On the rational range of application of different designs of pile foundations for residential construction in weak soils

Conclusions 1. At the present time, sectional driven piles of continuous square cross section are economically the most expedient for foundations supporting large-panel 9- and 16-story apartment houses built on weak soils of considerable thickness (more than 12–16 m).2. Of the square sectional pile designs employed in the USSR, the most technically rational and economically effective design is the sectional driven pile with a socket splice.3. A material-technical base now exists for the widespread use of square sectional piles. General-contracting organizations maintain pile-driving equipment in their inventory, all reinforced-concrete-products plants produce square driven piles, and an effective and reliable splice design has been developed.4. To increase the installation efficiency of pile foundations for buildings constructed on weak soils of considerable thickness, it is necessary to develop working drawings of type designs for square sectional piles, type plans for the foundations of apartment houses which are constructed of square sectional piles, estimated norms for their embedment at the construction site, and recommendations for the range of their rational application.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 23–26, March–April, 1977.     

Foundation strengthening by piles constructed by means of pneumatic punches

The writers propose methods for strengthening foundations on natural bases under straitened conditions by means of driven inclined and horizontal metal pipes filled with concrete, as well as by bored piles formed in the soil and constructed by using pneumatic punches. Results of investigations of the bearing capacity of the strengthened foundations are presented.Krasnoyarsk Civil Engineering Institute. Krasnoyarsk PromstroiNIIproekt Institute. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 26–28, July–August, 1993.     

Effective types of piles for farm buildings

Conclusions 1. Tee-section driven piles, intended for construction of framed farm buildings, transmitting a thrust of 100–200 kN to the foundations, behave as absolutely rigid elements for all practical purposes.2. For analysis of such piles, it is necessary to use a soil base model with a modulus of subgrade reaction increasing linearly as the depth increases and decreasing as the thrust increases.3. Under the thrust action on the lateral surface of the pile additional friction forces are developed, as a result of which the load-carrying capacity of the pile under the vertical load is increased.4. Weakening of the soil base by engineering canals passing alongside the pile brackets results in increased horizontal displacements. In wetted collapsible soil, the effect of weakening of the base is manifested to a greater extent than in soil having the natural water content.TsNIIÉ Psel' stroi. Siborggazstroi. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 11–15, July–August, 1981.     

Bed strength of T-section foundation blocks under inclined loads

Conclusions 1. The displacements of driven blocks can be determined from a bed model characterized by a coefficient of subgrade reaction that increases linearly with depth using proportionality coefficients from [3].2. Driven T-section blocks ensure that the computed loads are taken up at the design depth, and can be used as foundations for agricultural buildings with three-hinge frames with a span to 21 m, and a frame spacing of up to 6 m at sites with gentle relief, preferentially in regions with deep frost to 1.5 m.Central Scientific-Research Institute of Experimental Design and Planning for Agricultural Construction VNIIOSP. Moscow State Scientific-Research Institute for Agricultural Construction. Translated from Osnovania, Fundamenty i Mekhanika Gruntov, No. 3, pp. 16–18, May–June, 1988.     

Effectiveness of using pile foundations in housing construction in Tyumen

Conclusions 1. Pile foundations of residential buildings in Tyumen under the usual soil conditions with the use of 30×30 cm prismatic piles and low monolithic grillage are, as a rule, ineffective.2. The use of pile foundations with a high grillage does not produce perceptible advantages and their technicoeconomic indices are close to those of foundations with a low grillage.3. The use of grillage-free pile foundations permits obtaining indices comparable with strip foundations at a pile length up to 8 m (working length 6 m).4. The economic effectiveness of pile foundations under conditions of Tyumen can be increased by using short piles of rational designs having an increased bearing capacity under the given soil conditions.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 4–6, May–June, 1977.     

Development of foundations of small-section piles and their introduction to construction

Conclusions 1. The use of small-section piles for the foundations of lightweight buildings and structures significantly reduces material consumption and labor outlays for their construction.2. The technology and embedment equipment, as well as designs of small piles and pile foundations from these designs, which have been developed as a result of experimental construction, will make it possible to introduce these piles on a broader scale in construction practice.3. The basic positions of Construction Norm and Regulation II-17-77 with the refinements proposed in this paper can be used to compute the bearing capacity of small-section piles subject to vertical and horizontal loads and for dynamic tests.Deceased.Scientific-Research Institute of Industrial Buildings and Structures. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 6–8, January–February, 1981.     

