Study On Rock Mass Sub-Classification In Construction Stage For Road Tunnel

In recent decades, along with the development of road transportation rapidly, the scale of road tunnel construction is larger and larger. The road tunnel comes forward in great numbers, brought a new opportunity and challenges for technical development of tunnel nowadays.In numerous still need solve or perfect tunnel technique, the rock classification is one of the important topics attented by all engineering research, design and construction personnels for a long time. An integrated rock classification system should include two stages of design and construction usually. However, the current rock classification for road tunnel still lack a valid and perfect system in construction stage which gives construction many difficult problems. So, aims at a few important problems that need urgent solution and factual engineering demands, this paper makes the systematic study on the rock sub-classification system in construction stage. The material research work is summarized as following:1. Through investigation and statistical analysis on domestic and international great deal of rock classification index data, this paper builds up a rock sub-classification index system which accords with engineering fact comparatively. Then, it introduces each index's measuring means. In these means, it makes the theoretics study and analyse on rock mass discontinuities' parameters measurement based on digital photogrammetry specially to make in-suit fast measuring come true and improve work efficiency at the same time.2. Based on rock stability of double roadway road tunnel, this paper puts forward the partition method and criterion of rock stability grading and confirm method of self-steady span. Then, it also acquires the numerical value of each grading rock self-steady span by numerical simulation and similar model experimentation and makes rock sub-level partition, thereby, a theory standard is established for rock sub-classification in construction stage.3. Depend on the great of in-suit rock data information, based on theory of quanification, this paper puts forward the quantitative determining method for rock sub-classification in construction stage which improves the result's objectivity and reliability.4. Based on the research production of rock stability of double roadway road tunnel, through investigation, statistical analysis and numerical simulation checking computations on domestic and international great deal of tunnel data, this paper confirms the correlative design parameters of each sub-level rock of double-roadway road tunnel, the content include excavation methods, assistant methods, support types, structure forms and earlier timbering parameters etc, which is of great guidance significance for construction.5. This paper makes study on the program realization method about correlative problems which include in-suit classification index measurement and sub-level determining and compiles a software system based on Visual C++ to improve automatization of rock sub-classification. Finally, it proves that the theory of rock sub-classification system in construction stage is correct and the software is reliable and applied by the great of engineering examples.