PURPOSE: To execute works of embankment and breakwater economically in a short term of works by assembling block structures having partitioning blocks connected integrally to each other through a connecting shaft to built up a platform on the upper portion.

CONSTITUTION: An upper wall body 10 and lower wall body 11 extend from a side wall body 12 to present the U-shaped form. A strut 18 is provided between the upper and lower wall bodies 10, 11 to form a partitioning block 1. Each block 1 is provided on the upper portion and bottom respectively with a ceiling plate part 3 and a mounting base plate 2 to form a block structure 10 with a connecting shaft 30. A tire mat 102 connected to a waste tire is laid on a riprap 101 to build up block structures 100 in a predetermined position of the mat so that the inland sea side I is separated from the open sea side O. Riprap bales 103 for preventing the inland sea side I and the open sea side O end edge of mat from being washed and dug are piled. The foundation work and breakwater have effects of foot protection and wave lulling as they are. Thus, the embankment can be executed in a short term of work with low cost.