应县木塔部分横纹抗压木构件残损分析

Damage Analysis of Internal Wood Components of Yingxian Wood Pagoda Under Transverse Compression

对应县木塔二层明层和五层明层内槽转角柱的普拍枋、华拱和泥道拱等横纹抗压构件进行勘测,测量其尺寸与含水率,使用相机拍照记录其破坏特征,后期利用ImageJ软件分析其裂隙率及破坏状况,探讨两明层横纹抗压构件的开裂程度与分布。结果表明:二层明层内槽转角柱上的普拍枋横纹抗压开裂严重,其裂隙率均值为16.6%,多数端面呈散裂状,甚至枋体有完全压溃和部分脱落的现象,华拱和泥道拱横纹抗压裂隙率均值分别为7.7%和12.0%,且拱身已有部分剥离和折断现象;五层明层各内槽转角柱上的普拍枋、华拱和泥道拱横纹抗压破坏主要为细微开裂,其裂隙率均值分别为2.9%、2.6%和2.1%,较二层明层而言,开裂较为轻微;对于木塔两层横纹抗压构件的开裂分布,二层明层多出现在塔身西南和东北方位,而五层明层横纹抗压构件在开裂方位上不明显。本研究所采用的方法可以有效获取应县木塔内部构件的横纹抗压破坏状况及开裂分布,为今后木塔修复与保护工作提供一定的基础数据。

Based on the field survey of the second floor and the fifth floor of Yingxian Wood Pagoda,a comparative analysis of the damage conditions of the transverse compression members-Pupaifang,flower arm,and axial bracket arm on each hypostyle corner column was made in this paper,and the crack rate was measured using ImageJ to study cracking degree and distribution law of the transverse compression members of each layer.The results showed that the transverse compression cracking of Pupaifang of the second floor was serious,with the average crack rate of 16.6%.Most of the end faces were in the form of spallation,and even the brace body had the phenomenon of complete collapse and partial fall off.The average compression crack rate of the transverse compression of flower arm and axial bracket arm were 7.7%and 12.0%,respectively,and the arch body had the phenomenon of partial peeling and breaking.The transverse compression failure of Pupaifang,flower arm,and axial bracket arm of the fifth layer was mainly minor cracks,with the average crack rate of 2.9%,2.6%,and 2.1%respectively,and the degree of cracking was relatively moderate.For the cracking distribution of the twostorey transverse grain compression member,the second floor mostly appeared in the southwest and northeast of the tower,while the cracking distribution of the fifth floor transverse grain compression member was more uniform.The method used in this study can effectively obtain the transverse compressive damage status and crack distribution of the internal components of Yingxian wooden tower,providing a certain foundation for future repair and protection work of wood pagoda.