New technologies and equipment for constructing foundations

This article discusses new technologies for constructing combined foundations under large loads, a waste-free technology with sinking of driven piles to a given level on the basis of static sounding, a jet technology for constructing supports, the use of piles with small cross sections, methods of constructing foundations on slopes and sites with mine workings, and construction of foundations in rammed pits.Ufa Oil Institute. Scientific Research Institute of Industrial Construction. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 11–15, November–December, 1993.     

Effect of boring method on bearing capacity of short cast-in-place piles

Conclusions 1. Bored-hole/cast-in-place piles 4–10 m long tend to retain a constant value of the unit bearing capacity, irrespective of soil moisture. Driven piles, and piles cast in punched holes, undergo a loss unit bearing capacity (up to 20%) as their length is increased.2. With the saturation of high-porosity collapsible soils, the unit bearing capacity of bored-hole/cast-in-situ piles up to 10 m long diminishes two to three times, on average. For cast-in-place piles installed in a punched hole, and for driven piles, this reduction ranges up to only 30%. This trend is characteristic of soil layers whose collapsibility properties diminish with depth, from 2–3% to 1–1.5%.3. The unit bearing capacity of cast-in-place piles installed in punched holes is equal to that of driven piles, both for saturated and dry soil conditions.4. Following soil compaction, the unit bearing capacity of concrete cast-in-place piles installed in punched holes is higher than for bored-hole/cast-in-place piles, in the ratio of up to 2 for slightly moistened soils and 3–3.5 for saturated soils.5. All other conditions being equal, the unit bearing capacity is greater for driven piles, and somewhat smaller (by 10–15%) for piles cast in punched holes. The smallest unit bearing capacity is observed in bored-hole/cast-in-place piles (1.5–2 times less than for driven piles).Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 14–15, July–August, 1979.     

广东省高层建筑地基基础调查报告

本文调查了三十幢高层建筑的基础处理,包括钻孔灌注桩,锤击(振动)沉管灌注桩、预制钢筋混凝土桩、箱形基础及独立柱基等。重点总结了钻孔桩和锤击(振动)沉管灌注柱的设计、施工方法及其适用范围。报告最后提出了一些需要进一步研究的向题。     

高层建筑钻孔桩基长期沉降特性分析

结合上海地区26栋高层建筑钻孔桩基长期沉降观测资料,分析桩端持力层的种类、桩端压缩层中砂土比、桩周土层特性等因素对钻孔桩基长期沉降特性的影响,结果表明,桩基持力层的选择和压缩层内的砂土比对桩基沉降有较大影响,钻孔桩沉降受桩周土的影响明显小于打入桩基础。     

钻孔灌注桩工程技术中的若干问题

钻孔灌注桩的施工质量很难控制,尤其是当桩较长时常会造成经济上的损失和工程事故.作者探讨了钻孔灌注桩的有关问题,并介绍了一些施工质量控制的方法.     

某工程烟囱基础事故处理

在某210m高烟囱的桩基加固工程中,采用钻孔灌注桩部分托换原有桩基的方法.介绍施工场地准备、定位、开凿桩孔、钻孔灌注桩施工、后压浆施工以及桩基检测和底板桩孔恢复的施工特点和难点.通过采取有效的质量保障措施,使烟囱桩基得到加固,从而保证上部结构的继续施工.研究结果表明该加固方法切实有效.经过定期的沉降观测,烟囱沉降均匀,符合设计规范要求.     

Actual and calculated loads on piles and results of observing settlements of a large-panel building

Conclusions 1. During the construction period the loads on extreme piles along the axes of transverse bearing walls are considerably greater than on the middle ones.2. Under the effect of rigidity of the building a redistribution of the loads on the piles during its operation occurs even in the absence of a grillage, i.e., the more loaded piles are unloaded and the less loaded ones are additionally loaded.3. The actual loads on the piles in the operating period are considerably less than the calculated, which indicates the need to refine the recommendations of SNiP II-6-74 for the purpose of taking into account the useful loads in calculating the foundations of residential buildings.4. The factor =0.2, concerning conversion from settlements of single piles in static tests to settlements of piles in foundations under long-term load, given in the draft of the new edition of SNiP II-17-77, is acceptable.5. To accumulate data on the actual loads on pile foundations it is necessary to continue their measurements under various soil conditions.Deceased.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 17–19, May–June, 1977.     

