The object of research is the stabilization of clay soils of the road bed. The purpose of this work is to study the physical and mechanical characteristics of stabilized clay soil with quicklime. The influence of quicklime ground lime in an amount from 1% to 10% on the change in the basic physical properties and compressive strength of clay soil is considered. Method. As a soil, heavy silty loam with a Index of plasticity of 14.63 and a content of dust and clay particles of 79.92 % was used. The strength and physical properties of stabilized soil with quicklime ground were studied for the following indicators: compressive strength of water-saturated samples at 7 days of age, water uptake, moisture at the limit of liquidity, moisture at the limit of plasticity, index of plasticity, content of dust and clay particles.Results. Stabilization of the soil with quicklime ground lime in an amount of 1 % to 5 % improves the workability and workability of clay by increasing the optimum moisture content by 2.4-13.5 % and reducing the maximum density – 0.6-4.4 %. With the introduction of quicklime ground lime in an amount of 1 % to 10 % in clay soil, the compressive strength of water-saturated samples at 7 days of age increases from 0.05 MPa to 1.34 MPa. It has been established that with the introduction of quicklime in an amount of 1 % to 10 % into the soil, there is a decrease in the degree of heaving and swelling due to a decrease in water absorption by weight from 24.85 % to 13.34 % and a decrease in the amount of dust and clay particles from 79.92 % to 46.29 %.