Cisalhômetro: equipamento peneumático para medição da coesão aparente e ângulo de atrito interno do solo em condições de campo.

Abstract

The purpose of this work was project and develop a pneumatic equipment that is able in field conditions built a Coulomb Equation ( τ = c +σ n tanφ), determine the apparent cohesion (c) and the soil internal attrition angle ( ). The principle of the equipment functionality consists in the σ n application with a hydraulical cylinder. The values were obtained by the relation F = P/A, where, F is the Power, P is the Pressure and A is the area. The values of obtained by an analogical torquimeter indicates the relation F = T/d, where, F is the Power, T is the Torque and d is the length of the toggle. The equipment evaluation was made by the comparison of the registers obtained from the Cisalhometer and Sheargraph, whose was developed by Cohron (1963). The correlation and the determination coefficients were 0,84** and 0,99**, respectively. The maximum values of shear stress ( τ m), obtained from the field tests between the two evaluated equipments, showed that the Cisalhometer got a good functionality and well field performance. The easy manipulation, the agility to get the results and excellent repeatability allow the equipment to be used in field condition to evaluate the soil shear strength.