Testing reinforced soil cushions on the soaked subsidence base

Neogene friable deposits of the Quaternary age, widespread in Mongolia, belong to loess-like subsidence soils, mainly of type I in terms of subsidence, and are of kyrogenic-sublimation origin. As a result of the sublimation process of permafrost ice (the most recent Altai-Tunguska ice age, which covered most of the Euro-Asian region 15-18 thousand years ago) and seasonal deep frozen soils, occurring for many years in deep frozen subsidence soils, the structure is decompacted, as a result of the latter, porosity n=(50÷65)%, porosity coefficient e = (0.70÷0.84), density of dry soil ρd=(1.35÷1.60) ton/m3 or undercompacted, moisture content of sandy loam W=(0.04÷0.06) and loam W=(0.05÷0.08), as a result of repeated freezing and thawing, cracking and grinding of the solid part of the soil occurs, based on this, the content of silty parts is 50-60%. In recent years, experimental and theoretical studies have been actively carried out in many countries of the world to improve traditional soil cushion solutions using geosynthetic materials for horizontal and vertical reinforcement. Currently, in the soil conditions of Mongolia, research work has not been carried out to introduce the method of reinforced soil cushions due to the lack of an appropriate design standard and other regulatory documents. This article discusses the results of stamp field tests to determine the deformation characteristics of highly compacted soil cushions made of crushed stone-sand mixtures and local sandy loam soils with horizontal geosynthetic reinforcements from geogrid and geotextile, modeled in 6 different combinations on pre-soaked subsidence bases