3.8 METHODS OF SEISMIC RESISTANCE OF RAILWAY ROADBED

Abstract

Based on the analysis of damage to earthen engineering structures and special studies, specific and economically acceptable proposals for the design of the railway roadbed have been developed.

An earth bed is an engineering structure made of soil, on which the upper structure of the railway track is located. The roadbed receives static loads from the upper structure of the track and dynamic loads from the rolling stock and elastically transfers them to the base. In addition, the roadbed is designed to align the earth's surface within the railway track and give the track the necessary plan and profile. The roadbed is the most important element of the railway track, its load-bearing structure, on the reliability of which depends technical speed of trains and allowed static load on the rails, transmitted from the wheelsets of the rolling stock, the capacity and carrying capacity of the line. The roadbed must be strong, stable and durable, require a minimum of costs for its construction, maintenance and repair, as well as provide the possibility of extensive mechanization of work. An increase in trainloads and train speeds is possible with high strength and stability of the roadbed objects. The roadbed, being an open dynamic geotechnical system, functions in the following conditions difficult natural and climatic conditions, which negatively affects the state of the soil environment. Therefore, ensuring the stability of the roadbed is a complex problem that requires optimal technical solutions[1.2.3.4.5.6.7.8.9.10].

The roadbed is affected by loads from the rolling stock, the weight of the upper structure of the track, taking into account the drain prism and the weight of the overlying soil layers of the roadbed itself. The load from the rolling stock is temporary, and from the weight of the upper structure of the track and the ground of the roadbed – constant. Load from rolling stock on the main site of the earthworks the web is transmitted through the sleepers and the ballast layer and depends on the method of its transmission. During different periods of track operation, the pressure on the main platform can be different and have a maximum under the end parts of the sleeper in the sub-rail zone or along the track axis under the middle part of the sleeper[11.12.13.14.15].