Vízügyi Közlemények, 1965 (47. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

<119) ANCHORAGE PROBLEMS IN HYDRAULIC CONSTRUCTION By Dr. L. Hobst, Engr. (Brno, Czechoslovakia) (For the Hungarian text see pp. 475) The author is the head of the Department for Hydraulic Construction, sited in Brno, of the Research Institute for Engineering Structures, Bratislava. In this paper, prepared especially for our Review, anchorage problems arising in connection with structures are described. The paper consists of three parts, namely Part I, the determination of the necessary anchorage depth, Part II, the study of potential applications of anchorage and Part III, anchoring structures during construction. The objective of the paper is to open possibilities for the increased utilization of the properties of foundation rocks in the interest of structural design. This is accomplished by transmitting to the foundation rock — whether solid, or grained, the latter cohesive, or non-cohesive — over the anchor forces of predetermined magnitude and direction, which contribute to the stability of the structure. Principles governing the determination of the necessary anchoring depth in rocks of different composition are described in Part I. The resistance mobilized in solid rocks against pulling out of the anchor is investigated in Chapter 1, and the necessary depth is then determined for sound rocks (Chapter l.a) as well as for fissured rocks (Chapter l.b). Resistance of non-cohesive granular soils agains pull-out forces is dealt with in Chapter 2. Investigations were performed with the help of laboratory layer models (Figs. 3, 4, 5 and 6), three dimensional models (Figs. 7, 8 and 9) and field experiments (Figs. 10, 11 and 12). Necessary anchorage depths in non-cohesive loose granular soils are determined on the basis of experimental results (Chapter 2.d). The behaviour of anchors installed in cohesive soils is studied in Chapter 3. Investigations involved layer models (Figs. 13 and 14) and field experiments (Figs, 15, 16, 17, 18, 19 and 20). On the basis of these experiments calculation principles were developed for the necessary anchorage depLh in cohesive soils. The anchorage depth is selected to provide a mass of soil to which anchorage stresses can be transmitted, and which is capable of securing the anchor against pulling out (sec Fig. 21 ). Potential applications of anchorage are discussed in Part II of the paper. Anchorage can be used to secure structures against vertical, or lateral displacement, overturning, as well as sliding along a slip plane developing in the subsoil (Chapters 1, 2, 3 and 4, respectively

). The calculation of anchor forces is described for each case (Figs. 22 to 25). Stabilization of sliding slopes and preconsolidation of compressible soils are discussed as special applications of anchoring (Chapters 5 and 6). In connection with slope stabilization, anchorages for general civil engineering (road and railroad) purposes and in hydraulic construction are dealt with simultaneously (Figs. 26 to 29). Methods of realizing anchorage of structures are described in Part III. Chapter 1 deals with the design of prestressed units, Chapter 2 with joints between the anchor and the structure, while Chapter 3 with methods of anchoring the cables in soils and several details (prestressing of cables, sealing of anchors). A description is then given of structures built in Czechoslovakia with the help of anchoring. In conclusion the savings attainable by the use of anchored structures for the navigation locks at the planned Danube hydroelectric stations, are pointed out. THE RESOURCES MANAGEMENT PROFILE By M. Domokos, Engr. (For the Hungarian text see pp. 516) A methodological study of one form of the waterbalance, the resources management profile is presented in this paper, based on investigations and studies performed at the Research Institute for Water Resources Development, Budapest. Part I of the paper is devoted to the general definition of water resources development and the waterbalance.