Influência da umidade de compactação na dosagem de solo expansivo estabilizado com cal

Abstract

Expansive soils undergo volumetric instability due to variations in water content, which can adversely affect nearby structures. Lime stabilization is a widely adopted technique to mitigate this behaviour; however, its considerable environmental impact necessitates a more efficient and sustainable application. In this context, the dosage methodology based on the parameter 𝜂�𝐿�𝑖�𝑣�⁄ (porosity/volumetric lime content) plays a crucial role in modelling geotechnical properties and precisely determining the optimal lime content for stabilization. Moreover, while studies have demonstrated that initial water content significantly influences the soil's swelling behaviour, a knowledge gap persists regarding the effectiveness of 𝜂�𝐿�𝑖�𝑣�⁄ parameter in modelling these properties under varying initial water content conditions. Thus, this study aimed to analyze the influence of initial water content on the behaviour of an expansive soil stabilized with lime. For this purpose, an expansive soil from Paulista, Pernambuco, Brazil was studied, stabilized with different hydrated lime contents (0%, 2%, 3%, and 4%), different dry unit weights (13.5, 14.5, 15.5, and 16.5 kN/m³) and initial water contents (16%, 19.5%, and 23%). Oedometer expansion tests (obtaining free swell and swelling pressure) and total suction tests were conducted. The results showed that the initial water content significantly affects both free swell and swelling pressure developed by the samples. Moreover, except for samples with initial saturation close to 100%, the parameter 𝜂�𝐿�𝑖�𝑣�⁄ proved effective in modelling free swell and swelling pressure, generating a representative dosage curve for each initial water content. The different dosage curves were normalized to obtain a single mathematical expression, aiming to generalize the dosage methodology for this soil. Additionally, a strong correlation was observed between the swelling properties, leading to the establishment of two mathematical relationships for determining swelling pressure from free swell or the opposite. One relationship was obtained through simple linear regression of the experimental data, while the other was derived from the dosage equations based on the parameter 𝜂�𝐿�𝑖�𝑣�⁄. When analyzing the swelling properties as a function of initial total suction, a dual behaviour was observed. Up to 5000 kPa, the increase in initial total suction tends to enhance the expansive characteristics of the soil. Beyond 5000 kPa, the effect of initial total suction on swelling properties becomes less significant.