PSI - Issue 32

V. Epin et al. / Procedia Structural Integrity 32 (2021) 64–70 V.Epin/ Structural Integrity Procedia 00 (2021) 000–000

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1. Introduction For monitoring critical engineering structures operating in complex external conditions (temperature differences, aggressive environment) require special measuring systems adapted to such objects. Their stable and reliable operation is important to assess the current mechanical state of the structure and its forecast. This is an urgent task for engineering structures in the mining and processing industry since the structures are operated in an aggressive environment. One of these structures is the headframe of the mine shaft, which is used to lift the ore. Its mechanical condition depends on many external factors: the interaction of soil with the shaft, wind load, operation of mechanisms, corrosion of elements, etc., which need to be controlled. Such structures are built in unique geological conditions and are exposed to aggressive environments caused by precipitation, salt, and temperature changes. Under these conditions, the structures experience significant static and dynamic loads. One of the main factors determining the quasi-static deformation state of the elements of a headframe building is the deformation interaction of a part of the load-bearing columns with pile foundations, as well as the deformation interaction of the rest of the columns with the reinforced concrete head of the skip shaft. This deformation interaction is largely determined by the vertical displacements of the lower bases of the columns. To register changes in the values of the vertical component of the foundation settlement that interact with the ground, an original development based on a set of hydrostatic leveling sensors was used. The paper describes the features of installation and operation in conditions of low temperatures and aggressive environment of the hydrostatic leveling system adapted for the design under consideration. 2. The object of monitoring The object of monitoring is the metal structure of the headframe of the mine shaft of the mining and processing complex. The headframe is a precast-welded high-rise metal structure with a height of 64.35 m, that allows the lifting of potash ore from a mine with a depth of more than 800 meters. Seasonal temperature changes, deformation interaction with the ground, as well as corrosion degradation of the metal can determine the duration of quasi-static deformation processes with characteristic times lasting in days, months, years. This structure has a complex construction specific. During the shaft-sinking process the method of freezing the soil was used. Some elements of the foundation of the structure are located on frozen ground, which gradually thaws. This can potentially lead to unplanned vertical movements. The structure under study is shown in Fig. 1.

Fig. 1. The headframe under construction.