摘要
风化深度是石窟等石质文物稳定性、耐久性评价和保护方案制定的重要依据之一。本文在定性观察的基础上,利用环境磁学便携式磁化率仪对云冈石窟风化砂岩进行了现场风化程度无损探测,提出了云冈石窟片状风化砂岩风化程度定量分级标准,并探测了云冈石窟龙王庙沟西侧崖壁砂岩的风化深度。认为云冈石窟片状风化砂岩风化程度分为5级,云冈石窟片状风化砂岩在风化退质过程中磁化率值具有先升高后降低的特征。龙王庙沟西侧崖壁水平钻孔ZK3、ZK6处砂岩的风化深度分别为400mm和570mm,相应的风化速度为0.26350～0.26882mm/a和0.37549～0.38306mm/a,离沟口直线距离对此处砂岩的风化具有控制作用。风化的主要影响因素是武周山南崖壁的卸荷裂隙十分发育,它不仅导致石窟寺岩体边坡的失稳,也为水的入渗和渗流,石雕表面盐类的运移和积聚提供了良好的通道,更进一步加速了石雕文物的风化。建议对武周山南崖壁表面岩体进行防风化处理,并修建保护性窟檐以减小风化营力的作用。
Weathering depth is an important basis for assessment of stability and durability,and drafting protection proposal for cave relics.Based on qualitative observation,environmental magnetism portable magnetic susceptibility detector is used to detect the weathering degree of sandstone in Yungang Grottoes.A quantitative weathering grading standard of flaky weathered sandstone is proposed.The weathering depth of sandstone in the west side of Longwangmiao valley is detected.The flaky weathering degree of sandstone is divided into 5 grades.The magnetic susceptibility values increase first and then decrease.The weathering depths in the two horizontal borehole ZK3 and ZK6 are 400mm and 570mm respectively,and the corresponding weathering speeds are 0.26350~0.26882mm/a and 0.37549~0.38306mm/a.The Weathering degree is controlled by the distance to valley mouth.The main effect factor is the unloading cracks in the southern cliff of the Wuzhou Mountain,which not only leads to the rock slope slide,but also provides a good channel for infiltration and seepage of water,transportation and accumulation of the stone surface salts,and further weathering of the stone relics is then be accelerated.The measures of anti-weathering of the southern cliff of Wuzhou Mountain and construction of a brim to the Grottoes are proposed.
出处
《工程勘察》
2013年第9期69-74,共6页
Geotechnical Investigation & Surveying
基金
国家科技支撑计划项目课题(2009BAK53B01和2009BAK53B02)
山西省文物保护科学和技术研究课题(2012-kb-08)
山西省科技攻关项目(20130313035-2)
关键词
云冈石窟
环境磁学
磁化率
无损探测
风化深度
风化速度
Yungang Grottoes
environmental magnetism
magnetic susceptibility
nondestructive detection
weathering depth
weathering velocity
