基于N型回弹仪的粤北丹霞组碎屑岩单轴抗压强度试验研究

以粤北丹霞盆地晚白垩世丹霞组碎屑岩为对象,采用冲击动能为2.207 J的N型回弹仪对其单轴抗压强度与回弹击数的相关关系开展研究.通过对韶关仁化丹霞山世界地质公园内晚白垩世丹霞组出露的巴寨段和锦石岩段砂岩岩体进行原位回弹测试及声波波速测试试验,并对原位测试点岩体钻孔取芯进行单轴压缩试验.由现场回弹测试、声波波速测试和室内岩石单轴压缩试验结果可知,丹霞山世界地质公园内晚白垩世丹霞组出露巴寨段和锦石岩段砂岩的回弹值与岩体强度大体呈线性相关;砂岩、砾岩及砂砾岩的回弹值与波速呈线性相关.对波速、回弹值与单轴抗压强度之间的相关关系及拟合曲线变化趋势的研究结果表明,采用回弹值预测岩体单轴抗压强度具有一定的可靠性.研究结果对快速获取丹霞山景观危岩体的强度指标提供了一定的帮助.

Experimental Study on Uniaxial Compressive Strength of Danxia Formation Clastic Rocks in Northern Guangdong Based on N-type Schmidt Hammer

Taking the Late Cretaceous Danxia Formation Clastic Rock in the Northern Guangdong Danxia Basin as the research object, An N-type Schmidt hammer with an impact kinetic energy of 2.207J was used to study the correlation between the uniaxial compressive strength and the rebound value. The in-situ rebound test and sonic velocity test were carried out on the Bazhai and Jinshiyan sandstone exposed in the Late Cretaceous Danxia Formation in the Renhua Danxiashan World Geopark in Shaoguan, and the rock mass was drilled cores for uniaxial compression test. According to the results of the rebound test, sonic velocity test and rock uniaxial compression test, there is generally a positive correlation with a correlation coefficient of 0.94 between the rebound value and the uniaxial compressive strength of the sandstone; The rebound value is linearly related to the wave velocity. The correlation coefficients of sandstone and conglomerate (including sandy conglomerate) are respectively 0.96 and 0.85. The research results on the correlation between wave velocity, rebound value and uniaxial compressive strength and the trend of the fitted curve showed that the use of rebound value to predict the uniaxial compressive strength of rock masses has certain reliability. The research results provide some help for quickly obtaining the intensity index of the landscape dangerous rock mass in the Danxiashan.