Study On The Law Of The Overlying Strata And The Surface Movement Under Grouting To Reduce Surface Subsidence

The new scheme of equivalent materials simulation technique--model experiment ofequivalent materials under uniform temperature and humidity is proposed. The purpose is to analyze the law of the overlying strata displacement and the surface subsidence by model experiment of equivalent materials and to make the simulation results quantitative .On the base of Elastic Mechanics, theory of offset error is founded through analyzing the main origin of error and its amenability in the course of experiment.The dynamic displacement of overburden strata and surface is studied by adopting the method of numerical simulation, under the condition of idiographic geology. The process of the movement of overlying strata and surface is simulated factually.According to theory of key strata, the relation between overlying strata structure and bed-separations developing process is discussed. The stage property and period property of bed-separations development is also analyzed. The development law of strata fracture is analyzed in the cross direction by use of the equation for the deflection of strata beam. This depends on the strata's property of anti-pressure and non-anti-tensibility. At the same time, this takes the strain as index. The expression of strata beam's fracture distance between two steps is deduced based on its strain. The relation betweer development of bed-separations and width of face is also analyzed.The method of estimating the surface subsidence under grouting is studied in this dissertation. The effect of reducing subsidence is evaluated by the ratio of mining and grouting. What the distribution of fine coal ash influences upon subsidence is analyzed. The magnitude of grouting and surface attacked rate affecting the ratio of reducing subsidence is discussed. The relation of calculating parameter and surface attacked rate in the function is analyzed according to the functional relation between ratio of surface subsidence and ratio of mining and grouting. On the base of engineering practice and the theory of reducing subsidence by grouting, the law of surface subsidence under grouing is summarized elementarily.