以汶川映秀镇百花大桥边坡岩体为实例,运用结构而三维网络模拟法计算RQD值,具体步骤为:在概率统计结构面各项参数获取结构面模拟参数的基础上,利用Monte-Carlo法生成岩体节理三维网络,在边坡震时主滑平面、主滑横剖面、水平面上各方向布置测线模拟钻孔,获取54个钻孔岩石质量指标RQD值,以其期望值作为最终RQD.以结构面测量统计得到的等效钻探RQD为真值,对比体积RQD法和网络模拟法的相对误差(体积RQD法为24.6％；结构面三维网络模拟法仅为3.3％),证实结构面三维网络模拟法相对误差要小得多,精度显著提高.结构面三维网络模拟法是计算RQD的好方法,具有广泛的应用前景.%Taking the Baihua Bridge rock slope which is seated in Yingxiu Town as case study, three-dimensional discontinuity network simulation method is used to calculate the rock quality designation(RQD). On the basis of accessing discontinuity simulation parameters by statistics of discontinuity measurement data, three-dimensional discontinuity network picture is got by Monte Carlo method. Fifty four survey lines on behalf of drill are fixed up in all directions of main sliding planes, main sliding cross-sections and main sliding horizontal planes. Every RQD value of drilling is obtained by statistics of percentage ratio of sum of core length more than 10 cm of each drill core to total drilling, and then the final RQD value is defined as the expected value of these 54 RQD values. At the same time, volume RQD method is also used to calculate RQD. The relative error can be got by comparing the results from the two methods and the equivalent drilling RQD which is gained by measuring discontinuity surface. The relative error of volume RQD method is 24.6%, simultaneously relative error of three-dimensional discontinuity network simulation method decreases to 3.3%. It is proved that the three-dimensional discontinuity network simulation method has a low relative error and a high accuracy. Consequently, it is a good method to calculate RQD, and has a broad prospects in practical application.
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