ASSESSMENT OF JOINT VOLUME FREQUENCY IN ROCK MASS AND ITS APPLICATION IN ENGINEERING

The 3D joint surface network simulation is based on Monte-Carlo theory. It is the most common method to study growth regulation of rock mass joints, and joint volume frequency,v. v is determined by that is measured in the field. It is one of the key parameters which affect the result of joint network simulation. Using the 3D joint surface network simulation program, a new method is promoted to determine v. This method is based on the back analysis from line frequency to volume frequency. A value to a joint set is given as the initial joint volume frequency.the 3D joint surface network simulation program is adopted to generate a 3D network model which just contains the joint set. Then line frequency along the survey line's trend of the model can be calculated. Therefore, a series line frequency(v) can be got from the series volume frequency.Then the functional relationship can be built up between the line frequency and the volume frequency. Lastly, the actual volume frequency can be determined using the line frequency measured in survey line trend. This paper further takes the rock mass of Yujianhe dam site in Xifeng county, Guizhou province as an example. The results show that there are a good linear relation between v and .The ratio between v and max is 0.4~1.0 when the joint radius obeys to the lognormal distribution. The ratio is about 1.3~3.5 when the radius does negative index distribution. Eventually, the rock mass integrality at the Yujianhe dam site is appraised using and v respectively. The result shows that the latter is more precise than the former.