【作者】 张颖；

【导师】 穆保岗；

【作者基本信息】 东南大学 ， 岩土工程， 2022， 硕士

【摘要】 中国文化遗产留存丰富,以帝王类高规格陵墓为代表的地下结构广泛分布,其中壁画的原位保存受到赋存环境变化的长期影响。在漫长的历史过程中,当地形、地貌及地下水位变迁或者受到人为影响后,地下文物本体的宏观承载机制会发生演变,影响壁画所在区域的局部微小变形分布,导致壁画所在的颜料层、地仗层及后方支撑体之间的应变存在差异,潜在构成了壁画开裂、局部剥落的风险因素。本文依托国家重点研发计划墓葬壁画原位保护关键技术研究课题,对地下文物结构类型、地下结构承载机制演变、地仗层材料的力学参数测定及对比、水土变化对地下文物的长期影响进行了研究。研究内容和主要结论如下:(1)归纳总结了中国自商至清代发展出的典型地下结构形式。自商周至明清,随着材料及砌筑工艺的发展,古代地下墓葬结构形式主要分为六种,分别为竖穴土坑、梁板式、四面结顶式、四隅券进式、圆锥形穹窿顶、圆弧拱等,受力逐渐合理化,结构形式逐渐复杂化。(2)基于两处应用案例,探讨四面结顶式穹窿和直墙拱两种典型地下墓葬结构的壁画变形敏感区域演变规律。其墓顶结构的演变规律均遵循从无铰拱到两铰拱、三铰拱的潜在破坏发展趋势,基于砖石结构及地仗层的材料特性,承载机制的变化对颜料层、地仗层及后方支撑体之间的形变协调性产生影响,进而影响不同位置的壁画稳定性。(3)开展了不同配合比的壁画地仗层力学参数实验。实验结果显示,细泥层的抗压强度与弹性模量均高于粗泥层,麦草与麻丝掺入均降低了试块的抗压强度与弹性模量,且麦草降低的幅度远大于麻丝,古人掺用麦草和麻丝作为地仗层成分的主要原因是起到减轻重量和加筋作用、防止壁画开裂。(4)建立南唐二陵的三维数值模型,对比现场监测结果,分析当赋存环境变化时壁画敏感区域应力、应变变化规律。根据有限元计算结果:当覆土厚度或含水率发生变化时,拱顶高度一半处的变形和应力应变均为最大。保持覆土层厚度、减少覆土层的含水率等赋存环境的大幅波动对提高地下文物结构稳定性更为有利。更多还原

【Abstract】 There are rich cultural heritages in China,and underground structures represented by highstandard imperial mausoleums are widely distributed.The in-situ preservation of murals is affected by long-term changes in the environment.In the long historical process,after the topography,landform and groundwater level change or are affected by human beings,the macroscopic bearing mechanism of the underground cultural relics will evolve,affecting the local micro-deformation distribution in the area where the murals are located,causing the deformation difference between the paint layer,the base layer and the rear support where the mural is located.The deformation difference between the supports potentially constitutes an influencing factor for the local spalling of the frescoes.Relying on the key technology research topic of in-situ protection of tomb murals under the National Key Research and Development Program,this paper studies the structural types of underground cultural relics,the evolution of the bearing mechanism of the underground structure,the measurement and comparison of the mechanical parameters of the base layer materials,and the long-term impact of soil and water changes on the underground cultural relics.The research contents and main conclusions are as follows:(1)Summarizes the typical underground structures developed in China from the Shang Dynasty to the Qing Dynasty.From the Shang and Zhou Dynasties to the Ming and Qing Dynasties,with the development of materials and masonry techniques,ancient underground tombs were mainly divided into six structural forms,namely vertical pit,beam-slab type,foursided knot-top type,four-corner coupon entry type,and conical dome type.Top,arc arch,etc.,the force is more reasonable,and the structural form is gradually complicated.(2)Based on two application cases,the evolution law of the fresco deformation-sensitive area of two typical underground tomb structures,the four-sided dome and the straight wall arch,was discussed.The evolution law of the tomb roof structure follows the development trend of potential damage from unhinged arches to two-hinged arches and three-hinged arches.and the deformation coordination between the rear supports,which in turn affects the stability of the murals at different positions.(3)Experiments on the mechanical parameters of the mural base layer with different mix ratios were carried out.The experimental results of the mechanical parameters of the mural base layer show that the compressive strength and elastic modulus of the fine mud layer are higher than those of the coarse mud layer.The reduction is far greater than that of hemp silk.The main reason why the ancients mixed wheat grass and hemp silk as the ingredients of the base layer was to reduce weight and reinforce the effect of preventing frescoes from cracking.(4)Establish a three-dimensional numerical model of the Two Tombs of the Southern Tang Dynasty,compare the on-site monitoring results,and analyze the variation law of stress and strain in the sensitive area of the mural when the occurrence environment changes.According to the finite element calculation results: when the covering soil thickness or moisture content changes,the deformation and stress-strain at half the height of the vault are the largest.It is more beneficial to improve the structural stability of underground cultural relics by maintaining the thickness of the overburden layer and reducing the moisture content of the overburden layer and other large fluctuations in the occurrence environment.更多还原