ABSTRACT
Collapsible soils are unsaturated soils that undergo radical rearrangement of particles and great reduction of volume when wetting, with or without additional load application. These soils present serious problems for Geotechnical Engineering when there is a change of water content, causing additional deformations to the soils. The analysis of their behavior becomes an essential step for the success of an engineering project. Single and double edometric tests with controlled suction and the use of the Expanso-colapsometer were widely used to analyze the volume variation of the collapsible soils due to the change of water content , since they allow to evaluate the behavior of the collapsible soils in a way that simulate the conditions to which the soil will be submitted. The objective of this paper is to evaluate the elastic modulus in field of a collapsible soil of a residential complex in Petrolina-PE, with and without previous wetting. It was used in the field the Light Weight Deflectometer - LWD that is modern equipment that application load dynamic in a plate to the ground and allows measuring the deflections and quantifies the modulus of elasticity. The physical characterization of the soil was performed in the laboratory. The result showed a predominantly sandy soil with a modulus of elasticity ranging from 46.3 to 79.2 MPa and the wetting causes a reduction of 88%. In addition, it was found that the increase of moisture associated with the application of the dynamic load causes a reduction of its stiffness, occurring a decrease of the modulus of elasticity and, consequently, an increase of the deflection. From the results of the LWD, a criterion of identification of collapsible soil was established through the KLWD coefficient, attesting that Petrolina’s soil presents the following susceptibility to collapse: high for KLWD> 4.2, low for KLWD <2.8 and medium For KLWD between 2.8 and 4.2.
Keywords:
Collapsible Soil; Unsaturated Soil; Elasticity Modulus; Light Weight Deflectometer
