DE-WATERING EFFECT OF AQUIFER TO SURFACE SUBSIDENCE

In order to improve the predicting accuracy of mining subsidence,to explain the phenomena which the subsidence coefficient is larger than 1,and to decrease the mining damage,on the basis of bore-hole measuring of dynamic water level results,the 3 kinds of relations between overburden failure and de-watering of water-holding strata is obtained.The void ratio may decrease with the increasing of effective stresses after water losing.The mechanism of consolidation subsidence due to de watering of water-bearing strata is established.The calculation method of surface subsidence caused by underground mining and de-watering is derived using superposition principle.The example demonstrates that the consolidation subsidence due to de-watering accounts for 25% of the coal seam mining subsidence.