the “structure/soil-medium” system with variation of the latter's computational parameters are presented. A general computational algorithm, which takes into account any direction of contact-friction forces, and a program that runs the algorithm on a computer, as well as tables of the range of combinations of initial parameters, including parameters that account for seismic effects, are developed. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 14–18, May–June, 1996.     

矩形闭合地下连续墙桥梁基础竖向承载特性试验研究

针对矩形闭合地下连续墙--一种新型的桥梁基础,进行了闭合墙基础的竖向载荷模型试验,对其荷载传递机理和墙体内、外侧摩阻力以及承台土反力的分布规律与发挥发展过程等作了系统的研究。研究表明:闭合墙基础的竖向承载力由外侧摩阻力、内侧摩阻力、端阻力以及承台土反力四部分组成。外侧摩阻力自上而下发挥,内摩阻力缓于外摩阻力自下而上逐渐发挥,由于承台的"削弱效应",上部墙段的内摩阻力接近于0。承台土反力分布的总体特征是承台角点处最大,边缘处次之,中心区最小。随着荷载的增加,闭合墙侧摩阻力增加趋势变缓,荷载分担比逐步减小,而墙端阻力和承台土反力的增加幅度逐渐变大,墙顶增加的荷载大部分都由墙端阻力和承台土反力分担。     

Method of calculating pile fields and other vertically reinforced soil masses

A method is proposed for calculating the stabilization (reinforcement) of bases with layers of highly compressible soils by vertical strengthened elements in the form of ordinary, bored castin-situ, or auger-injected piles, punch holes, granular drains, etc. Such reinforcement reduces severalfold settlements and consolidation time of a weak base and also increases its resistance to horizontal (including dynamic) loads. The heads of the reinforcing elements can be embedded into the base as well as broadened (with “caps”) or joined by a ground beam. The soil deformation model in the ARM93 program takes into account nonlinearity under compression and shear as well as dissipation of the initial excess pore pressures initiated by the placement of fill and other preliminary loads. The authors developed “COMPGEO” applications programs for solving the main geotechnical problems on a computer. The programs realize adequate nonlinear models of soils and as a variant carry out the calculations according to the existing building codes SNiP. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 11–15, May–June, 1994.     

Mechanisms of large-scale landslides in China

Large-scale landslides in western China are famous for their size, complex formation mechanism and serious destruction. Data were collected from some typical large-scale landslides in mainland China in the 20th century. A number of geo-mechanical models have been identified: the “three sections” model (sliding; tension cracking; shearing), “retaining wall collapse”, “horizontal-pushing” in horizontal strata; large-scale toppling in counter-inclined strata; the creep-bending–shearing model etc. Large-scale rock landslides are generally accompanied by sudden brittle failure of the “locking section” along the potential sliding surface. The paper discusses the importance of this “locking section” which is key to assessing slope geohazard and to the development of control/mitigation measures.     

Refinement of the engineering method used to calculate foundation settlements and tilts of high-rise buildings

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. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 2–7, November–December, 2007.     

Use of gestalt in wayfinding design and analysis of wayfinding process

The authors brought forward the definition of “Gestalt space” and indicated this kind of space can be easily cognized. Three experiments showed that “classification” and “grouping” are the human strategies to solve wayfinding problems. “Similarity” and “Legibility” of the space are advantageous to help people to complete wayfinding tasks. The designer should provide the essential “Legibility” in Gestalt space, by using some techniques such as “break” and “accession” to settle the wayfinding problem. __________ Translated from Architectural Journal, 2007, (5): 89–91 [译自: 建筑学报]     

On some “generalizations” of analytical engineering methods

The studies of S. G. Bezvolev [1–3] are examined. Results of analyses performed by the procedure outlined in [1] are presented, and a soil model, which is based on this procedure [3], is discussed. In addition to this relation, the papers under consideration are also linked by the fact that they “generalize” the engineering methods proposed in [4, 5] for analysis of the settlements of slab and pile foundations. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 9–16, May–June, 2008.     

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.     

On the bearing capacity of sandy foundation beds

Results of analytical investigations using the software package “GEO-MIGG”, which establish the scale effect of a structure on the bearing capacity and settlement of the foundation bed, are presented. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 2–8, May–June, 2006. An erratum to this article is available at .     

Stress determination in soils from variation in level of infrared radiation during unloading

A procedure for and results of model experiments conducted on insulated soil specimens in connection with the development of a method of measuring stresses in soil masses in accordance with an “unloading” scheme using infrared radiometry are discussed. The principal feasibility of the complete unloading of a volume of a slightly cohesive soil without its “instantaneous” failure with simultaneous thermoradiation measurements is indicated. A linear relationship is established between the change in the intensity of the radiation flux during unloading and the contact stress on the boundary of the specimen, which simulates the level of stresses in the mass. The value of the coefficient linking the indicated values can be used to interpret IR measurements conducted in other tests of the type of soil in question, including in-situ tests. The study was conducted with support from the Russian Fund for Fundamental Research (Project. No. 93-05-09246) Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 2–6 January–February, 1995.     

Monitoring the deformability of laminar foundation beds during their engineering preparation

This paper outlines practical experience gained with the development and use of monitoring of the consolidation compaction of nonuniform peaty foundation beds by vertical drainage with a surcharge at the experimental testing ground “Ol’gino” in a suburb of Saint Petersburg, which makes it possible to establish the effectiveness of the engineering preparation of laminar foundation beds. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 21–24, September–October, 1999.