叶飞, 谌文武, 梁行洲, 张景科, 郭志谦, 郭青林. 2016: 敦煌莫高窟玉门组砂砾岩风化特征研究. 工程地质学报, 24(6): 1286-1293. DOI: 10.13544/j.cnki.jeg.2016.06.031
    引用本文: 叶飞, 谌文武, 梁行洲, 张景科, 郭志谦, 郭青林. 2016: 敦煌莫高窟玉门组砂砾岩风化特征研究. 工程地质学报, 24(6): 1286-1293. DOI: 10.13544/j.cnki.jeg.2016.06.031
    YE Fei, CHEN Wenwu, LIANG Xingzhou, ZHANG Jingke, GUO Zhiqian, GUO Qinglin. 2016: STUDY ON THE WEATHERING CHARACTERISTICS OF THE YUMEN GLUTENITE IN THE MOGAO GROTTOES IN DUNHUANG. JOURNAL OF ENGINEERING GEOLOGY, 24(6): 1286-1293. DOI: 10.13544/j.cnki.jeg.2016.06.031
    Citation: YE Fei, CHEN Wenwu, LIANG Xingzhou, ZHANG Jingke, GUO Zhiqian, GUO Qinglin. 2016: STUDY ON THE WEATHERING CHARACTERISTICS OF THE YUMEN GLUTENITE IN THE MOGAO GROTTOES IN DUNHUANG. JOURNAL OF ENGINEERING GEOLOGY, 24(6): 1286-1293. DOI: 10.13544/j.cnki.jeg.2016.06.031

    敦煌莫高窟玉门组砂砾岩风化特征研究

    STUDY ON THE WEATHERING CHARACTERISTICS OF THE YUMEN GLUTENITE IN THE MOGAO GROTTOES IN DUNHUANG

    • 摘要: 风化是引起莫高窟围岩(砂砾岩)破坏的一种重要病害,严重影响莫高窟的长期保存。为研究莫高窟玉门组砂砾岩的风化特征,选取莫高窟南侧一处崖体为试验点,采用逐层剥离的方法,分别在距崖体侧表面0cm、3cm、5cm、8cm及10cm深度处进行现场声波测试、回弹测试并取样进行X-射线衍射试验和易溶盐试验。试验结果表明:莫高窟围岩在风化作用下强度降低,现场声波测试和回弹测试结果均随着开挖深度的增加而不断升高;砂砾岩胶结物的主要矿物为石英、方解石、长石、白云石、石膏等,主要黏土矿物是绿泥石;其可溶盐主要包括Na2SO4、NaCl、CaSO4等。同时结合气象数据及试验结果,分析了影响岩体风化的主要因素,初步讨论了岩体的风化机理,包括:(1)温度应力引起岩体结构破坏和裂隙发育;(2)胶结物中的主要矿物方解石易于发生水化作用,转化成易溶的Ca(HCO32,发生迁移,破坏岩体的胶结结构;(3)盐风化也是岩体风化的一个重要方式,Na2SO4、CaSO4等可溶盐在水汽作用下发生溶解、结晶及水合作用,体积膨胀,对孔隙壁产生较大压力,致使岩体颗粒之间联结减弱,结构破坏,裂隙发育。

       

      Abstract: Weathering is one of the most important diseases in the surrounding rocks of Mogao Grottoes, which seriously affects the purpose for long-term preservation. To study the weathering characteristics of Yumen glutenite in Mogao Grottoes, a test point on the south side of Mogao Grottoes is selected. The method of step by step dissection is adopted and a series of experiments are conducted, such as X-Ray diffraction test, soluble salt test, field acoustic wave test and rebound test at different distances from the surface, which are 0、3、5、8 and 10cm. The results illustrate that the main salts involve Na2SO4、NaCl、CaSO4, and the main minerals are quartz, feldspar, calcite, dolomite while clay mineral is chlorite; the mechanical strength reduced due to the influence of weathering, which is confirmed by the field acoustic wave test and rebound test. Both of the results rise with the increase of depth. By analyzing Meteorological data and the results, the main effects on weathering are determined and the mechanism of rock weathering is discussed. Weathering includes that (1) temperature stress causes damage on the rock mass structure and fracture. (2) the main mineral calcite in the cement is easy to convert into soluble Ca (HCO3)2, which could affect the cementation of rock mass structure. (3) salt weathering is another important rock weathering. Salts migrate and enrich with moisture migration and hydrate with water, which causes damage to the cohesion between different particles and result in the breakdown of rock mass.

       

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