Abstract
To study the stability analysis of underground cavern groups at great depth and under high geostress field, a large-scale geomechanical model test system under true triaxial loading is newly developed. The model test system mainly consists of a steel structural frame and a hydraulic loading control system, which adopts active loading on six surfaces of the model block with a true triaxial stress considering trapezoidal loading steps in two horizontal directions. Newly-developed combinational ball-type sliding walls are installed on each side of the major loading surfaces, which can significantly reduce friction. Based on the system, a large-scale geomechanical model test for an underground cavern group is carried out. Major innovations and improvements have been made in terms of experimental techniques and advanced measurement methods/techniques. Precast blocks of analog materials are piled up and bonded to enhance the consistent mechanical properties of the whole model system. Digital photogrammetric technique, fiber Bragg grating(FBG) technology-based displacement sensing bars, and a newly developed mini-extensometers are employed to measure the deformation of surrounding rock mass. A new unique technique of grouted anchor and prestressed cables are conducted. The development process and phenomenon of fracture patterns of rock surrounding are observed and analyzed during excavating and overloading tests. The test results are compared with those of numerical simulations. These achieved results would provide certain guiding significance for study of similar practical engineering projects.
| Original language | English |
|---|---|
| Pages (from-to) | 1-7 |
| Number of pages | 7 |
| Journal | Chinese Journal of Rock Mechanics and Engineering |
| Volume | 29 |
| Issue number | 1 |
| Publication status | Published - Jan 2010 |
| Externally published | Yes |
Keywords
- Geomechanics
- Model test
- New experimental techniques
- Stability analysis
- True triaxial stress state
- Underground cavern group