漢城百濟의 ‘烝土築城’에 대한 硏究 (A study of fortress construction method called “Jeungto Chukseong” used in Hanseong Baekje)

서지정보

· 발행기관 : 서울역사편찬원
· 수록지 정보 : 서울과 역사 / 76호 / 41 ~ 92페이지
· 저자명 : 심광주

초록

『三國史記』 蓋鹵王條에 등장하는 ‘烝土築城’이 견고한 版築工法에 의하여 구축된 土城이라는 것이 지금까지의 일반적인 견해였다. 그러나 백제 도성처럼 ‘烝土築城’ 하였다고 기록된 大夏의 統萬城에 대한 검토결과 石灰로 성벽을 版築하였고, ‘烝土築城’은 生石灰를 소화하는 과정에서 발생하는 엄청난 열과 수증기를 의미하고 있음을 알게 되었다. 이에 따라 한성백제의 ‘烝土築城’도 石灰와 관련이 있을 것으로 판단되어 국내의 각 유적에서 출토된 석회시료를 수집하고, 과학적 분석을 시도하였다.
그 결과 5세기 중반까지의 백제의 석회는 고구려나 신라․가야와 마찬가지로 조개껍데기로 만든 貝灰였고 공사시 순수한 석회만 사용되었음이 확인되었다. 이에 비하여 연천 신답리고분과 통현리고분의 석회는 石灰石으로 만든 석회이며 석회에 모래와 점토를 섞어 강도를 높였음이 확인되었다. 이는 5세기 중엽부터 6세기 초 사이에 석회석 석회의 생산기술과 三合土 시공기술이 도입되었음을 의미하며, 그 기간 사이에 있는 것이 백제의 ‘烝土築城’ 기록이다. 蓋鹵王은 都城에 대한 대대적인 공사를 위하여 南朝의 劉宋이나 北魏로부터 석회기술을 포함한 새로운 土木․建築기술을 도입하였을 것으로 추정된다.
漢城百濟의 都城으로 추정되는 유적 중 풍납토성은 발굴결과 개로왕대의 수축과 석회 사용여부는 아직 확인되지 않았다. 반면 防禦用 山城인 몽촌토성에서는 版築土 내에서 石灰包含層이 확인되었으며 성벽의 높이도 최소한 4m 이상 增築하였음이 확인되고 있다. 이는 개로왕대에 방어력을 높이기 위하여 도성을 修築한 것이고, ‘烝土築城’이 축성공사에 石灰가 사용되었음을 의미하는 것임을 입증하는 것이라고 생각된다. 더 나아가 『삼국사기』의 ‘烝土築城’ 기록은 발달된 석회 관련 신기술이 우리나라에 도입된 시점을 알려주는 역사적인 사건으로서 토목․건축기술사 측면에서도 새롭게 조명되어야 할 것으로 생각된다.

영어초록

It has been generally accepted that "Jeungto Chukseong(Building a fortress by boiling soil)" described in King Gaero Section of Baekje History in Samguk Sagi(A history of three kingdoms) indicates construction of earthen fortress using a method called Panchuk(Placing earth between boards and hardening it). However, there is a record that Tongman Fortress in Jeokyeonha, Shaanxi, China, is also built using "Jeungto Chukseong" like the fortress in Hanseong Baekje. But it is found that the fortress was built using lime. Therefore, it is possible that for the "Jeungto Chukseong" indicated in Samguk Sagi, lime was used. To use unslaked lime safely, a process of making it to slaked lime is needed. In this process, unslaked lime reacts to water and generates a lot of stream and heat. And it is thought that this process is expressed as building a fortress by boiling soil.
To obtain lime, limestone or shell needs to be heated to over 900°C for a long time. When the limestone is heated and carbon dioxide is removed, it changes to calcium oxide(unslaked lime), a material with new property. When the calcium oxide reacts to water, it becomes calcium hydroxide and when it combines with carbon dioxide in the ground, it changes to calcium carbonate, which is hard like stone and waterproof. Using chemical change to make new material for construction means significant development of civil engineering technology at the time.
In China, lime began to be used in the Zhou Dynasty. At the time, lime was made by burning shells and it was applied to walls mostly. After the Han Dynasty, construction technology using stones and bricks developed and lime began to be used as mortar that binds bricks and stones. Mixing lime, sand, and loess to strengthen the foundation or build a strong structure started in the Southern and Northern Dynasties. "Jeungto Chukseong" using the mixture of lime, sand and loess was first used for Tongman Fortress, the capital of Daeha, in 424.
In Korea, lime was first used in Goguryeo for wall application or mortar. But the use of lime for the construction of fortress began during King Gaero of Baekje as indicated in the expression "Jeungto Chukseong" in Samguk Sagi. Lime used in the earth for the fortress found during the excavation of Mongchon Earthen Fortress in 1984 proves this. It is estimated that the mixture of lime, sand, and loess might be used for Pungnap Earthen Fortress, but it is not clear whether lime was actually used since the components of the fortress was not analyzed even though the cross section of the wall was examined during its excavation. To decide if Mongchon Earthen Fortress and Pungnap Earthen Fortress were built during King Gaero, analysis of components of each fortress needs to be carried out.
Lime has been widely used as construction material from ancient times. And lime does not exist in nature and it is produced through chemical change. It is caustic material that requires caution in production and handling. Therefore, production of lime and expansion of its use need to be seen in a new way in terms of the development of civil engineering technology.

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