利用地应力指标评判地下水封油库岩爆可能性及数值 分析验证研究

采用水压致裂技术对拟建地下水封油库区进行原地应力测量,测量结果表明,洞室深度段最大水平主应力10.0MPa左右,最小水平主应力6.0MPa左右。利用工程岩体分级标准判据(GB50218-94)、挪威Barton判据、候发亮判据、Hoek判据对地下洞室开挖岩爆可能性进行分析,结果表明地下洞室开挖后并不会由于工程扰动而发生岩爆现象。针对目前无法求得复杂洞室围岩应力重分布特征解析解,进而无法精确判断地下洞室岩爆开挖可能性的不足,采用FLAC2D有限差分软件对地下洞室分步开挖过程进行模拟,得到应力场重分布特征。以Barton判据的修正结合应力场重分布特征对岩爆可能性进行分析验证,结果表明在一些极易产生应力集中区域会发生岩爆现象,甚至中等岩爆,传统岩爆判据在洞室发生岩爆可能性整体上把握较好,局部存在一定误差。

ROCKBURST POSSIBILITY ANALYSIS USED IN-SITU STRESS INDEX AND NUMERICAL SIMULATION VALIDATION AT A UNDERGROUND WATER-SEALED OIL STORAGE CAVERN

The hydraulic fracturing technology is adopted to define the in-situ stress in the a region where will be build a underground water-sealed oil storage. The measurement result show that the maximum horizontal principal stress is about 10.0 MPa and the minor horizontal principal stress is about 6.0 MPa in the cavern depth. The possibility of the rockburst is analyzed by the Project Rock Mass Classification Criterion, Norway Barton criterion, Houfaliang criterion and the Hoek criterion. The result indicated after the underground cavern excavated, will not have the rock burst phenomenon as a result of the project perturbation. In view of present is unable to obtain the analytic solution of the redistributed stress surrounding the complex cavern, and to precisely judge the possibility of the rockburst in the excavation, the FLAC2D is used to simulate the process of the excavation and obtain the characteristic of the redistributed stress. The result indicated that extremely easy to produce the stress concentration region in some to have the rock burst phenomenon, even medium rock burst by the correction of the Barton rule, which indicate the typical rockburst rule is good at the rockburst possibility in the whole cavern, but not fit to the local cavern.