Research For The Surrounding Rock Mass Classification In The Complicated Conditions

The existing surrounding rock mass classification methods, such as the Q system,the RMR method, the HC method and the BQ method are only appropriate for the conditions of low or moderate field stress and low water pressure. The HC method is pointed to the surrounding rock mass classification method of the Code For Water Resources And Hydropower Engineering Geological Investigation of China. The BQ method is pointed to the surrounding rock mass classification method of the Standard for Engineering Classification of Rock Masses of China.By now, these methods are not proper to the conditions of high field stress and high water pressure. In general, if the major principal stress is greater than 20 MPa, then the field stress is called high field stress. And the high external water pressure is pointed to the external water pressure which is much greater than 1 MPa. In this article,some deep buried tunnels which have 20 MPa to 40 MPa high field stress and 1 MPa to 10 MPa high water pressure are discussed. There are many characteristics in these tunnels. The strata , belongs to hard rock, the hard surrounding rock and the much hard surrounding rock appears alternately. The occurrence of the strata is about erect. The strike of the tunnel is almost vertical to the strike of the strata.The rock burst is usually happened.A new method which is called normalization method is used to analyse the compatibility of classification results coming from different classification methods. The concept of compatibility and applicability is proposed by introducing the concept of reliability.In addition,the relations beween rock burst intensity and the surrounding rock mass rating is analysed.This will help people to modified the active code for rock mass classification in China.When the correlation, compatibility and applicability among the classification results coming from the common classification methods are analysed ,the disadvantage of common classification methods is found.Based on the famous Q system of Nick Barton, a new classification method called JPQ System which can be appropriate for the conditions of high field stress and high water pressure is proposed by introducing the critical water pressure resulting in hydro-splitting Pc and modifieding the SRF and Jw.Based on the famous RMR method of Bieniawski, a new classification method...