Abstract. The city of Arkhangelsk is located on a marshy plain, where the groundwater level used to coincide with the surface. The area preparation for construction consisted in filling a layer of sand over peat. Hence, the following characteristic geotechnical conditions of the newly developed areas: high groundwater level and long-term settlement of peat under sand embankment. That is why subsurface structures are protected by a drainage, and drains are installed over pile foundations. One problem developing in the course of drain operation and requiring expensive reinstallation activities is clogging of drain filters with fine organic and clay particles carried over by groundwater flow. The article presents the results of a survey of a building erected more than 30 years ago, which suffered from groundwater table rising due to the reduction of drain system's water intake capacity. Clogging of crushed stone cover above the drainpipe resulted in the reduction of the permeability factor. Laboratory surveys were conducted to estimate the reliability of drains with the pipes wrapped in geotextile. Drains with a layer of geotextile surrounding the stone filtering cover were also investigated. To simulate clogging, humus and clay particles were added to the water running through the filtering tube. It turned out that the second geotextile arrangement -around the stone cover with sand backfillingwas the most effective.

In recent years, much of the attention paid to theoretical and applied biomedicine, as well as neurobiology, has been drawn to various aspects of sexual dimorphism due to the differences that male and female brain cells demonstrate during aging: (a) a dimorphic pattern of response to therapy for neurodegenerative disorders, (b) different age of onset and different degrees of the prevalence of such disorders, and (c) differences in their symptomatic manifestations in men and women. The purpose of this review is to outline the genetic and epigenetic differences in brain cells during aging in males and females. As a result, we hereby show that the presence of brain aging patterns in males and females is due to a complex of factors associated with the effects of sex chromosomes, which subsequently entails a change in signal cascades in somatic cells.

No abstract

A reliable forecast of water depression in waterlogged areas depends on the due consideration of specific peat properties: a considerable change in the water permeability of peat once water hydrostatic uplift is removed, clogging over time, decomposition and other factors. The article presents an example of numerical simulation in Plaxis software of a perimeter drainage system, where groundwater level has been monitored for 1 year. Piezometers were installed on site at the distance of 7, 17 and 30 m from the drain pipe of a building under construction. Deformation-strength properties and filtration properties of peat were determined on samples taken from excavated pits. Besides, the samples were tested using filtration tubes to identify changes in water permeability of peat over time and depending on the amount of water filtered through peat. The survey took 90 days at the ambient temperature of 6 to 12 °C, which allowed avoiding rapid peat decomposition. The laboratory test results have shown that water permeability of natural-state peat samples has decreased by a factor of 2.7 to 3.1 with 450 to 580 liters of water filtered. The deviation of the design groundwater level calculated in Plaxis from its actual position did not exceed 0.07 m. Numerical simulation with due consideration of decreased water permeability of peat over time allows obtaining forecast results closer to the actual groundwater level.

The article describes the feasibility of using a stone-free drainage system for water depression in peaty soils. The purpose of the research is to develop economical and technological engineering solutions for drainage in peat soils. A specimen of a stone-free drainage system, including a perforated corrugated pipe 150 mm in diameter and expanded polysterene pellets as aggregate, was studied in laboratory conditions. Geotextile filters were wrapped around both the aggregate and the drain pipe. The drainage system specimen was subjected to a load equivalent to that applied by 1 to 4 m of backfilling sand. The study established high deformability of the drain pipe and the pelletized expanded polysterene aggregate, as well as a considerable decrease in the aggregate water permeability. Тhe burial depth of a typical stone-free drainage system shall be limited by 2.5 m. The article shows that the presence of clogging particles in drain water may lead to a considerable decrease in permeability of geotextile filters on drain pipes. The proposed design of stone-free drainage system in peaty soils ensures lower material consumption, cost, and workload. To reduce deformations of stone-free drainage system structural components, pipes and aggregate of non-yielding (stiff) materials shall be used.