敦煌石窟砂岩吸水特性及力学效应试验研究

Experimental Study on Water Absorption Characteristic and Mechanical Effect of Sandstone in Mogao Grottoes,Dunhuang,China

为研究水分对敦煌石窟围岩风化产生的影响,在室内进行砂岩岩样的无压吸水试验;并对吸水后的试样进行单轴压缩试验,分析吸水状态对砂岩力学参数变化的影响。试验结果表明,岩样的吸水特性曲线均表现为初始阶段吸水量迅速增加,然后缓慢增加,最后趋于平稳的过程。砂岩吸水率随时间的变化曲线可用指数函数进行拟合,砂岩单轴抗压强度和弹性模量随着吸水时间的增加均减小,且可分别采用不同的负指数函数来拟合。试验技术和方法为评价石窟围岩风化程度和揭示壁画病害机理提供了可行的手段和途径。

The effect of water on the weathering of surrounding sandstone at Dunhuang Grottoes has been studied reliably,and test of water absorption without water pressure of sandstone samples was carried out in the laboratory,then the uniaxial compression tests were carried out on the samples after water absorption.The experimental results showed that the water absorption characteristic curves of samples showed for the water absorption rapid increment initially,slow increment subsequently,and tending to be stable finally.According to experimental data,water absorption rate with time of sandstone samples could be expressed as exponential function approximately;on the other hand,the uniaxial compressive strength and elastic modulus with time could be expressed as negative exponential function fitting.The experimental technique and results can provide powerful research method and equipment guarantee for assessment of surrounding rock weathering and disease mechanism research and the technical scheme assessment of stony cultural relic protection.