塑そ性せい指し数すう

noun

plasticity index

Technical term in geotechnical engineering; the numerical difference between the liquid limit and plastic limit of a soil, indicating its plasticity range.

• この粘ねん土どの塑そ性せい指し数すうは20です。

  The plasticity index of this clay is 20.

• 塑そ性せい指し数すうが高たかい土つちは、水すい分ぶん量りょうの変へん化かによって大おおきく膨ぼう張ちょう・収しゅう縮しゅくします。

  Soils with a high plasticity index expand and shrink significantly with changes in moisture content.