Before the 20th century, tall retaining walls were often made from large masses of stone or concrete. Today, taller retaining walls are more often built as composite gravity walls.

在二十世纪以前，高大挡土墙往往由大量石料或混凝土组成，现在，高大挡土墙一般建成是复合重力墙形式。

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Before the 20th century, tall retaining walls were often made from large masses of stone or concrete. Today, taller retaining walls are more often built as composite gravity walls.

在二十世纪以前，高大挡土墙往往由大量石料或混凝土组成，现在，高大挡土墙一般建成是复合重力墙形式。

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