钻入阻力仪在云冈石窟砂岩表层风化原位评价中的试验研究

The Drilling Resistance Research on the Sandstone Surface Weathering of Yungang Grottoes

钻入阻力仪可通过微芯钻孔的方式,采集不同钻孔位置深度剖面上的钻削阻力曲线图,根据单位深度上测得的钻削阻力值差异状况,来判定被测物体的内部结构及风化状况。本文采用钻入阻力仪对云冈石窟风化砂岩进行了钻入试验,在10毫米直径金刚石钻头下,测定岩石表面0-20毫米深度的钻削阻力曲线。试验发现不同风化类型有不同的强度变化曲线,紧密型粒状风化、片状风化、空鼓均有特征明显的强度变化曲线,并根据钻削阻力曲线得出风化的深度,空鼓的厚度。另外根据所测得的风化和新鲜砂岩的钻入阻力仪值,尝试定义了云冈石窟所测区域风化砂岩的风化程度k。虽然该试验比较初步,但该试验研究为砖石文物风化程度及力学强度现场原位测试提供了新的思路。

Drilling resistance is the equipment to measure the rock profile strength with the depth of change in the structure of ancient and modern buildings,it could be used in the lab and heritage site and could take rock quality evaluation and conservation evaluation.The paper showed the drilling resistance experiment on coarse sandstone of Yungang Grottoes.It found that due to the impact of the coarse grain of sandstone,especially quartz particles,only the area of weathering formed by loose of sheet and detachment,were under better measurement.The results can come up with the weathering depth and the thickness of the detachment.According to the drilling resistance data of weathering and fresh sandstone,it defined the degree of weathering‘k',and the degree of weathering of four test area of Yungang Grottoes were 0、0.841、0.841、1.Although the test is preliminary,the study provides a new idea for in-situ testing of weathering degree and mechanical strength of stone cultural relics.