On the bottom, an 8 inch or 20 centimeter layer of sand was placed, then what's referred to as a geotextile layer, —a form of fabric—then a layer of waterproof plastic, then another geotextile layer, then another layer of sand.
在底部，放置了一层 8 英寸或 20 厘米厚的沙子，然后是所谓的土工织物层， 一种织物形式， 然后是一层防水塑料， 然后是另一层土工织物，然后是另一层沙子。
