Study On The Deformation And Failure Mechanisms Of Rocks Near Shandong Huangdao Underground Water-sealed Oil Storage Chamber And The Stability Analysis Of The Adjoining Rocks

Most countries have to cope with the increasing energy crisis. Thereby, there are a range of construction projects which are relevant to energy engineering in China and abroad. Those kinds of projects usually locate near massive brittle rocks, and the rocks are under sophisticated stress conditions accompanied with both shearing and tensile fractures. As a result, it is of great importance to clearly learn the deformation and fracture characteristics of rocks during constructing and operating. In this research, the granite near the Shandong Huangdao underground water-sealed oil storage engineering. Construction site is taken as an example to investigate the mechanical properties of brittle rocks. Both lab testing and numerical modeling are applied during the process. The research results are as follows.(1) The stress-strain measurements recorded during uniaxial and triaxial laboratory tests reveal the compressive deformation and brittle fracture characteristics. After some data treatment, the values of compressive elastic modulus, crack initiation stress, yielding stress and peak strength under different confining pressure are obtained. The results show that such parameters have a tendency of increasing linearly with the increasing of the confining pressure.(2) The Brazilian disc test is chosen as an indirect tensile deformation test approach. A new way to estimate the tensile elastic modulus of rocks which takes the heterogeneity of rock into account is put forward. The indirect tensile mechanical tests are carried using the granite near research area. The tests results indicate that tensile elastic modulus of rocks bigger in grain size is more inferior when compared with the compressive elstic modulus.(3) The MATLAB 7.1 software is chosen as a platform to develop a system to conduct the Digital Image Processing (DIP) for the rocks. The system can easily implement the segmentation of colored rock images. After the segmentation, the data can be exported to some numerical analysis software to generate complex grids which take the actual mesostructure of rocks into consideration. So, the non-homogeneous rock models can be generated for the numerical modeling in the next stage.The FLAC 5.0 software is applied to conduct the numerical modeling of rock deformation and fracture under the compressive and tensile stress conditions. Both homogeneous and non-homogeneous rock models are constructed, so the significant comparisons of the numerical modeling results are given. The results indicate that the modeling which takes the actual mesostructure of rocks into consideration will reveal the stress concentration better, so to some extent, it can describe the local tensile fracture behavior of rocks more precisely.(4) PFC software is used to simulate the failure process of the granite near oil-chamber construction site. The results indicate that PFC numerical simulation can describe the pocess in meso-scale. It takes into account the bondings between different minerals. The crack developing process accords well with the Acoustic emission results.(5) The geological investigation materils are collected then the quality of engineering rocks is derived. FLAC5.0 numerical simulation software is used to analyze the stability of rocks near oil chamber during the exaction based on the investigation results. The results can serve as important references in the next construction works.