中国南方气候环境下“软盖层”保护的模拟实验研究

Experimental study of soft capping for the protection of wall ruins in Southern China

"软盖层"保护遗址墙体是目前盛行于英格兰和苏格兰,且为中欧和北欧认可的一种保护技术。"软盖层"保护技术符合我国建设遗址公园的保护技术需求,根据苏格兰的研究报告推测"软盖层"保护技术适合在中国沿海域范围气候环境下应用。该项研究是对"软盖层"保护技术应用于安徽宣城广教寺遗址公园保护与展示工程实施可能性所做的模拟实验,实验地点于上海同济大学,实验周期为一年。实验方法为将两堵模拟实验墙分为四等部分,一部分墙头覆盖砖块模拟硬盖层保护和另外三部分墙头覆盖三种不同的植被(景天科植被、马尼拉草、四季青草)模拟软盖层保护,通过安装在各不同盖层下的温度数据记录仪每半小时采集的温度变化数据,通过手持式湿度仪于每月采集墙体的湿度数据,结合图像记录等方式采集每月墙体的表观变化和植被的生长情况变化。通过一年的实验研究及数据分析表明,在中国南方地区气候环境下,"软盖层"对墙体的保护效果主要体现在极端气候环境下。同时,"软盖层"在夏季对墙体的除湿功效显著,而且在冬季并没有增加墙体湿度的副作用。实验结果还表明,草的选择对"软盖层"的功效影响颇大,建议在进一步研究中需要寻找更适用作"软盖层"的植被和土壤。

Soft Capping is a popular way of protecting wall relics in England and Scotland and well-recognized in Central and Northern Europe. This technology might meet the need for protection of relics parks in China. According to Scottish research reports,soft capping protection technology should be suitable for natural and cultural environment in the coastal fringe area of China. An experimental study on soft capping to protect ruin wall was carried out in Shanghai for one year. The purpose of the research was to evaluate the effectiveness of soft capping to protect the wall ruins at Guangjiao Temple in Xuan Cheng,Anhui. Two test walls were built using old bricks to simulate the relic walls of Guangjiao Temple. The wall was studied under four conditions： A） the wall head was totally exposed to the environment,B） the wall head was capped with compound planting soil and crassulaceae plants,C）the wall head was capped with sterile soil and Agrostis stolonifera with a waterproof layer beneath and D） the wall head was capped with sterile soil and Zoysiamatrella. The conditions were set respectively to simulate hard capping and soft capping. Four temperature data loggers were installed just beneath the earth capping on the top wall head,with one data logger in the environment to record the change of temperature and humidity in a year. A moisture sensor was used monthly to collect the humidity data of the two walls and a digital camera was used to record changes in appearance of the two walls and the status of plants every month. Over the course of a one-year experimental study,we found that soft capping can work as a thermal blanket,but mainly under extreme climate conditions.Meanwhile,walls under soft capping are drier than those under hard capping in summer,but almost as wet as those under hard capping in other seasons. We also found that the choice of grass and earth are very important for the performance of soft capping. It is necessary to do the further study.