岩体体裂隙率野外测量及计算方法的研究

裂隙率作为表征岩体裂隙特征的一项重要参数,有线裂隙率、面裂隙率、体裂隙率3种表征方法。目前常用测线法、统计窗法获取线、面裂隙率仅能从一维或二维反映裂隙发育情况,其方法还存在测量结果随机性、应用受出露条件所限等不足;现有体裂隙率测量方法也存在着实际应用性较差、成本高等问题,尚缺乏简便易操作的野外测量方法。为此本文提出了一种新的野外测量岩体体裂隙率的工作方法--球体法。由于构造、成岩裂隙发育的组系性、方向性,球体法根据各组裂隙产状从不同方向进行观测,通过多次测量统计岩体出露面上裂隙的发育特征,推断岩体内部裂隙的发育状况,其值能更好地反映局部区域岩体内部裂隙发育程度。此外,在测量时利用专利仪器可以得到沿裂隙面法线方向上隙宽以及隙间距数据真实值,测量条件对出露面平整情况要求不高,测量结果受露头平整性影响不大,具有更好的实用性。本文以安庆大龙山采石场研究区为例应用球体法,野外现场测量表明该方法可以在较为方便操作的基础上实现快速测量;研究区体裂隙率均值为2. 286%,集中分布在1%~4%,结合研究区实际情况以及误差分析结果,球体法可以很好地反映研究区各个测量点的裂隙发育程度。

NEW METHOD OF FIELD MEASUREMENT AND CALCULATION FOR VOLUMETRIC FRACTURE RATE OF ROCK MASS

As an important parameter to characterize the fracture characteristics of rock mass,we characterize the fracture rate from the linear,surface and volumetric perspective. However,the available linear measurement method and statistical window method,which obtain the linear and surface fracture rate from 1-D or 2-D perspective,have the disadvantages of randomness of measurement results and limited application conditions. And the existing method of volumetric fracture rate also has some problems such as poor practical application and high cost. There is still a lack of easy-to-operate method to measure the rate of fissures in the field. Therefore,a new sphere method is proposed to measure volumetric fracture rate of rock mass in the field. Due to the unique tectonic and statistical regularity of the structure and diagenetic fissures,the sphere method observes each group of fracture occurrences from different directions. The development of the rock mass can be statistically inferred by measuring the developmental characteristics of each group of cracks on the limited exposed surface of rock mass. And its value can better reflect the development degree of the internal crack of the local rock mass. In addition,the spherical method can obtain the true value of the gap width and the gap spacing data along the normal direction of the fracture surface by using the patented instrument at the field. And the flatness of the exposed surface of the rock mass affect the measurement result hardly. Taking Dalongshan quarry in Anqing as the study area,field measurements of spheroid method show that the average volumetric fracture rate is 2.286% and the overall difference is concentrated in 1% ~4%. The method can realize rapid measurement on the basis of more convenient operation in the field. Combining the actual situation of the study area and the results of error analysis,the sphere method can reflect the degree of fracture development at each measurement point in the study area.