Conclusion

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The resolution of the June plenum of the CPSU Central Committee emphasizes the need, when developing and implementing new technological processes and machines, to proceed from the point that they meet the requirements of the most rational and economical use of social labor, material and monetary resources, ensure an increase in output, improve quality and reduce production costs, grow labor productivity, facilitate and improve the working conditions of workers, comply with safety regulations, and reduce the payback period of capital investments in comparison with the best achievements of domestic and foreign science and technology.

As can be seen from the materials contained in this book, the vibration method of driving piles meets all the specified requirements. This method, developed by Soviet scientists, engineers and production superintendents, made it possible to achieve a radical increase in labor productivity in the work of driving piles, sheet piles and ropes, extracting sheet piles, as well as drilling wells. Its use has facilitated the implementation of comprehensive mechanization of such labor-intensive production processes as laying trenches in weak water-saturated soils, constructing pile foundations for power line supports and a number of other works, while significantly improving their quality. Thanks to the use of the vibration method, the state received financial savings, the importance of which is difficult to overestimate; to judge its size, it is enough to point out that the savings achieved over the past ten years only on the immersion of metal sheet piles amount to at least 30-40 million rubles.

Therefore, every possible increase in the scale of implementation and further expansion of the scope of application of the vibration method in construction is an important national economic task. The solution to this problem can be achieved by acting in three directions – along the path of improving designs and organizing mass serial production of vibratory hammers of various types, power and purposes, using these machines for piling work in new areas of construction and introducing them into the production of those types of heavy and labor-intensive work, on which the vibration method has not yet been applied.

There are quite a few areas of construction in which the use of the vibration method could provide a great technical and economic effect. For example, currently, the sinking of mine shafts in quicksand and other unstable water-saturated soils is carried out using labor-intensive and low-productivity methods of freezing soils, sinking under compressed air, deep dewatering, etc. Meanwhile, in many cases they can be replaced by highly effective vibratory driving, which can be used either by lowering entire supports, or (with relatively small thicknesses of the unstable soil layer) by sinking shafts using the method of installing metal sheet pile fencing. The first of these methods was proposed even before the start of World War II [4], but at that time it could not receive proper development due to the lack of powerful vibration machines suitable for driving roof supports. Such machines have already appeared, and it must be assumed that in the near future special powerful low-frequency vibration hammers with longitudinal or longitudinal-rotational action will find use in mine construction. As for the second method, to put it into practice, vibratory metal sheet pile drivers can be used with modification of their designs in relation to the conditions of mine construction.

The first attempts to use vibratory hammers for sinking mine shafts using the method of constructing a fence made of metal sheet piles were recently reported by E. P. Shirai [67]. In the case he describes, the section of the shaft in quicksand was completed in 1.5 months (taking into account all the downtime and interruptions in work that took place) instead of the three required for excavation using the caisson method. The cost of sinking the mouth and section of the shaft in quicksand to a total depth of 19.7 m using the caisson method amounted to 986.8 thousand rubles. The actual cost of work performed using a vibratory hammer turned out to be equal to 557.8 thousand rubles. Thus, the cost of the structure was reduced by almost half.

A particularly significant technical and economic effect comes from the use of the vibration method of driving piles during the construction and dismantling of temporary pile structures from inventory elements. For example, in the peat industry, a large number of temporary supports for pumping stations and other structures are installed on piles. The use of vibratory drivers would make it possible not only to load, but also to easily remove these piles, and they could be used repeatedly, i.e., become inventory; this would provide significant savings in material resources.

In the forestry industry, in the construction of single-rail elevated railway lines, vibratory hammers can be widely used during the construction of pile supports for overpasses, etc.

When installing metal and reinforced concrete structures, as well as constructing various structures, lifting masts and derrick cranes held by steel screws are used. In many cases, instead of constructing anchors in the form of “deadmen” buried in special pits, it is much simpler, faster and cheaper to construct anchors from metal sheet piles driven into the ground by vibration.

The first experience of using such cable anchors at two sites gave positive results.

The experience of using VPP-2 vibratory loaders to loosen frozen building materials and coal on railway platforms during transportation is of considerable interest. The first work carried out in this direction at Stalingradgidrostroy by A. A. Smolyar and I. B. Pasalsky opens up great prospects for a significant reduction in labor costs, car downtime and a reduction in the cost of unloading work in winter conditions.

In Chapter 5, we showed that vibratory pile drivers can be successfully used not only for piling work, but also for compacting loose soils and developing frozen soils. In this regard, there is a need to create universal vibration machines that could be used as replacement equipment for cranes or tractors and, in combination with them, would be able to perform work such as compacting loose sand, developing frozen soils, driving piles, sheet piles and pipes, punching holes in frozen soil, drilling wells, etc.

These vibration machines could, in particular, be used in industrial and hydraulic engineering for compacting concrete mixtures in large masses. Here, powerful vibration equipment makes it possible not only to obtain a high packing density, but also to embed large aggregates into concrete, thereby reducing the consumption of cement per unit volume of concrete by two to three times, and consequently, significantly reducing its exotherm and shrinkage.

Separate laying of concrete mixtures with embedding of coarse aggregate using vibration is known to be used in Germany, where special machines of the “Mammut” type were created for this purpose.

Vibratory pile drivers can be used in exactly the same way. Since these machines are capable of exciting directed vertical vibrations, they will undoubtedly embed the stone and compact the mixture more effectively than vibrators of the Mammut type, during which circular horizontal inertial forces develop.

Equipping self-propelled cranes and tractors with vibration machines and replaceable equipment for them to perform various types of labor-intensive work will open up new broad opportunities for increasing labor productivity in construction.