Vízügyi Közlemények, 1965 (47. évfolyam)
4. füzet - Rövidebb közlemények és beszámolók
<122) BRIEF PUBLICATIONS AND REPORTS Máthé, A., Engr. : Approximate analysis of clastic frames supported on tlie soil. (For the Hungarian text see pp. 542) Elastic frames supported on the soil suffer deformation under external loads and the soil reaction. The contact surface is pressed into the soil. The magnitude of soil reaction is, according to the assumption of Winkler— Zimmermann, proportionate to the depth of penetration: P = «У, where p is the specific value of soil reaction in kg/sq.cm, ij is the depth of penetration in cm and с is the bedding coefficient in kg/cu.cm. It is not always possible to solve mathematically the differential equation of the elastic line. For this reason the difference equation (2) is recurred to using the approximating method of Gold —Levine. Combining Eqs. (2) and (1) we have EJ M = - — (p i+ 1 - 2pi + pi-,) (3) The surface of the frame resting on the soil is devided into Ax equal parts in a manner, that each panel point should form a division line. Linear distribution of soil reaction is assumed over each section. Over intermediate sections moments can be determined from the equation of the elastic line, Eq. (3), as a function of the soil reaction ordinates p;. These moments can, however, be determined also as frame moments due to external loads and the soil reaction. Determination of moments due to external loads is a simple task. For determining moments due to soil reaction moment influence lines must be constructed for intermediate cross sections, whereafter moments are obtained as products of the influence diagram and the soil reaction diagram. Moments determined in two different ways are equated and thus the number of equations for determining the unknown pi ordinates will be the same as that of intermediate cross sections. At intermediate panel points of the frame the ordinate of soil reaction is assumed to equal the mean value of soil reaction ordinates in cross sections preceding and following the panel point. Using a force and a moment equation the number of equations available for calculating the unknown p L soil reaction ordinates will be equal to that of unknown quantities. The method applied to the analysis of culverts is illustrated by a numerical example (Figs. 5 to 10, Table I). Illés, I., Engr. : Factors affecting the operation of aerated sand traps. (For the Hungarian text see pp. 552) The first experiments performed in Hungary in connection with aerated sand traps were described in No. 1964/3 of this journal. Recent investigations were carried out with the sand trap illustrated diagrammatically in Fig. 1, with screen lengths varying from 40, 60 to 100 cm, and with an air nozzle spacing of 4 cm. Screens were submerged to depths of 48, 96 and 144 cm, and air was injected at the rates 1.1, 1.5, and 2.0 cu.m/hour. Current velocities were determined with the help of solid floats. On the basis of the flow pattern observed several characteristic zones could be distinguished (Fig. 3). An unstable range is situated at the center, surrounded by a transition range, while a high velocity range is at the top. Experimental results were represented in a graphical form, which defined a relationship between screen submergence, screen length, velocity, activated water mass and rate of air injection (Figs. 4 to 6) and facilitate designing. Muszkalaij, L., Eng.: An abbreviated method of flow measurement. (For the Hungarian text see opp. 561)
