A TECHNIQUE FOR CUTTING BRITTLE UNDISTURBED LATERITIC SOIL BLOCK SAMPLES T. CÁSSIA DE BRITO GALVÃO 1∗ , VINCENT P. DRNEVICH 2 and DARRELL G. SCHULZE 3 1 Universidade Federal de Minas Gerais, Escola de Engenharia, Belo Horizonte, Brazil; 2 School of Engineering, 1284 Civil Engineering Building, Purdue University, West Lafayette, Indiana, U.S.A.; 3 Soil Science, Agronomy Department, Purdue University, West Lafayette, Indiana, U.S.A. ( ∗ author for correspondence, e-mail: cassia@etg.ufmg.br) Abstract. This note describes a technique for cutting undisturbed brittle block samples into smaller specimens for further geotechnical testing. This technique revealed very useful in dealing with col- lapsible soils, where the sampling is recommended to be done with block soil samples. A further use of this technique as an efficient way for sampling collapsible soils is proposed. Keywords: block sampling, collapsible soils, lateritic soils, undisturbed sampling 1. Introduction Lateritic soils cover 65% of the Brazilian land surface. Most of these soils have a macroporous and collapsible structure. The engineering conditions of these type of soils are, mainly: (i) Loss of soil strength with time; (ii) High void ratio; (iii) Aggregate deterioration; (iv) Easily compacts; (vi) Landslide prone; (vii) Depth of wetting affects slope stability. Therefore, these soils may be easily disturbed during sampling, sample transport and specimen preparation. The effects of phys- ical disturbance from sampling and transportation on shear strength are: (i) Re- duces unconsolidated undrained triaxial test strength and unconfined compression test strength; (ii) Increases consolidated undrained triaxial test strength; (iii) Little effect on drained direct shear test strength; (iv) Decreases cyclic shear resistance. The disturbance also effects the consolidation tests results as follows: (i) Re- duces the preconsolidation pressure, P c ; (ii) Reduces the compression index, c c ; (iii) Reduces the coefficient of consolidation, c v , in the vicinity of the preconsolid- ation pressure; (iv) Reduces the coefficient of secondary compression, c a . If the samples have experienced considerable disturbance during extraction, transport and specimen preparation, the test results and the predictions based on such results may be seriously in error, yet total duplication of in-situ conditions is virtually impossible. Quite obviously, therefore due care should be exercised to obtain samples with the least possible disturbance, possible disturbances must be accounted for during the interpretation of the results. Undisturbed samples are Environmental Monitoring and Assessment 84: 175–181, 2003. © 2003 Kluwer Academic Publishers. Printed in the Netherlands.