The Xinfengjiang reservoir in Guangdong Province, is one of the large reservoirs that have triggered earthquakes of magnitude greater than 6. Numerous earthquakes have occurred since the impoundment of the reservoir, making it one of the most active seismic zones in south China. In 2015, a set of deep-hole resistivity anomalies was observed in the Heping geoelectric station in Dongyuan county, located near the Xinfengjiang reservoir. After a field investigation, we found that a planned well drilling construction of new measuring channels was being carried out during that corresponding period of time. After careful comparison and analysis on the basis of the collected raw data, we had a reason to believe that drilling construction, rather than the inducement of the Xinfengjiang reservoir, was the main culprit for those unusual georesistivity values. So as to verify the above conjecture, we constructed a series of 3D finite element models based on the geological and hydrological information around Heping station and analyzed the drilling disturbances, respectively. Some significant conclusions were finally drawn according to the precise numerical simulation. This study gives a good example by combining numerical simulation with engineering practice as a way to understand the root cause of georesistivity anomalies in reality. 相似文献
Science China Earth Sciences - Helium gas is a scarce but important strategic resource, which is usually associated with natural gas. Presently, only one extra-large helium-rich gas field has been... 相似文献
Natural Hazards - From 2015 to 2017, construction for the Dalixi Eco-Industrial Park in Dalixi Village, Xingshan County in the Three Gorges Reservoir area, reactivated a series of ancient... 相似文献
Internal instability is a phenomenon of fine particle redistribution in granular materials under the seepage action and consequent change in the soil’s internal structure and hydraulic and mechanical properties. It is one of the primary causes of failures of sand-gravel foundations and embankment dams. The criteria establishment is considered the key to solving the erosion problems, so the existing internal stability criteria need a review and classification to study the recent development trends in soil seepage and erosion. Therefore, this paper aims at reviewing the internal stability factors of gap-graded soil with a focus on the internal erosion mechanism and internal stability evaluation based on geometric and hydraulic criteria. Firstly, the paper compared the effect of several commonly used geometric criteria for gap-graded soil evaluation, such as particle size, fine content, void ratio, and fractal dimension. Furthermore, it provided a hydraulic criteria overview and analyzed the effects of the hydraulic gradient, hydraulic shear stress, confining pressure, and pore velocity on internal erosion. The geometric–hydraulic coupling methods were introduced, with a detailed elaboration of the erosion resistance index method based on accumulated dissipated energy. The capabilities and limitations of these criteria were discussed throughout the paper. It was found that combined Kezdi’s criterion and Kenney and Lau’s criterion is more reliable to evaluate internal stability of soil. The gap-graded soil with fine particle content higher than 35% is not necessarily internally stable. Finally, the energy-based method (erosion resistance index method) can effectively reproduce the total amount of erosion mass and the final spatial distribution of fine particles and identifies erosion. The review's outcome can be used as a basis to evaluate the internal erosion risk for gap-graded soils. The evaluation methods discussed here can help identify the zones of relatively high erosion potential.