A SMP—1 super mini-penetrometer was made for the interest of knowing the distribution and strength of aggregates in unsaturated soils well. The work principle and buildup of this apparatus is briefly introduced; and then the feasibility and availability of the application of the apparatus are demonstrated through the penetration tests with the samples of dough and expansive soils treated by lime. It is shown from the test results that the curve of the resistance force to the end of the needle versus depth during penetration can be presented and the strength distribution isoline maps of aggregates in any vertical section or horizontal plane of the defined cube-like blocks of the samples

which can show the intra-structural diversity and nonuniformity of samples

are obtained with the application of the apparatus. The successful manufacture of the apparatus

therefore

provides a new method for studying the distribution

inner structure and strength of aggregates in engineering soils.