Construction of deep pile-columns at the Noril'sk combine

Conclusions 1. For design loads of up to 300 tons on piles it is convenient to use Type-NSF-40 precast piles, while for large loads and depths of over 24 m it is convenient to use bored piles with diameters of not less than 800 mm.2. It is important to take into account the fact that for bored piles it is necessary to apply careful techniques, especially in connection with continuous concreting and with mixing of the concrete with antifreezing chemical admixtures.Noril'sk. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 11–12, March–April, 1973.     

Bored/cast-in-place piles employing soil compaction of hole bottom,for the "Atommash" Plant

Conclusions 1. Compaction of the soil at the bottom of deep holes of 1-m diameter as described, raised the bearing capacity of piles at their ends, under the Volga-Don ground conditions, by three to five times.2. In view of the fact that the toe of long (exceeding 15 m) floating bored/cast-in-place piles of usual construction contributed only to a weak extent (up to 10% of the total resistance, under Volga-Don conditions) to the performance of the pile, right up to its failure, it is expedient and economically efficient to install such piles only in holes previously rammed at their ends. Under ground conditions of type II in regard to collapsibility, this measure is particularly important in order to avoid inadmissible pile settlements resulting from negative friction following soil collapse under the weight of its own thickness. Cast-in-place piles placed in prerammed holes were introduced in the construction of Section 5 of the Volga-Don "Atommash" Plant, and are recommended for buildings of a substantial number of stories in Volga-Don.Scientific-Research Institute of Bases and Underground Structures. (NII Osnovanii) Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 10–13, November–December, 1980.     

Experience with design and construction of foundations consisting of bored-grouted piles

Conclusions 1. In connection with the increase in the volume of application of foundations consisting of bored-grouted piles, in the construction field the need has arisen for development and serial production of special equipment and accessories for their construction.2. It would be advisable to issue normative literature for the methods of analysis, production, and acceptance of work relating to construction of bored-grouted piles. The methods of analysis should contemplate the use of electronic computers.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 18–21, November–December, 1982.     

超高层建筑中钻孔灌注桩后注浆技术分析及其应用

近年来,钻孔灌注桩后注浆技术在超高层建筑桩基中应用日益广泛。本文根据工程实践资料,介绍了后注浆加固机理,分析了后注浆钻孔灌注桩的承载力和变形特性,总结了后注浆施工工艺关键参数的确定方法,归纳了现场施工质量控制的关键环节,例举了苏州某超高层建筑钻孔灌注桩后注浆技术的成功案例,对推广钻孔灌注桩后注浆技术在超高层建筑桩基中的应用具有一定的价值。     

Slit foundations of industrial and civic buildings in the middle urals

The technological and economic advantages of slit foundations of industrial and civic buildings under conditions of the Middle Urals are shown. Their designs and results of tests at particular construction sites are described.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 8–10, September–October, 1992.     

Concrete-pipe piles in base of tall building

The writers present design and construction experience with foundations of a tall building on concrete-pipe piles under complex engineering-geologic conditions. Results of static tests on the piles are compared with the stabilized settlements of the building foundations. It is established that their values are close to each other.AP Section of the Construction Scientific-Research Institute of the Mininveststroi of the Ukraine. Kiev Specialized Administration No. 580 of the "Ukrburvod" Trust. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 20–22, March–April, 1993.     

Piles injected into predrilled holes in soils prone to slump-tyre settlement

Conclusions 1. Drill-and-inject piles of increased bearing capacity with a diameter of 250–400 mm and more and a depth of up to 50 m and more, which are embedded into underlying soils not prone to slump-type settlement can be used in loess soils classed as type-II in terms of proneness to slump-type settlement.2. The use of washing mud based on sodium silicate, which eliminates slump-type settlement of the soils during pile fabrication and reduces the friction against their lateral or surface by 10–15% within the limits of the stratum prone to slump-type settlement, lowering the negative loads on the pile, is effective when piles are injected into predrilled holes in soils prone to slump-type settlement.3. Drill-and-inject piles 250–400 mm in diameter and up to 50 m long have a design bearing capacity of from 0.50 to 2.50 MN and can be recommended for the installation of new, and the strengthening of existing foundations for civil and industrial projects in soils prone to slump-type settlement.4. A special set of equipment, which makes it possible to ensure the continuous production of work that includes the drilling of holes, assembly of reinforcing cages, and the filling of the holes with a hardening grout, should be used for the installation of these piles."Soyuzgidrospetsstroi." Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 18–20, January–February, 1988.