基于极限平衡法的边坡稳定性分析及数值模拟研究

通过对滑坡体的滑坡形式进行现场调查,确定了南侧和北侧2个具有代表性剖面,建立了剖面的地质特征模型。运用赤平投影技术分析了2个剖面的基本结构特征,在此基础上,应用极限平衡法和Geo-slope对边坡的稳定性进行了分析,并将结果作为滑坡处理的依据。

Experimental investigation into stress-relief characteristics with upward large height and upward mining under hard thick roof

According to geological conditions of No. 3 and No. 4 coal seams （namely A3 and B4） of the Pan＇er coal mine and the parameters of panels 11223, 11224, and 11124 with fully-mechanical coal mining, we built 2D similar material simulation and FLAC3D numerical simulation models to investigate the development of mining-induced stress and the extraction effect of pressure-relief gas with large height and upward mining. Based on a comprehensive analysis of experimental data and observations, we obtained the deformation and breakage characteristics of strata overlying the coal seam, the development patterns of the mining-induced stress and fracture, and the size of the stress-relief area. The stress-relief effect was investigated and analyzed in consideration with mining height and three thick hard strata. Because of the group of three hard thick strata located in the main roof and the residual stress of mined panel 11124, the deformation, breakage, mining-induced stress and fracture development, and the stress-relief coefficient were discontinuous and asymmetrical. The breakage angle of the overlying strata, and the compressive and expansive zones of coal deformation were mainly controlled by the number, thickness, and strength of the hard stratum. Compared with the value of breakage angle derived by the traditional empirical method, the experimental value was lower than the traditional results by 3°-4°below the hard thick strata group, and by 13°-19° above the hard thick strata group. The amount of gas extracted from floor drainage roadway of B4 over 17 months was variable and the amount of gas per month differed considerably, being much smaller when panel 11223 influenced the area of the three hard thick strata. Generally, the stress-relief zone of No. 4 coal seam was small under the influence of the hard thick strata located in the main roof, which played an important role in delaying the breakage time and increasing the breakage space. In this study we gained understanding of the stress-relief mechanism influenced by the hard thick roof. The research results and engineering practice show that the main roof of the multiple hard thick strata is a critical factor in the design of panel layout and roadways for integrated coal exploitation and gas extraction, provides a theoretical basis for safe and high-efficient mining of coal resources.

Geologic characteristics of the Chang'E-3 exploration region

We present topographic, geomorphologic and compositional characteristics of a l°×l° （-660 km2） region centered near the landing site of Chang＇E-3 using the highest spatial resolution data available. We analyze the topography and slope using Digi- tal Terrain Model （DTM） generated from Terrain Camera （TC） images. The exploration region is overall relatively flat and the elevation difference is less than 300 m, and the slopes of 80% area are less than 5~. Impact craters in the exploration region are classified into four types based on their degradation states. We investigate the wrinkle ridges visible in the exploration region in detail using TC and Lunar Reconnaissance Orbiter （LRO） Narrow Angle Camera （NAC） images. We calculate FeO and TiO2 abundances using Multispectral Imager （MI） data, and confirm two basaltic units： the northern part belongs to Imbrian low-Ti/very-low-Ti mare basalts, and the southern part is Eratosthenian low-Ti/high-Ti mare basalts. Finally, we produce a ge- ological map and propose the geologic evolution of the exploration region. We also suggest several rover traverses to explore interesting targets and maximize the potential scientific output.