To determine the design characteristics of the Kambaraty dam from the results of a model explosion it was necessary to establish the degree of similarity of blast-fill dams of different scales.It is known from similitude theory [I] that the equality of any two corresponding criteria is a sufficient and necessary condition of similarity of two phenomena or structures.Such criteria include the parameters of the system (in the case being considered these are the dimensions of the dam, blast energy, drop height of the rock, block character of the rock mass, indices of the physical and mechanical properties of the mass, etc.) and the parameters of the process (particle size of the material in the dam, deformation and strength properties, etc.).The total number of parameters of the system when modeling an explosion is greater than the main measurement parameters, and therefore it is impossible to realize the simplest case of theoretical similitude when similarity is fulfilled automatically, regardless of the absolute dimensions of the structures [2]. Hence it follows that in the case of exact mechanical similarity of blast-fill dams the scales of all main parameters should be related with the geometric scale.As a result it is necessary to model body forces (including the density and inertial forces), and they should be inversely proportional to the geometric scale.It becomes clear that in principle it is impossible to realize exact similarity of blast-fill dams under natural conditions, since in reality all body forces creating and compacting such dams are directly proportional to their dimensions.Blast-fill dams can be slmilar only with respect to their expanded mechanical similarity [3]. In this case scales of forces and deformations are introduced in addition due to some distortion of similarity of displacements of individual points.To predict the particle-size distribution it is convenient to divide the entire process of creating the dam into two stages: crushing of the rock mass and formation of the dam fill.These two stages are not interrelated, since in principle it makes no difference how the rock mass was raised into the air --its subsequent compaction does not depend on this.Therefore the explosion and drop of the rock can be examined separately.It is known that two analogous engineering-geologic masses will be similar also with respect to crushability if the consumption of explosives is proportional to the cube of the linear dimensions [4,5].In this case, in severely fractured rock masses any slight deviation from this proportionality as related to a change in the design functional relations of the charge on changing from one explosion scale to another [6] is unimportant, since crushing in this case is practically similar as a function of the parameters of the explosives [7]. This principle is confirmed by investigations of the results of blasting granites at the Medeo dam and in the Toruaigyr area. With the same engineering-geologic properties of the masses the granulometric compositions of the fills are q...
2. The shear moduli for small values of the initial lateral pressure and under conditions of a combined stress state for cohesive soil depend on the level of the initial lateral pressure and for the noncohesive on the change in the moisture content.In the interval of stresses created in the specimen, when the initial lateral pressure does not exceed 0.098 MPa and the average static stress does not exceed 0.3 MPa, the shear moduli are practically proportional to the average stress.3. Both volumetric strains and distortional strains under a brief dynamic shear load and under conditions of a combined stress state are far less than the strains from an equal static load.In this case, whereas the volumetric strains in shear for noncohesive soil have the character of compacting, for cohesive soils they are always loosening.
A number of impounding structures have been constructed in our country by means of blasting.The largest of them are the mudflow-control dam at Medeo, the dam of the Baipaza hydrodevelopment on the Vakhsh River, the height of which exceed 60 m, the 90-m-high dam on the Akh-Su River in Dagestan, coefferdams of the Nurek and Chlrkey hydrodevelopments, and a number of others.Thus the Soviet Union can rightfully be considered the pioneer of this method of constructing dams. Construction experience shows that the use of blast-fill dams at hlgh-head hydrodevelopments will have a maximum economic effect, since their construction can be accomplished in a shorter time and with smaller capital investments.However, the construction of dams by the blasting method has nonetheless not gained wide use. The main reason for this is the lack of knowledge about the properties of the material in such structures.An experimental 50-m-hlgh dam was constructed by the blasting method in February 1975 on the Burlyklya River* in the Kirgiz SSR ( Fig. i) for the purpose of obtaining the necessary data for substantiating the blast-fill dam project of the Kambaratln hydrodevelopment. To conduct the investigations on the experimental site, 10 shafts were driven to depths of 21-47 m at five sites (Fig. 2). These shafts were used during sinking for determining the granulometrlc composition, unit weight, and permeability of the earth over the height of the structure and subsequently (after filling the reservoir) as plezometers for measuring the drawdown curve of seepage [i].The seepage characteristics of the soll in the dam were determined at several water levels in the reservoir.The seepage drawdown curve for the maximum water level in the reservoir is shown in Fig. i. Table 1 gives the water-level elevations in the shafts at different water levels in the reservoir.The seepage properties of the soil composing the dam proved to be different in different zones.The central zone, located between shafts 1 and 3, has the maximum water-retalnlng capacity and the zones of the upstream and downstream shoulders of the dam have the minimum.Analytic methods were used for determining the numerical values of the permeability coefficients of the soll in the different zones of the dam. The permeability coefficient was determined by the equations of steady plane seepage for discharges and water levels in the shafts and upper pool recorded for 15-20 days. The values of the permeability coefficient were determined twice at the save level --in the first case by Eq. (I) on the assumption that the flow was laminar with a linear law of resistance, and in the second by Eq. (2) on the assumption that the flow is turbulent; this is seen from the equations = 2LQ/~v(h ~ + %) H(1) and = 2Ql~v(h, + h,) ~77.(2)where K Z and K t are the permeability coefficients, respectively, in the case of linear and quadratic laws of motion of the flow, cm/sec; Q is the seepage through the dam, mS/sec; hl and h2 are the depths of the seepage in the initial and end cross sections of the inves...
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