Research On Ground Subsidence Of A Power Plant In Fushun City

Ground subsidence is a environmental geological phenomenon toregional ground elevation reducing caused by the earth’s crust surface soilcompression, under the effects of natural or man-made. Because of theeffect of its geographical position, special geological environment and thecontinuous exploitation of Fushun Western Open, especially since2003,after the main stripping zone of north slope in the West Open-pit iseastward to E200-E3000(mining area coordinates), the ground subsidenceand deformation of Fushun power plant showed an obvious inccreasingtrend to bring a great security hidden trouble for the safe production.In this paper, the mechanism of land subsidence is analysed from theinternal and external aspects. The internal cause mainly includes thegeological structure factor including the regional fault activation and thefold structure function etc. and adverse geological structure. And theexternal factors mainly are human engineering activities, including theWest open pit mining, deep coal mine and natural gas mining of the deepwell, Laohutai coal mine and Shengli coal mine etc., coal mine earthquake,groundwater seepage and the engineering construction of Fushun powerplant. Activation of the regional structure is the first to result in landsubsidence, while the West open pit mining plays a leading role in theinduced ground subsidence.On the basis of the regional geological analysis, engineering geological conditions, a lot of rock mechanics testing and deformationmonitoring data, the finite difference method is used to analyse theinfluence on the stability of the plant surface caused by West open pitmining. Analysis results showed that, with the West Open-pit mining, thesettlement of ground to plant will gradually increase, in the case oftreatment measures are not taken to2014, the surface maximumcumulative deformation volume will reach538.0mm. With the WestOpen-pit mining, the plastic zone of the slope increase gradually, and theinfluence scope for the ground subsidence of the northern region of slopehas gradually increased, but the continuous sliding surface does not appear.Due to a large area, ultra-deep open pit mining, complex geologicalstructure, broken rock structure, low rock strength, coupled with theimpact of the underground mined-out area of the North West open pit,unloading deformation and creep deformation of the north slope in Westopen pit mine will continue to increase, leading to the continuousdevelopment of the factory ground subsidence, so we should strengthenland subsidence monitoring and forecasting.In this paper, based on the ground subsidence monitoring data from32monitoring points in plant, the gray theoretical prediction model wasconstructed, and the error checking of the prediction model is conducted,at the same time, the subsidence of the factory in the next three years ispredicted. In the prediction error test, the posterior differential ratio C are basically less than0.5, and small error probability P are basically greaterthan0.80, prediction models belong to qualified~good model to predict areasonable and credible model. Meanwhile, from the land subsidenceprediction value in the next three years, the plant area land subsidenceshowed a gradual growth trend.