由石灰、粘土和砂加水拌合配制而成的三合土,是一种古老的气硬性胶凝建筑材料,巳有几千年的历史。它多用于建筑物的基础垫层或室内地面垫层,具有密实坚固、不易透水、取材容易等优点。圆明园遗址中清晰可辨,许多建筑物基础就是使用的三合土。图为圆明园海宴堂遗址——用三合土浇灌的贮水池基础,呈倒梯形,建于1749年(乾隆13年)。火烧圆明园后,它外表层所贴青砖又被盗走,仅剩裸露的三合土基台。虽经一百多年风雨,仍巍然 Tri-soil made of lime, clay and sand mixed with water is an old gas-hard gelling building material that has a history of thousands of years. It is mostly used in the foundation cushion of the building or the floor cushion of the interior, and has the advantages of compactness, solidity, impenetrability to water and easy material extraction. The ruins of Yuanmingyuan are clearly discernible, and many buildings are based on the use of triaxial soil. The picture shows the ruins of the Yuanmingyuan Haiyantang - the reservoir base watered by the tri-soil. It is an inverted trapezium and was built in 1749 (13 years of Qianlong). After burning the Yuanmingyuan Garden, the blue bricks on the outer surface were stolen and only the bare tri-soil base station remained. After more than a hundred years of wind and rain, it is still sad