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The Alexander Column as a compositional center of the architectural ensemble of Palace Square in Saint Petersburg, Russia, has always been a matter of concern for both the public and specialists due to progressive deterioration of its granite shaft caused by crack formation. The article examines previous studies related to the inspection and restoration of the column's shaft and other parts above ground level, as well as reasons for crack initiation and propagation in the column. An analysis was performed on the anomalies in the Fennoscandian Shield and the structural-tectonic conditions at the Montferrand quarry site, revealing the presence of faults and circular features within the studied area. The research considers N.Hast's measurements of excess tectonic stresses in anomaly zones (southeastern Finland), which acted horizontally and resulted in the development of tensile cracks within the granite massif and later in the column’s shaft after its installation. The most dangerous type of deformation for the Alexander Column is its tilt in the northeast direction, recorded in 1937 and 2000. The article analyzes the construction features of the column's foundations and additional underground elements, as well as soil and groundwater characteristics based on archival data. The contamination history of the underground space is taken into account, and an analogy-based method is used to assess the engineering-geological and hydrogeological conditions of the underground load-bearing structures within the placement zone of the Alexander Column and the New Hermitage buildings. The results of visual observations on the nature of deterioration and deformation of the pavement around the monument, as well as its pedestal, indicating the development of uneven settlement of the foundation, are presented. The article concludes with general recommendations for organizing and implementing comprehensive monitoring to forecast the deformation dynamics of the Alexander Column.

Introduction. Periodic geodetic observations are used to control the position of building structures and soil massifs. Since tilt is considered to be one of the most dangerous types of building deformations, this paper considers existing methods for its determination. When a horizontal displacement (tilt) is detected, it is of particular importance to assess not so much its angle but its direction. This allows preventive measures to be timely enforced. Therefore, determination of the direction of horizontal displacements at small tilt angles presents a relevant research problem. In order to increase the sensitivity of the considered measuring device, it is proposed to use the action of electric field.Aim. Calculation of electrical voltages that ensure reliable operation of the device under consideration, depending on its geometric dimensions and characteristics of the materials used.Materials and methods. The device was made of conductive, semiconductive and dielectric materials. Calculations were based on an analysis of forces acting on a vertically suspended load in the presence of electric field. The conditions of equilibrium and instability of the position of the load arising due to strong positive feedback in electric field were considered.Results. Calculations were performed to support a reasonable choice of geometric and electrophysical characteristics of the developed device. A formula was obtained for the values of electrical voltages that could ensure troublefree operation of the device. The calculated values of operating voltages were found to be acceptable for practical application. The main structural elements of the device and one of the possible methods for registering information signals were proposed.Conclusion. Due to the instable position of the load in a sufficiently strong electric field, the developed device allows the direction of displacements to be measured even when their values tend to zero. This makes the developed device promising for practical application. However, it should be noted that, under such small displacements, the accuracy of the device depends on the manufacturing conditions and random factors.

Modern surgical treatment of cataracts provides effective results. The study of the position of the intraocular lens (IOL) in the capsule bag can be considered as one of the most important factors influencing the final visual and refractive result of the operation.Aim: comparative analysis of clinical and functional results and position of the IOL in the capsular bag, namely decentration and tilt, when performing femtolazer-assisted phacoemulsification (FLACS) and standard phacoemulsification (CPCS). Materials and methods. We surveyed 57 patients (57 eyes). FLACS was performed in 27 patients, CPCS – in 30 patients. Standard methods of research were used, determination of the position of the IOL (decentration and tilt) in the capsular bag on the device OCT-Casia2 (TOMEY, Germany) and study of wave front were conducted.Results. Comparative analysis of the obtained results showed no significant difference between groups in postoperative visual acuity, however, there was the trend towards higher performance corrected distance visual acuity and uncorrected distance in the group FLACS (0.68 ± 0.18 and 0.74 ± 0.2) compared to the group CPCS (0.58 ± 0.28 and 0.65 ± 0.24). Internal higher order aberrations were significantly low in the group with femtolazer accompaniment: in 3 mm zone almost 2 times (p = 0.041), in 5 mm zone 1.3 times (p = 0.047). Vertical decentration in a CPCS group made 0.217 ± 0.26 mm, in FLACS group – 0.118 ± 0.05 mm, the vertical tilt – 0.75 ± 0.37° and 0.54 ± 0.36 respectively. Conclusion. Decentralizations and IOL tilt tended to lower indices in the FLACS during the observation period up to 2 months after the operation, which was accompanied by lower values of higher order internal aberrations.