過去の高松塚古墳石室内の温湿度変動解析: 保存施設稼働時の気象条件の影響と，発掘直後の仮保護施設の影響

摘要

In order to investigate the causes of the deterioration of the mural paintings of Takamatsuzuka Tumulus, it is very important to clarify temperature and humidity variations in the stone chamber. We estimated how the environmental condition surrounding the stone chamber and the work conducted inside the chamber affect temperature and humidity there by making use of a numerical simulation. The simulation was based on the measurement data and records of Takamatsuzuka Tumulus in the past. We made an analytical model taking into account the mound and the conservation facility and set up each condition in terms of factors which influence temperature and humidity in the stone chamber. We considered records of the past as far as possible to make the model and set up the boundary conditions. The following two periods were investigated:rn1) The period from the discovery of the mural paintings to the beginning of the operation of the conservation facility, hence from 1972 to 1976rn2) The period from the beginning of the operation of the conservation facility to before the dismantlement of the stone chamber, hence from 1976 to 2005rnAs the first step, we investigated the effect of the temporary shelter set up immediately following the excavation of the tumulus in the former period and the effect of outside air temperature change on temperature and humidity in the stone chamber during the operation of the conservation facility in the latter period.rnThe obtained main results are as follows:rn1. Outside air temperature change was one of the main causes of temperature rise in the stone chamber for 30 years.rn2. Other causes that affect temperature rise in the stone chamber are as follows: 1) controlling of the temperature of the antechamber and preparation room, 2) heat transfer of the building frame of the conservation facility, 3) temperature variation in the mechanical room, 4) people entering and exiting from the stone chamber and 5) mound condition.rn3. Before the excavation, relative humidity in the stone chamber was nearly 100% throughout the year.rn4. By setting up the temporary shelter after the excavation, amplitude of temperature in the stone chamber became larger than it was before the excavation, while relative humidity in the stone chamber slightly decreased from nearly 100 %.rn5. By setting up the temporary shelter after the excavation, the inside surface relative humidity of the south side wall and ceiling decreased and the south side wall and ceiling dried slightly.rnFuture tasks are to investigate other causes of temperature rise in the stone chamber during the operation of the conservation facility and the influence of entering and conducting works on temperature and humidity in the stone chamber from the time of its excavation to before its dismantlement.%過去の高松塚古墳の石室周囲の環境が，石室内の温湿度変動に及ぼす影響について測定値や 記録などを元に，影響を与える要因を取り上げて数値シミュレーションを用いて推定を行っ た。検討は，1）保存施設稼働から石室解体前までと，2）発掘から保存施設稼働までの二つ の期間に対して行うこととした。1）については，まず石室内の温度測定値の分析を行い，こ の期間の石室内の温度上昇は，外気温の上昇より大きいことを確認し，この要因の検討を行う ことを主たる課題とした。